A1 Title: Uncomplicated removal of epidural catheters in 4,365 patients with international normalized ratio greater than 1.4 during initiation of warfarin therapy Presenting Author: Spencer S Liu MD Presenting Author's Institution: Hospital for Special Surgery - New York, NY Co-Authors: Asokumar Buvanendran MD - Rush University Medical Center - Chicago, IL Eugene R Viscusi MD - Thomas Jefferson University - Philadelphia, PA Erin Hutton RN - Hospital for Special Surgery - New York, NY Timothy Lubenow MD - Rush University Medical Center - Chicago, IL
Abstract: Background: Current guidelines from the American Society of Regional Anesthesia state that an international normalized ratio (INR) of 1.4 is the upper limit of warfarin anticoagulation for safe removal of an epidural catheter. However, these guidelines are based on expert consensus, and there is controversy regarding this recommendation as being ―too conservative‖.
Methods: Prospective (3,211) and retrospective (1,154) patients undergoing total joint replacement followed by daily warfarin thromboprophylaxis were enrolled in this observational study. All NSAIDs and anticoagulants were held prior to surgery, and all patients had normal coagulation test results before their surgery. Patients were followed twice a day by the acute pain service, no other anticoagulants except NSAIDs were administered, and epidural analgesia was discontinued per institutional protocol. Only patients with INR greater than 1.4 at time of removal of epidural catheter were included. Neurological checks were performed for 24 hrs after removal.
Results: A total of 4,365 patients were included, and 79% underwent knee replacement and 18% hip replacement. Mean age was 68 yrs and weight was 81 kg. Mean duration of epidural analgesia was 2.1 days (SD of 0.6). Mean INR at time of epidural removal was 1.9 (SD of 0.4) with range of 1.5 to 7.1. No spinal hematomas were observed (0% incidence with 95% CI 0-0.0009%).
Conclusions: Our series of 4,365 patients had uncomplicated removal of epidural catheters despite INRs ranging from 1.5 to 7.1. Removal was only during initiation of warfarin therapy when several vitamin K factors are likely to still be adequate for hemostasis. Our findings do not necessarily contradict the ASRA guidelines, as we followed recommendations to cautiously remove catheters and to perform subsequent neurological checks.
Additional File #1: 1021611092640Table_1_9_21_10.doc Click here to view
Table 1: Perioperative characteristics
Total HSS Rush TJU (n= 4365) (n= 1617) (n= 1594) (n=1154) Age (yrs) 67.7 11.8 70.4 10 65.8 13.4 66.5 10.8 Gender (F/M) 2991/1374 1141/476 1110/484 740/414 Weight (kg) 80.9 18.9 79.8 17.9 78.9 19.4 86.4 18.4 Total knee 3486 1617 774 1095 replacement (n) Total hip 800 0 770 30 replacement (n) Other surgery 79 0 50 29 Epidural needle
Tuohy 17 G (n) 2338 744 1594
Weiss 17 G (n) 873 873
Hustead 18 G (n) 1154 1154 Epidural catheter 20 G 4365 1617 1594 1154 (n) Number of attempts to place epidural (median/mode) n/a 1/1 n/a n/a Duration of epidural catheter (days) 2.1 0.6 2 0.2 2.2 0.7 1.9 0.1 Values are mean + SD unless otherwise stated. HSS=Hospital for Special Surgery. Rush=Rush University Medical Center. TJU=Thomas Jefferson University Medical Center
Additional File #2: 2021611092640Table_2_11_26_10.doc Click here to view
Table 2: Anticoagulation test results and number of epidural catheters removed per day
POD1 POD2 POD3 International normalized ratio Total 1.7 0.3 (1.5-3.5) 1.9 0.4 (1.5-5.9) 1.8 0.4 (1.5-7.1) HSS 1.2 0.1 (1.5-3.5) 1.9 0.5 (1.5-5.9) 2.1 0.8 (1.5-7.1) Rush 1.6 0.1 (1.5-2.0) 1.7 0.2 (1.5-4.6) 1.8 0.3 (1.5-3.9) TJU 2.1 0.4 (1.7-2.3) 1.8 0.4 (1.5-4.9) n/a Prothrombin Time (sec) HSS 11.5 1.2 18 6.1 20.8 9.7 Partial thromboplastin time (sec) HSS 29.6 15 43 9 37 8.9 Platelet count (#/nl) HSS 220 65 196 63 206 77 Epidural catheters removed (#) Total 40 4090 140 HSS 5 1595 12 (5 post POD3) Rush 34 1342 128 (90 post POD3) TJU 1 1153 0 All values are mean + SD (range). HSS=Hospital for Special Surgery. Rush=Rush University Medical Center.
TJU=Thomas Jefferson University Medical Center
Additional File #3: 3021611092640INR_Histogram.TIF Click here to view
(TIFF file) A2 Title: Creation of a Digital Atlas for Ultrasound Guided Regional Nerve Blocks Presenting Author: Kathleen Milne BSc Presenting Author's Institution: University of Western Ontario - London, Ontario Co-Authors: Jon Brookes FRCA - University of Western Ontario - London, Ontario Danielle Stothart MD - University of Western Ontario - London, Ontario Sugantha Ganapathy FRCPC - University of Western Ontario - London, Ontario Marjorie Johnson PhD - University of Western Ontario - London, Ontario
Abstract: Real time ultrasound guidance for regional nerve block performance is increasingly becoming the preferred technique for many anesthesiologists. Although there is potentially an improvement in safety as well as efficacy attached to the use of ultrasound, its use brings with it a steep learning curve. The novice regional anesthetist must rapidly learn to integrate knowledge of surface and 3D structural anatomy, interpretation of a moving 2D ultrasound image, and then manipulate a needle in real time. ASRA recommendations for education and training in regional anesthesia recommend an approach which includes visualizing key landmarks, identification of nerves on short axis imaging, and confirmation of normal anatomy. Time is often limited in resident training programs in which to acquire these skills. We have developed a computer based learning tool with the aim of enabling the trainee regional anesthetist to bring together the requisite skills before performing the common upper limb nerve block procedures, and subsequently reinforcing this knowledge. We also anticipate medical students will find the content useful for helping with anatomy learning including brachial plexus anatomy and the course of peripheral nerves. Cadaver dissections were made of anatomical areas of interest, and photographs of the surface anatomy of a volunteer, ultrasound imaging, slides from the Visible Human project, and videos of US imaging taken during nerve block procedures were incorporated into an interactive computer interface. Narration was added to the block videos giving a real time walkthrough of structures encountered. Content is divided by block type. Anatomical structures were labeled on both the dissections, slides and ultrasound images, enabling the user to integrate the 2D images with 3D anatomy. Probe positions are demonstrated on the surface photographs which correlate with the ultrasound images shown. The interface permits the user to selectively identify structures of interest at an individual pace. Currently included approaches to the brachial plexus include interscalene, supraclavicular, infraclavicular, and axillary. Radial, median, and ulnar blocks are also covered. The software has been designed to allow easy addition of further media and content, and it is anticipated that the project will expand to include trunk and lower limb blocks, and incorporate a self testing feature. We plan to make the project available in an online format to widen accessibility amongst the medical profession.
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A3 Title: Effectiveness of a Prevention Strategy for In-hospital Falls Following Total Joint Arthroplasty Presenting Author: Sanjay K Sinha MD Presenting Author's Institution: St. Francis Hospital and Medical Center - Hartford, CT Co-Authors: Jonathan Abrams MD - St. Francis Hospital and Medical Center - Hartford, CT Sivasenthil Arumugam MD – St. Francis Hospital and Medical Center - Hartford, CT Steven Schutzer MD - St. Francis Hospital and Medical Center - Hartford, CT Courtland Lewis MD - St. Francis Hospital and Medical Center - Hartford, CT
Abstract: Background: Falls in hospitalized patients are the most commonly reported adverse event in the hospital setting. The financial burden to the health care system from fall related injuries is expected to exceed $32 billion by 2020. At the Connecticut Joint Replacement Institute (CJRI) between July 31, 2007 and December 31, 2008 there were 49 falls in 3206 patients. Subsequently, despite patient education and consistent use of the Hendrich II Fall Risk Assesment tool, falls continued to be the most common complication in this unit. Most falls were related to patients who ventured to the bathroom unassisted. A subgroup of 188 consecutive patients, of which 6 fell during their hospital stay, showed that the Hendrich II scores were unreliable in predicting falls. For these reasons, a fall prevention strategy was developed, where every patient was deemed to be at high risk for a fall. Patients were enlisted as partners and preoperatively asked to sign a written pledge (legally non-binding) to call for assistance when getting out of bed, chair or going to the bathroom; likewise, the nursing staff pledged to be available in a timely manner. This fall prevention program was termed as ―Call, Don‘t Fall‖ and was initiated on July 1, 2009.
Method: All patients undergoing total joint arthroplasty at CJRI from July 1, 2009 to June 30, 2010 (Intervention Group) were presented with standard fall prevention education material prior to surgery and were asked to sign the pledge which was renewed every shift with formal signatures of the patient and the nurse assigned to the patient. Any patient who fell was interviewed and assessed for injury, mental status, type of analgesia (especially the presence of femoral nerve catheter). Falls were defined as any unplanned descent to the floor. The control group consisted of patients admitted to the same unit the previous year from July 1, 2008 to June 30, 2009
Results: There were no differences in demographic or clinical parameters between the intervention and the historical control groups. A significant drop in the number of falls occurred after the launch of the fall prevention program (13 versus 31), p=0.006. Two patients in the intervention group sustained injuries. More women fell in intervention group compared to the control group but, the result did not reach statistical significance. Patients undergoing TKA had more falls than THA patients [Odds Ratio 7.4(95% CI 1.0 – 15.4)]. Of the patients who fell, a statistically similar percentage of patients had femoral nerve catheters in place at time of the fall, comparing intervention group to control group . Bathroom-related falls accounted for 69% of falls in intervention group. Falls were assisted in 15% of patients in the intervention group.
Discussion: There was a 60% drop in the risk of falling after the fall prevention program was instituted [Relative Risk 0.4(95% CI 0.2–0.8)]. Signing a written pledge, renewing the pledge every shift, and treating every patient as a high fall risk, resulted in a meaningful reduction of fall rate. The presence of a femoral nerve catheter maybe a contributing factor to the increased incidence of fall rates in TKA patients.
Additional File #1: 1030111232417Falls_ASRA_Stats_1_.doc Click here to view
Group Characteristics
Control Group Intervention Significance (July 1, 2008 – Group June 30, 2009 (July 1, 2009 – June 30, 2010) Number 2168 2196 Age ( years) 66.3 11.1 66.0 11.1 NS Mean SD Sex F/M (%) 59/41 59/41 NS BMI (kg/m2 30.9 7.5 33.7 12.0 NS SD) Mean SD Surgery(%) THA 38.8 39.3 TKA 59.5 58.5 NS TSA 1.7 2.2
Additional File #2: 2030111232417Falls_ASRA_Stats_2_.doc Click here to view
Characteristics of Patients who Fell
Control Intervention Significance Group(July 1, Group(July 1, 2008 – June 30, 2009 – June 30, 2009 2010) Number of Falls 31(1.4) 13(0.6) *0.006 (%) Number of Injury 2 1 0.556 Age( years) 68.7 10.2 65.5 9.40.340 0.340 Mean SD Sex F/M (%) 61/39 85/15 0.130 BMI Mean SD 30.9 7.5 33.7 12 0.370 Surgery (%) THA 19.4 7.7 TKA 80.6 84.6 TSA 0 7.7 Femoral Nerve 58.1 38.5 0.234 Catheter (%) Bathroom Related 67.9 69.2 0.930 (%) Assisted Falls (%) 10 15.4 0.613
A4 Title: Saphenous Nerve Block in the Adductor Canal: When Described Using Anatomical Position, the Nerve is Not Posteromedial to the Superficial Femoral Artery Presenting Author: Daryl Henshaw MD Presenting Author's Institution: Wake Forest University School of Medicine - Winston-Salem, NC Co-Authors: Robert S. Weller MD - Wake Forest University School of Medicine - Winston-Salem, NC
Abstract: Introduction: Recent descriptions of single-shot ultrasound-guided (USG) saphenous nerve (SAPH) block within the adductor canal rely upon the easy identification of the superficial femoral artery (SFA) and the known relationship of SFA and SAPH, even when SAPH is not identifiable. For catheter placement, however, it is intuitive that the catheter should be placed near the nerve‘s most likely position relative to the SFA if SAPH is not visible. There is, however, variability in the literature as to the exact position of the SAPH in the distal adductor canal. For example, some references show the nerve posteromedial (1,2) while others show the nerve anterior or anterolateral to the SFA (3,4). Although some of this variability is real, some is due to an inconsistency among authors in the use of true anatomical position when describing ultrasound figures. Gray‘s Anatomy (5) defines the anatomical position as standing, arms at sides, with eyes, palms and feet facing forward. For the thigh, anatomical position places the medial and lateral femoral condyles in the coronal plane with the linea aspera directly posterior. Using results from a cadaveric trial of long-axis (LAX) in-plane (IP) and short-axis (SAX) IP SAPH catheter placements, we describe the location of the SAPH with respect to the SFA in the distal adductor canal using anatomical position for clarity.
Methods: Although the thigh was externally rotated for USG SAPH catheter placement, anatomical position unambiguously describes the relationship of SAPH to SFA. In 8 unembalmed cadavers a SAPH catheter was placed in the distal adductor canal. Either LAX or SAX views of the SFA were obtained (L13-6 MHz probe, Sonosite, Bothell, WA). An 18-g Tuohy needle was placed IP between sartorius and SFA from distal for LAX (n=5), or between SFA, sartorius and vastus medialis from anterior for SAX (n=3). After saline injection for positional confirmation, a 20-g multiorifice catheter was threaded 4 cm and 0.2 ml of methylene blue was injected. Dissection of the thigh was then performed to identify the location of SAPH in relation to the SFA and the spread of dye. One additional cadaver was dissected without prior catheter placement.
Results: In 9 dissections the SAPH was identified running from lateral to the SFA in the proximal adductor canal, to anterior or anteromedial to the SFA at the adductor hiatus (Figs. 1 and 2). The SAPH was not found in any cadaver posteromedial to the SFA between adductor longus and SFA in the distal adductor canal. In 7/8 catheter placements, dye was seen inside the adductor canal staining SAPH. In 1 LAX approach, the catheter did not penetrate the fascia overlying the adductor canal and SAPH was not stained.
Conclusions: The anatomical position is recommended to avoid confusion when referring to the relationship of anatomic structures and when labeling ultrasound images. In 9 dissections, SAPH was found to be anterior or anteromedial to the SFA at or just above the adductor hiatus; it was not found posteromedial to the SFA as shown in some publications.
References 1. Reg Anesth Pain Med. 2009;34:578-580. 2. J Can Anaesth. 2010;57:683-688. 3. Reg Anesth Pain Med. 2010;35:222-223. 4. Acta Anaesthesiol Scand. 2011;55:14-19. 5. Standring, Elsevier, 40th Ed, 2008.
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A5 Title: Continuous peripheral nerve block compared with single injection peripheral nerve block: a systematic review and meta-analysis of randomized controlled trials Presenting Author: Ann Bingham MD Presenting Author's Institution: Oregon Health and Science University - Portland, OR Co-Authors: Matthew Abrahams MD - OHSU - Portland, OR Rongwei Fu PhD - OHSU - Portland, OR
Abstract: Background: Continuous peripheral nerve catheters are believed by many practitioners to be superior to single injection nerve blocks. Several randomized controlled trials have demonstrated benefits in pain control, satisfaction, and outcomes with continuous perineural techniques compared to single injection techniques.1-14 Other trials have not shown a difference in outcomes.15-18 Single shot (SS) nerve blocks are potentially easier to perform by a greater number of practitioners and may carry less risk. It is therefore important to clarify the benefits, if any, of continuous peripheral nerve blocks (cPNB) compared to SS nerve blocks.
Objectives: Our purpose was to clarify whether there is benefit in pain scores, side effects, opioid use, patient satisfaction or functional outcomes with continuous peripheral nerve blocks versus single bolus nerve blocks.
Methods: We conducted a systematic review and meta-analysis of all prospective, randomized trials which have compared single injection nerve blocks with a continuous technique. Methodological quality was determined independently by two reviewers. Twenty-one studies involving a total of 702 patients were eligible for analysis, Table 1. Data was extracted, meta-analyses were conducted to compare the catheter group with the standard treatment group, and mean differences between the two groups were combined using a random effects model. Results. cPNB resulted in decreased rating of worst pain compared to SS nerve blocks on POD 1 [Weighted mean difference (WMD) -1.77 , 95% confidence interval (CI) -2.43— -1.11, P 0.000], POD 2 (WMD -1.71 , 95% CI -2.92— -0.50, P 0.006) and POD 3 (WMD -0.68, 95% CI -1.26— -0.10, P 0.011), Figure 1a-d. cPNB were associated with higher patient satisfaction scores compared to SS blocks (WMD 2.04, 95% CI 1.24-2.85, P 0.000), Fig. 1e. Though several studies have compared functional outcomes5, 15, 30-33the data reported was not in sufficient quantity for meta-analysis. Watson, et al found earlier mobilization34, while White, et al and Elliot, et al reported decreased hospital LOS with a cPNB technique.6,11 Buckenmaier, et al found no statistical difference in time to return to employment or ADL.15 Salinas, et al found no difference in degrees of knee flexion at 6 or 12 weeks between groups.5 Several studies found a statistically significant decrease in opioid use for the cPNB group compared with the SS group.1-6, 11-13, 34, 35
Conclusions: This meta-analysis of randomized controlled trials demonstrates a statistically significant reduction in postoperative pain and an increase in patient satisfaction with the use of cPNB compared to SS techniques at all measured data points. Though there was insufficient opioid data for meta-analysis there is a trend toward decreased opioid use in the cPNB group. Although there was a statistically significant difference in VAS pain scores this might not translate to a clinically significant difference. 36 Limitations of this analysis are those inherent in all meta- analyses, including possibility for publication bias and selective outcome reporting. Future trials should focus on comparison of cost, complications and long-term functional recovery.
Additional File #1: 1030111211347ASRA_Figure_1.doc Click here to view
Figure 1. Results of meta-analysis, continuous infusion catheter group versus single injection. a. POD 0 combined analysis of VAS pain scores for worst pain, pain with movement, and worst pain with movement, catheter vs. single injection.
Study %
ID WMD (95% CI) Weight
Hirst (1996) 0.40 (-1.60, 2.40) 11.23
Zaric (2004) -3.10 (-4.85, -1.35) 13.26
Watson (2005) 0.17 (-0.71, 1.05) 23.54
Cuignet (2005) -1.00 (-1.62, -0.38) 27.24
Capdevila (2006) -0.78 (-1.58, 0.02) 24.74
Mariano (2009) (Excluded) 0.00
Overall (I-squared = 69.3%, p = 0.011) -0.79 (-1.62, 0.04) 100.00
NOTE: Weights are from random effects analysis
-4.85 0 4.85
b. POD 1 combined analysis of VAS pain scores for worst pain, pain with movement, and worst pain with movement, catheter vs. single injection.
Study %
ID WMD (95% CI) Weight
Hirst (1996) -0.80 (-4.02, 2.42) 3.64
Zaric (2004) -2.50 (-3.80, -1.20) 13.17
Watson (2005) -1.62 (-5.04, 1.80) 3.26
Cuignet (2005) -2.00 (-2.63, -1.37) 21.58
Capdevila (2006) -1.30 (-2.25, -0.35) 17.20
Mariano (2009) -3.50 (-5.14, -1.86) 10.13
Fredrickson (2010) -2.00 (-3.08, -0.92) 15.61
Buckenmaier (2010) -0.23 (-1.33, 0.87) 15.41
Overall (I-squared = 53.6%, p = 0.035) -1.77 (-2.43, -1.11) 100.00
NOTE: Weights are from random effects analysis
-5.14 0 5.14
c. POD 2 combined analysis of VAS pain scores for worst pain, pain with movement, and worst pain with movement, catheter vs. single injection.
Study %
ID WMD (95% CI) Weight
Borgeat (1997) 2.20 (1.30, 3.10) 9.96
Borgeat (1998) 2.10 (1.21, 2.99) 9.98
Klein (2000) 1.00 (-0.01, 2.01) 9.64
Borgeat (2000) 2.20 (1.14, 3.26) 9.51
Ilfeld (2002) 3.90 (2.31, 5.49) 7.90
Ilfeld (2002) 3.70 (2.08, 5.32) 7.80
White (2003) 2.10 (1.27, 2.93) 10.16
Ilfeld (2003) 2.30 (-0.11, 4.71) 5.63
Kean (2006) 0.90 (-0.35, 2.15) 8.92
Mariano (2009) 3.00 (1.96, 4.04) 9.58
Fredrickson (2010) 0.00 (-0.50, 0.50) 10.91
Overall (I-squared = 85.5%, p = 0.000) 2.04 (1.24, 2.85) 100.00
NOTE: Weights are from random effects analysis
-5.49 0 5.49
Additional File #2: 2030111211347ASRA_Table_1.doc Click here to view
Table 1. Studies included for analysis. cPNB = Continuous peripheral nerve block, ssPNB = single shot peripheral nerve block, VAS = Visual analogue scale, NS = Normal saline. *P<0.05 favoring cPNB, **P<0.05 favoring ssPNB, † median, • mean
Author (year N (Continuous/SS) Block performed (Surgery) VAS (Continuous/SS) Other outcomes (cPNB/ssPNB) Quality published) Score Buckenmaier (26/26/21) Adults undergoing unilateral Paravertebral (breast). Initial Worst postoperative VAS Nausea, mood, level of symptom distress, 8 • (2010) surgery for localized breast cancer. block with 0.1% ropivacaine at POD 1 : 2.5/2.7/2.8* time to return to normal activities not Worst postoperative VAS T1 and T6 and 0.5% • significantly different. ropivacaine with catheter at POD 3 : 2.2/2.4/1.8 Worst postoperative VAS T3. 0.2% Ropivacaine/0.1% POD 5•: 1.8/2.5/1.7 Ropivacaine/NS infusion for 72 Worst postoperative VAS hours. POD 7•: 1.2/2.7/1.9 Elliot (2010) (27/27) Adult patients, ASA status Popliteal (ankle and hindfoot). VAS POD 0†: 1.2/1.0 mg morphine used POD 2†:10/20* 8 unspecified, undergoing ankle or hindfoot 20ml of 0.5% bupivacaine VAS POD 1†: 1.7/3.7* mg morphine used POD 3†: 7.5/10* surgery. initial bolus. 0.25% VAS POD 2†: 1.3/2.8* total mg morphine used POD 1-3†: bupivacaine vs. NS for 72 VAS POD 3†: 1.1/2.6* 30/52.5* hours. Fredrickson (31/30) Adult patients, ASA I-II, Interscalene (shoulder). Initial Worst pain with Satisfaction score†: 9/9 10 (2010) undergoing arthroscopic subacromial bolus 30ml ropivacaine 0.5%. movement POD 1 †: 2/4* Tramadol tablets required POD 2†: 0/1* decompression, lateral clavicle excision, Infusion of 2ml/hr 0.2% Worst pain with Tramadol tablets required POD 2†: 0/1* or stabilization. ropivacaine with 5ml per hour movement POD 2 †: 3/5 demand dose for 48 hours vs. catheter removal in PACU. Frassanito (22/22) Adult patients, ASA I-III, Lumbar plexus (knee). Initial Pain (VAS) at 6 hr•: 0.4/0 Total mg tramadol consumption •: 185/236 9 • (2009) undergoing total knee arthroplasty under bolus 0.6% ropivacaine 30ml Pain (VAS) at 12 hr : 1.7/1.6 Pain (VAS) at 24 hr•: 3.7/5.1 regional anesthesia with sedation. Infusion of ropivacaine 0.2% at • 10ml/hr for 48 hr vs. SS. Also Pain (VAS) at 36 hr : 4.8/3.1 Pain (VAS) at 48 hr•: 3.2/1.7 SS sciatic nerve block for all
pts. Mariano (2009) (15/15) Adult subjects, ASA status Interscalene (shoulder). Initial Worst pain POD 0†: 0/0 Satisfaction with analgesia†: 10/7* 12 † unspecified, undergoing elective shoulder bolus 40ml ropivacaine 0.5%. Worst pain POD 1 : 4/7.5* mg oxycodone consumed POD 1†: 0/20* Worst pain POD 2†: 2.8/8* † surgery. Infusion of 0.2% ropivacaine or † mg oxycodone consumed POD 2 : 0/30* 0.9% NS. Worst pain POD 3 : 5/6
Williams (2009, (76/79) Adult participants, ASA I-II, Femoral (knee). Initial bolus NRS w/ movement POD 1†: mean mg oxycodone consumption POD 1- 12 2007, 2007, undergoing elective ACL reconstruction 0.25% levobupivacaine 30ml. 2/3* 4: 88/94 † 2006) under spinal with sedation (block Infusion of 0.25% NRS w/ movement POD 2 : performed in PACU). levobupivacaine or 0.9% NS at 2/4* 5ml/hr until 270ml reservoir depleted. Capdevila (2006) (23/30/30) Adult patients, ASA I-III, Interscalene or popliteal VAS w/ movement 10 min†: % Patients very satisfied: 63/57/22* 9 0/0/0
Additional File #3: 3030111211347ASRA_Abstract_Refer.doc Click here to view
References.
1. Ilfeld BM, Morey TE, Wright TW, Chidgey LK, Enneking FK. Continuous interscalene brachial plexus block for postoperative pain control at home: A randomized, double-blinded, placebo-controlled study Anesth Analg. 2003;96(4):1089-95, table of contents.
2. Kean J, Wigderowitz CA, Coventry DM. Continuous interscalene infusion and single injection using levobupivacaine for analgesia after surgery of the shoulder. A double-blind, randomised controlled trial J Bone Joint Surg Br. 2006;88(9):1173- 1177.
3. Klein SM, Grant SA, Greengrass RA, et al. Interscalene brachial plexus block with a continuous catheter insertion system and a disposable infusion pump Anesth Analg. 2000;91(6):1473-1478.
4. Mariano ER, Afra R, Loland VJ, et al. Continuous interscalene brachial plexus block via an ultrasound-guided posterior approach: A randomized, triple-masked, placebo-controlled study Anesth Analg. 2009;108(5):1688-1694.
5. Salinas FV, Liu SS, Mulroy MF. The effect of single-injection femoral nerve block versus continuous femoral nerve block after total knee arthroplasty on hospital length of stay and long-term functional recovery within an established clinical pathway Anesth Analg. 2006;102(4):1234-1239.
6. White PF, Issioui T, Skrivanek GD, Early JS, Wakefield C. The use of a continuous popliteal sciatic nerve block after surgery involving the foot and ankle: Does it improve the quality of recovery? Anesth Analg. 2003;97:1303-1309.
7. Borgeat A, Perschak H, Bird P, Hodler J, Gerber C. Patient-controlled interscalene analgesia with ropivacaine 0.2% versus patient-controlled intravenous analgesia after major shoulder surgery. Anesthesiology. 2000;92:102.
8. Borgeat A, Tewes E, Biasca N, Gerber C. Patient-controlled interscalene analgesia with ropivacaine after major shoulder surgery: PCIA vs PCA. Br J Anaesth. 1998;81:603.
9. Borgeat A, Schappi B, Biasca N, Gerber C. Patient-controlled analgesia after major shoulder surgery. Anesthesiology. 1997;87:1343. 10. Capdevila X, Dadure C, Bringuier S, et al. Effect of patient-controlled perineural analgesia on rehabilitation and pain after ambulatory orthopedic surgery: A multicenter randomized trial Anesthesiology. 2006;105(3):566-573.
11. Elliot R, Pearce CJ, Seifert C, Calder JDF. Continuous infusion versus single bolus popliteal block following major ankle and hindfoot surgery: A prospective, randomized trial. Foot Ankle Int. 2010;31(12):1043.
12. Ilfeld BM, Morey TE, Enneking FK. Continuous infraclavicular brachial plexus block for postoperative pain control at home: A randomized, double-blinded, placebo-controlled study Anesthesiology. 2002;96(6):1297-1304.
13. Ilfeld BM, Morey TE, Wang RD, Enneking FK. Continuous popliteal sciatic nerve block for postoperative pain control at home: A randomized, double-blinded, placebo-controlled study Anesthesiology. 2002;97(4):959-965.
14. Zaric D, Boysen K, Christiansen J, Haastrup U, Kofoed H, Rawal N. Continuous popliteal sciatic nerve block for outpatient foot surgery--a randomized, controlled trial Acta Anaesthesiol Scand. 2004;48(3):337-341.
15. Buckenmaier CC,3rd. Double-blinded, placebo-controlled, prospective randomized trial evaluating the efficacy of paravertebral block with and without continuous paravertebral block analgesia in outpatient breast cancer surgery. .
16. Hirst GC, Lang SA, Dust WN, Cassidy JD, Yip RW. Femoral nerve block. single injection versus continuous infusion for total knee arthroplasty Reg Anesth. 1996;21(4):292-297.
17. Frassanito L, Vergari A, Messina A, Pitoni A, Puglisi C, Chierichini A. Anaesthesia for total knee arthroplasty: Efficacy of single-injection or continuous lumbar plexus associated with sciatic nerve blocks - A randomized controlled study. European Review for Medical and Pharmacological Sciences. 2009;13:375.
18. Cuignet O, Mbuyamba J, Pirson J. The long-term analgesic efficacy of a single- shot fascia iliaca compartment block in burn patients undergoing skin-grafting procedures. Journal of Burn Care & Rehabilitation. 2005:409.
19. Dickerson K, Scherer R, Lefebvre C. Systematic reviews: Identifying relevant studies for systematic reviews. Br Med J. 1994;309:1286-91.
20. Goebel S, Stehle J, Schwemmer U, Reppenhagen S, Rath B, Gohlke F. Interscalene brachial plexus block for open-shoulder surgery: A randomized, double-blind, placebo-controlled trial between single-shot anesthesia and patient- controlled catheter system. Arch Orthop Trauma Surg. 2010;130:533.
21. Martinez Navas A, Echevarria Moreno M. Continuous versus single-dose sciatic nerve block to complement a femoral block after total knee replacement surgery: A randomized clinical trial Rev Esp Anestesiol Reanim. 2006;53(4):214-219.
22. Ilfeld BM, Mariano ER, Girard PJ, et al. A multicenter, randomized, triple- masked, placebo-controlled trial of the effect of ambulatory continuous femoral nerve blocks on discharge-readiness following total knee arthroplasty in patients on general orthopaedic wards. Pain. 2010;150(3):477.
23. Ilfeld BM, Meyer RS, Le LT, et al. Health-related quality of life after tricompartment knee arthroplasty with and without an extended-duration continuous femoral nerve block: A prospective 1-year follow-up of a randomized, triple-masked, placebo-controlled study. Anesth Analg. 2009;108:1320.
24. Ilfeld BM, Le LT, Meyer RS, et al. Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment total knee arthroplasty: A randomized, triple-masked, placebo-controlled study Anesthesiology. 2008;108(4):703-713.
25. Ilfeld BM, Ball ST, Gearen PF, et al. Ambulatory continuous posterior lumbar plexus nerve blocks after hip arthroplasty: A dual-center, randomized, triple- masked, placebo-controlled trial Anesthesiology. 2008;109(3):491-501.
26. Ilfeld BM, Ball ST, Gearen PF, et al. Health-related quality of life after hip arthroplasty with and without an extended-duration continuous posterior lumbar plexus nerve block: A prospective, 1-year follow-up of a randomized, triple- masked, placebo-controlled study. Anesth Analg. 2009;109(2):586.
27. Ilfeld BM, Vandenborne K, Duncan PW, et al. Ambulatory continuous interscalene nerve blocks decrease the time to discharge readiness after total shoulder arthroplasty: A randomized, triple-masked, placebo-controlled study. Anesthesiology. 2006;105(5):999-1007.
28. Haasio J, Tuominen M, Rosenberg PH. Continuous interscalene brachial plexus block during and after shoulder surgery Ann Chir Gynaecol. 1990;79(2):103-107.
29. Tamosiunas R, Gudas R, Karbonskiene A, Marchertiene I. Bupivacaine for continuous interscalene brachial plexus analgesia after shoulder surgery Medicina (Kaunas). 2004;40(4):351-357. 30. Williams BA, Bottegal MT, Kentor ML, Irrgang JJ, Williams JP. Rebound pain scores as a function of femoral nerve block duration after anterior cruciate ligament reconstruction: Retrospective analysis of a prospective, randomized clinical trial Reg Anesth Pain Med. 2007;32(3):186-192.
31. Williams BA, Dang Q, Bost JE, et al. General health and knee function outcomes from 7 days to 12 weeks after spinal anesthesia and multimodal analgesia for anterior cruciate ligament reconstruction Anesth Analg. 2009;108(4):1296-1302.
32. Williams BA, Kentor ML, Irrgang JJ, Bottegal MT, Williams JP. Nausea, vomiting, sleep and restfulness upon discharge home after outpatient anterior cruciate ligament reconstruction with regional anesthesia and multimodal Analgesia/Antiemesis. Reg Anesth Pain Med. 2007;32(3):193.
33. Williams BA, Kentor ML, Vogt MT, et al. Reduction of verbal pain scores after anterior cruciate ligament reconstruction with 2-day continuous femoral nerve block: A randomized clinical trial Anesthesiology. 2006;104(2):315-327.
34. Watson MW, Mitra D, McLintock TC, Grant SA. Continuous versus single- injection lumbar plexus blocks: Comparison of the effects on morphine use and early recovery after total knee arthroplasty Reg Anesth Pain Med. 2005;30(6):541- 547.
35. Fredrickson MJ, Ball CM, Dalgleish AJ. Analgesic effectiveness of a continuous versus single-injection interscalene block for minor arthroscopic shoulder surgery. Reg Anesth Pain Med. 2010;35:28.
36. Kelly AM. The minimum clinically significant difference in visual analogue scale pain score does not differ with severity of pain. Emerg Med J. 2001;18:205-207.
A6 Title: Cervical Spine Disease is a Risk Factor for Persistent Phrenic Nerve Paresis following Interscalene Block for Shoulder Surgery Presenting Author: Lei Li MD Presenting Author's Institution: Hospital for Special Surgery - New York , NY Co-Authors: James Beckman MD - Hospital for Special Surgery - New York, NY Jonathan Beathe MD - Hospital for Special Surgery - New York, NY Pratima Gondipalli MD - Rivernorth Anesthesia Consultants S.C. - Chicago, IL Victor M Zayas MD - Hospital for Special Surgery - New York, NY
Abstract: Introduction: Persistent phrenic nerve paresis (PPNP) has been sporadically reported following interscalene brachial plexus block (ISB). (Ediale et al, 2004). We previously reported 9 cases of PPNP following shoulder surgery in the sitting position under ISB over a time period of 8 years (9/2000 – 10/2008) (Zayas et al, 2009). A total of 18,619 ISB were performed during this time period resulting in an incidence of 1 in 2069. Six of these patients had a history of cervical spine disease and chiropractic manipulation of the cervical spine. Here we present evidence that preexisting cervical spine disease is a potential risk factor for the development of PPNP.
Materials and Methods: For each case of PPNP in the original series, we randomly selected 6 control cases matched by surgeon, surgical procedure and occurring within 2 years of the index case. After IRB approval and informed consent, information was obtained for each case control from the medical record, via questionnaire and a phone interview. Chi square test or Fisher‘s Exact test was used to compare the difference between groups for categorical parameters such as gender and existing cervical spine disease, while t test was used for numerical parameters such as body mass index (BMI). Statistical significance was defined at a p value less than 0.05.
Results: There were no significant differences between groups in gender, age, weight, height, BMI, side of ISB, paresthesia versus nerve stimulator technique, or use of bupivacaine in the local anesthetic solution. Local anesthetic solutions in both groups contained epinephrine. Although the PPNP group showed a higher incidence of chiropractic manipulation of cervical spine than the control group, the difference was not statistically significant (42.9% vs. 28.3%, p = 0.23). Patients with PPNP had a significantly higher incidence of cervical spine disease (85.7%) compared to the control group (26.4%), p < 0.004).
Discussion: The results suggest that a history of cervical spine disease is a potential risk factor for PPNP following shoulder surgery under ISB. Caution must be used when interpreting these results as nerve injury has been reported following shoulder surgery under general anesthesia without ISB. As such, it is unclear whether the ISB contributed to the development of PPNP. Further evaluation is required to determine if epinephrine containing local anesthetic solutions contribute to nerve injury in the setting of preexisting cervical spine disease and surgical traction.
References Ediale K J et al. Clin Anesth. 2004;16:573-575. Zayas VM, et al. Reg Anesth Pain Med. 2009;32:131.
A7 Title: "Roaming The Range" A safe and effective model for the use of opioid range orders. Presenting Author: Cindy Kuklenski ADN Presenting Author's Institution: Shawnee Mission Medical Center - Shawnee Mission, KS Co-Authors:
Abstract: Background: In a survey of our 408-bed community hospital, a regulatory agency challenged our use of range orders and pain medications citing the scope of nursing practice. Initially, the hospital changed practice to meet the regulatory agency‘s suggestions. An evaluation of this practice change found the patients to be dissatisfied with pain management and nurses frustrated in attempting to comply with the new practice parameters. Interviews with nurses revealed their struggles and frustration with pain management, citing that the complex nature of pain and numerous variables that exist within patient condition make the flexibility range orders provide imperative to individualize pain control interventions. After examining our hospital‘s challenge regarding the use of range orders, review of the literature and dialogue with the regulatory agency revealed the primary issue to be the inherent potential for variability in interpretation of medications ordered in a range and the result of adjusting the dose.
Methods: Recognizing the inability to control the infinite variables, two consistent indicators were identified with each PRN opioid administration; consistent assessment and the goal of the intervention. Utilizing Pain Management Guidelines established by the Kansas State Board of Nursing, literature including American Society for Pain Management Nurses (ASPMN), /American Pain Society (APS) range order position statement, current, related articles, and assistance from ASPMN members, a ―RANGES‖ model, outlining important safety and assessment elements, guidelines for acceptable range orders, and policy was developed. Shawnee Mission Medical Center‘s Pain Management Quality Improvement Team, led by the Acute Pain Management Nurse, developed a pneumonic for the ―RANGES‖ model. The pneumonic is used to guide RN assessment and facilitate consistent medication administration decisions.
Results: The model was approved by Nursing Practice Council and the Pharmacy and Therapeutics Committee. It satisfied the regulatory agency and is consistent with the Kansas State Board of Nursing guidelines on pain management. Staff received education utilizing various approaches, including case studies, one-on-one dialog, pocket tools and poster presentations. A required computer-based-learning (CBL) program was then completed by 901 nurses. Conclusions: The ―RANGES‖ model and tool(s) facilitated safe and effective nursing practice that encouraged critical, individualized decision-making at the bedside; revealed no change in adverse events from pain medication administration and the increased satisfaction of patients and nursing staff. A8 Title: The Analgesic Efficacy Of Oblique Sub-Costal Transverses Presenting Author: Abeer A. Sherif MD in anesthesia, diploma in biostatitics Presenting Author's Institution: El-Menoufia University - Shebin Elkom, Egypt Co-Authors: Essam Bader FRCSI - Bugshan Hospital - Jeddah, Jeddah Khaled Aboelfetooh MD - The Analgesic Efficacy Of Oblique Sub-Costal Trans - Jeddah, Jeddah
Abstract: Background: The trend for using laparoscopic technique for abdominal surgery raised the need for the re-evaluation of the issue of postoperative analgesic requirement. Oblique -sub costal TAP (OSTAP) block is a variation of TAP block; capable of providing reliable coverage of upper abdominal wall. In this prospective, randomized, double-blinded study; we try to evaluate the analgesic efficacy of OSTAP block for patients undergoing laparoscopic procedures as a part of the concept for balanced anesthesia.
Patients: 100 ASA physical status I or II patients were included in this study. . Patients in group A (n = 50) received a combination of standard general anesthetic with an ultrasound-guided OSTAP block. Group B (n = 50) patients received standard general anesthesia. Hourly data included pain score, blood pressure, ventilatory frequency, sedation score, nausea and vomiting.
Results: OSTAP block group showed reduction in VAS at all time of assessment after the block. This going on with reduction in 24h requirement of morphine; lower incidence of PONV (P≤ 0.001*); and lower sedation score that was statistically significant in comparison to control group.
Conclusions: OSTAP block, as a component of a balanced analgesic technique, provided optimum analgesia in comparison to standard general anesthetic; so it is considered to be a promise for patients undergoing laparoscopic procedures involving abdominal wall incisions.
Additional File #1: 1120110192442figures.doc
80.00 79.00 78.00 77.00 76.00 Group I 75.00 Group II 74.00 73.00 72.00 71.00 70.00
Figure 1: Mean arterial blood pressure at different period of follow up in
the two groups.
89.00
87.00
85.00
83.00 Group I Group II 81.00
79.00
77.00
75.00
Figure 2: Heart rate at different period of follow up in the two groups.
Group I Group II
8
7
6
5
4
3
2
1
0 PACU 2 hrs 4 hrs 6 hrs 8 hrs 12 hrs 24hrs
Figure 3: Comparison between the two studied groups regarding VAS at different period of follow up.
Additional File #2: 2120110192442Table_1.doc
Table 1: Clinico-demographic data, inraoperative fentanyl and postoperative morphine consumption in the two studied groups.
Group I Group II
No. % No. % Sig.
Sex
Male 35 70.0 32 64.0 0.465
Female 15 30.0 18 36.0
Age
Range 18.0 - 67.0 18.0 - 68.0 0.553
Mean ±S.D 42.2±12.9 43.9±14.6
BMI
Range 20.2-29.1 20.1-29.3 0.338
Mean ±S.D 24.8±2.8 24.3±2.5
Operative time
Range 40.0-85.0 45.0-90.0
Mean ±S.D 60.0±11.9 64.04±11.6 0.089
PONV
Positive 8 16.0 28 56.0 0.001*
Negative 42 84.0 22 44.0
Inopfent. 5.0 - 20.0 15.0- 100 Range 0.0001* 9.70±3.699 42.60±19.46 Mean ±S.D
Popr 24 hr 4.0 - 10.0 10.0 - 30.0 Range 0.0001* 5.72±1.49 18.10±3.64 Mean ±S.D
Additional File #3: 3120110192442Table_2.doc
Table 2: Comparison between the two studied groups regarding sedation at different period of follow up.
Sedation level Group I Group II
No. % No. % Sig.
PACU
Awake & alert 0 0.0 0 0.0
Quietly awake 32 64.0 0 0.0 0.0001*
Sleep but easily aroused 15 30.0 20 40.0
Deep sleep 3 6.0 30 60.0
2 hrs
Awake & alert 0 0.0 0 0.0
Quietly awake 43 86.0 0 0.0
Sleep but easily aroused 7 14.0 19 38.0 0.0001*
Deep sleep 0 0.0 31 62.0
4 hrs
Awake & alert 0 0.0 0 0.0
Quietly awake 50 100.0 0 0.0 0.0001*
Sleep but easily aroused 0 0.0 34 68.0
Deep sleep 0 0.0 16 32.0
6 hrs
Awake & alert 0 0.0 0 0.0
Quietly awake 50 100.0 4 8.0 0.0001*
Sleep but easily aroused 0 0.0 30 60.0
Deep sleep 0 0.0 16 32.0
8 hrs
Awake & alert 15 30.0 0 0.0 Quietly awake 35 70.0 5 10.0 0.0001*
Sleep but easily aroused 0 0.0 43 86.0
Deep sleep 0 0.0 2 4.0
12 hrs
Awake & alert 12 24.0 0 0.0
Quietly awake 37 74.0 12 24.0 0.0001*
Sleep but easily aroused 1 2.0 30 60.0
Deep sleep 0 0.0 8 16.0
24 hrs
Awake & alert 16 32.0 0 0.0
Quietly awake 34 68.0 0 0.0
Sleep but easily aroused 0 0.0 50 100.0 0.0001*
Deep sleep 0 0.0 0 0.0
A9 Title: The Analgesic Role of Transverses Abdominis Plane Block for Pediatric Patients Undergoing Lower and Middle Abdominal Surgery Presenting Author: Abeer A. Sherif, MD in anesthesia, diploma in biostatistics Presenting Author's Institution: Elmenoufia University - Alexandria, Alexandria Co-Authors: Somaya Elshaikh MD - National Cancer Institute, Cairo University - Cairo, Cairo Ahmed Mostafa MD, MRCS - National Cancer Institute, Cairo University - Cairo, Cairo Reda Hasan Tabashy MD - National Cancer Institute, Cairo University - Cairo, Cairo
Abstract: Background: Post-operative analgesia have been provided by different techniques in pediatric patients. Caudal block remains the gold standard for regional blocks used for postoperative analgesia for abdominal surgery in pediatric patients. Transversus abdominis plane (TAP) block is a new peripheral nerve block that has been demonstrated to provide effective postoperative analgesia in adults, that is characterized by decreased postoperative pain scores and opioid requirements. This prospective, randomized, double-blinded study was designed to evaluate the intra- and postoperative analgesic efficacy of TAP block in pediatric patients. In the same study we compare the efficacy of ultrasound-guided TAP block versus caudal analgesia for lower and middle abdominal surgery in pediatric population as a part of a concept for balanced analgesia.
Patients and Methods: 90 ASA Ι, ΙΙ, and ΙΙΙ (cancer patients). patients aged 2 -8 years were enrolled in the study. They were assigned to one of three groups Group 1 (n = 30) received standard general anesthesia (GA), Group 2 (n = 30) received standard GA and caudal block with 1 ml/kg of 0.5% bupivacaine, and Group 3 (n = 30) received standard GA and TAP block. The following parameters were recorded : Intra-operatively, HR, MAP, Post-operative pain was assessed by FLACC Scale. Incidence of agitation was also assessed. Postoperative pain scores, the time to the first administration of opioid analgesic agents, and opioid use during the initial 24 postoperative hours were also assessed.
Results: Group Ι patients showed higher intra-operative fentanyle consumption. Caudal block group, showed comparable consumption of intra-operative fentanyle to TAP block group; The time to first analgesic requirement was prolonged in TAP block group, with statistical significant difference in comparison to other two groups. Group Ι demonstrated higher FLACC scores at all time intervals durin 24 postoperative hours. Conclusions: TAP provide superior analgesic efficacy and a significant decrease of systemic analgesics demand that was comparable to caudal epidural analgesia , with the added advantage of for prolonged postoperative analgesia.
A10 Title: Optical Detection of the Brachial Plexus for Peripheral Nerve Blocks: An in vivo Swine Study Presenting Author: Marcus Brynolf MD Presenting Author's Institution: Karolinska University Hospital - Stockholm, - Co-Authors: Micha Sommer MD - Academic Hospital of Maastricht - Maastricht Adrien E Desjardins PhD - Philips Research - Eindhoven Marjolein van der Voort PhD - Philips Research - Eindhoven Benno H.W. Hendriks PhD - Philips Research - Eindhoven
Abstract: Accurate identification of nerves is critical to ensure safe and effective delivery of regional anesthesia during peripheral nerve blocks. Nerve stimulation is commonly used, but it is known to be unreliable. Even when nerve stimulation is performed in conjunction with ultrasound guidance, determining when the needle tip is at the nerve target region can be challenging. In this in vivo pilot study, we investigated whether close proximity to the brachial plexus and penetration of the axillary artery can be identified with optical reflectance spectroscopy, using a custom needle stylet with integrated optical fibers. With this stylet, broadband light spanning the visible and near-infrared wavelengths is delivered to tissue at the needle tip with one fiber, and reflected light received by a second fiber is spectrally resolved with two spectrometers in an external console. Spectra acquired from tissue are dependent on the concentrations of molecules such as hemoglobulins and lipids, for which the wavelength- dependencies of optical absorption are distinct. Ultrasound-guided insertions to place the needle tip in close proximity to the brachial plexus at the axillary level were performed at multiple locations in two swine, with the stylet positioned in the cannula of a 20-gauge stimulation needle. During each insertion, optical reflectance spectra were acquired with the needle tip in skeletal muscle, at the surface of muscle fascia, and at the nerve target region; confirmation of the final needle position was provided by nerve stimulation. Additionally, an insertion to the lumen of the axillary artery was performed in a third swine. Differences in the spectra were quantified with lipid and hemoglobin parameters that provided contrast for optical absorption by the respective chromophores. The transition of the needle tip from skeletal muscle to the nerve target region was associated with higher lipid parameter values (P < 0.001) and lower hemoglobin parameter values (P < 0.001). The transition of the needle tip from muscle fascia to the nerve target region was associated with higher lipid parameter values (P = 0.001). Intraluminal access of the axillary artery was associated with an elevated hemoglobin parameter.
We conclude that spectroscopic information obtained with the optical needle is distinct from nerve stimulation and complementary to ultrasound imaging, and that it could potentially allow for reliable identification of the injection site during peripheral nerve blocks.
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A11 Title: Ultrasound-Guided Regional Anesthesia Performance in the Early Learning Period Presenting Author: Nidhi Haldipur BSc Presenting Author's Institution: Toronto Western Hospital - Toronto, Ontario Co-Authors: Ahtsham U Niazi FRCPC - Toronto Western Hospital - Toronto, Ontario Arun Prasad FRCPC - Toronto Western Hospital - Toronto, Ontario Vincent W Chan FRCPC - Toronto Western Hospital - Toronto, Ontario
Abstract: Background and Objectives: Success in performing ultrasound-guided peripheral nerve blockade demands sound knowledge of sonoanatomy, good scanning techniques and proper nerve visualization and needle positioning. However, the learning curve for acquiring proficiency in ultrasound-guided regional anesthesia (UGRA) has not been defined. The objective of this study was to determine the number of peripheral nerve block procedures required to achieve proficiency. We also evaluated whether inclusion of a teaching session on a low-fidelity phantom simulator model facilitated attainment of proficiency.
Methods: Following institutional ethics board approval, twenty PGY-2 anesthesiology residents with no previous experience in UGRA were randomly assigned into two groups. Both groups received conventional teaching which included four half-hour didactic lectures on upper and lower limb peripheral nerve blocks such as supraclavicular, sciatic, axillary, ankle, interscalene and femoral blocks with ultrasound guidance. Using a low-fidelity simulation model, one group further received an hour-long teaching on proper hand-eye coordination to visualize the needle and to advance the needle to hit the target. Using a logbook, each resident recorded the number of successful and failed UGRA blocks performed over a 4-month period. A successful block was defined as one effective for surgical anesthesia without supplementation and that was performed within 15 minutes with only verbal guidance from a staff anesthetist. For each resident, cumulative sum (CUSUM) charts were created to track progress using a predetermined acceptable failure rate of 30%. Continuous assessment of progress using CUSUM quantitatively demonstrates the threshold number of blocks before levels of proficiency can be expected.
Results: The total number of attempted blocks ranged from 9 to 41. In the simulation training group, an average of 22 blocks was performed and 6 out of 10 residents (60%) demonstrated proficiency within 25 blocks. A minimum of 10 nerve blocks was required to achieve proficiency. In contrast, in the conventional training group, an average of 19 blocks was performed and only one resident (10%) achieved proficiency with 25 block attempts. Although statistical significance was not achieved (60% vs. 10%, p=0.057), there was a trend demonstrating a marked improvement in success rates for the group receiving simulation training.
Conclusions: Although considerable variability exists in the rate at which proficiency is achieved, this study demonstrates that the addition of an hour-long teaching session with the practice on a simulator model decreases the minimal number of procedures required to attain proficiency.
References 1. Marhofer P, Chan VW. Ultrasound-guided regional anesthesia: current concepts and future trends. Anesth Analg 2007: 104(5):1265-1269.
A12 Title: Ropivacaine Blocks LPS- and TNFa-induced Src Activation, Intracellular Adhesion Molecule-1 Phosphorylation and Production of Monocyte Chemoattractant Protein-1 in H838 Lung Cancer Cells Presenting Author: Gina Votta-Velis MD, PhD Presenting Author's Institution: University of Illinois at Chicago and Jesse Brown VA - Chicago, IL Co-Authors: Tobias Piegeler MD - University of Illinois at Chicago - Chicago, IL Guoquan Liu BS - University of Illinois at Chicago - Chicago, IL Jose Aguirre MD - Balgrist Orthopedic University Hospital, Universit - Zurich, Switzerland Beatrice Beck-Schimmer MD - Institute of Anesthesiology and Physiology - Zurich, Switzerland
Abstract: Introduction: Recent clinical observations indicate that regional anesthesia may favorably affect cancer outcome (1). However, scarce literature is available elucidating the role of local anesthetics at a molecular level. It is well known that local anesthetics have anti-inflammatory effects. Endothelial barrier dysfunction is a sine quo condition for the process of metastasis, as is vascular hyper-permeability in Acute Lung Injury (ALI). ALI due to inflammatory hyper-permeability is mediated in part by increased ICAM-1 (Intracellular Adhesion Molecule-1) expression, and this was shown to be decreased by ropivacaine (2). Scientific evidence implicates ICAM-1 in tumor invasion in vitro and in metastasis in vivo, and hence in the malignant potential of various types of cancer. Circulating cancer cells extravasate to secondary sites probably using a process similar to inflammatory cells (3). Another potent regulator of endothelial permeability is Src-kinase (4). We have demonstrated in previous experiments that ropivacaine protects against capillary leakage by suppressing Src activation. Src family protein tyrosine kinases also play a critical role in a variety of cellular signal transduction pathways regulating diverse tumorigenic processes such as cell division, motility, angiogenesis (5) and metastasis (6). Monocyte Chemoattractant Protein-1 (MCP-1) attracts monocytes and macrophages to sites of inflammation (7) and its production is associated with angiogenesis and tumor invasion (8).
Methods: In this study, we examined the effect of ropivacaine on LPS-induced Src activation and ICAM-1 phosphorylation as well as on Tumor Necrosis Factor - (TNF -induced production of MCP-1 by H838 lung cancer cells. Cells were stimulated for 4 hrs with lipopolysaccharide (LPS) in the absence or presence of 1 nM – 1 M Ropivacaine, lysed, and proteins separated by SDS-PAGE. After transferring to nitrocellulose membranes, H838 derived proteins were immunoblotted to assess the level of total Src, active Src ( phospho-Tyr418), total ICAM-1, and phospho-ICAM-1 (pTyr518). H838 cells were also stimulated with TNF with and without ropivacaine to determine its effect on pro-inflammatory cytokine MCP-1 production. H838 culture media was collected and MCP-1 measured by ELISA assay, and these data were normalized to total cell protein.
Results: Western blot analysis revealed that ropivacaine dose dependently (1 nM- 10 M) decreased Src activation and ICAM-1 phosphorylation induced by 4 hr LPS treatment in H838 lung cancer cells. Ropivacaine also significantly decreased TNF - induced MCP-1 production after 4 hrs in H838 cells.
Conclusions: We demonstrated the importance of ropivacaine in attenuating Src activation and ICAM-1 phosphorylation in lung cancer cells as well as in decreasing MCP-1 production. It appears that inflammation and tumor malignant potential have common molecular mediators and possibly similar mechanisms. Our results indicate that local anesthetics such as ropivacaine might affect these processes through the same pathway. These findings, which warrant further investigation, support the use of regional anesthesia techniques in cancer patients.
Additional File #1: 1030111143421References.doc
References 1. Wuelthrich PY et. al. Anesthesiology. 2010;113(3):570. 2. Blumental S et. al. Anesthesiology. 2006;104:961. 3. Rosette C et. al. Carcinogenesis. 2005 ;26 :943. 4. Hu G et. al. Microvasc Res. 2009;77:21. 5. Summy JM et. al. Cancer and Metastasis Reviews. 2003;22:337. 6. Guarino M. J Cell Physiol. 2010;223:14. 7. Deshmane SL et. al. J Interferon Cytokine Res. 2009;29:313. 8. Valkovic T et. al. Virchows Arch 2002;440.
A13 Title: Life and Limb: The Role of Regional Anesthesia in Major Earthquake Relief Presenting Author: Andres Missair MD Presenting Author's Institution: University of Miami - Miami, FL Co-Authors: Ernesto Pretto MD - University of Miami - Miami, FL Lebron Cooper MD - University of Miami - Miami, FL Jeffrey Frohock MD - University of Miami - Miami, FL David Lubarsky MD - University of Miami - Miami, FL
Abstract: Introduction: The importance of regional anesthesia in the battlefield has been well documented (1). More recently, peripheral nerve blocks have also proven to be an important tool in a civilian scenario. In the immediate aftermath of the 2010 Haiti Earthquake, safe and successful anesthetic care was provided in the absence of supplemental oxygen, electricity, and any general anesthesia capabilities utilizing single shot nerve blocks and ketamine MAC sedation (2). During this experience it became apparent that the majority of patient survivors presented with limb injuries, underscoring the significant role that regional anesthesia could assume in such settings. Consequently, we felt that a review of epidemiologic data from other major earthquakes was warranted in order to optimize disaster preparedness for future relief operations.
Methods: In order to identify reports on acute medical care in the aftermath of natural disasters, a Medline search was conducted using the keywords ―injury pattern, earthquake, wounds, limb, anesthesia‖ in the timeframe form 1900 to 2010. Publications which did not comment on injury pattern or specified case numbers were excluded from analysis.
Results: 78 studies were reviewed. A total of 26 articles reporting on 14 major earthquakes and the treatment of over 29,384 patients met inclusion criteria. The predominant injury pattern identified was extremity injury (62.66% average per event) ranging from laceration and fracture to compartment syndrome and crush injury. Lower limb involvement invariably exceeded 60% of these cases. Conversely, cranial, thoracic, and abdominal injuries combined represented less than 36% of all cases across earthquake survivors (Table 1)(3). Anesthetic techniques utilized included general, regional, and MAC anesthesia. Reported perioperative mortality ranged from 0% to 19%. Identified anesthetic complications included laryngospasm and PONV.
Conclusions: Based on this analysis, early disaster surgical intervention will focus on surviving patients with limb injury. In addition, our experience in Haiti demonstrates that a purely regional anesthetic combined with ketamine MAC sedation can provide safe operating conditions with minimal equipment and absent operating room infrastructure, making it ideally suited for medical disaster relief (2). A well-equipped portable nerve block kit, designed to provide basic monitoring and ketamine MAC capabilities, can serve as the first critical step in effective and safe anesthetic care during the acute phase of humanitarian aid. We have developed such a portable nerve block kit capable of 60 procedures under emergency conditions and in the absence of any general anesthesia infrastructure (Fig 1). Supply emphasis was placed on airway management, basic monitoring, IV access, resuscitation, and single-shot nerve stimulated blockade (Table 2).
References 1) Buckenmaier et al.,―Regional Anesthesia in Austere Environments,‖ Reg Anesth Pain Med. 2003. 2) Missair et al.,―Surgery Under Extreme Conditions in the Aftermath of the 2010 Haiti Earthquake: The Importance of Regional Anesthesia,‖ Prehosp Disaster Med. 2010. 3) Tanaka et al., ―The Kobe Earthquake: The System Response,‖ Eur J Emerg Med. 1996.
Additional File #1: 1011411084817HAITI_2011_TABLE_4.pdf
ketamine
Additional File #2: 2011411084817RADAR_LIST_1.pdf
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A14 Title: Postoperative morning hyperglycemia increases risk for periprosthetic joint infection after hip and knee arthroplasty Presenting Author: Boris Mraovic MD Presenting Author's Institution: Thomas Jefferson University - Philadelphia, PA Co-Authors: Christina Jacovides BS - Thomas Jefferson University - Philadelphia, PA Jeffrey Joseph DO - Thomas Jefferson University - Philadelphia, PA Javad Parvizi MD - Thomas Jefferson University - Philadelphia, PA
Abstract: Background: Periprosthetic joint infection (PJI) is a serious complication after major orthopedic surgery. Postoperative morning hyperglycemia > 200 mg/dL was found to increase a risk for deep wound infection on day 1 (POD 1) after cardiac surgery. Indeed, JCAHO in SCIP project and National Quality Forum recommend a 6 a.m. blood glucose (BG) to be < 200 mg/dL on POD1 and POD2 after cardiac surgery.(1,2,3) We investigated whether postoperative hyperglycemia increased the risk for PJI after hip and knee replacement surgery.
Methods: After IRB approval, our computerized database was reviewed for elective primary total hip and knee arthroplasty from 2000 to 2008. Only patients with completed medical records and BG data were included in the study. BG values closest to 6:00 A.M. on POD1 were used. Patients were classified with PJI if they had surgical intervention for infection within 2 years after primary surgery. Non- infected patients had no intervention with a minimum of one year follow-up. The data were analyzed using t-test, chi-squared and Fisher‘s exact test.
Results: There were 101 infected patients and 1847 non-infected patient. Patients with PJI compared with non-infected patients had significantly higher BMI (32 ± 9 vs 30 ± 7 kg/m2, p=0.003. longer operative time (135.2 ± 69.6 vs 108.8 ± 35.5 min, p<0.001) and longer hospital stay (6.5 ± 8.3 vs 4.1 ± 1.4 days, p<0.001) and more BG values >200 mg/dL on POD1 (7 vs 3 %, p=0.049). There was no difference in age between groups (64.7 ± 11.6 vs 62.9 ± 11.8 years old, p=0.14), but infected patients tend to be male (55 vs 37 %, p<0.001), had higher ASA physical status 3 and 4 (53 vs 39%, p<0.001), had knee vs hip surgery (59 vs 31%, p<0.001) and had more bilateral surgeries (24 vs 14%, p=0.007).
Discussion: Postoperative morning hyperglycemia (>200 mg/dL) was associated with an increased risk for PJI that required surgical intervention more than 2-fold. Further studies are required to determine whether optimizing blood glucose postoperatively would decrease the incidence of PJI after major orthopedic surgery.
References 1. Frunary AP et al. J Thorac Cardiovasc Surg. 2003;125:1007-1021. 2. www.jointcommission.org 3. www.qualityforum.org
A15 Title: Nerve impalement prior to extraneural injection is not equivalent to intraneural injection: a human cadaveric study Presenting Author: Joanne Guay MD, FRCPC Presenting Author's Institution: University of Montreal - Montreal, Quebec Co-Authors: Detlev Grabs MD, PhD - University of Quebec at Trois-Rivieres - Trois- Rivières, Quebec
Abstract: Introduction: Intraneural injection of local anesthetic is considered by certain authors as an extremely effective form of regional anesthesia. Others fear that this technique might be associated with an increase incidence of transient/permanent nerve injury. The purpose of this study was to evaluate the efficacy of prior epineurium perforation followed by extraneural injection to replace intraneural injection.
Methods: With approval of the local Ethics Committee, sciatic nerves of human cadavers embalmed according to the Thiel‘s technique were injected at random (block randomization by three and stratified by the site [mid-femoral or popliteal] of injection) under real-time ultrasound guidance. Group control (C) consisted of extraneural injection of 10 mL of 0.2% methylene blue (n=4); Group prior nerve perforation (PNP) consisted of nerve impalement followed by injection as in Group C (n=4); and Group intraneural (I) consisted of intraneural injection of 2 mL of solution followed by 8 mL around the nerve (n=4). After a soaking time of 40 min, nerves were dissected and the inside coloration of both component was scored as followed: 0=absent; 1=<50%; 2=50%; 3=>50%; 4=complete. Mean total scores (tibial plus peroneal) of the 3 groups were compared with an ANOVA.
Results: Intraneural injection produced a higher degree of inside nerve coloration than the two other techniques of injection: I=7.8±0.5 (Mean±SD) vs. PNP=0.3±0.5 or C=1.8±2.4 (P<0.0001).
Conclusions: Prior epineurium perforation followed by extraneural injection cannot be proposed as a technique to replace intraneural injection.
Type of Site Surface Delay Tibial Peroneal Total score injection (cm2) (min) score score Control Total 0.37±1.0 38.5±5.8 0.5±0.6 1.3±1.9 1.8±2.4
Intraneural Total 0.57±1.0 40.5±3.3 3.8±0.5 4.0±0 7.8±0.5* Injection Prior Nerve Total 0.46±0.2 40.3±0.5 0.3±0.5 0±0 0.3±0.5 Perforation Successful Table. Inside nerve coloration score Failed block Events in PACU block Score scale: O=Absent; 1=<50%, 2=50%; 3=>50%; 4=Complete *P<0.0001 for Median time for preparation (ID to Intraneural injection vs. control or prior nerve perforation.44 mi ns. 45 mins. surgery)
Directly from the OR to the surgical 173/1166 0/160 (0%) dept. (15%)
Shivering in PACU 52/1166 (4%) 9/160 (6%)
Nausea or vomiting in PACU 51/1166 (4%) 7/160 (4%)
Confusion in PACU 16/1166 (1%) 4/160 (3%)
Median length of stay in PACU 55 mins. 93 mins.
Successful Failed block Events in PACU block
Median time for preparation (ID to 44 mins. 45 mins. surgery)
Directly from the OR to the surgical 173/1166 0/160 (0%) dept. (15%)
Shivering in PACU 52/1166 (4%) 9/160 (6%)
Nausea or vomiting in PACU 51/1166 (4%) 7/160 (4%)
Confusion in PACU 16/1166 (1%) 4/160 (3%)
Median length of stay in PACU 55 mins. 93 mins.
A16 Title: Consequences of incomplete nerve blocks: An analysis of 1,326 interscalene blocks for shoulder surgery Presenting Author: Kenneth Jensen MD, BBA Presenting Author's Institution: University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen Co-Authors: Jens Børglum MD, PhD - University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen
Abstract: Aim: To investigate the consequences for patient care and the post-anaesthesia care unit (PACU) when interscalene nerve blocks for shoulder surgery fail.
Methods: Prospective cohort study of 1,326 consecutive interscalene nerve blocks during a 4-year period (2007-2010). A successful nerve block was defined by its ability to (i) provide for surgical anesthesia without the need to convert to general anaesthesia or use escape blocks, or (ii) provide effective postoperative analgesia without the need for opioids or escape blocks. All patients had the block placed prior to surgery, either by ultrasound or nerve stimulation guidance. With regional anaesthesia, the patient was able to receive slight sedation; with general anaesthesia, propofol and remifentanil infusions were used. No patient was given long-acting opioids until it was deemed necessary postoperatively. Patients were discharged from the PACU according to specific criteria modified from Aldrete.
Results: The anaesthetic plan consisted of general anaesthesia in 83% and regional anaesthesia in 17%. Failed blocks were seen in 121/1106 (11%) and 39/221 (18%), respectively. Hypotensive-bradycardic reactions during surgery occurred in 29/182 (16%) of awake patients, regardless of the sedative requirements or block technique. Table 1 lists the most frequent perioperative events (apart from pain) and time consumption involved.
Discussion: The primary concern of failed interscalene blocks seems to be increased length of stay (LOS) in the PACU rather than delays before surgery, adding almost 40 minutes to LOS. Pain is the most important determinant for this delay, whereas other complaints such as shivering, PONV or confusion are not only infrequent, but hardly seems to contribute to this increased LOS.
Conclusions: We find that interscalene nerve block failure in shoulder surgery causes significant postoperative pain. Pain is the primary impediment to well-being and effective flow from the PACU, and interscalene nerve block is an effective preemptive treatment. Further studies are needed to address the impact on mobilization and restoration of normal activities when the patients are discharged from hospital.
Additional File #1: 1012911134050Table_1__Perioperat.pdf Click here to view
A17 Title: ―Twitch or No Twitch‖ Evaluation of a new end point for ultrasound-guided supraclavicular nerve block. Presenting Author: Michael Fortunato MD Presenting Author's Institution: Penn State Hershey Medical Center - Hummelstown, PA Co-Authors: Sanjib Adhikary M.D. - Penn State Hershey Medical Center - Hershey, PA Patrick McQuillan M.D. - Penn State Hershey Medical Center - Hershey, PA
Abstract: Background: The use of Ultrasound (US) leading to the reduced risk of pneumothorax has made the supraclavicular approach to brachial plexus more commonly used.(1) With this technique and using multiple needle passes, to either elicit a desired motor response or for administration of local anesthetics around the plexus, it has been felt there is an increase in both the risk of neuropraxia and patient discomfort leading to dissatisfaction.(2) It is known from the available literature that a motor response elicited from a stimulation current of 0.2mA or less has a very high association with intraneural needle placement.(3,4,5,6) With use of current US technology, the presence of septum within the neural bundle makes it impossible to make a clear distinction between intra and extraneural needle placement within the sheath of the brachial plexus.
Objective: We hypothesize that nerve stimulation can be used to rule out intra neural injection once needle placement has been achieved using real-time US guidance.
Methods: After obtaining informed consent, five supraclavicular blocks were conducted in patients scheduled to have surgery in and around the wrist. Initially, a pre-procedural scan was performed to identify the brachial plexus. The skin was then prepared and draped using sterile technique. Sedation and analgesia were administered for patient comfort. Using a 6-13 MHz linear US probe, the brachial plexus trunks/divisions; displayed as distinct, round-to-oval structures present inside the sheath, were identified lateral to the subclavian artery. A stimulating block needle was then positioned inside the sheath, in the middle of the plexus, under direct visualization. At that point, the nerve stimulator was connected to the block needle and adjusted to 0.2mA, 0.1 ms, and 2Hz. If no twitch (motor response) was elicited, the position of the needle was considered acceptable and 1 mL of normal saline was injected slowly to confirm spread inside the sheath. Once the spread was confirmed without any associated parasthesias, 0.5% ropivicaine was injected (in fractionated doses of 3-4 ml) until the neural structures were seen being displaced inside the sheath. If a twitch response was initially elicited with nerve stimulation, needle position was adjusted until no twitch was observed while maintaining needle placement within the sheath. Injection through the needle was then performed as described above.
Results: In all five patients, the end point of no twitch along with the use of real time US resulted in successful blockade of the upper limbs without multiple passages of the needle and any identifiable neurologic deficits in any patient post procedure. We also determined that the amount of local anesthetic required for the block was significantly lower than what has been traditionally required, 15-17 mL as compared to 23 mL(1).
Conclusions: We contend that the use of nerve stimulation can be used to rule out intraneural injection once correct needle placement has been determined under US guidance. This technique may also lead to the use of less volume of local anesthetic; however, this finding needs to be validated by further clinical studies
Additional File #1: 1012011191236References_abstract.doc
References 1. Neal J, Gerancher J.C, Hebl J, Ifeld B, McCartney C, Franco C, Hogan Q. Upper Extremity Regional Anesthesia. Reg Anesth Pain Med. 2009; Vol 34-2 March. 2. Beach M, Sites B, Gallagher J. Use of a nerve stimulator does not improve the efficacy of ultrasound-guided supraclavicular nerve blocks. J Clin Anesth. 2006; 18:580-584. 3. Bigeleisen PE, Moayeri N, Groen GJ.1235-43. Extraneural versus intraneural stimulation thresholds during ultrasound-guided supraclavicular block. Anesthesiology. 2009 Jun;110(6). 4. Gadsden J, McCally C, Hadzic A, Monitoring during peripheral nerve blockade. Curr Opin Anaesthesiol. 2010 Oct;23(5):656-661. 5. Tsai TP, Vuckovic I, Dilberovic F, Obhodzas M, Kapur E, Divanovic KA, Hadzic A. Intensity of the stimulating current may not be a reliable indicator of intraneural needle placement. Reg Anesth Pain Med. 2008 May-Jun;33(3):207-210. 6. Robards C, Hadzic A, Somasundaram L, Iwata T, Gadsden J, Xu D, Sala-Blanch X. Intraneural injection with low-current stimulation during popliteal sciatic nerve block. Analg. 2009 Aug;109(2):673-677. 7. Hadzic A, Vloka J, Hadzic N, Thys DM, Santos AC. Nerve stimulators used for peripheral nerve blocks vary in their electrical characteristics. Anesthesiology. 2003 Apr;98(4):969-974. 8. Wehling MJ, Koorn R, Leddell C, Boezaart AP.Electrical nerve stimulation using a stimulating catheter: what is the lower limit? Reg Anesth Pain Med. 2004 May- Jun;29(3):230-233.
A18 Title: ‗Needle to nerve time‘ comparison of four different echogenic ultrasound guided regional anaesthesia nerve block needles Presenting Author: Saurabh Ricky Nagpaul MBBS ,FRCA Presenting Author's Institution: University College London Hospitals NHS Trust - London, London Co-Authors: Navkiran Kaur Bsc(Med), MBBS,FANZCA - University College London Hospitals NHS Trust - London, London Damon Kamming BSc(Hons), MBChB, FRCA - University College London Hospitals NHS Trust - London, London Mark Edwards BMedSci, BMBS, MRCP, FRCA - University College London Hospitals NHS Trust - London, London
Abstract: Background and Aims: Ultrasound guidance for regional anaesthesia (UGRA) has been showed to improve the speed of neural blockade when compared with traditional techniques1. The success and safety of UGRA is dependent on being able to dynamically visualise the nerve block needle's trajectory towards the nerve2. This is known to be more difficult with deep nerves as compared to superficial nerves. Needles that reflect a greater proportion of the ultrasound back to the probe are termed 'echogenic' needles. Using 'echogenic' needles for UGRA may make it easier to visualise the needle's trajectory towards the nerve.Such needles may therefore improve the 'needle to nerve time' of UGRA.
Primary Aim: Direct comparison of 'needle to nerve time' to reach two phantom nerves (Blue Phantom - Peripheral Nerve Block Ultrasound Training Model) i.e superficial nerve(10 mm deep) and deep nerve(20 mm deep) using the following four different 'echogenic' nerve block needles : 1) Needle A-Braun Stimuplex® D (22G×50mm) 2) Needle B-Braun Stimuplex D® plus (22G×50 mm) 3) Needle C-Pajunk Sonoplex Stim cannula (22G×50mm) 4) Needle D-Polymedic® needle (22G×50mm)
Secondary Aim: To see whether level of UGRA experience influenced 'needle to nerve time.'
Methods: Forty-six anaesthetists from our hospital volunteered to be the subjects of our study after getting approval from institutional board review. The anaesthetist placed each of the four needles using an in-plane approach and linear array probe (6-10Mhz)(Sonosite S nerve ) into the phantom to firstly aim for the superficial nerve followed by aiming for deep nerve. The time taken for each needle shaft to be fully visualised and the needle tip to be identified just above the target by the subject were recorded for both superficial and deep targets respectively by the researchers. The needles were not inserted near any prior needle-track marks. A randomised schedule predetermined the order in which the needles were placed into the phantom.
Statistical analysis: One-way ANOVA was used to compare different needle types for all subjects, using the total time taken to hit the target. For finding out whether level of ultrasound guided regional anaesthesia experience influenced time taken using different needles, 2-way ANOVA was used.
Results: For superficial target there was no difference between any of the needles, and level of experience did not influence the overall time taken with any needle. For deep targets, needle C was significantly quicker for the total time taken (p<0.05) than any other needle, although interestingly this was again irrespective of level of experience of the anaesthetists.
Conclusion and Discussion: We have demonstrated that echogenic needle C (Pajunk Sonoplex Stim cannula) has the fastest 'needle to nerve time' compared to other echogenic needles included in this study. Both experienced and inexperienced UGRA anaesthetists demonstrated improved 'needle to nerve time' with this echogenic needle. A limitation of this study is its in vitro nature. Nevertheless this needle would be a very useful addition to any nerve block trolley for deep UGRA blocks or patients with a high body mass index for both inexperienced and experienced UGRA anaesthetists.
References 1) Williams, Stephan R, Chouinard, Philippe, Arcand Genevieve , Harris ―Ultrasound Guidance Speeds Execution and Improves the Quality of Supraclavicular Block‖ Anesth & Analgesia 97(5), November 2003, 1518-1523. 2) R K Deam, R Kluger, M J Barrington, and C A McCutcheon. "Investigation of a new echogenic needle for use with ultrasound peripheral nerve blocks. " Anaesth Intensive Care 35.4 (2007): 582-586.
Additional File #1: 1012611072732deep_graph1.docx Click here to view A19 Title: Long Term Functional Outcomes of Regional Anesthesia in Total Knee Arthroplasty Presenting Author: Stephen Choi MD, FRCPC Presenting Author's Institution: Sunnybrook Health Sciences Centre, University of Toronto - Toronto, Ontario Co-Authors: Amy Trang MD - University of Toronto - Toronto, Ontario Deborah Kennedy PT - Sunnybrook Health Sciences Centre, University of T - Toronto, Ontario Nicole Carmichael PhD - Sunnybrook Health Sciences Centre, University of T - Toronto, Ontario Colin J McCartney MBChB, FRCA, FRCPC - Sunnybrook Health Sciences Centre, University of T - Toronto, Ontario
Abstract: Background: Regional anesthesia (RA) has been hypothesized to have a positive impact on functional outcome after total knee arthroplasty (TKA). However there are few randomized controlled trials (RCTs) that examine functional outcomes as a primary endpoint when utilizing RA. This article reviews the available literature describing the use of functional outcomes in assessing the impact of RA on TKA. Our aim was to assist anesthesiologists to interpret, select and apply relevant measures when used to evaluate the impact of RA on function after TKA.
Methods: Following a systematic Pubmed, EMBASE, and Cochrane Central Register search, we reviewed all 22 RCTs published between January 1990 and October 2010 where regional anesthesia was utilized in total knee arthroplasty and a functional outcome measure was reported as an endpoint. The search was limited to randomized controlled trials (RCTs), English language, and human adults. Studies were excluded if they did not evaluate at least one standardized or accepted functional outcome measure in the post-operative period. The quality of each study was assessed using the Jadad score. Each study was scored by two authors (S.C. and C.M.).
Results: We identified 1,490 patients in 22 RCTs where a RA technique was utilized in TKA and a functional outcome was reported. The functional outcome measures reported varied widely, including both performance-based and self report measures. Functional outcome measures were the primary endpoint in only three RCTs. RA procedures utilized were highly variable in terms of block type, infusion duration and potency. Furthermore, most outcomes reported were either single assessments or a short series in the immediate post-operative period rather than multiple assessments over a longer period.
Conclusions: At the present time there is no definitive evidence that RA improves long-term functional outcome after TKA. Further investigation needs to be conducted to elucidate the role that RA has on outcome after TKA using appropriate measures of function.
Additional File #1: 1022711225258Refs.doc Click here to view
1. Aveline C, Le Roux A, Le Hetet H, Vautier P, Cognet F, Bonnet F. Postoperative efficacies of femoral nerve catheters sited using ultrasound combined with neurostimulation compared with neurostimulation alone for total knee arthroplasty. Eur J Anaesthesiol 2010;27(11):978-984. 2. Buvanendran A, Kroin JS, Della Valle CJ, Kari M, Moric M, Tuman KJ. Perioperative oral pregabalin reduces chronic pain after total knee arthroplasty: a prospective, randomized, controlled trial. Anesth Analg 2010;110(1):199-207. 3. Carli F, Clemente A, Asenjo JF, Kim DJ, Mistraletti G, Gomarasca M, et al. Analgesia and functional outcome after total knee arthroplasty: periarticular infiltration vs continuous femoral nerve block. Br J Anaesth 2010;105(2):185-195. 4. Bergeron SG, Kardash KJ, Huk OL, Zukor DJ, Antoniou J. Functional outcome of femoral versus obturator nerve block after total knee arthroplasty. Clin Orthop Relat Res 2009;467(6):1458-1462. 5. Ilfeld BM, Le LT, Meyer RS, Mariano ER, Vandenborne K, Duncan PW, et al. Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment total knee arthroplasty: a randomized, triple- masked, placebo-controlled study. Anesthesiology 2008;108(4):703-713. 6. Ilfeld BM, Meyer RS, Le LT, Mariano ER, Williams BA, Vandenborne K, et al. Health-related quality of life after tricompartment knee arthroplasty with and without an extended-duration continuous femoral nerve block: a prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study. Anesth Analg 2009;108(4):1320-1325. 7. Kadic L, Boonstra MC, MC DEWM, Lako SJ, J VANE, Driessen JJ. Continuous femoral nerve block after total knee arthroplasty? Acta Anaesthesiol Scand 2009;53(7):914-920. 8. Krenzel BA, Cook C, Martin GN, Vail TP, Attarian DE, Bolognesi MP. Posterior capsular injections of ropivacaine during total knee arthroplasty: a randomized, double-blind, placebo-controlled study. J Arthroplasty 2009;24(6 Suppl):138-143. 9. Shum CF, Lo NN, Yeo SJ, Yang KY, Chong HC, Yeo SN. Continuous femoral nerve block in total knee arthroplasty: immediate and two-year outcomes. J Arthroplasty 2009;24(2):204-209. 10. Barrington MJ, Olive DJ, McCutcheon CA, Scarff C, Said S, Kluger R, et al. Stimulating catheters for continuous femoral nerve blockade after total knee arthroplasty: a randomized, controlled, double-blinded trial. Anesth Analg 2008;106(4):1316-21, table of contents. 11. Campbell A, McCormick M, McKinlay K, Scott NB. Epidural vs. lumbar plexus infusions following total knee arthroplasty: randomized controlled trial. Eur J Anaesthesiol 2008;25(6):502-507. 12. Paauwe JJ, Thomassen BJ, Weterings J, van Rossum E, Ausems ME. Femoral nerve block using ropivacaine 0.025%, 0.05% and 0.1%: effects on the rehabilitation programme following total knee arthroplasty: a pilot study. Anaesthesia 2008;63(9):948-953. 13. Kardash K, Hickey D, Tessler MJ, Payne S, Zukor D, Velly AM. Obturator versus femoral nerve block for analgesia after total knee arthroplasty. Anesth Analg 2007;105(3):853-858. 14. Toftdahl K, Nikolajsen L, Haraldsted V, Madsen F, Tonnesen EK, Soballe K. Comparison of peri- and intraarticular analgesia with femoral nerve block after total knee arthroplasty: a randomized clinical trial. Acta Orthop 2007;78(2):172-179. 15. Salinas FV, Liu SS, Mulroy MF. The effect of single-injection femoral nerve block versus continuous femoral nerve block after total knee arthroplasty on hospital length of stay and long-term functional recovery within an established clinical pathway. Anesth Analg 2006;102(4):1234-1239. 16. Zaric D, Boysen K, Christiansen C, Christiansen J, Stephensen S, Christensen B. A comparison of epidural analgesia with combined continuous femoral-sciatic nerve blocks after total knee replacement. Anesth Analg 2006;102(4):1240- 1246. 17. Holmstrom A, Hardin BC. Cryo/Cuff compared to epidural anesthesia after knee unicompartmental arthroplasty: a prospective, randomized and controlled study of 60 patients with a 6-week follow-up. J Arthroplasty 2005;20(3):316- 321.
Additional File #2: 2022711225258Table_I.doc Click here to view Table I – RCTs assessing the impact of regional anesthesia on functional outcome Author/Year Jadad N Groups (n) Primary Outcome Functional Outcome Functional Outcome Result Comments Score Aveline 11001 92 1. CFNB US (46) 1. Local anesthetic dose 1. Knee ROM POD 2 and 5 1. Improved by US to 50o from 45o on Powered to detect 25cc difference 1 2010 2. CFNB PNS (46) POD 2 (p=0.0064) in local anesthetic dose
Buvanendran 11111 240 All patients PCEA 1. Incidence of 1. KOOS-PS, 3 and 6 months 1. KOOS reduced at 6 months (p=0.003) Powered to detect reduced 20102 (5) 1. Pre-op pregabalin neuropathic pain 2. Active/Passive ROM, 1-3 days 2. 1-3 days 83.4o v 79.5o flexion incidence of neuropathic pain o o 300mg, 150mg BID x 2. Achieving discharge and 3 months (p=0.001), 1 month 107 v 103.4 Clinically insignificant difference 10 days, 75 mg BID criteria flexion (p=0.0254) for ROM x 10 days (120) 3. Achieved earlier by mean 9h (p=0.001) 2. Placebo (120)
Carli 11111 40 48h infusion 1. Pain 1. Knee ROM first 3 days 1. No difference Powered to detect reduced pain 20103 (5) 1. CFNB 48h(20) 2. Morphine Consumption 2. 2MWT POD 1-3 2. No difference 2MWT, CHAMPS not validated 2. Continuous 3. 6MWT POD 1-3 and 6 weeks 3. No difference in TKA periarticular LA 48h 4. CHAMPS 4. No difference WOMAC only assessed at single (20) 5. SF-12 5. No difference time point 6. WOMAC at 6 weeks 6. Benefit for FNB, 28.0 to 19.7 (p=0.04) 7. Knee Society Score at 6 7. Benefit for FNB, 137.7 to 156.6 weeks (p=0.05)
Bergeron 11111 60 1. FNB (20) 1. Pain 1. HSS Knee Score at 6 weeks No difference Powered to detect reduced pain 20094 (5) 2. Obturator (20) and 1 year Secondary analysis after long term 3. Placebo (20) follow up of previous study 27/60 patients analyzed
Ilfeld 11111 50 1. CFNB 1 day (25) POD 1 1. 6MWT POD 1 1. No difference WOMAC data, secondary 20095,6 (5) 2. CFNB 4 days (25) 1. Pain 2. Knee ROM 2. No difference analysis, data extrapolated on at 2. Achieving discharge 3. WOMAC 1 week, 1, 2, 3, 6, 3. No difference least one time point in 32-40% of criteria 12 months post-operatively subjects in each group 3. 6MWT POD 1 (8h after randomization)
Kadic 11001 53 1. PCA (26) 1. Pain 1. Knee ROM POD 3-6, 3 1. Knee ROM POD 3-6 improved by 5- Powered to detect reduced opioid 20097 (3) 2. PCA + CFNB 48h 2. Morphine consumption months 10o for CFNB (p=0.0012), no consumption (27) 3. Opioid related side 2. WOMAC 3 months difference 3 months Attempting 90o flex at POD 3-6 effects 3. KSS 3 months 2. No difference (discharge criteria) 3. No difference Error for measurement in knee ROM 5o
Krenzel 10001 67 1. CFNB 24h + 1. Pain 1. Knee ROM POD 1 1. No difference Sample size requirements to 20098 (2) Posterior capsule 2. Fentanyl consumption 2. Ambulation distance POD 1 2. No difference achieve adequate power not met Ropi 0.5% (35) for primary outcome 2. CFNB 24h + Posterior capsule saline (32)
Shum 10001 60 1. PCA (20) 1. Pain At 2 years 1. No difference Powered to detect mean difference 20099 (2) 2. CFNB Ropi 0.15% 2. Morphine consumption 1. Knee ROM 2. No difference in morphine consumption of 10mg 48h (20) 3. Opioid related side 2. Oxford Knee Questionnaire 3. No difference 3. CFNB Ropi 0.2% effects 3. KSS
Additional File #3: 3022711225258Table_II.doc Click here to view
Table II Functional Validated Time to Administer Comments Outcome for TKA
Performance Based ROM Yes Up to 12 weeks Measurement error 5o
TUG Yes Plateaus at 10 weeks Can replace ST in early post-operative period
ST Yes Returns to baseline at 6 weeks Difficult to administer immediately post-op
6MWT Yes Plateaus at 26 weeks Minimum 300 metres needs to be achieved Greatest change 6 to 9 weeks
SPWT Yes Returns to baseline at 6 weeks Can be a surrogate to 6MWT in early post-operative period
Self-Reported WOMAC Yes Greatest change 9 to 13 weeks Reported in three subsections or summated
KOOS Yes Most sensitive to change at 6 to 12 months Better than WOMAC for young (<60 years), active patients
LEFS Yes Greatest change 4 to 12 weeks Equivalent to WOMAC Plateaus at 6 months
A20 Title: Ward staff knowledge of Interscalene Block, in a Central London Teaching Hospital Presenting Author: Maria Capoluongo MBBS,BSc Presenting Author's Institution: University College London Hospital - London, London Co-Authors: Khalid Syeed MBBS, FRCA - University College London Hospital - London, London John Dick MBBS, FRCA - University College London Hospital - London, London
Abstract: Introduction: With the ever expanding use of regional anaesthesia for routine and emergency procedures, we are facing the challenge of training and education in these relatively unknown techniques. The importance of staff knowledge of pain management techniques has been highlighted in a number of sources (1,2). We decided to undertake a knowledge survey for one of the regional techniques that we use daily in our hospital trust.
Methods: Ward staff were invited to complete an anonymised questionnaire about interscalene block under supervision, on our orthopaedic wards, over a two week period. A total of 7 questions were asked. The answers were given in a free text format with no use of other information aids. Their answers were compared to model responses based upon commonly available internet resources (3,4).
Questions Table 1 (Attachment 1)
Results: There were a total of 45 participants. Of which 25 were nursing staff of varying seniority and 20 were junior doctors from surgical specialties responsible for orthopaedic patients.
Question 1: What is an interscalene block? None of the responses matched our model answers. 16(35.6%) people didn‘t answer. Of those that were incorrect, 2(4.4%) thought it was a nerve block, 27(60%)thought it was used for shoulder surgery. Graph 1 (attachment 2)
Question 2: What are its side effects? None of the participants identified the model answers. 10(22.2%) did not know, 35(77.8%) were incorrect. Graph 2 (attachment 3) Question 3: What are its complications? 9(20%) wrote nerve damage, 2(4.4%) wrote pneumothorax, 12(26.7%) didn‘t know, of the others 22(48.9%) were incorrect.
Question 4: How long would the effects be expected to last? There was a large variation on answers received. 21(46.7%) wrote 12-24hrs, 7(15.6%) 12hrs, 4(8.9%) 8hrs, 5(11.1%) 2hrs, 2(4.4%) 6 hrs, 2(4.4%) 24-48hrs, 1(2.2% ) 72hrs, 1(2.2%) few days, 1(2.2%) 6-8 weeks, 1(2.2% ) 3-6 months.
Question 5: Are there any contraindications to its use? 31(68.7%) gave local anaesthetic allergy as a contraindication,3(6.7%) gave clotting abnormalities, 11(24.4%) did not know.
Question 6: When should it be reviewed by a doctor? 6(13.3%) wrote > 24hrs, 1(2.2%) next day, 2(4.4%) 8hrs, 5(11.1%) >12hrs, 1(2.2%) 4hrs post op, 6(13.3%) wrote if there was neurovascular compromise, 1(2.2%) if respiratory problems were present, 23(51.1%) did not know.
Question 7: Would you like more training in peripheral nerve block care? 45(100%) wanted further training.
Conclusions: The results highlight a lack of ward staff knowledge of this commonly performed block. This may have implications upon patient care and safety postoperatively. However all participants recognised this deficiency in knowledge and were keen for further training. We would recommend regular and ongoing formal teaching of peripheral nerve blockade care to improve quality of patient care.
References 1. Rawal N. 10yrs of acute pain services. Challenges and Achievements. Reg Anesth Pain Med. 1999;24(1):68-73. 2. Post operative pain management. Good clinical practice. General recommendations and principles of successful pain management. Produced in consultation with The European Society of Regional Anaesthesia and Pain Therapy. 3. www.nysora.com 4. www.rcoa.ac
(unable to open these zip files) Additional File #1: 1022311153358Questions.docx Click here to view
Additional File #2: 2022311153358graph_1.docx Click here to view
Additional File #3: 3022311153358graph_2.docx Click here to view
A21 Title: The contribution of TAP blocks to reduced hospital length of stay following robotic radical prostatectomy Presenting Author: Clare Morkane MBBCh Presenting Author's Institution: University College Hospital, London - London, London Co-Authors: Khalid Syeed MBBS - University College Hospital, London - London, London Damon Kamming MBBS - University College Hospital, London - London, London Caroline Pritchard MBBS - University College Hospital, London - London, London
Abstract: Introduction: Transversus abdominis plane (TAP) blocks performed under ultrasound guidance, are easy to perform, provide consistent analgesia below the umbilicus, and have displayed a good safety profile (1). The indications for this block are now expanding into laparoscopic surgery (2). A robotic radical prostatectomy program was initiated in our centre in April 2010. After the first 6 months, a multimodal analgesic protocol was introduced in the perioperative setting which included an ultrasound guided TAP block.
Aim: To analyse the outcomes from an evolving enhanced recovery programme following the introduction of the robotic radical prostatectomy surgery.
Methods: We retrospectively collected data from the first 41 consecutive patients in the programme. Of these, 22 patients received routine post operative analgesia which included IV paracetamol, diclofenac and IV morphine. The other 19 patients followed a multimodal analgesic protocol which included IV paracetamol, diclofenac, tramadol, and a post surgical TAP block placed, using real time ultrasound guidance, using 20mls of 0.375% bupivicaine placed bilaterally, between the costal margin and iliac crest, in the region of the anterior axillary line. Outcome data including hospital length of stay, total post operative morphine consumption at 24 hours, and pain scores were collated.
Results: On introduction of the multimodal/TAP protocol, compared to a standard analgesic regime, there was a significant reduction in mean IV morphine (36.3mg vs 9.9mg; p=0.006; Graph 1), and an increase in mean tramadol required (142.3mg vs 17.6mg; p<0.001), during the first 24 hours postoperatively. There were no differences in mean pain scores at rest or on movement observed between the goups (mean score 1.3 vs 1.4 respectively; p=0.72). Mean hospital stay was significantly reduced in the multimodal/TAP group compared to the standard analgesia group (3.4 vs 2.0 days respectively; p=0.002). There were no complications relating to the use of TAP blocks. Conclusions: This multimodal analgesic regime during robotic radical prostatectomy is seen to reduce postoperative morphine use, contribute to reduced hospital stay, and aid the enhanced recovery process. Future randomised controlled trials are required to evaluate the exact contribution TAP blocks can make to the enhanced recovery process in this surgical population.
1. John G. McDonnell, Brian O'Donnell et al.The Analgesic Efficacy of Transversus Abdominis Plane Block After Abdominal Surgery: A Prospective Randomized Controlled Trial. Anaesth Analg. 2007;104(1):193-197. 2. Conaghan P, Maxwell-Armstrong C, Bedforth N et al. Efficacy of transverses abdominis plane blocks in laparoscopic colorectal resections. Surg Endosc. 2010 Oct;24(10):2480-2484.
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A22 Title: Ambulatory Interscalene Block After Total Shoulder Arthroplasty Presenting Author: Jay Tokeshi MD Presenting Author's Institution: Oregon Health and Science University - Portland, OR Co-Authors: Matthew Abrahams MD - Oregon Health and Science University - Portland, OR Jean-Louis Horn MD - Oregon Health and Science University - Portland, OR
Abstract: Introduction: Total shoulder arthroplasty is a painful surgical procedure that usually requires a multiple day hospitalization for optimal pain control. Previous studies have shown that an interscalene nerve block provides superior analgesia, decreased opioid consumption, improved patient satisfaction, and decreased time to discharge readiness.1, 2 With the development of continuous nerve catheters and the advent of portable infusion pumps, at our institution total shoulder arthroplasty patients are scheduled to be discharged on postoperative day 1. However, to date, no study has reported the use of ambulatory continuous brachial plexus nerve blocks after total shoulder arthroplasty in a large series.
Methods: After institutional review board approval, the electronic medical records of all patients who underwent a total shoulder arthroplasty or hemiarthroplasty with a single surgeon from April 2008 to February 2011 were reviewed. Patients who underwent the procedure as a result of an acute trauma and ASA class 4 patients were excluded. Patient demographics including age, sex, and ASA class were recorded. In addition, discharge date and follow up notes by the surgeon and our adult pain service were reviewed for possible complications and to determine the reason for delayed discharge.
Results: One hundred forty eight records were reviewed. Fifteen patients were excluded based on our exclusion criteria. Average age of our patients was 64.9 ± 13, 71 were men and 62 were women, 2 were ASA class 1, 63 were ASA class 2, 62 were ASA class 3, and 6 were unclassified but based on history would likely have been ASA class 2 or 3. Three received a single shot interscalene nerve block, 7 patients had no regional anesthetic, and the rest received a continuous interscalene catheter. Sixty-seven patients (50.4%) were discharged on postoperative day 1, 37 (27.8%) on postoperative day 2, and 29 (21.8%) on postoperative day 3 or later. Of the 67 patients discharged on postoperative day 1, 3 received a single shot block and 2 received no regional anesthesia.
Conclusions: As we move towards a bundled payment reimbursement model it is increasingly necessary to determine when regional anesthesia can change the outcome and length of stay after surgery. Our experience has shown that patients undergoing a total shoulder arthroplasty can be successfully discharged early with an ambulatory continuous brachial plexus catheter. It is important to determine which patients undergoing a total shoulder arthroplasty are best suited for an ambulatory nerve block, barriers to discharge, and possible risks and complications.
References 1. Ilfeld B, et al. Anesth Analg. 2005;101:1319-1322. 2. Ilfeld B, et al. Anesthesiology. 2006;105:999-1007. 3. Ilfeld B, et al. Reg Anesth Pain Med. 2005;30:429-433. 4. Fredrickson M, Ball C, Dalgleish A. Reg Anesth Pain Med. 2008;33:122-128.
A23 Title: Continuous Paravertebral Catheters in Patients Who Underwent Minimally Invasive Cardiac Surgery: A Case Series Presenting Author: Johnny K Lee MD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Beverly Pearce-Smith M.D. - University of Pittsburgh Medical Center - Pittsburgh, PA Lawrence Wei MD - University of Pittsburgh - Pittsburgh, PA Jacques Chelly MD - University of Pittsburgh Medical Center - Pittsburgh, PA
Abstract: Introduction: Minimally invasive surgery is a relatively new approach to cardiac procedures done through several small thoractomy incisions. This is done in an effort to reduce the morbidity associated with cardiac procedures approached with a full sternotomy. In combination with the physiolgical benefits of regional anesthesia techniques during recovery, fast tracking surgical strategies may provide a benefit on surgical outcome (Carli, 2011). Paravertebral nerve block techniques have gained a recent resurgence in popularity as an effective mode of analgesia post thoracotomy. Paravertebrals may be just as effective as thoracic epidural analgesia and associated with fewer side effects and less incidence of devastating neurological complications (Davies, 2006). Recent meta-analyses demonstrated that thoracic paravertebrals may decrease pulmonary complications and facilitate earlier extubation (Joshi, 2008), (Lynch, 2010). We aim to describe a novel modality of postoperative pain control after minimally invasive cardiac surgery.
Methods: Following IRB approval, we performed a retrospective review of 11 patients who received continuous paravertebral catheters for postoperative analgesia undergoing minimally invasive maze, mitral valve replacement, or LIMA to LAD CABG procedures. All surgeries were performed by a single surgeon. Depending on the type of surgery, patients received preoperative bilateral or unilateral paravertebral continuous catheters at levels T3 or T4. Patients were given ropivacaine 0.5% bolus during the initial placement of the block. Infusate consisted of either lidocaine 0.25% or bupivacaine 0.0625%. Inclusion criteria include age greater than 18 - 85 years old, ASA physical status I-IV, who underwent a minimally invasive cardiac surgery (coronary artery bypass, mitroplasty, mitral valve repair, or maze procedure) under the care a single cardiothoracic surgeon, from the dates 9/1/2008 to 12/15/2010. Exclusion criteria included patients who have psychological disease, history of narcotic or substance abuse, on chronic anticoagulation, antiplatelet therapy within one week of the procedure, or had a contraindication to the surgery, paravertebral block, allergy or intolerance to local anesthetic, or women who were pregnant or post partum.
Results: Eleven patients were retrospectively studied (2 F/9 M). Median postoperative pain scores at 6, 12, 24, and 48 hrs were 3 (range 0-8, n= 9), 2.25 (0-6, n = 10), 2.5 (0-4, n = 8), and 2 (0-6, n=5), respectively. 5 of 9 patients were extubated in the OR. Median length of ICU stay was 1 day (1-7, n= 9).
Conclusions: Continuous paravertebral nerve blocks may be an effective and beneficial modality of postoperative pain control for minimally invasive cardiac surgery.
References 1. Reg Anesth Pain Med. 2011:36: 63-72 2. Br J Anaesth. 2006 Apr;96(4):418-26 3. Anesth Analg. 2008. Sep;107(3):1026-40 4. Semin Cardiothorac Vasc Anesth. 2010 Mar;14(1):47-8 A24 Title: Changes in anesthesia related factors in ambulatory knee and shoulder surgery: United States 1996-2006 Presenting Author: Pamela M Shaw BS Presenting Author's Institution: Hospital for Special Surgery - New York, NY Co-Authors: Cassie Kuo MD - Hospital for Special Surgery - New York, NY Yan Ma PhD - Hospital for Special Surgery - New York, NY Alison Edwards MStat - Weill Cornell Medical College - New York, NY Madhu Mazumdar PhD - Weill Cornell Medical College - New York, NY
Abstract: Background: Little nationally representative information is available on how changes in ambulatory orthopedic surgery have affected anesthesia practice over time.
Objectives: We sought to characterize temporal changes in factors surrounding ambulatory orthopedic surgery and anesthesia.
Methods: Data from the National Survey of Ambulatory Surgery for the years of 1996 and 2006 were analyzed. Entries indicating the performance of a knee ligamentoplasty, a meniscectomy or a shoulder arthroscopy were identified and included in the sample. Temporal changes in a number of variables associated with orthopedic ambulatory surgery were assessed, including: 1) the number of procedures being performed, 2) patient and health care system related demographics and 3) anesthesia related variables.
Results: Nationwide, the total number of ligamentoplasties, meniscectomies and shoulder arthroscopies increased from 1996 to 2006 by 66% (N=258,932 to N=428,712), 51% (N=456,698 to N=690,164), and 349% (N=93,105 to N=418,188) respectively (P<0.0001). Between 1996 and 2006 the use of peripheral nerve blocks increased from 0.6% to 9.8% for meniscectomies (P<0.0001), from 1.5% to 13.7% for ligamentoplasties (P<0.0001), and from 11.5% to 23.9% for shoulder arthroscopies (P<0.0001), respectively. Neuraxial anesthesia utilization fell from 11.8% to 6.3% for meniscectomies (P<0.0001) and 13.6% to 7.3% for ligamentoplasties (P<0.0001) from 1996 to 2006, respectively.
Conclusions: Substantial increases in the number of ambulatory knee and shoulder procedures occurred overtime, relating to increased demand for anesthesia providers in this field. Trends towards increased use of peripheral nerve blocks may have to be considered by educators when preparing residents for practice.
Additional File #1: 1022811134158Table_1.doc Click here to view
Table 1
Ligamentoplasty Meniscectomy Shoulder Arthroscopy Year 1996 2006 1996 2006 1996 2006 P-value P-value P-value Total N= 258,932 428,712 456,698 690,164 93,105 418,188 <15 1.1 1.6 <0.0001 0.7 0.2 <0.0001 0.1 0.1 0.4392 15-44 55.8 45.1 <0.0001 43.5 29.6 <0.0001 50.1 28.4 <0.0001 Age group 45-64 32.9 42.5 <0.0001 39.1 51.1 <0.0001 37.9 56.4 <0.0001 (%) 65-74 8.6 7.4 <0.0001 13.7 13.1 <0.0001 9.5 9.4 0.1102 >75 1.6 3.4 <0.0001 3.1 6.1 <0.0001 2.5 5.7 <0.0001
Gender Male 57.6 56.5 <0.0001 60.5 55.6 <0.0001 65.8 54.6 <0.0001 (%) Female 42.4 43.5 <0.0001 39.5 44.4 <0.0001 34.2 45.4 <0.0001 Private 70.1 73.2 <0.0001 67.9 69.0 <0.0001 68.1 68.8 <0.0001
Insurance Government 15.3 20.1 <0.0001 13.0 25.7 <0.0001 18.0 27.6 <0.0001 (%) Medicare 10.8 3.6 <0.0001 16.0 4.0 <0.0001 10.1 2.3 <0.0001 Other 3.8 3.1 <0.0001 3.2 1.4 <0.0001 3.9 1.4 <0.0001 Hospital 86.0 52.5 <0.0001 87.2 62.7 <0.0001 83.9 52.4 <0.0001 Facility Free Type (%) 14.0 47.5 <0.0001 12.8 37.3 <0.0001 16.1 47.6 <0.0001 Standing
Additional File #2: 2022811134158Table_2.doc Click here to view
Table 2
Ligamentoplasty Meniscectomy Shoulder Arthroscopy Year 1996 2006 1996 2006 1996 2006 P-value P-value P-value Total N= 258,932 428,712 456,698 690,164 93,105 418,188 53.2 56.4 Anesthesiologist 60.3 58.8 <0.0001 63.8 54.2 <0.0001 <0.0001 9.7 11.3 CRNA 11.5 14.6 <0.0001 11.4 15.9 <0.0001 <0.0001 Anesthesia 2.1 0.9 <0.0001 3.2 1.1 <0.0001 6.5 0.5 <0.0001 Provider (%) Other Physician 23.5 26.2 Anesthesiologist/CRNA 20.0 18.9 <0.0001 16.4 21.2 <0.0001 <0.0001 7.1 5.7 Other Combination 6.2 6.9 <0.0001 5.3 7.6 <0.0001 <0.0001 General 74.7 74.7 0.8417 75.1 71.9 <0.0001 84.8 86.9 <0.0001 Neuraxial 13.6 7.3 <0.0001 11.8 6.3 <0.0001 N/A N/A N/A Anesthesia IV sedation/MAC 11.3 17.6 <0.0001 11.9 20.8 <0.0001 6.7 11.6 <0.0001 Type (%) Peripheral Nerve Block 1.5 13.7 <0.0001 0.6 9.8 <0.0001 11.5 23.9 <0.0001 Topical 8.8 15.8 <0.0001 8.3 13.0 <0.0001 5.7 4.8 <0.0001 Other 3.4 4.3 <0.0001 2.2 3.7 <0.0001 3.0 4.2 <0.0001
A25 Title: Can a head-mounted display improve ergonomics in ultrasound-guided regional anesthesia? Presenting Author: Ankeet D Udani MD Presenting Author's Institution: Stanford University Medical Center - Stanford, CA Co-Authors: T. Kyle Harrison MD - Veterans Affairs Palo Alto Heath Care System - Palo Alto, CA Steven K Howard MD - Veterans Affairs Palo Alto Heath Care System - Palo Alto, CA T. Edward Kim MD - Veterans Affairs Palo Alto Heath Care System - Palo Alto, CA John G Brock-Utne MD, PhD - Stanford University Medical Center - Stanford, CA
Abstract: Background: The use of a head-mounted display (HMD) in clinical anesthesia has been described. The practice of ultrasound-guided regional anesthesia (USRA) requires positioning the ultrasound machine so that the operator can visualize the screen often in ergonomically-challenging environments. A HMD provides continuous, real-time, ultrasound imaging within the practioner‘s visual field. We tested the feasibility of using HMD technology to improve the ergonomics of USRA.
Methods: The clinical scenario of performing preoperative USRA with limited workspace was simulated using a pig hind-quarter with intact popliteal fossa and sciatic nerve on a gurney in an actual block room. A HMD (MicroOptical CV-3, MyVu, Wellesley, MA, USA) (Fig. 1) was connected to the S-video output of an ultrasound machine (MicroMaxx, Sonosite, Bothell, WA, USA) and positioned out of the practioner‘s procedural field. Two anesthesiologists (one expert and one novice in USRA) performed a total of 10 ultrasound-guided popliteal-sciatic nerve blocks. For each procedure, the sciatic nerve was visualized in short-axis with a 13-6 MHz linear transducer transmitted via HMD to the left eye piece (Fig. 2), an 18 gauge Tuohy-tip epidural needle (B. Braun, Bethlehem, PA, USA) was directed in-plane from lateral to medial toward the target nerve (Fig. 3), and injectate deposited around the nerve. An independent observer measured the number of times the practitioner‘s attention was directed away from the procedural field and overall block quality for each USRA procedural attempt.
Results: All 10 USRA procedures were successfully completed based on proper needle control and visualization and circumferential injectate spread around the sciatic nerve. Neither practitioner redirected his attention away from the procedural field to directly view the ultrasound monitor while performing any of the USRA procedures.
Conclusions: HMD technology allows for real-time, ultrasound image display in the practioner‘s procedural field independent of ultrasound machine placement. Within the constraints of a limited workspace and its challenging ergonomics, the functionality of an easy set-up and block performance may outweigh the additional cost and tethered nature of the HMD. This technology may also assist the novice practioner in proper needle and probe alignment which may be an additional benefit. Larger prospective studies are needed to quantify the ergonomic effects and potential educational benefits of HMD technology in USRA.
References 1) Anesth Analg. 2009;109:1135-1146. 2) Anesth Clin. 2008;26:681–692. 3) J Clin Anesth. 2009;21:253-257.
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A26 Title: Safety Associated with the Removal of Paravertebral Catheters in Trauma Patients Receiving Enoxaparin for Thromboprophylaxis Presenting Author: Brian Gierl MD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Emerson Conrad MD - UPMC - Pittsburgh, PA Louis Alarcon MD - UPMC - Pittsburgh, PA Jacques Chelly MD, PhD, MBA - UPMC - Pittsburgh, PA
Abstract: It is established that pulmonary embolism is the third-leading cause of death in trauma patients who survive the first day after trauma.1 Enoxaparin has been shown to be the thromboprophylaxis drug of choice in trauma patients.2 The use of regional anesthesia has been shown to decrease morbidity and mortality in this patient population. However, the most recent ASRA guidelines advise against the use of epidural anesthesia and cautioned on the use of paravertebral blocks in patients receiving enoxaparin.3 We previously reported our preliminary experience on the safety of paravertebral catheter placement and removal in patients with multiple rib fractures receiving enoxaparin without interruption over a 13 month period. This study expands upon the original finding.
Methods: The acute interventional perioperative pain IRB-approved database was searched for patients with rib fractures who benefited from continuous paravertebral blocks while receiving enoxaparin between January 1, 2005 and November 31, 2010. The time of the placement and removal of continuous paravertebral blocks, and the time of initiation of enoxaparin therapy and its duration were recorded along with any bleeding and/or hematoma associated with the removal of the catheter. In these patients, either one or two paravertebral block catheters (PBCs) (≤4 or >4 ribs fractured on the same side, respectively) were placed after review of the chest radiograph. Patients were positioned in either the sitting or in the lateral position. Next, the spinous processes were identified and an 18 G Tuohy needle was introduced 2.5 cm lateral to the midline in search of the transverse process. The needle was redirected and positioned 1 cm beyond the inferior border of the transverse process. Next, 5 ml of ropivacaine 0.5% was injected through the needle and the PBC threaded 4 cm beyond the needle's tip. The PBC was secured with a steri-strip and an additional 10 ml of ropivacaine 0.5% was injected through the catheter. Finally, the catheter was covered with a transparent dressing.
Results: During the study period 527 continuous PBCs were placed in 342 patients corresponding to 2120 catheter-days including 372 PBCs placed in 237 patients who received enoxaparin 30 mg SC BID. The PBCs remained in place for 4.1 ± 1.7 days range (0.2 – 11). Following the removal of the PBCs without dosing interruption no major bleeding and/or hematoma were recorded. One patient‘s PBC was removed after blood was aspirated from the catheter prior to initiating the anesthetic infusion. Two other reports included serosanguinous oozing and a localized cellulitis at the insertion site.
Discussion: These data support the concept that it is not necessary to withhold enoxaparin thromboprophylaxis prior to the removal of a ―deep‖ perineural catheter. This is also supported by our recent report on 3,588 orthopedic patients who received various types of thromboprophylaxis, including 916 patients who were receiving LMWH without dosing interruption while either a lumbar plexus or a sciatic catheter was being removed.5
References 1. Geerts, NEJM. 1994; 331:1601–1606. 2. Geerts, Chest. 2008; 133; 381-453. 3. Horlocker, Reg Anesth Pain Med. 2010;35(1):64-101. 4. Gierl & Chelly, Poster presention ASRA 2010. 5. Chelly, J Arthro. 2008; 23:350-354.
A27 Title: Creating Balanced DUID Policy for the Opioid Using Driver Presenting Author: Brian G. Wilhelmi MD, JD Presenting Author's Institution: Johns Hopkins Hospital - Baltimore, MD Co-Authors: Steven P. Cohen MD - Johns Hopkins Hospital - Baltimore, MD
Abstract: Introduction: Driving Under the Influence of Drugs (―DUID‖) is a phrase that is used to designate the action of driving an automobile following ingestion, inhalation, absorption, or injection of drugs or medications other than alcohol that could interfere with the driver‘s capacity to safely operate a vehicle. While many substances, both legal and illegal, may cause impairment when taken prior to driving, the ability of opioids to impair drivers creates a special challenge for policy makers, law enforcement, and the physicians who treat patients.
Methods: This presentation is based upon a literature review concerning the epidemiology of opioid use, abuse, and DUID, the psychomotor effects of opioids, and state policy concerning DUID.
Results: Since the early 1990's the use of opioid medication in acute and chronic pain management has skyrocketed as several studies have demonstrated clinical benefit and practice guidelines have changed accordingly. Concomitant with the rise of use has been a rise of abuse documented in increased numbers of opioid related emergency room admissions, poisonings, and drug related crime. DUID whereby opioid using drivers become involved in traffic accidents is a poorly studied topic which has recently become the subject of national press attention. Several government agencies have released recent reports detailing not only opioid abuse, but also the rise of opioid using drivers. Clinical studies involving the acute use of opioids demonstrate clear correlation with subjective experiences of feelings incompatible with driving such as "feeling high" and "floating" without necessarily experiencing objective impairment. However, chronic opioid uses appear to have a tolerance that prevents them from experiencing similar psychomotor impairment. State law concerning DUID involving opioids is very diverse and reflective of a subject that is uneducated by the medical community. These laws lead to ineffective prosecution and a diversity of potentially inappropriate outcomes.
Discussion: Enhancing scientific knowledge concerning opioid-induced psychomotor impairment is a priority for a nation with an opioid based strategy for acute and chronic pain control. The medical community that advocates for opioid usage must provide the legal community with evidence to strengthen DUID enforcement and prosecution or face continued uncertainty with traffic accidents. International groups of experts have begun to provide a roadmap for future research. Until this evidence has created a critical mass, the legal framework for DUID must be changed to include rules that provide for standardized roadside and toxicological assessment of drivers to provide further epidemiological data and certainty of legal outcome. By instituting this legislation now, a framework will be available for not only opioids, but the host of prescriptions drugs used by the driving public.
Conclusions: As the U.S. medical system attempts to reintegrate acute and chronic pain patients into society, success will be based partially on creating legislation to accommodate these individuals as part of the driving public.
Additional File #1: 1022811191748Exhibit_4.doc Click here to view Exhibit 4: Incidence of Opioid Use in Drivers Suspected of Driving Under the Influence Author Years Studied Population Number of Subjects % Positive for Opioids Appenzeller et al. 2005i 2001-2002 Drivers suspected of Driving Under the 210 1% Influence in Luxembourg Augsburger et al. 2005ii 2002-2003 Drivers suspected of Driving Under the 440 16% Influence in France Christophersen et al. 1996 Drivers suspected of Driving Under the Norway = 140 Norway = 6% 1999iii Influence in Norway, Denmark, Finland, Iceland, Denmark = 255 Denmark = 1% Sweden Finland = 270 Finland = 0% Iceland = 40 Iceland = 0.25% Sweden = 86 Sweden = 5% Fitzpatrick et al. 2006iv Unspecified Drivers suspected of Driving Under the 2,000 7.5% Influence in Ireland Jones et al. 2007v 2004-2005 Drivers arrested for DUID in Sweden 14,811 12% Ojaniemi et al. 2009vi Drivers suspected of Driving Under the 31,963 13.8% Influence in Finland Palmentier et al. 2009vii 2001-2005 Drivers suspected of Driving Under the 42 16% Influence in Ontario Senna et al. 2010viii 2005 Cases of DUID submitted for toxicological 4,794 15% testing Smink et al. 2001ix 1995-1998 Drivers suspected of Driving Under the 1665 17.4% Influence in The Netherlands Toth et al. 2009x 2000-2007 Drivers suspected of Driving Under the 1740 12% Influence in Hungary
i Brice Appenzeller et al., Drugs and Chronic Alcohol Abuse in Drivers, 155 Forensic Science International 83-90 (2005). ii Marc Augsburger et al., Concentration of Drugs in Blood of Suspected Impaired Drivers, 153 Forensic Science International 11-15 (2005). iii A.S. Christophersen et al., Drugged Driving in the Nordic Countries – A Comparative Study Between Five Countries, 106 Forensic Science International 173-190 (1999). iv P. Fitzpatrick et al., Drinking, Drugs and Driving in Ireland: More Evidence for Action, 12 Injury Prevention 404-408 (2010). v A.W. Jones et al., Concentrations of Scheduled Prescription Drugs in Blood of Impaired Drivers: Considerations for Interpreting the Results, 29(2) Therapeutic Drug Monitoring 248-260 (2007). vi Karoliina K. Ojaniemi et al., Trends in Driving Under the Influence of Drugs: A Register-Based Study of DUID Suspects During 1977-2007, 41 Accident Analysis and Prevention, 191-196. vii J-P.F.P. Palmentier et al., Alcohol and Drugs in Suspected Impaired Drivers in Ontario from 2001 to 2005, 16 Journal of Forensic and Legal Medicine 444-448 (2009). viii Maria-Cristina Senna et al., First Nationwide Study on Driving Under the Influence of Drugs in Switzerland, 198 Forensic Science International 11-16 (2010). ix B.E. Smink et al., Driving Under the Influence of Alcohol and/or Drugs in the Netherlands 1995-1998 in View of the German and Belgian Legislation, 120 Forensic Science International 195-203 (2001). x Anita R. Toth et al., The Role of Licit and Illicit Drugs in Traffic (Hungary 2000-2007), 11 Legal Medicine S419-S422 (2009).
Additional File #2: 2022811191748EXHIBIT_6.doc Click here to view
EXHIBIT 6: Acute Effects of Opioids on Non-Drug Abusing Volunteers as Measured by Subjective Reports on a Visual Analog Scale Difficulty Drug Dose Coasting High Concentrating Sleepy Dizzy Placeboi Lactose Tabs 13.6 7.3 12.4 27.4 3.6 Morphineii 30 mg 22.2 19.5 23.4 36.5 17.6 40 mg 32.8 31.8 33.7 58.1 23.2 60 mg 42.1 22.0 41.8 78.0 39.4 Hydrocodone/Aceta 5 mg/500 mg 12.3 4.4 17.8 33.4 7.3 iii minophen 10 mg/500 mg 16.2 14.9 26.0 37.6 11.6 20 mg/1000 mg 33.4 24.6 39.8 59.9 24.8 Oxycodoneiv 10 mg 24.8 25.1 28.3 59.6 18.9 20 mg 31.3 41.0 39.3 68.3 32.3 30 mg 39.1 51.9 50.2 70.8 38.3 Acetaminophenv 1000 mg 11.3 2.3 15.5 36.0 1.7
i James Zacny and Sandra Gutierrez, Characterizing the subjective, psychomotor, and physiological Effects of Oral Oxycodone in Non-Drug Abusing Volunteers 170 Psychopharmacology 242-254 (2003). ii James P. Zacny et al., supra at 51; James Zacny and SA Lichtor, Within-subject comparison of the psychopharmacological profiles of oral oxycodone and oral morphine in non-drug abusing volunteers, 196(1) Psychopharmacology 105-116 (2008). iii James P. Zacny et al., supra at 51. iv James Zacny and Sandra Gutierrez, Characterizing the subjective, psychomotor, and physiological Effects of Oral Oxycodone in Non-Drug Abusing Volunteers 170 Psychopharmacology 242-254 (2003). v James P. Zacny et al., supra at 51.
Additional File #3: 3022811191748EXHIBIT_9.doc Click here to view
EXHIBIT 9: Standard Of Impairment Used for DUID Conviction ―Incapacity‖ AL, AR, IL, KS, NV, MD, NM, ND, OK, PA, SD, VT, WI, WY ―Impaired‖ AZ, FL, HI, IN, KY, MT, SC, VA, NY* ―Per Se‖ Any Amount of Prohibited Drug AZ, DE, GA, IN, MN, PA, UT or Any Amount of Prohibited Drug Metabolite ―Per Se‖ Any Amount of Prohibited Drug IL, IA, MI, RI, WI ―Per Se‖ A Specified Amount of Prohibited NV, OH, VA Drug ―Per Se‖ Any Amount of Prohibited Drug NC, SD when Under 21 years old ―Not Having Normal Use of Mental or TX Physical Faculties‖
A28 Title: The Risk of Neurologic Complications Following Chlorhexidine Antisepsis for Spinal Anesthesia Presenting Author: Hans P Sviggum MD Presenting Author's Institution: Mayo Clinic – Rochester, MN Co-Authors: Katherine W Arendt M.D. - Mayo Clinic - Rochester, MN Adam K Jacob M.D. - Mayo Clinic - Rochester, MN Michelle L Mauermann M.D. - Mayo Clinic - Rochester, MN Terese T Horlocker M.D. - Mayo Clinic - Rochester, MN
Abstract: Introduction: Chlorhexidine is a commonly-used antiseptic solution that has several advantages over other antiseptic agents.(1) However, chlorhexidine is not FDA approved for use prior to lumbar puncture due to an absence of clinical evidence. Historical animal studies have demonstrated an association between chlorhexidine and neurotoxicity.(2) The incidence of neurologic complications (NC) following spinal anesthesia (SA) is low, with an estimated incidence of 0.005% to 0.13%.(3) However, previous studies have not controlled for type of skin antisepsis. Currently, there is no information available on the neurotoxic risk associated with chlorhexidine skin antisepsis for SA in clinical practice. The objective of this retrospective cohort study was to test the hypothesis that the incidence NC after SA and chlorhexidine skin antisepsis is not different than the overall incidence of NC after SA previously reported in the literature.
Methods: All patients aged ≥ 18 years who underwent SA at Mayo Clinic Rochester from January 2006 to November 2010 were retrospectively identified. Data including patient demographics, type of surgical procedure, regional technique (including needle type, level of insertion, medications, complications), and postoperative outcomes (including neurologic complications) were collected. The primary outcome variable was the presence of any new or progressive NC documented within 7 days of SA. Neurologic complications were confirmed by chart review and followed until resolution. The likelihood of SA contributing to the patient‘s NC was independently categorized as likely, unlikely, or possible by 3 assigned investigators (including one neurologist). Consensus among all reviewers was required for final category assignment. The frequency of NC was summarized using point estimates along with 95% confidence intervals (CI).
Results: A total of 11,095 patients received 12,495 SA during the study period. All patients received 2% chlorhexidine gluconate plus 70% isopropyl alcohol (ChloraPrep®) for skin antisepsis prior to SA. Overall, 57 cases (0.46%, 95% CI 0.34% to 0.58%) met criteria for NC (any type of deficit). After independent review, none of the NC were thought to be likely associated with the SA. Five NC (0.04%, 95% CI 0.00% to 0.08%) were possibly associated with the SA. All neurologic deficits possibly associated with SA completely resolved within 30 days.
Discussion: The overall incidence of NC (0.46%) after SA was higher than reported in previous studies. However, the majority of NC were peripheral nerve injuries. No cases of NC were likely associated with SA; and 0.04% of NC cases were possibly associated to SA. This incidence is no different than previously reported rates of NC after SA without attention to skin antisepsis. These results support the hypothesis that chlorhexidine can be used for skin antisepsis in patients undergoing SA without increasing the risk for NC attributed to the SA.
References 1. Hebl J. Reg Anes Pain Med. 2006;31:311-323. 2. Henschen A et al. Acta Neuropathol. 1984;63:18-23. 3. Brull R et al. Anesth Analg. 2007;104:965-974.
A29 Title: Ultrasound (US) Simulation of Phantom Femoral Nerve Blockade (FNB) Decreases Time to Perform a FNB Presenting Author: Imanuel R Lerman MD, MS Presenting Author's Institution: Yale New Haven Hospital - New Haven, CT Co-Authors: Dmitri Souzdalnitski MD/PhD - Cleveland Clinic - Cleveland, OH Dallen Mill MD - Yale New Haven Hospital - New Haven, CT Feng Dai PhD - Yale New Haven Hospital - New Haven , CT Kevan Stanton MD - Yale New Haven Hospital - New Haven , CT
Abstract: Ultrasound guidance (USG) techniques are relatively new and a rapidly developing field in both pain medicine and regional anesthesia. Performing USG procedures can be a challenging new skill for trainees (1,2). US simulation permits the novice to become more comfortable with USG procedures, US equipment and needle manipulation.
An anatomically-correct, high-fidelity US simulator phantom has been developed for FNB practice that is capable of providing real-time feedback upon completion of successful simulated femoral nerve contact. Feedback is comprised of visual (LED light) and audio (piezoelectric buzzer [PBZ]) when a trainee completes an accurate successful simulated nerve block (Figure 1). We hypothesized that the LED and PBZ feedback would improve a trainee‘s ability to perform an accurate FNB.
To test the hypothesis, 30 subjects comprised of medical students and residents were enrolled and placed in one of three groups: LED and PBZ feedback (F), voice feedback alone (V), and no feedback (N). All three groups performed two separate FNB ultrasound simulation sessions five to seven days apart. Each FNB simulation session was comprised of ten timed FNB trials. Upon completion of simulated successful femoral nerve contact, group F was alerted by a green light LED and audio buzz of the PBZ. Group V was notified by a preceptor‘s voice when they had completed successful simulated nerve contact. Group N was instructed to perform a simulated FNB and to cease needle pass attempts based on whether or not the subject thought they had completed simulated nerve contact. The time (in seconds) of each successful femoral nerve contact was recorded with WINDAQ software that translated and exported the voltage recordings into a Microsoft Excel document.
The data was analyzed by fitting a fixed-effects model using the linear mixed- effects models (MIXED) procedure in PASW Statistics 18 software, in which group, session and group*session effected were specified as covariates with a diagonal variance-covariance matrix and repeated measures was assumed.
All three groups decreased the time necessary to carry out the FNB simulation between the first and second sessions (p < 0.005, Table 1). Group F exhibited an estimated simulation FNB mean time (± standard error) to completion of 12.75±0.33 seconds for session one and 8.62±0.31 seconds for session two, compared to Group V which exhibited a FNB mean time to completion of 13.03±0.25 seconds for trial one and 11.82± 0.34 seconds for trial two, while Group N exhibited a FNB mean time to completion of 15.64±0.13 seconds for session one and 14.00±0.29 seconds for session two (Table 2). The mean difference (± standard error) between trial one and two for group F was -4.13±0.46 seconds compared to group V with a mean difference of -1.21±0.42 seconds and for group N a mean difference of -1.64±0.32 seconds (Table 1). The mean difference among all groups was significantly different (p < 0.001 ,Table 3).
Feedback based USG simulation significantly decreased the time needed to carry out the simulated FNB procedure and demonstrated the greatest mean difference between each session. Practice application of a feedback based US simulation curriculum may significantly facilitate learning of USG techniques.
Additional File #1: 1022811192309Figure_1.pdf Click here to view
Additional File #2: 2022811192309Table_1_3.pdf Click here to view
Table 1. Table 2.
A30 Title: Ultrasound-Guided Intra-articular Corticosteroid Injections with Fluoroscopic Confirmation for the Treatment of Hip Osteoarthritis Presenting Author: Michael D Danko MD Presenting Author's Institution: University of Cincinnati - Cincinnati, OH Co-Authors: James Bruns MD - University of Cincinnati - Cincinnati, OH Hammam Akbik MD - University of Cincinnati - Cincinnati, OH
Abstract: Background: Intra-articular corticosteroid injections are a common modality in the treatment of osteoarthritis for patients that have failed more conservative management options. The most common method for confirming intra-articular placement is with fluoroscopy. The following two cases detail the use of ultrasound guidance for the injection of corticosteroids into the hip joint to treat osteoarthritis.
Case Report: The first patient was a 41-year-old man with lumbar degenerative disk disease and left hip osteoarthritis that resulted in low back and hip pain. His previously treatment modalities, which included nonsteroidal anti-inflammatory drugs, opioids, physical therapy, epidural and lumbar facet injections, had not provided sustainable relief. A corticosteroid hip injection was performed as a diagnostic and therapeutic measure to treat the patient‘s hip pain.
The second patient was a 76-year-old man with long-standing osteoarthritis who had also failed conventional therapy. In addition, this patient had recently been treated with a series of lower back procedures, including lumbar epidural steroid injection, medial branch block, and radiofrequency ablation, for the treatment of post-laminectomy syndrome. The patient had good relief of his low back pain, but had persistent hip pain, for which bilateral corticosteroid hip injections were performed.
Both procedures used identical methodology. The patients were placed in the supine position, and the anterior aspect of the hip joint was scanned with a SonoSite low frequency, curved ultrasound probe at a depth setting of 6.5 cm. Under direct ultrasound guidance, the femoral head-neck junction was visualized with the overlying hip joint capsule and a 22G, 3.5‖ spinal needle was used to access the joint space. After negative aspiration, the position of the needle was then confirmed with fluoroscopy using contrast dye. Finally, a combination of 80mg of methylprednisolone and 5 ml of 0.25% bupivacaine was injected into the joint without complication.
Discussion: Image guidance is recommended for intra-articular hip injections due to the depth of the joint and surrounding neurovascular structures[1]. Fluoroscopically-guided injection has been the standard technique for this procedure to date. We believe that ultrasound can replace fluoroscopy as the standard image guidance technique for intra-articular hip injections by offering comparable efficacy[2] with notable clinical advantages. Ultrasound does not produce ionizing radiation or require contrast dye. It provides better imaging of soft tissue structures, especially the surrounding nerves and blood vessels[3]. In addition, ultrasound enables continuous visualization during needle placement and injection of medication. Ultrasound is also more cost-effective and portable than fluoroscopy.
References 1. Smith J. Office-based ultrasound-guided intra-articular hip injection: technique for physiatric practice. Arch Phys Med Rehabil. 2006;87:296-298. 2. Micu M. Steroid injection for hip osteoarthritis: efficacy under ultrasound guidance. Rheum. 2010;49(8):1490-1494. 3. Peng P. Ultrasound-guided interventional procedures in pain medicine: a review of anatomy, sonoanatomy, & procedures. Reg Anesth Pain Med. 2009;34:458-474.
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A31 Title: Can Hypotension from Intrathecal Ropivacaine for Cesarean Section (C/S) be prevented with 6% Hetastarch more effectively than Prophylactic IV Ephedrine ? Presenting Author: Akwasi P Amponsah MD Presenting Author's Institution: UMDNJ- Robert Wood Johnson Medical School - New Brunswick, NJ Co-Authors: Shaul Cohen MD - Robert Wood Johnson Medical School - New Brunswick, NJ Sarah Lasalle DO - Robert Wood Johnson Medical School - New Brunswick, NJ Shruti Shah MD - Robert Wood Johnson Medical School - New Brunswick, NJ Wendy Daley MD - Robert Wood Johnson Medical School - New Brunswick, NJ
Abstract: Introduction: The use of prophylactic IV Ephedrine or 6% Hetastarch is effective for prevention of hypotension from spinal anesthesia for cesarean section (C/S) when compared with lactated Ringer's solution (LR) alone. This study was designed to determine which treatment is the most effective for the prevention of hypotension from combined spinal-epidural (CSE) anesthesia for C/S: IV LR, IV 6% Hetastarch, IV ephedrine or IV 6% Hetastarch with IV ephedrine.
Methods: Following IRB approval & informed consent 244 parturients scheduled for elective C/S with CSE were studied. In all patients, the epidural space was located at L4-5 or L3-4 interspaces using epidural needle in lateral decubitus position. The epidural catheter was inserted immediately following administration of 10 mg ropivacaine with 100 mcg epinephrine and 25 mcg fentanyl intrathecally. The patients were randomized into 4 groups: GI (n=60) received IV 2L LR prior to induction of spinal anesthesia, GII (n=66), received IV 1L LR & upon the spinal injection, received IV ephedrine 30 mg for 15 min, GIII (n=57) received IV 500 ml 6% Hetastarch + 1L LR prior to spinal injection, GIV (n=61) received IV 500 ml 6% Hetastarch + 1L LR prior to spinal injection, and upon the spinal injection also received IV ephedrine 30mg for 15 min. Immediately after the spinal induction, the patients were positioned supine with left uterine displacement. BP was measured with automatic BP device every 2 min for the duration of the surgery. Hypotension was defined as a systolic BP (SBP) < 100 mm Hg & < 80% of the baseline BP. Hypotension was treated with IV boluses of ephedrine 5 mg q2 min. Reactive hypertension was defined as an increase in SBP > 20% above baseline. None of the patients needed General Anesthesia in any groups.
Results: There were no significant difference in demographics, efficacy of blocks, and nausea and vomiting among the groups. Hypotension and hypotension requiring treatment were higher for group I when compared with groups II-IV (p<0.02). Patients in all four groups were satisfied with the treatment.
Conclusions: IV prophylactic ephedrine is much cheaper and is as effective as 6% Hetastarch for the treatment of hypotension from intrathecal ropivacaine for C/S. The cost of: 1L LR is $14.31, 1 Amp ephedrine (50mg/ml) is $24.30, & 500 ml 6% Hetastarch is $294.34 (average wholesale prices per "The Red Book" 2008)
Additional File #1: 1011811134924table1_ephed_v_heta
Table 1
Group I Group II Group III Group IV
Age (yrs) 32 5 31 6* 32. 6 33 5
Weight (lbs) 180 38.0 181 40 180 41 181 41
Height (In) 63 9 64 2.5 63 2.6 64 2.3
Parity (n) Primi (%) 14(23) 13 (20) 20 (35) 11 (18)
Parity (n) Multi (%) 46 53 37 50
Efiicacy (n)1 (%) 55(92) 61 (92) 54 (95) 58(95)
Efiicacy 2 (uncomfortable) 1(2) 3(5) 1(2) 2(3)
Efficacy 3 (sedation) 3 (5) 2 (3) 2 (4) 1 (2)
Nausea (Rx) 19(32) 13(20) 16(29) 28 (46)
Vomiting 9(16) 16 (25) 6(11) 16(26)
Hypotension 26(44)** 10(16) 15(27) 13(22)
Hypotension Rx (IV Ephedrine bolus) 24(40)*** 8(13) 9(16) 10(17)
Overall Satisfaction 9.6 1.0 9.8 0.6 9.6 0.8 9.6 0.9
* II < IV, P< 0.004, ** I>II, III>IV ,P< 0.02,*** I >II, III & IV, P <0.001
A32 Title: Quantifying Cardiovascular Risks in Patients with Metabolic Syndrome undergoing Total Joint Arthroplasty Presenting Author: Eric Schwenk MD Presenting Author's Institution: Jefferson Medical College - Philadelphia, PA Co-Authors: Kishor Gandhi MD, MPH - Jefferson Medical College - Philadelphia, PA Javad Parvizi MD - Rothman Institute - Philadelphia, PA Eugene Viscusi MD - Jefferson Medical College - Philadelphia, PA
Abstract: Background: The coexistence of diabetes, hypertension, obesity, and dyslipidemia is defined as metabolic syndrome. The World Health Organization (WHO) and the National Cholesterol Education Program/ATP III have developed guidelines to define the syndrome. A previous study by the authors determined that there was a significant difference in the occurrence of postoperative cardiovascular complications after total joint arthroplasty between patients with and without metabolic syndrome (1). The purpose of this study is to examine each component of the metabolic syndrome and its impact on cardiovascular complications.
Methods: Following IRB approval of this retrospective study, the sample for this analysis (n=8517) consisted of all patients who underwent primary hip and knee surgeries between January 2004 and June 2007. Patient information was gathered in a database with local and systemic complications. The past medical history of these patients was extracted from the preoperative clearance office and medical records at a tertiary care academic university hospital. A modified definition of the metabolic syndrome was developed based on ATP III guidelines. Metabolic syndrome was defined by the presence of three of the four following criteria: Obesity (BMI≥30), Diabetes, Hypertension, or Dyslipidemia. Bivariate and multivariate analyses were conducted to compare patients with and without metabolic syndrome. Primary outcome measured was the occurrence of any postoperative cardiovascular complications (myocardial infarctions, arrhythmias, CHF, DVT, and PE's) after adjusting for potential confounders (age, gender, race, smoking status, presence of metabolic syndrome). Patients, with and without metabolic syndrome, undergoing total joint arthroplasty (TJA) during a three-year period were analyzed for postoperative complications. The risks of multiple comorbidities from metabolic syndrome on complications were analyzed with multivariate analysis.
Results: Of the 8517 patients, 1132 patients met the criteria for metabolic syndrome (Table 1). Patients with metabolic syndrome had significantly higher risk of cardiovascular complications compared to controls (p = 0.017, OR=1.64, CI: 1.09-2.46) (Table 2). The risk of an adverse event increased by 29% and 32%, respectively, when there were 3 or 4 syndrome components (Table 3).
Discussion: Patients with metabolic syndrome undergoing TJA have increased risk for cardiovascular complications. Regression modeling showed the risks of post- operative cardiovascular events to be significantly increased when either 3 (OR = 1.58, CI: 1.03-2.41) or 4 (OR = 1.64, CI: 1.09-2.46) of the comorbidities are combined. Metabolic syndrome may serve as a screening tool to allow better utilization of limited healthcare resources and enable implementation of strategies that optimize these patients and can minimize these untoward complications.
References 1. Gandhi et al. Anesthesiology. 2007; 107:A1425.
Additional File #1: 1011311154859Table_1___ASRA.doc Click here to view
Table 1: Preoperative Demographics of Patients with and without Metabolic Syndrome in the Study Population
All Patients Patients without Patients with P [n = 4132] Metabolic Syndrome Metabolic value [n = 3000] Syndrome
[n = 1132]
Mean Age 64.4 + 11.8 64.07 + 12.8 65.23 + 8.8 0.006
Sex 0.169
Females 2373 1749 (73.7) 625 (26.3)
Males 1758 1251 (71.2) 507 (28.8)
Race 0.001
White 3142 2316 (73.7) 826 (26.3) Black 456 282 (69.1) 174 (30.9)
Other 534 402 (72.6) 132 (27.4)
Smokers 0.311
No 4101 2980 (72.7) 1121 (27.3)
Yes 31 20 (64.5) 11 (35.5)
Surgical Data
Hips
Knees 2148 1713 (79.7) 435 (20.3) <0.001
1984 1287 (64.9) 697 (35.1)
Hips
Primary
Revisions 1858 1456 (78.4) 402 (21.6) <0.001
290 257 (88.6) 33 (11.4)
Unilateral
Bilateral 2046 1632 (79.8) 414 (20.2) 0.931
102 81 (79.4) 21 (20.6)
Operative time 109.28 107.53 115.49 0.259
Knees
Primary
Revision 1837 1195 (65.1) 642 (34.9) 0.547
147 92 (62.6 55 (37.4) Unilateral
Bilateral 1655 1049 (63.4) 606 (36.6) 0.002 329 238 (72.3) 91 (27.7)
Operative time 124.70 124.18 125.69 0.693
Numbers in brackets are percentages.
Additional File #2: 2011911154910Table_2___ASRA.doc Click here to view
Table 2: Logistic Regression Model
P value and odds ratio based on logistic regression model adjusting for age, sex, race, surgery type (hips vs. knees, primary vs. revision, unilateral vs. bilateral), operating room time, and co- morbidities (CAD, CHF, cerebrovascular disease, and coagulopathies).
Variables in the Equation
95% C.I.for OR Odds B S.E. Wald df Sig. Ratio Lower Upper
Step 1 Age .053 .010 27.633 1 .000 1.054 1.034 1.075
Gender .235 .203 1.352 1 .245 1.265 .851 1.882
Race -.143 .242 .349 1 .555 .867 .540 1.392
Primary Vs Revision .602 .409 2.169 1 .141 1.826 .819 4.069
Type of Surgery .351 .220 2.555 1 .110 1.421 .924 2.187
Unilateral/Bilateral joint .616 .348 3.140 1 .076 1.852 .937 3.661
O.R. Time .000 .003 .013 1 .910 1.000 .994 1.006
Cerebrovascular disease -.955 .729 1.715 1 .190 .385 .092 1.607
Coagulopathies .205 1.040 .039 1 .844 1.227 .160 9.413
Congestive Heart Failure .854 .498 2.936 1 .087 2.349 .884 6.240
Coronary Artery Disease -.205 .293 .490 1 .484 .815 .459 1.446
Metabolic Syndrome .494 .207 5.688 1 .017 1.638 1.092 2.457
Constant -7.380 .810 82.944 1 .000 .001
Additional File #3: 3011911154910Table_3___ASRA.doc Click here to view
Table 3: Frequency of Patients with Metabolic Syndrome Components (obesity, dyslipidemia, diabetes or hypertension) and Incremental Increase in Cardiovascular Risk with Each Component.
Metabolic Syndrome Frequency Odds Ratio [95% C.I.] Components n = 4132
0 1020 (24.7) 0.806 [0.484-1.34]
1 1206 (29.3) 0.624 [0.392-0.992]
Dyslipidemia 131 (3.2) 0.270 [0.370-1.97]
Obesity 607 (14.7) 1.03 [0.583-1.83]
Diabetes 11 (0.3) -
HTN 457 (11.1) 0.480 [0.229-1.00]
2 774 (18.7) 1.12 [0.695-1.795]
Dyslipidemia & Obesity 62 (1.5) 1.35 [0.319-5.70]
Dyslipidemia & HTN 195 (4.7) 0.822 [0.325-2.8]
Dyslipidemia & Diabetes 16 (0.4) -
Obesity & HTN 416 (10.1) 1.48 [0.827-2.66]
Obesity & Diabetes 36 (0.9) 0.742 [0.095-5.79]
HTN & Diabetes 49 (1.2) 0.524 [0.070-3.95]
3 897 (21.7) 1.58 [1.03-2.41]
Dyslipidemia, Obesity, & HTN 489 (11.8) 1.48 [0.873-2.50]
Dyslipidemia, Obesity, & DM 26 (0.6) 1.5 [0.194-11.6] Dyslipidemia, HTN, & DM 105 (2.5) 1.5 [0.583-3.83]
Obesity, HTN, & DM 277 (6.7) 1.36 [0.702-2.62]
3 or 4 Risk Factors
Metabolic Syndrome 1132 (27.4) 1.64 [1.09-2.46]
Numbers in brackets present the percentages
A33 Title: Re-engineering Patient Controlled Analgesia to Improve Pain Control and Patient Outcomes Presenting Author: Lance Patak MD, MBA Presenting Author's Institution: University of Michigan - Ann Arbor, MI Co-Authors: Sunavo Dasgupta MD - University of Michigan - Ann Arbor, MI Alan Tait PhD - University of Michigan - Ann Arbor, MI Chad Brummett MD - University of Michigan - Ann Arbor, MI
Abstract: Background: Inadequate pain relief may delay surgical recovery, increase length of stay and readmissions, decrease patient satisfaction, and increase health care costs. Increased anxiety has been reported to be the most important psychological factor affecting PCA use and is associated with more frequent unsuccessful demand doses during the lockout period and higher pain scores (1). A lack of knowledge and understanding regarding how the PCA device works also contributes to poor efficacy of a PCA (2). However, in one study, providing detailed PCA information to patients pre-operatively did not improve their experiences with PCA (3). It is therefore important to identify which factors contribute to increased anxiety and decreased understanding. The aims of this study are to identify which PCA attributes contribute to negative experiences for adult patients and how new design features might improve pain control.
Methods: Inclusion criteria: adult patients ≥ 18 years, PCA used for postoperative pain with 24-hour minimum use. Exclusion criteria: non-English speaking, history of chronic pain, quadriplegic patients. Eligible patients were randomized to one of two categories: 1) current PCA use or 2) PCA discontinued within 24 hours. After verbal consent, each subject completed a 17-item survey. A combination of yes and no, open-ended and Likert scale questions addressed patient satisfaction with pain control, understanding of how to use the PCA pump and any reported difficulties. Other questions elicited information regarding management of the lockout period and evaluation of new PCA design features. Based on an estimated 1250 eligible patients seen at our institution and using standard survey methodology, we determined that a sample of 474 subjects would be required to provide a representative sample of the target population.
Results: Of the 109 patients surveyed thus far, 25% were unsatisfied with their pain control; and of these, 70% felt they were unable to control their pain and 56% reported difficulties using the PCA pump. Sixteen percent of patients reported not knowing if the pump would deliver medicine when they pushed the button; and of these, 44% reported that this uncertainty made their pain worse. Being unable to tell if medicine was being delivered and having to watch the clock were the most common reported difficulties. The majority of patients preferred at least one of the new PCA design features: having a light on the button (49%) or having the cable light up (36%) to make it easier to find, having the button vibrate (46%) or having the button light up (56%) when the pump was ready to give more medicine.
Conclusions: Whereas 75% of patients surveyed to date appear satisfied with their current PCA, when presented with alternative PCA designs to improve communication and feedback, the majority indicated that they preferred the modified PCA. Given that certain attributes of the current PCA technology may negatively impact patient outcomes, it behooves the pain community to develop innovative strategies to optimize the effectiveness of this important pain modality.
Future Directions: Recruitment will continue to satisfy the power analysis. A prototype with new PCA features has been engineered (Figure 1), which we plan to study.
Additional File #1: 1020211142952Patak_ASRA_PCA_Refe.doc Click here to view
References:
1. Perry, F., Parker, R. K., White, P. F., & Clifford, P. A. (1994). Role of psychological factors in postoperative pain control and recovery with patient- controlled analgesia. The Clinical Journal of Pain, 10(1), 57-63; discussion 82-5. 2. Chumbley, G. M., Hall, G. M., & Salmon, P. (2002). Patient-controlled analgesia: What information does the patient want? Journal of Advanced Nursing, 39(5), 459-471. 3. Chumbley, G. M., Ward, L., Hall, G. M., & Salmon, P. (2004). Pre-operative information and patient-controlled analgesia: Much ado about nothing. Anaesthesia, 59(4), 354-358.
Disclosure: The University of Michigan has filed for a patent covering the subject matter of this abstract. Drs. Patak, Dasgupta and Brummett are listed among the inventors for this patent.
Additional File #2: 2020811113436Patak_PCA_Figure_1.doc Click here to view
Re-engineering Patient Controlled Analgesia to Improve Pain Control and Patient Outcomes
The University of Michigan prototype handset incorporates an LCD screen to effectively communicate pump status (e.g. in lockout, medication availability) and offer pain assessment questions (Figure 1) to the patient which enable auto titration of pain medication.
“Is your pain control satisfactory?”
Ye No s
Do Check CO2 and
nothing vitals, No Ye
Is increase s
“Your medicine cannot safe? “Would you like be increased, would more pain you like to speak to a medication?” nurse?” Ye No No Ye s s Do Page Titrate down nothing Nurse lockout period or titrate up bolus size if PCA HANDSET IS DESIGNED TO FIT INTO “Would you like to THE PALM OF YOUR HAND. speak with a nurse?” lockout at minimum No Ye ―Your medication s has been increased‖ Do Page nothing Nurse
FIGURE 1: PROTOTYPE HANDSET WITH LIGHT UP CABLE AND LCD SCREEN (RIGHT) FOR EASY IDENTIFICATION WITH INTERACTIVE ALGORITHM (LEFT) DEVELOPED IN COLLABORATION WITH THE UNIVERSITY OF MICHIGAN DEPARTMENT OF ANESTHESIOLOGY AND SCHOOL OF ENGINEERING.
Study %
ID WMD (95% CI) Weight
Hirst (1996) 0.40 (-1.83, 2.63) 11.78
Zaric (2004) -1.50 (-3.15, 0.15) 14.39
Watson (2005) 0.00 (-3.83, 3.83) 6.62
Cuignet (2005) -1.00 (-1.57, -0.43) 18.81
Capdevila (2006) -1.30 (-2.56, -0.04) 16.20
Mariano (2009) -5.20 (-6.62, -3.78) 15.47
Fredrickson (2010) -2.00 (-3.14, -0.86) 16.72
Overall (I-squared = 82.0%, p = 0.000) -1.71 (-2.92, -0.50) 100.00
NOTE: Weights are from random effects analysis
-6.62 0 6.62
d. POD 3 combined analysis of VAS pain scores for worst pain, pain with movement, and worst pain with movement, catheter vs. single injection.
A34 Title: The Safety Evaluation of DepoFoam® Encapsulated Bupivacaine Administered by Epidural Nerve Block in Rats and Dogs Presenting Author: Brigitte M Richard PhD Presenting Author's Institution: Pacira Pharmaceuticals, Inc - San Diego, CA Co-Authors: Laura R Ott BS, LAT - MPI Research - Mattawan, MI Robert C Switzer PhD - NeuroScience Associates - Knoxville, TN Daryl C Thake D.V.M., Dipl. ACVP - Midwest ToxPath Sciences, Inc. - Chesterfield, MO Dean Haan BS - MPI Research - Mattawan, MI
Abstract: DepoFoam bupivacaine (DB; bupivacaine extended-release liposome injection) is being investigated for postsurgical analgesia via epidural. Toxicology studies after epidural DB administration were conducted in rats and dogs. The lumbosacral procedure was selected as it is commonly performed for lower limb surgeries.
Groups of 10 rats/sex received either DB (1.5 mg), bupivacaine solution (Bsol, 0.75 mg), DepoFoam vehicle, saline, or lidocaine 1.5 % with 1:200,000 epinephrine (lido/epi) followed after 15 minutes with DB (0.75 mg). 5/sex/group were sacrificed on Day 3; the remainder on Day 15. Toxicokinetic (TK) samples were taken from satellite animals (9/sex/group). Similarly, groups of 6 male dogs received either DB (45 mg), Bsol (15 mg), DepoFoam vehicle, saline, or lido/epi followed after 15 minutes with DB (45 mg). Three (3) dogs were sacrificed on Day 4; the remainder on Day 22. TK samples were taken from the 3 dogs/group designated for a 2-week recovery period. Endpoints included clinical signs, clinical pathology, organ weights and histopathology examination of a full tissue list including injection sites. Hematoxylin and eosin (H&E)-stained paraffin sections of spinal cord (SpC) were examined microscopically at 3 sampling sites (cervical, thoracic, lumbar [dosing site]). In addition, portion of the lumbar SpC underlying the injection site was examined for signs of degeneration using a sensitive silver stain method. A grading system for pathological score was used to define gradable lesions (i.e., minimal to severe).
Results were recorded by section of spinal cord involving white matter tracts or grey matter. Results in rats revealed no DB-related toxic effects; lethality was related to overdose of Bsol. Microscopic findings revealed no treatment -induced degeneration in the Spc of rats at either Day 3 or Day 15. Occasional instances of single axon staining were observed infrequently in SpC across dose groups. This is consistent with a background incidence of minimal spontaneous axonopathy which is commonly observed in sections of SpC from rats of the strain and age used in this study. All tissues were within normal limits. Similarly in dogs, no DB-related toxic effects were noted; there was no evidence of limb impairment in animals treated with DB alone (ED), and most animals treated with Bsol (4/6) or lido/epi plus DB (5/6) or Bsol (4/6) had impaired limb function that was seen on Day 1 only. Microscopic findings revealed no treatment-associated effects either on Day 4 or Day 22. The only microscopic observation in the SpC tissues was minimal perivascular lymphoid infiltration on Day 4 in the SpC from one animal treated with Bsol. Furthermore, there were no relevant differences in the severity of degenerative changes at the dosing site in SpC across dose groups. Cmax was 20% higher despite a threefold higher dose of DB vs. Bsol (45 vs. 15 mg). In conclusion, these studies demonstrate the safety and local tolerance of DB in clinically relevant models. The preclinical data support the first-time-in-human trial of DepoFoam bupivacaine by the epidural route.
A35 Title: Safety and Tolerability of DepoFoam® Encapsulated Bupivacaine for Intra- articular use in Rabbits and Dogs. Presenting Author: Brigitte M Richard PhD Presenting Author's Institution: Pacira Pharmaceuticals, Inc. - San Diego, CA Co-Authors: Paul E Newton PhD - MPI Research - Mattawan, MI Laura R Ott BS - MPI Research - Mattawan, MI Dean Haan BS - MPI Research - Mattawan, MI Abram N Brubaker PhD - MPI Research - Mattawan, MI
Abstract: DepoFoam bupivacaine (DB; bupivacaine extended-release liposome injection) uses multivesicular liposomal DepoFoam® technology to deliver bupivacaine over an extended period of time; it is currently being evaluated to prolong post-surgical analgesia in the setting of local administration into the surgical wound. As bupivacaine has also been used via direct infusion into the intra-articular space and reports of such use may be associated with chondrolysis, studies were conducted to evaluate the potential local and systemic toxicity of DB in the intra-articular setting, with special attention to any effect on wound healing in a surgical model of meniscectomy and osteochondral debridement.
After surgery, groups of rabbits and dogs (4/sex) were dosed with DB (1.5 mg/kg, 4.5 mg/kg, or 7.5 mg/kg, note that DB 25 mg/mL instead of 15 mg/mL was used for the highest dose), bupivacaine solution (Bsol, 7.5 mg/mL, 2.25 mg/kg) or saline (2+2 [for recovery] animals/sex/group). All groups received 0.3 mL/kg with the exception of animals given the 1.5 mg/kg dose of DB (0.1 mL/kg). The doses were administered via bolus injection. Endpoints included body weights, food consumption, clinical pathology, and toxicokinetic analysis on day 1. Histopathology examination of a full tissue list was performed on days 3 and 15 including surgical sites. Macroscopic examinations of wound healing were recorded beginning on day 2 through day 15 postdosing. There were no test article-related microscopic changes in either sex at both Day 3 and Day 15 necropsies. At Day 3, the surgically-induced damage areas (in both femur and meniscus) were filled with red blood cells (hemorrhage) and an acute inflammatory reaction characterized by accumulation of fibrin and occasional neutrophils. At Day 15, the surgically-induced damage areas (in both femur and right medial meniscus) were filled with fibroblasts and collagen fibers (fibrosis). In the femur there was also formation of new vessels (neovascularization) and hemorrhage. The severity of these lesions ranged from minimal to mild and was similar across groups. No chondrocyte toxicity was seen. The attenuation of Cmax with DB vs. Bsol was ≈ twofold, suggesting a safety factor of the same magnitude for DB as compared with Bsol at equivalent doses. In summary, there were no signs of systemic toxicity seen in any of the groups. Locally, DB had no affect on wound healing and did not induce more lesions, or lesions more severe, than either the Bsol or the saline control. Particularly, the examination of articular cartilage in the tibiofemoral joint surgical site and right medial meniscus revealed no histopathological evidence that DB induced chondrocyte toxicity.
The data reported here are the first published demonstration of the safety of DB after intra-articular infiltration in surgical models in toxicology species. Based on these results, DepoFoam bupivacaine should be adequately safe for further investigations in clinical trials in surgical patients.
A36 Title: Efficacy of mirtazapine in preventing intrathecal morphine-induced nausea and vomiting after Cesarean section Presenting Author: Fang-Lin Chang MD Presenting Author's Institution: Tri-Service General Hospital, National Defense Medical Center - Taipei, Taipei Co-Authors: Michael J Sheen MD - Linkou Chang Gung Memorial Hospital - Taipei, Taipei
Abstract: Background: The intrathecal morphine for Caesarean section delivers excellent postoperative analgesia but the side effects of nausea and vomiting is frequent. We tested the efficacy of mirtazapine, an antidepressant that blocks receptors associated with vomiting, on the incidence of nausea and vomiting after intrathecal morphine.
Methods: Eighty patients scheduled for elective Cesarean section under spinal anaesthesia were randomly allocated into two equal groups that received either mirtazapine 30 mg or placebo 1 hr before operation in a prospective, double-blind manner. All patients received an intrathecal injection of 10 mg of 0.5% hyperbaric bupivacaine and 0.2 mg preservative-free morphine. Nausea and vomiting was evaluated at 3, 6, 12, 18, and 24 hr after intrathecal morphine administration. The primary outcome measure was the incidence of nausea and vomiting.
Results: The incidence of nausea and vomiting was significantly less in patients receiving mirtazapine compared with placebo (28.1% vs. 61.3%, respectively; P= 0.005). The onset time of PONV between groups was also significantly different in the mirtazapine patients〔mean (SD): 8.4 (2.3) hr〕 compared with placebo〔4.2 (1.6) hr〕 (P< 0.0001). The severity of nausea and the number of vomiting episodes were significantly decreased in mirtazapine patients compared with placebo both at 3-6 hr and at 6-12 hr periods.
Conclusion: We conclude that preoperative mirtazapine 30 mg decreased the incidence, delayed the onset time, and reduced the severity of PONV in women for elective Cesarean section under spinal anesthesia with 10 mg of 0.5% hyperbaric bupivacaine and 0.2 mg of preservative free morphine.
A37 Title: Improved Block Skill Results in the Reduction of Local Anesthetic Volume for Ultrasound-Guided Supraclavicular Block Presenting Author: Hideaki Hayashi MD Presenting Author's Institution: Kansai Rosai Hospital - Amagasaki, Hyogo Co-Authors: Sawami Kiyonaka MD - Kansai Rosai Hospital - Amagasaki, Hyogo
Abstract: Introduction: Ultrasound (US)-guided supraclavicular block is an excellent anesthetic and analgesic option for upper extremity surgery. Among factors that determine the necessary volume of local anesthetic, block skill, as measured by the number of cases experienced, seems to be a major determinant. I retrospectively reviewed the outcome of a supraclavicular block case series to investigate the relation between the improvement in block skill and the reduction of local anesthetic volume.
Methods: Data on patient characteristics, anesthetic technique, surgical procedure and block outcome were collected from medical charts and anesthesia records for 200 consecutive patients who had received US-guided supraclavicular block for upper extremity surgery. All block procedures were performed by one of the authors (H.H.) over 24 months using the standardized technique (1). Data are expressed as mean ± S.D. (range).
Block Technique: With both arms placed along the body and the head turned to the contralateral side, a high-frequency linear probe (SonoSite S-Nerve or GE LOGIQe) was placed in the supraclavicular fossa parallel to the clavicle for a transverse view of the subclavian artery and brachial plexus located over the first rib. A 70-mm, 21- gauge block needle (Sonolect CCR; Hakko, Tokyo) was advanced in a lateral-to- medial direction towards the ―corner pocket‖ of the plexus using the in-plane technique. After penetrating the brachial plexus sheath, local anesthetic was deposited in divided doses while changing the needle tip position to ensure adequate spread of the anesthetic within the sheath. Paresthesia elicitation was never intentionally sought, and electric nerve stimulation was not attempted.
Results: Data from 122 men and 78 women aged 15 to 85 were analyzed. Ropivacaine 0.5% was used in 118 patients, and lidocaine 1.5% with 1:200,000 epinephrine in 82 patients. Two hundred patients were divided into 4 groups of every 50 consecutive patients. The mean local anesthetic volume used for each group was 28 ± 2 (21 – 30), 26 ± 2 (20 – 30), 22 ± 3 (15 – 27) and 20 ± 2 (14 – 28) mL respectively, showing a significant decrease with an increase in the number of blocks experienced. Elapsed time from block placement to incision was 20 ± 5 (12 – 52) min. One hundred eighty-eight patients (94%) had successful surgical anesthesia without supplementation of any other analgesics. The number of patients requiring supplemental local anesthetic infiltration or fentanyl administration did not differ among 4 groups (4, 3, 2 and 3 patients for each group). Horner syndrome was noticed in 9 patients. No case of vascular puncture, neurologic deficit, or symptomatic hemidiaphragmatic paresis or pneumothorax was noted.
Discussion: This review showed that improved block skill was associated with a reduction of local anesthetic volume used for US-guided supraclavicular block. It also suggests that the necessary volume of local anesthetic can be decreased to 20 mL when skilled practitioners perform an US-guided supraclavicular block. These findings remain to be confirmed by prospective controlled study.
References (1) Perlas A, Lobo G, Lo N, et al. Ultrasound-Guided Supraclavicular Block: Outcome of 510 Consecutive Cases. Reg Anesth Pain Med. 2009;34:171-176.
A38 Title: Bilateral-dual TAP-block: Is pulmonary function affected? Presenting Author: Maria Petersen MD Presenting Author's Institution: Copenhagen University Hospital: Bispebjerg - Copenhagen NV, Copenhagen Co-Authors: Jimmi Elers MD - Copenhagen University Hospital: Bispebjerg - Copenhagen NV, Copenhagen Jens Børglum MD, PhD, MBA - Copenhagen University Hospital: Bispebjerg - Copenhagen NV, Copenhagen Jann Mortensen MD, DMSc - Copenhagen University Hospital: Rigshospitalet - Copenhagen O, Copenhagen Christian Maschmann MD - Copenhagen University Hospital: Bispebjerg - Copenhagen NV, Copenhagen
Abstract: Background and Objectives: The administration of ultrasound-guided (USG) transversus abdominis plane (TAP) blocks has been shown both clinically and statistically to reduce postoperative pain in various abdominal surgical procedures in several studies. The TAP block can be considered a well documented procedure to sufficiently block the sensory afferent nerves in the plane between the transversus abdominis and the internal oblique muscle. However, motor nerves innervating the muscles of the abdominal wall are present in the same plane. It has, to our knowledge, never been investigated whether and to which extent the application of a TAP block affects the motor functions of the abdominal muscles. In our department, the so-called bilateral dual TAP block (BD-TAP block) has been developed recently. The BD-TAP block requires injection of local anesthetics at four sites into the abdominal wall, aiming to anaesthetize the entire abdominal wall. Our aim with this study was to investigate whether an USG BD-TAP block affects the pulmonary function as a result of blocking the motor nerves to the muscles of the abdominal wall, which sometimes contributes to the respiratory work, particularly as accessory expiratory muscles.
Study Design: A double-blinded, randomized, cross-over study.
Methods: Twelve healthy male subjects, aged 18 to 37 years, were randomized into two groups: One group received a BD-TAP-block with four single-shot injections of 15 ml of bupivacaine 2.5 mg/ml at each site. The other group received a block with 15 ml of saline at each of the four sites. Cross-over took place 3 weeks later with the same participants, except one, who dropped out due to personal reasons not related to the study. Before, as well as one hour after the application of the blocks, all subjects underwent measurement of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and maximal expiratory pressure (MEP). All measurements were performed in a sitting position.
Results: Following the bupivacaine block, mean (SEM) FEV1 increased 15 (45.5) ml compared to the saline block, which showed a mean (SEM) FEV1 increase of 34 (57.4) ml (p=0.62). Mean (SEM) FVC increased with 15 (79.8) ml after a block with bupivacaine and 37 (48.7) ml after a block with saline (p=0.78). Following the block with bupivacaine, mean (SEM) fall in MEP was 14 (6.7) cmH2O and after the saline block 6 (7.1) cmH2O (p=0.35).
All participants reported subjective symptoms after bupivacaine block, whereas the number of affected dermatomes varied between subjects after a bupivacaine block when evaluated by both ethanol on skin test and monofilament test. However, neither affection of dermatomes, nor subjective symptoms were recorded when the blocks were performed with saline.
Conclusions: The administration of an ultrasound-guided BD-TAP-block with bupivacaine 2.5 mg/ml does not result in statistically significant decrease in pulmonary function in healthy male subjects. However, additional studies on patients with a suspected impaired pulmonary function post-operatively are warranted in order to further investigate this clinical issue.
Key words: TAP block, respiratory muscles, bupivacaine, pulmonary function
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A39 Title: Continuous Femoral versus Posterior Lumbar Plexus Nerve Blocks for Analgesia Following Hip Arthroplasty: A Randomized, Controlled Study Presenting Author: Vanessa J Loland MD Presenting Author's Institution: University of California San Diego - San Diego, CA Co-Authors: Edward R Mariano MD - University of California San Diego - San Diego, CA Sarah J Madison MD - University of California San Diego - San Diego, CA NavParkash S Sandhu MD - University of California San Diego - San Diego, CA Preetham J Suresh MD - University of California San Diego - San Diego, CA
Abstract: Background: Hip arthroplasty frequently requires potent postoperative analgesia, often provided with an epidural or posterior lumbar plexus local anesthetic infusion. However, American Society of Regional Anesthesia (ASRA) guidelines now recommend against epidural and continuous posterior lumbar plexus blocks during administration of various perioperative anticoagulants often administered following hip arthroplasty. Since current ASRA guidelines allow for simultaneous administration of nearly any perioperative anticoagulant and a continuous femoral nerve block, it is a possible analgesic alternative; but whether it provides comparable analgesia to a continuous posterior lumbar plexus block following hip arthroplasty remains unclear. We therefore tested the hypothesis that differing the catheter insertion site (femoral vs. posterior lumbar plexus) following hip arthroplasty has no impact on postoperative analgesia.
Methods: Preoperatively, subjects undergoing hip arthroplasty were randomly assigned to receive either a femoral or posterior lumbar plexus stimulating catheter (StimuCath, Teleflex Medical, Research Triangle Park, North Carolina) inserted 5-15 cm or 0-1 cm past the needle tip, respectively. Postoperatively, patients received perineural ropivacaine, 0.2% (basal 6 mL/hour, bolus 4 mL, 30 min lockout) for at least two days using an electronic portable infusion pum (PainPump2, Stryker Instruments, Kalamazoo, MI). The primary end point was the average daily pain scores as measured with a Numeric Rating Scale (0-10) recorded in the 24-h period beginning at 07:30 the morning following surgery, excluding twice-daily physical therapy sessions. Secondary end points included pain during physical therapy, ambulation distance, and supplemental analgesic requirements during the same 24- h period, as well as satisfaction with analgesia during hospitalization.
Results: All 47 subjects exhibited a sensory and motor block within 15 min after a local anesthetic bolus was administered via the catheter (Figure 1). The mean (SD) pain scores for subjects receiving a femoral infusion (n=25) was 3.6 (1.8) versus 3.5 (1.8) for patients receiving a posterior lumbar plexus infusion (n=22) resulting in a group difference of 0.1 (95% confidence interval -0.9 to 1.2; p=0.78; Figure 2). Because the confidence interval fell within a pre-specified -1.6 to 1.6 range, we conclude that the effect of the two analgesic techniques on postoperative pain were equivalent. Similarly, we detected no differences between the two treatments with respect to the secondary end points, with one exception: subjects with a femoral catheter ambulated a median (10th-90th percentiles) 2 (0-17) m the morning following surgery, compared with 11 (0-31) m for subjects with a posterior lumbar plexus catheter (data nonparametric; p=0.02; Figure 3).
Conclusions: Following hip arthroplasty, a continuous femoral nerve block is an acceptable analgesic alternative to a continuous posterior lumbar plexus block when using a stimulating perineural catheter. However, early ambulatory ability suffers with a femoral infusion, since a femoral nerve infusion appears to weaken the quadriceps femoris muscle to a greater degree than a posterior lumbar plexus infusion.
Additional File #1: 1011611224755Figure_1.pdf Click here to view
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Additional File #3: 3011611224755Figure_3.pdf
A40 Title: Ultrasound-Guided (Needle In-Plane) Perineural Catheter Insertion: The Effect of Catheter Insertion Distance on Postoperative Analgesia Presenting Author: Vanessa J Loland MD Presenting Author's Institution: University of California San Diego - San Diego, CA Co-Authors: NavParkash S Sandhu MD - University of California San Diego - San Diego, CA Sarah J Madison MD - University of California San Diego - San Diego, CA Preetham J Suresh MD - University of California San Diego - San Diego, CA Edward R Mariano MD, MAS - University of California San Diego - San Diego, CA
Abstract: Background: When using ultrasound guidance to place a perineural catheter for a continuous peripheral nerve block, keeping the needle-in plane and nerve in short- axis results in a perpendicular needle-to-nerve orientation (1). Many have opined that when placing a perineural catheter via the needle, the acute angle may result in the catheter bypassing the target nerve when advanced beyond the needle tip. Theoretically, greater catheter tip-to-nerve distances result in less local anesthetic- to-nerve contact during the subsequent perineural infusion, leading to inferior analgesia. While a potential solution may appear obvious—advancing the catheter tip only to the tip of the needle, leaving the catheter tip at the target nerve—this technique has not been prospectively evaluated. e therefore hypothesized that during needle in-plane ultrasound-guided perineural catheter placement, inserting the catheter a minimum distance (0-1 cm) past the needle tip is associated with improved postoperative analgesia compared with inserting the catheter a more- traditional 5-6 cm past the needle tip.
Methods: Preoperatively, subjects received a popliteal-sciatic perineural catheter for foot or ankle surgery using ultrasound guidance exclusively (needle in-plane and nerve in short-axis). Subjects were randomly assigned to have a single-orifice, flexible catheter inserted either 0-1 (n=50) or 5-6 cm (n=50) past the needle tip. All subjects received a single-injection mepivacaine (40 mL of 1.5% with epinephrine) nerve block via the needle, followed by catheter insertion and a ropivacaine 0.2% infusion (basal 6 mL/h, bolus 4 mL, 30 min lockout), through at least the day following surgery. The primary end point was average surgical pain as measured with a 0-10 numeric rating scale the day following surgery. Secondary end points included time for catheter insertion, incidence of catheter dislodgement, maximum (―worst‖) pain scores, opioid requirements, fluid leakage at the catheter site, and the subjective degree of an insensate extremity.
Results: Average pain scores the day following surgery for subjects (Tables 1 & 2) of the 0-1 cm group (n=50) was a median (interquartile) of 2.5 (0.0-5.0), compared with 2.0 (0.0-4.0) for subjects of the 5-6 cm group (n=50; p=0.42). Worst pain scores during the same time period for subjects of the 0-1 cm group was a median (interquartile) of 6.0 (3.0-9.0), compared with 7.0 (3.0-8.0) for subjects of the 5-6 cm group (p=0.37). Similarly, among the secondary end points, no statistically significant differences were found between the two treatment groups (Table 3).
Conclusions: This study did not find evidence to support the hypothesis that for popliteal-sciatic perineural catheters placed using ultrasound guidance and a needle in-plane technique, inserting the catheter a minimum distance (0-1 cm) past the needle tip improves (or worsens) postoperative analgesia compared with inserting the catheter a more-traditional distance (5-6 cm). Caution is warranted if extrapolating these results to other catheter designs, ultrasound approaches, or anatomic insertion sites.
References 1. Ilfeld, Fredrickson, Mariano: Ultrasound-guided perineural catheter insertion: three approaches but few illuminating data. Reg Anesth Pain Med. 2010;35:123- 126.
Additional File #1: 1011611220023Figure_1.pdf Click here to view
Additional File #2: 2011611220023Figure_2.pdf Click here to view
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A41 Title: Blood Transfusion And Incidence Of Deep Venous Thrombosis In Total Hip Arthroplasty under General Anesthesia versus Spinal Anesthesia. Presenting Author: Sanjay K Sinha MD Presenting Author's Institution: St.Francis Hospital and Medical Center - Hartford, CT Co-Authors: Olga Solovyova BS - St.Francis Hospital and Medical Center - Hartford, CT Steven Zerbini BS - St.Francis Hospital and Medical Center - Hartford, CT Jonathan Abrams MD - St.Francis Hospital and Medical Center - Hartford, CT Sivasenthil Arumugam MD - St.Francis Hospital and Medical Center - Hartford, CT
Abstract: Introduction: Spinal Anesthesia (SA) has been shown to decrease blood transfusions and deep venous thrombosis (DVT) in patients having total hip arthroplasty (THA)(1). We hypothesized that advances in perioperative management for THA would provide the same benefit for general anesthesia (GA) as has been previously shown by SA.
Methods: Patients undergoing primary THA from December 1, 2008 to September 1, 2010 under GA and SA (by two high volume arthroplasty surgeons) were identified from the Connecticut Joint Replacement Institute Registry. Four hundred consecutive patients (200 in each group) were studied. The GA group received a standardized GA; SA patients received bupivacaine 10-12 mg. All surgeries were performed through a posterolateral approach and received DVT prophylaxis (Enoxaparin 40 mg subcutaneously for 10 days followed by aspirin 325 mg twice a day for 6 weeks or Coumadin). Their preoperative hematocrit (Hct), lowest recorded Hct during hospitalization, discharge Hct and any transfusion of packed red blood cells (pRBC) were noted. All patients had a screening Doppler ultrasound for DVT within 3 weeks post discharge. Differences in categorical data was compared between groups with chi square; continuous variables were analyzed with t-test.
Results: Groups were demographically similar. The starting and discharge Hcts were similar, however, patients in the SA group had lower "lowest" recorded Hcts and received more blood transfusions compared to GA group (31.5% versus 15.5%,) SA patients received more blood (0.5 units, 95% CI 0.4 – 0.6) than the GA patients (0.3 units, 95% CI 0.2 – 0.4) (p=0.006). None of the patients were transfused introperatively. The surgical time was shorter in the SA group compared to GA group; an analysis of covariance controlling for surgical time showed lower amount of transfusion in the GA group [adjusted mean for GA : [0.3 unit (95% CI 0.2 – 0.4)] ; SA : [0.5 unit, (95% CI 0.4 – 0.6)] (p=0.007). Two and zero patients (GA and SA respectively) developed DVT; 1 patient in the SA group developed pulmonary embolus.
Discussion: In our retrospective series, SA for THA increased the risk of receiving a blood transfusion compared to GA. (Relative risk 1.9, 95% CI 1.3¬ – 2.8, p<0.001). The lower recorded Hct in SA patients was likely from higher fluid requirements to counteract the effects of sympathectomy resulting in hemodilution; however, fluid administered to patients was not analyzed. There was no increase in the risk of DVT with GA for THA. These results are in conflict with previously published reports that advocate use of SA for THA. However, previous data should be interpreted with caution because of absence of chemoprophylaxis in study patients, now standard practice in arthroplasty patients.(2) A major limitation of this study was that transfusions of pRBC were triggered by surgeons based on vital signs, Hct level and clinical judgment rather than formally established transfusion protocol; uncontrolled transfusion practices by the two surgeons may have had a confounding effect on our results.
Conclusion: The results of this retrospective analysis warrants a prospective, randomized study to compare GA versus SA for THA.
References 1. Modig J. Anesth Analg. 1983:62;174-180. 2. Mauermann W. Anesth Analg. 2006:103;1018-1025.
Additional File #1: 1030111230246GA_v_SA_ASRA_Stats_.doc Click here to view
Patient Characteristics
GA group SA Group Significance Number 200 200 Age (years) 62.6 10.3 64.5 12.9 0.102 Height (cm) 165.8 10.0 166.3 9.2 0.528 Weight (kg) 83.0 17.3 80.1 17.6 0.101 Sex (F/M) 109/91 97/103 0.313 ASA Status (%) I 5 15 II 82.5 78.7 0.505 III 12.5 13.7 Surgical Time(mins) 74 14 62 25 <0.001* Hematocrit(%)
Preoperative Hct 39.7 3.7 39.8 3.8 0.787 Lowest Hct 27.6 3.6 26.8 3.7 0.029* Discharge Hct 28.5 3.3 28.1 3.4 0.319 Units of pRBC transfused. Mean(95% 0.3(0.2–0.4) 0.5(0.4–0.6) 0.006* CI) Percentage of patients with number of Unit pRBC transfused
0 Units 1 Units 83.5 68.5 2 Units 8.5 19.5 3 Units 6.5 20 4 Units 1 1.5 0.5 1.5
A42 Title: Onset and Duration of Ultrasound Guided Supraclavicular Nerve Blocks Using Ropivacaine vs. Ropivacaine-chloroprocaine Mixture Presenting Author: Alexander I Kim MD Presenting Author's Institution: University of New Mexico Health Sciences Center - Albuquerque, NM Co-Authors: Arpad Zolyomi MD - University of New Mexico Health Sciences Center - Albuquerque, NM Christopher Arndt MD - University of New Mexico Health Sciences Center - Albuquerque, NM Tony Yen MD - University of New Mexico Health Sciences Center - Albuquerque, NM Firoz Vagh MD - University of New Mexico Health Sciences Center - Albuquerque, NM
Abstract: Background: This prospective, randomized, double-blinded study was performed with the hypothesis that combining chloroprocaine with ropivacaine for ultrasound guided supraclavicular block would result in faster onset of surgical anesthesia than ropivacaine alone, while maintaining the same duration of action.
Methods: Sixty patients undergoing outpatient upper extremity surgery were randomly allocated to supraclavicular brachial plexus block using a mixture of 10ml 3%-chloroprocaine with 20ml 1%ropivacaine and 1:300,000 epinephrine (n=30) versus a mixture of 10ml normal saline with 20ml 1% ropivacaine and 1:300,000 epinephrine (n=30). A researcher blinded to the mixture administered, performed the block and tested sensation and motor function at 3 minute intervals until complete loss of sensation and motor function, or up to 40 minutes. Participants were asked to complete a questionnaire rating their pain on a numeric pain scale for 24 hours post-operatively. The endpoint for duration of action was return of any pain. Patient characteristics were summarized as means and standard deviations. Time to event Kaplan-Meier analyses and Wilcoxon tests were used to evaluate the two mixtures based on the onset of action and duration of action. Time to complete block was summarized using medians and interquartile ranges between the 25th and 75th percentile.
Results: The two groups did not differ with respect to age, sex, or weight. The length of performing the block (defined as insertion of needle to withdrawal of needle) was 3.7 minutes in both groups. Ulnar nerve motor block was not faster with ropivacaine-chloroprocaine(R/C) [median=19 minutes (interquartile range 10-28 minutes)] compared to ropivacaine-normal saline (R/NS) [median=25 (16-40), p=0.13]. Ulnar nerve sensory block onset was not faster with R/C [median=16 (10-28)] compared to R/NS [median=22 (13-34), p=0.26]. Median nerve motor block onset was not faster with R/C [median=18 (10-34)] compared to R/NS [median 25 (19-40), p=0.13]. Median nerve sensory block onset was faster with R/C [median=9 (4-16)] compared to R/NS [median=16 (10-22), p=0.03]. Radial nerve motor block onset was faster with R/C, with 73% blocked at 7 minutes [median=7 (4-10)] compared to 52% blocked at 7 minutes with R/NS [median=7 (7-13), p=0.03]. Radial nerve sensory block onset was faster with R/C [median=6 (4-10)] compared to R/NS [median=10 (7-13), p=0.01]. Musculocutaneous nerve motor block onset was faster with R/C [median=7 (4-13)] compared to R/NS [median=13 (7-22), p=0.003] Musculocutaneous nerve sensory block onset was faster with R/C [median=9 (4- 10)] compared to R/NS [median=10 (7-16), p=0.04]. In regards to the duration of action, subjects in the R/C group reported any degree of pain sooner [median=566 minutes (428-670] than those in the R/NS group [median=718 (597-851), p=0.02].
Discussion: Although statistically significant differences exist in several nerve distributions between the onset of action of ropivacaine-chloroprocaine versus ropivacaine alone, the modest gains achieved in hastening onset by the addition of chloroprocaine may not be clinically significant. On the other hand, the addition of chloroprocaine significantly shortened the duration of the blocks.
Additional File #1: 1022711231020Median_time_to_bloc.docx Click here to view
Additional File #2: 2022711231020P_value.docx Click here to view Additional File #3: 3022711231020graph_for_any_pain.docx Click here to view
A43 Title: Comparison of single shot versus continuous femoral local anesthetic nerve block in patients undergoing knee arthroplasty Presenting Author: Jay S Grider DO, PhD Presenting Author's Institution: University of Kentucky - Lexington, KY Co-Authors: Michael E Harned MD - University of Kentucky - Lexington, KY Sloan Paul MD - University of Kentucky - Lexington, KY Giordani Mauro MD - University of Kentucky - Lexington, KY
Abstract: Introduction: Femoral nerve blockade has become commonplace for the management of post-operative pain after knee arthroplasty.(1) Despite the widespread use of the technique, there is relatively little literature to suggest that continuous infusion is superior to a single shot technique combined with systemic analgesics.(1) The aim of this study is to compare the efficacy of continuous femoral nerve block versus single shot femoral nerve block using ropivacaine for the control of postoperative pain following knee arthroplasty.
Methods: Following IRB approval, 80 consecutive patients scheduled for knee arthroplasty were enrolled in this prospective, randomized, double-blind clinical trial. Thirty minutes prior to the start of surgery all patients received a nerve stimulator-guided femoral nerve block (FNB) with 30 ml of 0.5% ropivacaine. Patients were then randomized to either no further local anesthetic treatment (ssFNB), or to receive a femoral perineural Contiplex (BBraun) catheter (ccFNB) immediately following the initial FNB. At the conclusion of surgery a continuous infusion of 0.2% ropivacaine at 8 ml/hour was begun in the ccFNB group. Postoperatively, rescue intravenous PCA morphine was available as needed for the first 48 hours with use of oral oxycodone thereafter. Visual analog pain scores (VAS) at rest and with range of motion on POD 2 and 3 were obtained. Hospital length of stay (HLOS) was standardized for discharge to a rehabilitation facility at POD 4 unless surgical factors dictated otherwise. Passive knee range of motion and pain scores were obtained from the rehabilitation facility at POD 21 day.
Results: Seventy-two patients completed the clinical trial (ssFNB=40;cFNB=32) with 8 subjects in the cFNB group experiencing preoperative catheter dislodgement/malfunction. Groups were similar in regard to age, sex, weight and ASA class. Mean +/- SD VAS score in the evening of POD 1 was significantly lower (p<0.01) in the ssFNB group (2.4+/-3.1) versus the ccFNB group (3.4+/-3.7). The single ropivacaine injection (ssFNB) provided sensory blockade through to the morning of POD 2 in 68% of patients, with loss of blockade occurring in all ssFNB patients by the evening of POD 2. Subjects in both groups were able to participate satisfactorily in rehabilitative physical therapy on POD 2, with VAS scores in the ssFNB (3.8+/-2.8) and ccFNB groups (4.0+/-2.2) being essentially identical. However, mean POD 2 morphine consumption in the ssFNB group (8.6mg) was significantly higher (p< 0.05) than the ccFNB group (3.7mg). Mean POD 3 VAS was significantly less in the ccFNB group (2.4+/-2.7) versus the ssFNB group (3.7+/- 1.9). There were no local anesthetic or opioid analgesic complications throughout the postoperative period in either group. Three subjects in the ssFNB group could not participate in the physical therapy secondary to discomfort while all subjects with ccFNB participated. Eight subjects in the ssFNB group required primary hospitalization longer than four days with a mean length of stay HLOS of 6.2 days compared with 2 subjects in the ccFNB group requiring extended primary hospitalization with a mean HLOS being a similar 6 days. Passive knee range of motion data at discharge from the rehabilitation facility (POD 21) was similar for ssFNB subjects (mean 106°; n=21) and ccFNB subjects (mean 110°; n=12).
Conclusions: 1) Continuous femoral local anesthetic nerve block provides better and more consistent analgesia in the post-operative period following knee arthroplasty compared with single injection FNB. 2) Continuous FNB decreased the need for postoperative opioid consumption. 3) Every patients receiving continuous FNB for postoperative pain were able to complete participation in rehabilitation activities. 4) Patients in the ccFNB group were more likely to be discharged for rehabilitation at POD 4. 5) Patients in the ssFNB group were more likely to require prolonged primary hospitalization.
References 1) Paul JE, Arya A, Hurlburt L, Cheng J, Thabane L, et. al. Femoral nerve block improves analgesia outcomes after total knee arthroplasty: A meta-analysis of randomized controlled trials. Anesthesiology. 2010;113:1144-1162.
A44 Title: Comparison of continuous transversus abdominis plane block (TAPB) with thoracic epidural analgesia (TEA) for post operative analgesia following abdominal surgery – a randomized open label study. Presenting Author: Jonathan Brookes FRCA Presenting Author's Institution: London Health Sciences Centre University Hospital - London, Ontario Co-Authors: Sugantha Ganapathy FRCPC - London Health Sciences Centre University Hospital - London, Ontario Danielle Stothart MD - London Health Sciences Centre University Hospital - London, Ontario Lakshmi Subramanian B.Sc - London Health Sciences Centre University Hospital - London, Ontario Patrick Colquhoun FRCSC - London Health Sciences Centre University Hospital - London, Ontario
Abstract: Introduction: Thoracic epidural analgesia (TEA) is considered the gold standard for abdominal surgery. TEA may be contraindicated in the presence of coagulopathy or infection. TAPB may be used as an alternate analgesic technique, but has never been directly compared to TEA. This study compares outcomes between patients receiving TEA and TAPB following major abdominal surgery.
Methods: After IRB approval and informed consent, 50 patients are scheduled to be randomized into two groups in this open label study. Group 1 received catheter congruent TEA initiated with 0.25% bupivacaine to establish a sensory block between T6-T12 bilaterally. Patient controlled epidural analgesia (PCEA) was continued for 48-72 hours with a mixture of bupivacaine 0.1% with hydromorphone 10 mcg/mL with a basal rate of 6mL/h and PCEA bolus of 3mL, lockout period of 20 minutes. Group 2 had bilateral TAPB catheters inserted using ultrasonography. A bolus of 25 to 30mL per side of 0.5% ropivacaine was used to distend the space, and 2 catheters per side were then inserted. The catheters were connected to an elastomeric pump set to deliver 2mL/catheter/hr of 0.35% ropivacaine for 48- 72hours. Patients in the TAPB Group were also provided with IV patient controlled analgesia (PCA) using hydromorphone or morphine.
All patients received a standardized general anesthetic. Opioids were titrated intraoperatively as required. The following variables were collected postoperatively at predetermined time periods: verbal reported pain scores at rest and during cough, satisfaction scores and sedation scores, nausea and pruritus scores. Time to onset of bowel sounds, first flatus and first bowel movement, hemodynamic variables, incidence and duration of significant hypotension, opioid consumption and adverse events were collected from patient charts.
Results: The initial 21 patients (8 TEA and 13 TAPB) are included in this report. Surgeries consisted of colon resection, pancreatic surgery and closure ileostomy. Demographics, pain scores, satisfaction scores and morphine consumption were not significantly different between the groups. Pulse oxymetric saturation, respiratory rate and sedation scores at all time points were similar between the groups. Time to first bowel sounds, first bowel movement and length of hospital stay were also similar between the groups.
Discussion: TAPB provides comparable analgesia to TEA with high patient satisfaction. Opioid consumption measured as IV morphine equivalent was significantly higher with TEA, possibly because of fixed basal delivery rates. TAPB can be a viable alternative to TEA for providing postoperative analgesia following abdominal surgery.
References McDonell JG et al. Anesth Analg. 2007 104:193-197. Hebbard P. Anesth Analg. 2008 106:274-275.
Additional File #1: 1021511105431Atable_1_tapb_VS_TE.doc Click here to view Variable TEA TAPB p
Age (mean +/- SD) 51.4 (9.8) 60.0 (11.7) 0.1
Sex (M/F) 2/6 8/5
Weight (mean +/- SD) 82.1 (19.77) 89.2 (36.71) 0.6
Height (mean +/- SD) 168.8 (11.9) 163.9 (21.6) 0.6
ASA (1,2,3,4) 2,2,4,0 2,6,4,1
Table 1: Demographics TAPB vs TEA
Additional File #2: 2021511105431ATable_2TAPB_vs_TEA.doc Click here to view
Variable TEA TAPB p
VRS Rest/cough 4H 1.9(3) /2.7 (3) 2.5(2) /3.2 (2) 0.6/0.7
VRS Rest/cough 8H 0.8(1) /2.3 (2) 1.3(1.6) /2.7 (2) 0.5/0.7
VRS Rest/cough 0.8(0.9) /2.6 (2) 1.4(1.5) /2.8 (2) 0.3/0.8 12H
VRS Rest/cough 1(0.9) /3 (1.5) 1.5(2) /3.4 (3) 0.6/0.7 16H
VRS Rest/cough 0.8(0.9) /3.3 (1.8) 1.5(1.8) /3.1 (2) 0.3/0.9 24H
VRS Rest/cough 1(1.4) /3.7 (3) 0.1(1) /2.5 (1.7) 0.9/0.3 36H
VRS Rest/cough 0.9(1) /3.4 (3) 1(1) /2.3 (1.5) 0.7/0.3 48H
VRS Rest/cough 0.7(1.3) /2.7 (2.5) 1.3(1.4) /2.8 (2) 0.4/0.96 72H
VRS Satis 4H 8.8(2) 8 (2) 0.4
VRS Satis 24H 8.5(1.6) 8.7 (1.2) 0.8
VRS Satis 48H 9.2(1.3) 8.4 (1.5) 0.3
Table 2. TAPB vs TEA Efficacy variables. Values are mean (SD)
Additional File #3: 3021511105431ATable_3_TAPB_VS_TE.doc Click here to view
Morphine consumption TEA TAPB p (mg)
Absolute/equivalent 0-12hrs 4.6 (1.8)/45.6(18.38) 17.2 (12.0)/17.2(12 0.02/0.001
Absolute/ Equivalent 12-24hrs 5.4 (1.7)/54.4(16.7) 12.3 (9.4)/12.3(9.4 0.1/<0.0001
Absolute/ Equivalent 24-48hrs 10.2 (4.6)/102.2(45.7) 9.8 (9.0)/9.75(8.9) 0.908/<0.0001
Table 3: TAPB vs TEA: Narcotic consumption as IV morphine equivalent.. Values are mean(SD)
A45 Title: Ultrasound guided paravertebral blocks for breast surgery: a retrospective analysis comparing outcomes in matched patients that received general anesthesia Presenting Author: Kathryn Lambourne MD Presenting Author's Institution: University of Wisconsin School of Medicine and Public Health - Madison, WI Co-Authors: Melissa Ramsey BS - University of Wiscosin School of Medicine and Publ - Madison, WI Mario Hevesi BS - University of Wisconsin - Madison, WI Melanie Donnelly MD - University of Wisconsin School of Medicine and Pub - Madison, WI Kristopher Schroeder MD - University of Wisconsin School of Medicine and Pub - Madison, WI
Abstract: Introduction: Persistent postsurgical pain plagues 10-50% of women undergoing breast surgery. Published studies have begun to suggest that preincisional paravertebral blocks have the ability to reduce the incidence and severity of postsurgical breast pain. In the perioperative period, the use of preoperative paravertebral blocks for breast surgery has been reported to decrease pain, nausea, and shorten the duration of hospital stays. One study even suggests a potential decrease in cancer recurrence when paravertebral blocks are used as the primary anesthetic for breast surgery. Complications of paravertebral blocks are rare but are potentially serious and include pneumothorax, vascular puncture, and hypertension. Recently ultrasound guidance has gained popularity in the field of regional anesthesia. Ultrasound guidance has allowed anesthesiologists to perform nerve blocks in shorter times, with decreased block onset times, decreased local anesthetic requirements, and increased success rates. Data is lacking, but it seems conceivable that ultrasound guidance would also add a degree of safety. To this point, only case reports have been published describing ultrasound guided paravertebral blocks for breast surgery. At the University of Wisconsin, we have been routinely performing ultrasound guided paravertebral blocks for breast surgery.
Methods: We retrospectively reviewed the charts of 20 patients undergoing breast surgery with paravertebral block as the primary anesthetic and 20 matched patients undergoing breast surgery under general anesthesia. Correlation coefficients were calculated comparing length of hopsital stay, severity of postoperative pain thru POD 1, postoperative opioid requirements, and incidence of PONV between the two groups. Logistic regression analysis was then performed on each variable and the difference in means was evaluated by the two-tailed t-test.
Results: There was no difference between the paravertebral and general anesthesia groups in patient demographics. Postoperative opioid requirement was statistically reduced in the group of patients that received a paravertebral block, from an average of 5mg IV morphine equivalent to 1.4mg IV morphine equivalent (p = 0.03). There was a trend, although without statistical significance, toward decreased hospital stay, from 730 min to 508 min (p= 0.13), average pain score on POD 1, from 1.8 on 10 point scale to 1.3 (p= 0.25), and postoperative nausea, decreased incidence of 27% to 14% (p= 0.37).
Discussion: In this retrospective review comparing patients undergoing breast surgery with ultrasound guided paravertebral regional anesthesia as their primary anesthetic compared to matched patients undergoing breast surgery with general anesthesia, having a paravertebral block was shown to significantly reduce the opioid requirement postoperatively. Further studies that evaluate the use of ultrasound guidance for paravertebral blocks should be done to determine safety and efficacy data compared to standard landmark guided techniques.
A46 Title: Ultrasound-guided versus anatomical landmark-guided ankle blocks: A six- year retrospective review Presenting Author: Natalie WY Wong BHSc Presenting Author's Institution: Toronto Western Hospital - Toronto, Ontario Co-Authors: Ki Jinn Chin MBBS, FANZCA, FRCPC - Toronto Western Hospital - Toronto, Ontario Alan J.R. Macfarlane MBChB, MRCP, FRCA - Glasgow Royal Infirmary - Glasgow, n/a Vincent W.S. Chan FRCPC - Toronto Western Hospital - Toronto, Ontario
Abstract: Background and Objectives: The conventional anatomical-landmark guided (ALG) technique of ankle block is often perceived as unreliable for producing surgical anesthesia.(1) Ultrasound-guided (USG) techniques of ankle block have been described (2,3,4), which may increase block success. We performed a six-year retrospective case-control study of ankle block for foot surgery to compare the efficacy of USG and ALG techniques.
Methods: We reviewed the clinical records for all ankle blocks performed at a single institution from 2004-2009 and extracted demographic, intraoperative and postoperative outcome data. We divided blocks into two groups for comparison depending on whether they were performed using an ALG technique (in which all five nerves were blocked using surface landmarks) or an USG technique (in which the posterior tibial and deep peroneal nerves were blocked with ultrasound guidance).
Results: We identified 144 ALG and 627 USG (total 771) ankle blocks for inclusion in the primary analysis. The majority of blocks (80%) were performed by trainees. Successful surgical anesthesia was more likely in the USG group (relative risk (RR) 1.3, P<0.001, 95% confidence interval (CI) 1.1-1.5). Patients in the ALG group were more likely to require supplemental local anesthesia (RR 2.9, P<0.001, 95%CI 1.6-5.0), unplanned general anesthesia (RR 2.2, P=0.002, 95%CI 1.3-3.6), or supplemental fentanyl (RR 1.9, P=0.007, 95%CI 1.2-3.0). Admission and discharge pain scores in the post-anesthetic care unit were similar in both groups. However, patients in the ALG group were more likely to receive intravenous opioids (RR 1.7, P=0.014, 95%CI 1.1-2.5) and they received a significantly higher mean dose of opioids (10.8mg versus 8.8mg IV morphine, ALG vs. USG, P=0.015). The incidence of post-operative neurological deficit was low and similar in both groups (0.7% vs 1.1%, ALG vs. USG, P=0.652).
Conclusions: This study demonstrates that USG posterior tibial and deep peroneal nerve blockade improves the efficacy of ankle block compared to a conventional ALG technique, particularly in the hands of less-experienced practitioners.
References 1. Anaesth Intensive Care. 2004;32:368-371. 2. Reg Anesth Pain Med. 2009;34:256-260. 3. Reg Anesth Pain Med. 2009 Jan-Feb;34:24-8. 4. Reg Anesth Pain Med. 2010 Mar-Apr;35:217-221.
Additional File #1: 1013111164559Intraoperative_and_.doc Click here to view
Intraoperative and postoperative outcomes Intraoperative outcomes USG ALG P value Mean difference (95% CI) Successful surgical anesthesia 83.7% (505 / 603) 64.9% (87 / 134) < 0.001 RR (95% CI) 1.3 (1.1, 1.5) 0.8 (0.7, 0.9) Required supplemental local anesthesia 4.7% (28 / 600) 13.4% (18 / 134) < 0.001 RR (95% CI) 0.3 (0.2, 0.6) 2.9 (1.6, 5.0) Required unplanned general anesthesia 6.8% (41 / 603) 14.9% (20 / 134) 0.002 RR (95% CI) 0.5 (0.3, 0.8) 2.2 (1.3, 3.6) Required supplemental fentanyl 8.7% (52 / 599) 16.4% (22 / 134) 0.007 RR (95% CI) 0.5 (0.3, 0.8) 1.9 (1.2, 3.0) Intraoperative fentanyl dose (all patients) 31.7 ± 39.8 43.3 ± 48.9 0.005 -11.7 (-19.8, -3.6) Intraoperative fentanyl dose (excluding recipients of an unplanned GA) 28.3 ± 35.1 39.4 ± 48.7 0.006 -11.1 (-19.0, -3.2) Postoperative outcomes USG ALG P value Mean difference (95% CI) Admission pain scores 0.7 ± 1.8 0.8 ± 1.9 0.458 -0.1 (-0.5, 0.2) Admission pain scores ≥ 5 6.5% (33 / 504) 5.3% (6 / 114) 0.611 Discharge pain scores 0.3 ± 1.1 0.7 ± 1.5 0.003 -0.4 (-0.6, -0.1) Discharge pain scores ≥ 5 1.8% (9 / 503) 2.6% (3 / 114) 0.557 Received any analgesia (opioid or non-opioid) 47.6% (243 / 510) 53.7% (65 / 121) 0.230 Received any opioid (oral or IV) 33.6% (136 / 405) 43.7% (45 / 103) 0.056 Opioid dose (oral & IV) expressed as IV morphine equivalents (mg) 8.8 ± 5.6 10.8 ± 6.5 0.015 -2.0 (-3.6, -0.4) (all recipients of any opioids) Received IV opioids 12.8% (65 / 509) 21.5% (26 / 121) 0.014 RR (95% CI) 0.6 (0.4, 0.9) 1.7 (1.1, 2.5) IV opioid dose expressed as IV morphine equivalents (mg) 12.9 ± 7.4 14.6 ± 7.7 0.354 -1.6 (-5.5, 1.8) (all recipients of IV opioids only) Supplemental fentanyl is defined as total dose >100mcg or >1dose of ≥50 mcg. Continuous data are expressed as mean ± standard deviation and categorical data as % (n / N). ALG = anatomical landmark-guided technique, CI = confidence interval, GA = general anesthesia, IV = intravenous, RR = relative risk, SD = standard deviation, USG = ultrasound-guided technique. A47 Title: Does long term use of Opioids improve Pain scores? Presenting Author: Pankaj Mehta MD Presenting Author's Institution: Massachusetts General Hospital - Quincy, MA Co-Authors: Chen Lucy MD - MGH - Boston, MA Jianren Mao MD,PhD - MGH - Boston, MA
Abstract: Introduction: Opioids analgesics continue to be the main stay of treatment of chronic non-malignant pain in today‘s era. Coupled with the recognition that they simultaneously improve mood and general functioning, it easily makes them the drug of choice in chronic pain management for non-malignant pain. Pain Medicine Experts have continuously cautioned practitioners regarding excessive escalation of opioid doses with the initial dose increase being achieved in weeks. It‘s important to recognize that the need for dose escalation could be the result of three things- Opioid Tolerance, Opioid induced abnormal sensitivity (Hyperalgesia) or Actual disease progression
Aim: It has been well documented in animal models that repeated administration of opioids not only results in the development of tolerance (a desensitization process) but also leads to a pro- nociceptive state (sensitization) process. This sensitization may exacerbate and easily confuse the clinical picture of pharmacological tolerance and both clinical and preclinical studies suggest that long-term use of opioids may be associated with abnormal sensitivity to pain. The net effect of either of these two processes is an apparent decrease in the analgesic efficacy. Despite a long debate there is still a lack of original clinical research evaluating opioid efficacy . In this retrospective study we have attempted to review 871 electronic health records of chronic pain patients, who visited our pain center in 2007 and analyzed the effect of change in opioid doses on subjective pain scores.
Methods: Only patients with at least 3 visits, with a well-documented dose and Visual Analogue Score (VAS) were included for data analyses. Only 109 out of 871 records could fit our inclusion criteria. All opioid doses were converted into PO Morphine equivalents and percentage change calculations were used for change comparisons.
Three significant Dose Change Visits were identified, a significant Dose Change Visit being defined as a consultation visit resulting in a +/-15% change in opioid dose compared to the first visit.
1. % Changes in morphine dose and VAS over three most significant consultant visits were recorded for all the patients 2. Two major groups were identified Group 1: Decreasing trend in morphine doses over 3 visits Group 2: Increasing trend in morphine doses over 3 visits
3. In order to analyze the effect of dose change on particular sub-types of pain we divided the study population into Group A (Neuropathic Pain), Group B (Nociceptive Pain), Group C ( Fibromyalgia) and Group D (Mixed Pain ) and performed subgroup analyses.
Results: 1. As Morphine dose was stepped up over first two visits, the VAS actually worsened. As it was increased further there was some improvement in the VAS. 2. During cumulative Decrease or Increase analysis we found that – As Opioid dose Increases VAS Increases As Opioid dose Decreases VAS Decreases
Conclusion: It was clear from our results that chronic use of opioids does not significantly improve VAS score. An early ceiling effect was also observed during analyses, the most plausible reason of which could be early onset opioid hyperalgesia.
Additional File #1: 1022011110004Overall_Visits.pdf Click here to view
Additional File #2: 2022011110004SubGroup_Analyses.pdf Click here to view
Additional File #3: 3022011110004Cumulative_Increase.pdf Click here to view
A48 Title: A survey of the use of peripheral nerve catheters in the UK Presenting Author: Ashwani Gupta MBBS MD FRCA EDRA Presenting Author's Institution: Queen Elizabeth Hospital, Kings Lynn, United Kingdom - Kings Lynn, Norfolk Co-Authors: James Stimpson MBChB FRCA MRCP - Queen Elizabeth Hospital,Kings Lynn - Kings Lynn, Norfolk Joseph Carter MBChB FRCA - Queen Elizabeth Hospital,Kings Lynn - Kings Lynn, Norfolk
Abstract: Background and Aims: Perineural catheters (PNCs) enable prolongation of regional analgesia and can been inserted at various anatomical sites.1 The aim of this survey was to collect information regarding PNC usage within the United Kingdom by evaluating the practise of UK regional anaesthetists.
Methods: Data was collected using the online survey site www.surveymonkey.com An invitation to participate in this survey was sent out to the members of the Regional Anaesthetists of Great Britain and Ireland group e-mail.
Results: A total of 168 responses were generated out of 619 emails sent (response rate 27%). Only 46.1% of respondents offer a PNC service within their hospital. The most common locations were interscalene and femoral nerve (see figure 1.) Nerve stimulator and ultrasound guidance were equally used as part of the insertion technique with most (73%) using needle to establish the block. The catheter usually (67%) remained in situ for <48 hours. Of respondents, 6.7% had observed temporary neuropraxias but none had seen cases of permanent nerve injury. The most common reasons for not offering a catheter service were lack of infrastructure (63%), lack of skills (36%), lack of equipment (31%) or unnecessary for current practice (31%) (see figure 2.)
Conclusions: There is a large variation in practice in the NHS trusts depending on the availability of resources and expertise. Currently, less than half of regional enthusiasts in the UK offer this service. Barriers to introduction are not insurmountable.
References 1) X Capdevila, P Pirat, S Bringuier et al. Continuous Peripheral Nerve Blocks in Hospital Wards after Orthopaedic Surgery. Anesthesiology. 2005; 103: 1035-1045.
Additional File #1: 10128111633371012711144526Doc1.docx Click here to view
A49 Title: Incidence of Acute Renal Dysfunction Decreased in Hip Stabilization Surgery under Regional versus General Anesthesia Presenting Author: Linda Le-Wendling MD Presenting Author's Institution: University of Florida - Gainesville, FL Co-Authors: Azra Bihorac MD - University of Florida - Gainesville, FL Stephen Lucas MD - University of Florida - Gainesville, FL Adam Wendling MD - University of Florida - Gainesville, FL Kalia Sadasivan MD - University of Florida - Gainesville, FL
Abstract: Introduction: Hip fractures occur commonly in the elderly population with an incidence of roughly 1% and 0.4% in women and men respectively over the age of 65[1], leading to serious morbidity[2]. Mortality rates have been reported to be 11- 23% at 6 months and 22-29% at one year[3]. Recent studies have demonstrated a high incidence of acute kidney injury (AKI) in patients with hip fractures (16% and 67% in patients with and without baseline renal insufficiency) and worsening outcomes in this population, including a higher likelihood of pre- and post-operative complications and higher mortality rates both in-hospital and out-of hospital[4].
Objective: The aim of this retrospective chart analysis was to determine the effect of type of anesthesia on the incidence of AKI using the modified RIFLE criteria for diagnosis and classification of AKI.
Methods: This is a retrospective cohort study of 308 elderly patients (age 65 years or greater) who underwent operative treatment (percutaneous pinning, open reduction internal fixation, or bipolar hip arthroplasty) for low-impact hip fracture at the University of Florida between 2006 and 2008. These patients underwent either RA (neuraxial anesthesia with conscious sedation) or GA (inhalational or intravenous anesthetic) for their intraoperative anesthetic. Creatinine data was gathered by review of electronic records during hospitalization for hip fracture repair and included admission, highest and discharge creatinine values. The billing database for the UF&Shands Hospital provided detailed information on all discharged patients‘ demographics, preoperative comorbidities, outcomes, and charge data as well as International Classification of Diseases, 9th edition, Clinical Modification (ICD-9-CM) codes for up to 15 diagnoses and procedures. Univariate analysis was completed using SAS software (v.9.1.3, Cary, N.C.)
Results: Patients who underwent regional anesthesia (n= 73) were older and less likely to require postoperative intensive care unit (ICU) admission. There was a higher incidence of diabetes in the GA group (Table 1). Most notable is that patients who underwent surgery under general anesthesia (group GA) had more AKI as based on the modified RIFLE criteria compared to those who had regional anesthesia (group RA) (Table 2). None of the patients in the regional anesthesia group (as compared to 2% of the patients in the general anesthesia group), had renal failure. No patients in the RA group required renal replacement therapy, compared to 3% in the GA group.
Conclusion: There is an association between increasing incidence and severity of acute kidney injury in the patients that undergo surgery under general versus regional anesthesia.
References 1. Brauer, C.A., et al., Incidence and mortality of hip fractures in the United States. JAMA, 2009. 302(14): p. 1573-1579. 2. Farahmand, B.Y., et al., Survival after hip fracture. Osteoporos Int, 2005. 16(12): p. 1583-1590. 3. Haleem, S., et al., Mortality following hip fracture: trends and geographical variations over the last 40 years. Injury. 2008. 39(10): p. 1157-1163. 4. Bennet, S.J., et al., Acute renal dysfunction following hip fracture. Injury. 2010. 41(4): p. 335-338.
Additional File #1: 1022211133437Table_1.doc Click here to view
Table 1: Demographic and clinical characteristics of patients
General Anesthesia Regional Anesthesia P (n=235) (n= 73)
Demographics
Age (years) 80 (7) 83 (8) 0.01
169 (72%) 58 (79%) 0.20 Sex (female) (n, %)
Primary payer Medicare (n, %) 228 (97%) 72 (99%) 0.45
Weekend Admission (n, %) 74 (31%) 9 (12%) 0.001
Comorbidities
Congestive heart failure (n, %) 42 (18%) 11 (15%) 0.58
Peripheral vascular disease (n, %) 13 (6%) 1 (1%) 0.14
Cerebral vascular disease (n, %) 13 (6%) 5 (7%) 0.68
Connective Tissue/Rheumatic Disease (n, %) 7 (3%) 4 (5%) 0.31
Chronic Anemia (n, %) 2 (1%) 0 (0%) 0.43
Chronic obstructive pulmonary disease (n, %) 66 (28%) 19 (26%) 0.73
Cancer (n, %) 13 (6%) 7 (10%) 0.22
Dementia (n, %) 30 (13%) 6 (8%) 0.29
Diabetes Mellitus (n, %) 37 (16%) 5 (7%) 0.05
Chronic Liver Disease (n, %) 2 (1%) 0 (0%) 0.43
Resource utilization
Arterial line placement (n, %) 8 (3%) 1 (1%) 0.37
Central venous line placement (n, %) 17 (7%) 4 (5%) 0.60
Pulmonary artery catheter placement (n, %) 2 (1%) 0 (0%) 0.43 Length of stay (days) (median, IQR) 5 (4,7) 5 (4,7) 0.38
Days from admission to surgery (mean, SD) 1.1 (1.4) 0.8 (1.2) 0.19
ICU admission (patients) (n %) 25 (11%) 2 (3%) 0.04
ICU length of stay (median, IQR) 2 (1, 5) 4 (3, 6)
Need for mechanical ventilation (n %) 10 (4%) 1 (1%) 0.25
Regional analgesia
Blood Transfusion (n %) 9 (4%) 0 (0%) 0.09
Tracheostomy (n %) 2 (1%) 0 (0%) 0.43
Percutaneous endoscopic gastrostomy tube (n 1 (0.4%) 1 (1%) 0.38 %) Hospital charges (US dollars) (median, IQR) 40900 (32500, 52400) 38400 (33800, 51300) 0.53
ICU charges (US dollars) (mean, SD) 14,694 (12,439) 24,900 (26,729) 0.67
Disposition at discharge
Home (n, %) 29 (12%) 6 (8%)
In-patient rehabilitation (n, %) 47 (20%) 14 (19%)
Nursing home (n, %) 159 (68%) 53 (73%)
Postoperative Complications
Myocardial Infarction (n, %) 13 (6%) 5 (7%) 0.68
Sepsis (n, %) 2 (1%) 0 (0%) 0.43
Severe sepsis (n, %) 1 (0.4%) 0 (0%) 0.58
Arrhythmia (n, %) 60 (26%) 13 (18%) 0.18
Venous thromboembolism (n, %) 2 (1%) 0 (0%) 0.33
Acute Anemia (n, %) 30 (13%) 13 (18%) 0.28
Readmission (n, %) 43 (18%) 16 (22%) 0.46
Time elapsed to readmission (median, IQR) 6 (3, 16) 8 (6, 14) 0.3 Reason for readmission
Wound/surgery related issues (n, %) 12 (28%) 3 (19%) 0.46
Pneumonia (n, %) 8 (3%) 4 (5%) 0.23
GI (n, %) 6 (2%) 2 (3%) 0.33
Cardiac (n, %) 6 (2%) 3 (4%) 0.64
Pulmonary embolism (n, %) 4 (9%) 0 0.21
Outcomes
In-hospital mortality (No, %) (n, %) 8 (3%) 2 (3%)
Additional File #2: 2022811131041Table_2_ASRA.docx Click here to view
A50 Title: Ultrasound-Guided Intrafascicular and Perifascicular Injection in the Proximal Brachial Plexus in a Cadaver Model Presenting Author: Steven L Orebaugh MD Presenting Author's Institution: Univ. of Pittsburgh School of Medicine - Pittsburgh, PA Co-Authors: Jessen Mukalel MD - Univ. of Pittsburgh - Pittsburgh, PA Jonathan Weimer BS - Univ. of Pittsburgh - Pittsburgh, PA Patrick Filip MD - Allegheny General Hospital - Pittsburgh, PA Paul Bigeleisen MD - Univ. of Pittsburgh - Pittsburgh, PA
Abstract: Background and Objectives: Intrafascicular injection into peripheral nerves is known to be hazardous(1). Some authors warn that intrafascicular injection at very proximal levels may have the potential to enter and damage the substance of the spinal cord itself (2). In this observational study, we injected dye under ultrasound guidance into a fascicle, or into the perifascicular region, of the roots of the proximal brachial plexus, to evaluate how pressures, fluid spread and entry into the central nervous system would differ between injections at these two sites.
Methods: Seven non-preserved cadavers were injected and then subjected to dissection. A Sonosite S-nerve unit with a 8-15 MHz linear transducer was utilized to image the brachial plexus in the interscalene groove. Under ultrasound guidance, a 50 mm stimulating needle (B-Braun) was advanced until its tip was imbedded into the fascicle of the C-5 or C-6 nerve root (seven injections), or was directly adjacent to it (two injections). Particulate, colored ink was then injected. Injections were performed manually in the first three specimens. In the latter four specimens, injections were conducted with the aid of an electronic pump (Fusion 2000, Chemyx, Stafford, TX) while pressures were measured with an in-line transducer (PV350, Fluke, Everett, WA). After the ink was injected, the specimens were dissected to evaluate the brachial plexus and the neuraxis. The trunks, the nerve roots in the intervertebral foramina, as well as the spinal cord and its meninges, were inspected grossly. In specimen 6, sections were removed for microscopic analysis.
Results: Two intra-fascicular (IF) and one peri-fascicular (PF) manual injections were performed in the first three specimens (one injection in each). Injection into the fascicle produced spread proximally into the subarachnoid space. Distal spread into the lateral cord of the plexus was also observed in one specimen. Dye spread into the epidural space was noted for the perifascicular injection. In none of the first three specimens was the spinal cord itself affected. Six IF injections, along with one PF injection, were performed in the final four specimens using the automated injection system. The mean peak pressure achieved for these injections directly into the fascicles was 49.3 PSI, with a range of 37.8-66.2 PSI. Four of these IF injections revealed spread distally into the trunks or cords of the plexus, while in the other two, spread was confined to the root into which injection occurred. In the sixth specimen, the injection on the left side was between two visible fascicles within the C-6 root. This led to distal spread into the cords, with no proximal spread. IF and PF injection in this specimen was confirmed with histologic analysis. In none of these four specimens was the spinal cord grossly affected by spread of the ink-stained injectate.
Discussion: In 2 of the IF injections, spread of the ink proximally into the subarachnoid space was evident, while one PF injection resulted in spread into the epidural space. Peri-fasicular injections in this region may actually be sub-epineurial (3), since the epineurium is difficult to identify on ultrasound. In none of the specimens was there evidence of spread into the sub
References 1. Hadzic A, et al. Reg Anesth Pain Med. 2004;29:417. 2. Boezaart AP. Reg Anesth Pain Med. 2009;34:3-8. 3. Orebaugh SL, et al. Reg Anesth Pain Med. 2010;35:450. 4. Benumof JL. Anesthesiology. 2000;93:1541.
Additional File #1: 1030111104628ASRA_abstract_ISB_F.pdf Click here to view
A51 Title: Postoperative Analgesia with the Subsartorial Saphenous Nerve Block in Anterior Cruciate Ligament Reconstruction Presenting Author: Mary F. Chisholm MD Presenting Author's Institution: Hospital for Special Surgery - New York, NY Co-Authors: Heejung Bang PhD - Weill Cornell Medical College - New York, NY Marco Lotano MD - Hospital for Special Surgery - New York, NY Dorothy Marcello BA - Hospital for Special Surgery - New York, NY Michael Gordon MD - Hospital for Special Surgery - New York, NY
Abstract: Previous studies show that femoral nerve blocks (FNB) and femoral nerve catheters contribute significantly to postoperative (postop) pain management following arthroscopic ACL reconstruction with patellar tendon autografts. With the rapid progress and application of ultrasound to the performance of regional nerve blocks, an alternative treatment modality for postoperative pain in the ACL patient presented itself. The subsartorial saphenous nerve block (SSNB), performed 5-7 cm proximal to the knee, anesthetizes the antero-medial aspect of the knee through its infrapatellar branch. In this study, we evaluated whether analgesia following ACL reconstruction with patella tendon autograft using the SSNB approach was comparable to that provided by the traditional FNB.
Methods: Randomized double blinded controlled clinical trial was conducted using eighty ASA 1-3 patients, ages 16-65 undergoing ambulatory ACL reconstruction with patella tendon autograft. Exclusion criteria included: patient refusal, BMI > 35, allergy to study medications, NRS scores >3 with frequent opioid use preoperatively, lower extremity neurological deficits, or diabetes mellitus. Patient demographics were not statistically different between the two groups with respect to age, BMI, sex, and ASA status. All blocks were performed by anesthesiologists following patient randomization. The individuals assessing all outcome measures were blinded to the patient group. Patients were sedated with Midazolam and propofol in the OR, where the nerve block was performed prior to spinal anesthesia. Postoperatively, all received cryotherapy and parenteral Dilaudid prn until NRS <4 postop. At discharge, patients were given prescriptions for Schedule 3 narcotics prn, and placed on a scheduled NSAID regimen for the first three postopdays.
Results: NRS pain scores were evaluated by a blinded research assistant starting 2.5 hrs post-spinal, and at 30 min intervals postop until discharge. Upon discharge patients were instructed to complete pain diaries, including pain scores at rest and with movement every 4 hrs while awake, and number of pain pills consumed. Patients were contacted on POD1 and 2 to ascertain the level of patient satisfaction with the analgesic regimen.
Discussion and Conclusion: In this study we assessed if the SSNB will provide effective and prolonged analgesia following arthroscopic ACL reconstruction with patella tendon autograft, as a potential alternative to the FNB for postop pain control. In our study, we found equivalence between the two study groups with reference to postop day 1 and 2 NRS pain scores at rest (Fig. 1). In addition, there was no statistically significant difference in opioid use, as measured in daily oral morphine equivalents, between the SSNB and FNB groups (Fig. 2). While patients did report greater satisfaction with the FNB on POD1 in comparison to the SSNB group, the differences were insignificant by POD2 and clinically insignificant overall (Table 1). Collectively, these data support our hypothesis that the SSNB provides similar and adequate postop analgesia when compared to the femoral nerve block, following arthroscopic ACL reconstruction with patella autograft. Further investigation regarding postop quadriceps weakness is needed.
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Additional File #3: 3030111174543IRB__29133_ASRA_Tab.doc
Table 1: Patient Satisfaction
Femoral Nerve Block Group Saphenous Nerve Block Group
POD 1 POD 2 POD 1 POD 2
Satisfaction* 1.73±1.04 2.07±1.06 2.36±1.64 2.28±1.59 Significant difference on POD 1 (p=0.0476). Number Reporting 15 13 16 10 Nausea
Number Reporting 2 2 1 0 Vomiting
Used Anti-Emetics 9 8 9 9
Number Reporting 27 26 26 24 Drowsiness
Number Reporting 10 13 13 14 Itching
Number Reporting Dry 16 13 13 15 Mouth
Number Reporting 5 4 6 5 Headaches
*Satisfaction rated on scale of 1-7: 1=very satisfied, 2=somewhat satisfied, 3=slightly satisfied, 4=neither satisfied or dissatisfied, 5=slightly dissatisfied, 6=somewhat dissatisfied, 7=very dissatisfied
A52 Title: Ultrasound guided saphenus nerve block in the adductor channel. A cadaver study. Presenting Author: Sofie L Andersen, Medical Doctor Presenting Author's Institution: University Hospital Of Copenhagen, Hvidovre - 2300, Denmark Co-Authors: Joergen Tranum-Jensen Professor, Medical Doctor - University of Copenhagen - Copenhagen, Denmark Henning L Andersen Medical Doctor - University Hospital of Copenhagen, Frederiksberg - Copenhagen, Denmark
Abstract: Background and Aims: The saphenus nerve block represents an attractive alternative to femoral nerve block because of its pure sensory innervations and the increasing concern about motor block in relation to physiotherapy and rehabilitation after knee surgery. The saphenus nerve in the adductor channel is easily visualized by ultrasound at mid thigh level. Other nerves travelling in the adductor channel may be important for the analgesic effect to the knee when blocking the saphenus nerve in the adductor channel. We aim to determine the spread of 15 ml of injectate used for saphenus nerve block in the adductor channel by a subsartorius inline shortaxis approach at mid thigh level and to determine if this volume would affect other nerves.
Methods: Five cadaver legs were used for ultrasound guided saphenus nerve block in the adductor channel. 15 mL of polyurethrane was used for injection. The legs were stored under cool conditions allowing the polyurethrane to harden. The spread of the injectates was verified by dissection and compared to the ultrasound videos and still pictures. Ultrasound scanning identified the saphenus nerve under the sartorius muscle and antero-medial to the femoral artery at mid thigh level. The needle was advanced inplane in the cleavage between the vastus medialis muscle and the sartorius muscle towards the saphenus nerve. The injected volume was aimed to cover most of the surface of the nerve in proximity to the artery. One injection was intended to fill the subsartorius compartment above the roof of the adductor channel to see if this was sufficient to affect the saphenus nerve.
Results: The saphenus nerve was easily identified by ultrasound scanning on all specimens. Test injections were made to aid positioning of the needle. The main volume often created a sharp well-defined half-moon shaped halo around the saphenus nerve. A control scan distally along the nerve often revealed the injected volume to completely surround the saphenus nerve as it detached from the artery. No other nerves were apparently affected by the injected volume. The subsartorius injection was easier to place and gave a clear separation of the muscle and roof of the adductor channel but did not affect the saphenus nerve on the ultrasound scan. The dissections revealed that the adductor channel was completely filled by the polyurethrane in all specimens except for the subsartious injection. The saphenus nerve was identified in all specimens. We did not find other smaller nerves in the adductor channel affected by the injected polyurethrane, maybe because the plastic mass was difficult to dissect. However the polyurethrane could be followed distally along the femoral artery into the hiatus of the popliteal fossa through the adductor magnus muscle. The one injection made in the subsartorius compartment above the roof of the adductor channel did not affect the saphenus nerve that penetrated the roof more distally on the medial side of the knee.
Conclusion: This study showed that an ultrasound guided injection of a volume of 15 ml at mid thigh level completely fill the adductor channel. Other nerves in the adductor channel may also be affected by this injection but was not discovered by the dissection.
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A53 Title: Preoperative pain score and gender predict need for rescue block after ambulatory knee surgery (resubmitted with corrections) Presenting Author: Tse-Sun Ku MD Presenting Author's Institution: University of California San Francisco - San Francisco, CA Co-Authors: Alok Sharma MD - University of California San Francisco - San Francisco, CA Pedram Aleshi MD - University of California San Francisco - San Francisco, CA
Abstract: Background: The routine use of regional anesthesia for ambulatory knee surgery is controversial. Prior studies associated peripheral nerve blocks (PNB) with shorter post-anesthesia care unit (PACU) stay and lower pain scores after knee arthroscopy. However, there are a wide range of knee surgeries and these findings cannot be generalized. Our surgeons request PNB based on the expected severity of post-operative (post-op) pain. Some patients who do not receive a preoperative (pre-op) block have severe post-op pain and require rescue PNB in the PACU. This study was undertaken to identify risk factors for rescue blocks in a heterogeneous cohort of ambulatory knee surgery patients.
Methods: After obtaining IRB approval, 278 consecutive patients undergoing outpatient knee surgery were retrospectively studied. Bilateral procedures and patients receiving subarachnoid blocks were excluded. A separate study analyzed anterior cruciate ligament (ACL) reconstructions. Other surgeries on the ACL and major ligaments were categorized as complex. Patient demographics, pre-op pain score, PNB, time to readiness for discharge from PACU, post-op opiate use, highest post-op numerical rating scale (NRS) pain score, and incidence of post-op nausea/vomiting (PONV) were recorded. Block failures were included in the pre-op block group. Predictors of rescue block were explored using Pearson‘s chi-square test for categorical data (Fisher‘s exact test for counts less than 5) and one way analysis of variance for continuous data (Kruskal-Wallis test for non-normally distributed variables). Variables associated with rescue blocks in univariate analysis were included as predictors in multiple logistic regression.
Results: Meniscectomy and chondroplasty were the most common procedures. 146 (52.6%) patients received pre-op PNB (femoral 131, femoral/obturator 11, femoral/obturator/sciatic 5). 16 (12.1%) of the remainder required rescue blocks (femoral 2, obturator 1, sciatic 9, femoral/sciatic 4). 10 (62.5%) of this subset required obturator or sciatic PNB in addition to successful pre-op femoral PNB. Rescue blocks were significantly associated with longer recovery time, higher NRS pain score, and greater post-op opiate consumption (see Table 1). There was a trend toward higher incidence of PONV in patients receiving rescue blocks. Patients needing rescue blocks were more likely to be women undergoing complex surgery and tended to have higher pre-op pain scores (see Table 2). In multiple logistic regression, female gender and pre-op pain score were predictive of rescue blocks while surgical complexity trended toward significance (see Table 3).
Discussion: Patients receiving rescue blocks have longer recovery time, higher pain scores, and use more opiates in the PACU. Female gender and pre-op pain score are predictive of severe pain requiring post-op PNB. Femoral nerve block alone may be insufficient for satisfactory analgesia after outpatient knee surgery. Further study is required to determine whether pre-op PNB allocation based on these factors can decrease perioperative resource use.
Additional File #1: 1020511115021table1.pdf Click here to view
Additional File #2: 2020511115021table2.pdf Click here to view
Additional File #3: 3020711134917table3.pdf Click here to view
A54 Title: The Insider‘s Experience to the Transversus Abdominis Plane (TAP) Catheters for Analgesia for Cesarean Section (CS) Presenting Author: Allison S Haller MD Presenting Author's Institution: University of Florida - Gainesville, FL Co-Authors: Linda Le-Wendling MD - University of Florida - Gainesville, FL Andrea Esch DO - University of Florida - Gainesville, FL Barys Ihnatsenka MD - University of Florida - Gainesville, FL
Abstract: Introduction: Transversus abdominis plane (TAP) single injections are utilized to improve postoperative analgesia. Data suggests there is no added benefit when neuraxial morphine is utilized. 1 To determine the efficacy of TAP blocks first-hand for post-cesarean analgesia, individuals of the Regional Anesthesiology and Perioperative Pain Management division at the authors‘ institution opted to receive TAP catheters for postoperative analgesia following cesarean section (CS).
Cases: All three physicians are without significant medical and each previously had a CS with epidural, spinal and general anesthesia. 2 of the 3 subjects noted prolonged neuropathic pain along the incision for at least 9 months after their first CS. The subjects‘ second CSs were all performed with spinal bupivacaine (9 to 12.5mg), fentanyl (25mcg) and duramorph (100 to 150mcg). All TAP catheters were placed using ultrasound guidance in the recovery area at the conclusion of the CS prior to spinal regression with no additional sedation. TAP planes were opened with 20ml of 0.5% ropivacaine prior to introduction of TAP catheters, and all TAP catheters were tested with lidocaine 2% with 1:200k epinephrine for intravascular placements. Catheters were initiated with basal infusions of ropivacaine 0.2% at 6 to 10ml/h with boluses of 6 to 10ml every one hour for breakthrough pain. Subjects were also given ropivacaine 0.5% boluses of 10 to 15 ml per side for improved analgesia or after disconnections to allow ambulation, with resultant excellent analgesia lasting roughly 3 to 5 hours. Oral opioids were entirely spared while the TAP catheters were utilized for roughly 5 to 6 postoperative days, with nonsteroidal anti-inflammatory medications for analgesic supplementation. Opioids were resumed sparingly, after TAP catheters were removed, until roughly one to two weeks, when pain was minimal without analgesics. 2 subjects did not note neuropathic pain while the 3rd noted a transient, 10 day course of neuropathic pain 4 weeks after the second CS. 2 subjects were discharged within 30 hours of surgery.
Discussion: Acutely, moderate to severe pain with CS seemed to last one to two weeks. Neuraxial morphine result in superior analgesia in the first 24 hours, but many individuals cannot tolerate the side effects. The benefits of maintaining TAP catheters for continued analgesia included the opioid sparing as well as the ability for increased physical activity with analgesia. Additionally, breastfeeding was established without exposing the newborn infants to systemic opioids during the first 5 postoperative days. Entrapment of the ilioinguinal and iliohypogastric nerves during Pfannenstiel incision has been documented to result in a majority of chronic pain symptoms post-CS2 and there may be a role for peripheral deposition of local anesthetic in possibly mitigating the potential for chronic neuropathic pain. The subjects uniformly opted for smaller initial doses with TAP catheters compared to single injections because of continued dosing through the catheter. Further boluses of ropivacaine 0.5% through the catheters were limited to 15ml per side for the same reason. The subjects noted excellent analgesia with catheter bolusing and no systemic effects.
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A55 Title: A Retrospective Evaluation of Preoperative Peripheral Nerve Blockade for Ambulatory Arthroscopic ACL Reconstruction Presenting Author: Joshua M Cohen MD Presenting Author's Institution: University of California-San Francisco - San Francisco, CA Co-Authors: Pedram Aleshi MD - University of California-San Francisco - San Francisco, CA Alok Sharma MD - University of California-San Francisco - San Francisco, CA
Abstract: Introduction: No clear consensus, even among our institution‘s orthopedic surgeons, exists as to the appropriateness of peripheral nerve blockade for ACL reconstruction. This ambiguity is illustrated by two recent studies: one which showed no differences in opioid consumption or pain scores for patients receiving femoral nerve blocks prior to ACL reconstruction (1), and another which showed that patients receiving combined femoral and sciatic preoperative blocks had lower pain scores, decreased opioid consumption, and shorter PACU stays compared to patients receiving only femoral blocks (2). The aim of this present study was to compare the use of a preoperative single-shot femoral nerve block to femoral and sciatic nerve blocks for patients undergoing ambulatory arthroscopic ACL reconstruction.
Methods: After IRB approval, a retrospective chart review of all patients undergoing arthroscopic ACL reconstruction at a single ambulatory center between 10/2/2009 and 12/3/2010 was performed. Preoperative block choice was largely determined by surgeon preference. Block technique (ultrasound and/or nerve stimulation), local anesthetic type and volume, and use of inhalational and intravenous agents were left to the discretion of the attending anesthesiologist. All patients received a general anesthetic with placement of an LMA. Patient characteristics such as age, gender, weight, height, and BMI were recorded. Surgical information was recorded including length of surgery, attending surgeon, preoperative nerve block and opioids, intraoperative ketorolac and opioids. Finally, information related to the PACU course was recorded including the duration of stay until meeting discharge criteria, rescue blocks, opioids, ketorolac, highest VAS pain score, and PONV.
Results: Of the 155 electronic anesthetic records reviewed, five patients were excluded from the study. The remaining 150 patients consisted of 79 who received both preoperative femoral and sciatic nerve blocks (Group FSNB) and 71 who received only a preoperative femoral nerve block (Group FNB). Differences in patient characteristics and primary and secondary outcomes are listed below. Baseline patient characteristics between groups were similar except for a higher age for patients in Group FNB. Patients in Group FSNB had a longer operative duration, were more likely to receive an autograft, received fewer intraoperative and postoperative morphine equivalents, had lower maximum VAS pain scores, and received fewer rescue blocks in the PACU. No statistically significant difference was demonstrated in PACU duration (the primary outcome variable), incidence of PONV, or frequency of ketorolac administration.
Discussion: The results suggest that the addition of a sciatic nerve block to a femoral nerve block prior to ACL reconstruction may decrease the intraoperative and postoperative opioid requirements and result in increased patient comfort in the PACU. A prospective study will be conducted to further examine the effects of these preoperative nerve blocks in the ambulatory setting.
References 1. Matava MJ et al. (2009) Am J Sports Med. 37: 78-86. 2. Jansen TK et al. (2009) AANA J 77: 213-218.
Additional File #1: 1122710111839Chart1.doc Click here to view Femoral & P- Femoral Value Sciatic (n=79) (n=71)
Demographic data
Age, mean ± SD, y 30±10 34±9 .009
Sex, male/female, n 34/37 49/30 .082
Weight, mean ± SD, kg 73±14 78±16 .081
Height, mean ± SD, cm 172±10 173±10 .304
BMI, mean ± SD, kg/m² 25±3 25±4 .138
Surgical information
Duration of surgery, median (min- <.001 154 (81-345) 92 (50-170) max), min
% receiving ketorolac in OR 9/71 12/79 .658
Primary/revision ACL, n 60/11 63/16 .449
Autograft/allograft, n 48/23 38/41 .016
OR morphine equivalents, median <.001 10 (0-33) 18 (5-184) (min-max), mg
PACU information
Time to achieve PACU discharge 121 (68- .783 121 (41-239) criteria, median (min-max), min 314)
% receiving ketorolac in PACU 6/71 13/79 .141
PACU morphine equivalents, median .002 8 (0-158) 11 (0-39) (min-max), mg Total morphine equivalents, median <.001 20 (0-163) 33 (10-193) (min-max), mg
Highest PACU VAS pain score (0-10), <.001 4 (0-10) 6 (0-10) median (min-max)
PONV incidence 16/71 13/78 .366
A56 Title: The Sensitivity and Positive Predictive Value of Blood Pressure and Heart Rate Decrease to Confirm Correct Thoracic Epidural Placement Following an Epidural Test Dose Presenting Author: Na-Yon Nam MD Presenting Author's Institution: Northwestern University, Feinberg School of Medicine - Chicago, IL Co-Authors: Mark C Kendall MD - Northwestern University, Feinberg School of Medici - Chicago, IL Robert J McCarthy PharmD - Northwestern University, Feinberg School of Medici - Chicago, IL Antoun Nader MD - Northwestern University, Feinberg School of Medici - Chicago, IL
Abstract: Introduction: Prior to initiating epidural anesthesia a test dose is frequently administered to detect intravascular and/or intrathecal catheter placement. The sympathetic blockade produced by a 5 mL test dose of 1.5% lidocaine with 1:200,000 epinephrine at the T10 to T11 interspace and the resultant hemodynamic changes are not well described.1 The purpose of this study was to evaluate the effects of a 5 ml test dose on systolic blood pressure, diastolic blood pressure, and heart rate for 30 minutes. A secondary objective was to determine the sensitivity and the positive predictive value of the blood pressure and heart rate changes on confirming catheter placement in the epidural space.
Methods: Following IRB approval, ASA I-III female patients (>18 y/o) undergoing uterine artery embolization had a thoracic epidural catheter placed at the T01 to T11 interspace using the loss of resistance to air technique. All patients received a test dose of 5mL of lidocaine 1.5% with epinephrine 1:200K. Following the test dose, systolic/diastolic blood pressure (SBP/DBP) and heart rate were recorded. Epidural catheter placement was confirmed using fluoroscopy. The sensitivity of a 10% decrease in SBP, DBP or HR in predicting epidural catheter placement was compared to the preceding time intervals using the Gart and Nam Score. Fisher‘s exact test was used to detect differences in the positive predictive value (PPV) of a 10% change in SBP, DBP and HR at the same time interval. A P value < 0.05 was considered statistically significant.
Results: Ninety-five patients completed the study. Epidural catheter placement was confirmed in all subjects. Sensitivity and PPV are shown in the table. The sensitivity of a 10% decrease in SBP for detection epidural placement peaked at 15 minutes after the injection with a positive predictive value (PPV) of 63%. The sensitivity for diastolic blood pressure peaked at 10 minutes with a PPV of 69%. The PPV for diastolic blood pressure at 20 minutes following test dose was 82%.
Discussion: Following a low thoracic epidural placement, a 10% decrease in diastolic blood pressure was a more sensitive predictor of correct epidural catheter placement when compared to a 10% decrease in systolic blood pressure or heart rate for confirming correct epidural placement. After 15 minutes, the sensitivity and positive predictive value of a 10% change in heart rate, systolic and diastolic blood pressures remains relatively unchanged.
Conclusions: The sensitivity of a 10% decrease in SBP, DBP and HR for confirming correct epidural catheter placement at the low thoracic level is low. There was no significant increase in the sensitivity or positive predictive value of these changes beyond 15 minutes following the injection of the test dose.
References: 1.Anesthesiology. 1995 Sep;83(3):604-610.
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A57 Title: A Comparison of Ultrasound Guided Injection of Local Anesthetic Into or Around the Musculocutaneous Nerve in Patients Undergoing Forearm and Wrist Surgery Presenting Author: Paul E Bigeleisen MD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Annelot Krediet MD - UPMC - Pittsburgh, PA Andrew P Lucic MD - UPMC - Pittsburgh, PA
Abstract: Background: Intraneural injection has been purported to be a risk for neural injury during regional nerve block. To date, all of the prospective studies on intraneural injection suggest that the technique is safe and efficacious when performed distal to the nerve root with blunt needles. No studies have been performed to compare the efficacy of intraneural injection versus extraneural injection. In order to compare the efficacy of intraneural and extraneural injection, we reviewed our IRB approved ultrasound archives and medical records of twenty one patients who received axillary block for surgery of the fore-arm and hand. From this archive we were able to find 11 patients who had intraneural injection of the musculocutaneous nerve and 10 patients who had extraneural injection of the musculocutaneous nerve using 2% mepivacaine (Fig. 1). We were not able to clearly identify the median, radial and ulnar nerves in these retrospective scans, so we did not include them in our analysis.
Methods: All patients had ultrasound guided block using a Sonosite S-Nerve platform with a 13 MHz or 15 MHz transducer. The patients had the sensory (pinprick of the lateral forearm) and motor function (elbow flexion) of the musculocutaneous nerve tested after injection and before block of the median, radial and ulnar nerves was performed. In these patients, local anesthetic was injected until the musculocutaneous nerve was either completely surrounded with local anesthetic (extraneural injection with halo) or until the nerve swelled (intraneural injection).
Discussion: Both techniques, intraneural and extraneural injection, were successful in anesthetizing the musculocutaneous nerve rendering the forearm and hand akinetic and insensate in the distribution of the musculocutaneous nerve. All patients completed surgery under sedation with out any local infiltration by the surgeon in the distribution of the musculocutaneous nerve. Block of the musculocutaneous nerve was completely resolved within four hours in all patients. All patients were phoned at home within 48 hours of the completion of the surgery. None of them had weakness or pain or diminished sensation in the distribution of the musculocutaneous nerve.
Intraneural injection required less local anesthetic and had a faster to time to surgical block. In the setting where rapid onset is required or where minimizing the total dose of local anesthetic is important, intraneural injection may have advantages over extraneural injection. Further studies will be needed to determine the efficacy and safety of both techniques on other nerves in the body.
Additional File #1: 1022811202609intra_v_extra_table.doc Click here to view
Results:
Intraneural Extraneural
# 11 10
Mean Age 37? 43
Mean dose 1.3 ± 4.6± in ml
Time to 1.4 ± 5.3±
Motor and
Sensory Block in min
Success 11/11 10/10
Motor
Success 11/11 10/10
Sensory
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A58 Title: Post-Operative Pain Following Knee Arthroplasty: Rose of Gender and Obesity Presenting Author: Syed Azim MD Presenting Author's Institution: Stony Brook University Medical Center, Stony Brook, NY - Stony Brook, NY Co-Authors: Rebecca Sangster MD - Stony Brook University Medical Center, Stony Brook - Stony Brook, NY Christine Curcio MD - Stony brook University Medical Center, New York - Stony Brook, NY Dominick Coleman MD - Stony brook University Medical Center, New York - Stony Brook, NY Ruth Reinsel PhD - Stony Brook University Medical Center, NY - Stony Brook, NY
Abstract: Introduction: Optimized peri-operative pain management of patients undergoing total knee arthroplasty (TKA) is essential for patient health, satisfaction, rehabilitation and for prevention of chronic pain following surgery. Currently, at our institution post-operative pain management of patients for TKAs involves a peripheral femoral nerve catheter combined with opioids, non-opioid analgesics (pregabalin) and non-steroidals. Here we tested the hypothesis, that this multi- modal analgesic regimen would provide adequate pain relief for all TKA patients with average pain scores <3-4 over the first 24 hrs post-operatively.
Methods: With approval from the IRB we collected retrospective data from 100 patients undergoing TKA under this anesthetic regimen during 2009 (consent waived). Data collection included demographic data, visual analogue pain scores (VAS, 0-10) collected every 4 hours thereafter until the femoral nerve catheter was discontinued. In addition, opioid consumption was recorded as the amount of morphine equivalents administered during the first 24 hrs.
Results: Demographic analysis revealed that the mean age of the TKA patients was 65.5 ±11.1 years with a mean body mass index of 33.2 ±6.7 and 60% were female. Further, 33 % of our TKA patients had average pain scores of >6 (‗High pain‘ Group) in spite of indwelling functioning femoral nerve catheters and also predictably consumed significantly more opioids than the ‗Low Pain‘ Group over the first 24 hrs post-operatively. A chi-square test demonstrated that ‗younger‘ age was a significant independent variable (p=0.035) between the ‗High Pain‘ (HP) and ‗Low Pain‘ (LP) groups. We also observed that the HP group trended to be more obese compared to the LP group.
Conclusions: Our retrospective analysis demonstrated that the majority of our patients were female with a BMI>33 (33.2 ±6.7) and further that younger patients were at higher risk for acute post-operative pain compared to elderly patients. Specifically, in spite of multi-modal analgesic care which included indwelling femoral nerve catheters, pregabalin and NSAIDS, 33% of our patients undergoing unilateral TKA experienced excessive pain (>6 VAS) during the first 24-hr post-operatively and also tended to be characterized by higher BMIs. We are in the process of implementing a prospective study to improve our pain management and to examine the impact of circulating levels of leptin which is a hormone involved in regulating body weight and is known to be increased in conjunction with proinflammatory cytokines including IL-6 and TNF-alpha in most obese adults.
Additional File #1: 1022811191853Retrospective_study.pdf Click here to view
Additional File #2: 2022811191853Retrospective_study.pdf Click here to view
Additional File #3: 3022811191853Retrospective_study.pdf Click here to view
A59 Title: Reproducibility of ―off-cart‖ Measurements of Musculoskeletal Structures in Ultrasound Images Presenting Author: Xiang Li PhD Presenting Author's Institution: Minhang Hospital of Shanghai - Shanghai, Shanghai Co-Authors: Manoj Karmakar MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong Jiawei Li Mphil - The Chinese University of Hong Kong - Hong Kong, Hong Kong Tony Gin MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong
Abstract: Background: ―In-cart‖ measurements of distance and area in an ultrasound (US) image during an US scan can be time consuming and it also interrupts the scan. ―Off-cart‖ methods, which use image analysis computer software to perform such measurements, have previously been described. However, there are no data comparing the accuracy of such methods, which this study was designed to evaluate.
Methods: After ethics approval and the written informed consent, two groups of subjects were recruited for this study. Group 1 comprised of 10 adult volunteers who had a transverse scan of the median nerve (MN) in the mid-forearm. Group 2 comprised of 30 adult patients who had a sagittal scan of the right infraclavicular fossa, with the arm abducted and the transducer positioned infero-medial to the coracoid process, before the induction of anesthesia. In both groups the US system settings were standardized and every effort was made to align the transducer perpendicular to the median nerve or the axillary artery during the US scan.
Representative US images were recorded on tape and still images were captured (3 images per subject) from the video loops using Adobe® Premier Pro 2.0 and stored in a computer in TIFF format (720 x 576 pixels and 8-bit gray scale levels) for the ―off-cart‖ measurements. In Group 1, the echotexture of the MN was analyzed by measuring the echo intensity (EI), and the spatial distribution of pixels in the MN US image. The image was first normalized, during which, the gray-scale values of all the pixels in the images were adjusted to two reference points (pure black=0; pure white=255). EI and cross sectional area (CSA) of the MN were then measured using the histogram function in Adobe® Photoshop CS2 and the measurement function in Image-Pro® Plus 6.2 (IPP) respectively. For echotexture analysis the noise in the image was reduced using the median filter of IPP. The default median value (128) of the gray-scale range (0-256) was used as the common threshold. The grayscale image was thereby converted to a binary image. The white area index (WI) and black area index (BI) of the MN was also determined using IPP. In Group 2, the ―off-cart‖ measurement of distance from the skin to the anterior wall of the axillary artery and the CSA of the axillary artery was also performed using IPP. Each measurement described above was performed independently by two observers and was repeated by one of the observer after one month. Interobserver and intraobserver variability was then tested on the measurements made using the intraclass correlation coefficient (ICC) and the paired samples t-test. A p value less than 0.05 was considered statistically significant.
Results: There was no significant difference in the various parameters measured by the two observers, and on the two days (p > 0.05) (Table 1). ICC of all the measurements made by the two observers and on the two days was greater than 0.75, which indicates that there was good interobserver agreement and intraobserver consistency.
Conclusion: We have demonstrated that the ―off-cart‖ method of measuring distance, area and echotexture in US images that was used in this study is reproducible and may be used to replace ―in-cart‖ methods of measurements for research purposes.
Additional File #1: 1012711221429table_1__intraobser.tif Click here to view
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A60 Title: Total Knee Arthroplasty as Ambulatory Surgery: Proof of Concept Presenting Author: Andrew P Lucic MD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Jacques Chelly MD, PhD, MBA - UPMC - Pittsburgh, PA
Abstract: Background: It is well established the next decades are going to be associated with a very significant increase in demand for joint replacement and related expenses. Consequently, it is critical to evaluate the feasibility of providing safe and cost- effective cadre to patients. We previously reported that the combination of improve surgical and anesthesia and acute perioperative techniques led to the possibility of performing total hip replacement as an ambulatory procedure in over 40% of a non-selected population. Using a quad-sparing MIS technique for total knee replacement in combination of the use of regional anesthesia has led to the concept that total knee replacement also represents a procedure that can be performed as an ambulatory procedure.
Materials and Methods: Between Jan. 19th, 2011, and Feb. 23rd, 2011, we reviewed our IRB approved database for non pre-selected patients scheduled for unilateral total knee arthroplasty using a quadsparing technique. Each patient received preoperatively a femoral and sciatic nerve block using either 17 mL of ropivacaine 0.2% (femoral) or saline (sciatic). Following the block a perineural catheter was placed for postoperative infusion of local anesthetics. In the recovery room the perineural catheter was infused with either bupivicaine 0.0625% at 5 mL/hr (femoral) or bupivicaine 0.0325% at 3 ml/hr (sciatic). The nurses were encouraged to bolus 3 ml/hr in femoral or sciatic catheters depending on the distribution of pain prior to administering any narcotic medication. Each patient also was given access to oxycodone 5 mg for moderate breakthrough pain and 10 mg for severe pain.
Results: Of the 32 quadsparing knees 65% were discharged within 2 days and 10% within 1 day. The over all average length of stay was 2.48 days. The average age was 64.2 years of age (61 years old discharged in less than 2 days, 70 years old for those discharged in greater than 2 days).
Discussion: Our data confirm the concept that total knee can be performed as an ambulatory surgery. This was previously demonstrated using a pre-selected and conditioned patient population. Our patient population is not selected and therefore are more representative of others practices. The projected number of total knee arthroplasty is expected to increase significantly over the next decades. Although some of this increase is due to our aging population, it is also the result of the fact that this procedure is performed in younger patients. Therefore there is a real financial incentive to develop fast tracking pathways allowing minimizing the length of stay in the hospital and in rehabilitation centers following joint replacement. We previously demonstrated before that total hip arthroplasty can be performed as an outpatient surgery in 44% of the patients. Our present data suggest that the same process can be applied to the performance of total knee replacement. Such an approach represents an opportunity for considerable saving since it is estimated that the cost of recovery following a total knee replacement is between $15 to 20,000.
Additional File #1: 1022811195123ASRA_references_TKA.doc Click here to view
References Berger RA, Kusuma SK, Sanders SA, Thill ES, Sporer SM. The feasibility and perioperative complications of outpatient knee arthroplasty. Clin Orthop Relat Res. 2009 Jun;467(6):1443-9. Berger RA, Sanders S, D'Ambrogio E, Buchheit K, Deirmengian C, Paprosky W, Della Valle CJ, Rosenberg AG. Minimally invasive quadriceps-sparing TKA: results of a comprehensive pathway for outpatient TKA. J Knee Surg. 2006 Apr;19(2):145-8.
Berger RA, Sanders S, Gerlinger T, Della Valle C, Jacobs JJ, Rosenberg AG. Outpatient total knee arthroplasty with a minimally invasive technique. J Arthroplasty. 2005 Oct;20(7 Suppl 3):33-8.
Mears DM, Mears SC, Chelly JE, Dai F, Vulakovich KL. THA with a minimally invasive technique, multimodal anesthesia, and home rehabilitation. Clin Orthop Relat Res. 2009 467:1412-1417. A61 Title: Thoracic Paravertebral Block Reduces Symptoms and Severity of Chronic Pain and Improves Health Related Quality of Life after Breast Cancer Surgery. Presenting Author: Manoj K Karmakar MD Presenting Author's Institution: The Chinese University of Hong Kong - Shatin, New Territories Co-Authors: Anthony M-H Ho MD - The Chinese University of Hong Kong - Shatin, New Territories Anna Lee PhD - The Chinese University of Hong Kong - Shatin, New Territories Winnie Samy BN - The Chinese University of Hong Kong - Shatin, New Territories Wing C Chan FRCS - The Chinese University of Hong Kong - Shatin, New Territories
Abstract: Background: A single-injection thoracic paravertebral block (TPVB) performed before general anesthesia (GA) for breast cancer surgery reduces acute postoperative pain, analgesic consumption and reduces the prevalence and severity of chronic pain. However there are no data on whether a TPVB affects health- related quality of life (HRQOL) in breast cancer survivors, which this study was designed to investigate.
Methods: After ethical approval and written informed consent 180 women, less than 70 yrs, ASA 1-3, undergoing modified radical mastectomy (MRM) were recruited for this prospective, randomized, double-blind, controlled study. Patients were randomized to one of the three study groups: Gp 1 (standardized GA, control group), Gp 2 (GA with a preincisional single-injection TPVB and a paravertebral infusion of saline) and Gp 3 (GA with a preincisional single-injection TPVB and a continuous TPVB with 0.25% ropivacaine). Outcomes were recorded by a blinded outcome assessor before surgery, early postoperative period (72-h) and at 3 and 6 months (telephone interview) after discharge. Anxiety and depression was measured using HADS (Hospital Anxiety and Depression Scale). HRQOL was measured using the validated Hong Kong Chinese version of the Short Form-36 (SF-36). Repeated measure analysis of variance (ANOVA), Kruskal Wallis test and χ2 test were used to compare outcome differences between groups.
Results: Of the 180 women, 177 completed the study. The three study groups were comparable at baseline. Gp 1 required more (p=0.001) morphine during surgery than Gp 2 and Gp 3. There were no differences in pain scores at rest or on movement, between the groups, during the 72-h after surgery. The incidence of chronic pain (%, 95% CI) was comparable between the groups at 3 months [Gp 1, 73 (62-85), Gp 2, 60 (47-73) and Gp 3, 57 (44-70), p=0.13] and 6 months [Gp 1, 35 (23-47), Gp 2, 30 (18-42) and Gp 3, 30 (18-42), p=0.78]. During the follow up there was a difference in the mean pain score on movement over the operative site between groups (p=0.02). Compared to the Gp 1, Gp 3 had lower pain scores on movement over the operative site during the follow up (p=0.049). Patients in Gp 1 also reported more pain symptoms than in Gp 2 and Gp 3 at 3 months (p=0.02) and 6 months (p=0.04). The HADS score was comparable among the groups during the study except at discharge when more patients in Gp 1 were anxious (p=0.04) and depressed (p<0.01) than in the other groups. Table 1 shows the mean physical component summary (PCS) and mental component summary (MCS) scores of the SF-36 over time. For the PCS scores, at 3 months Gp 3 had higher (mean difference 3.6, 95% CI: 0.6 to 6.6) PCS scores than in Gp 1 but there was no difference between Gp 1 and Gp 2 (p=0.07). At 6 months, there was no difference in PCS scores between the groups (p=0.06). For the MCS scores, Gp 1 had significantly lower MCS scores than Gp 2 (p=0.01) [mean difference 4.4, 95%CI: 0.6 to 8.3] but not Gp 3 (p=0.123) during the follow up.
Conclusions: Continuous TPVB reduces symptoms and severity of chronic pain, and produces a short-term improvement in physical HRQOL after MRM. A pre-incision single-injection TPVB also reduces symptoms and severity of chronic pain but seems to only improve mental HRQOL.
Additional File #1: 1012711191543Table_1_0_Karmakar_.tif Click here to view (cannot paste in)
A62 Title: Effect of Optimal Regional Analgesia on Arterial Tone after Total Hip Arthroplasty Presenting Author: Enrique Goytizolo MD Presenting Author's Institution: Hospital for Special Surgery - New York, NY Co-Authors: Stavros Memtsoudis MD PhD - Hospital for Special Surgery - New York, NY Dorothy Marcello BA - Hospital for Special Surgery - New York, NY Valeria Buschiazzo . - Hospital for Special Surgery - New York, NY Ansara Vaz BA - Hospital for Special Surgery - New York, NY
Abstract: Introduction: Pain causes activation of the sympathetic nervous system, leading to vasoconstriction, hypertension and tachycardia. For older patients with significant cardiac history, any increase in vascular tone and thus cardiac afterload could potentially cause serious complications. Thus, the goal of the optimal analgesic is to not only decrease pain, but also prevent potentially adverse hemodynamic consequences.
Methods: This double-blinded randomized controlled clinical trial was designed to study the effect of optimal regional analgesia on arterial tone after total hip replacement (THR) on patients ages 60-100. Patients undergoing THR were randomized to receive either combined spinal epidural alone (CSE) or CSE with lumbar plexus block (LPB). The Pulsecor monitor was used to measure the augmentation index (AI), which has been validated as a measure of arterial tone and can be obtained non-invasively from a regular blood pressure cuff. Arterial tone was recorded at the following times: 1) before surgery in the holding area, 2) in the operating room before the start of surgery, 3) in the post anesthesia care unit (PACU) after recovery of the spinal block, 4) in the PACU, 2 hours after the initial assessment, 5)on post operative day(POD) 1, and 6) on POD2. Our study was powered to detect a 30% difference in AI between the two groups. Secondary outcomes were: 1) pain scores in the PACU and on POD1 and POD2 while patients were at rest, after pain was controlled, 2) Use of anti-emetic medication (or number of occurrences), 3) Incidence of nausea/vomiting, 4) temperature and leukocyte count as markers of immune activation, and 5) total opioid use (including epidural patient controlled analgesia and oral opioid consumption).
Results: After obtaining written, informed consent, 92 patients were enrolled. 2 patients were excluded due to equipment failure shortly after enrollment. Of the remaining patients, 44 patients received CSE alone and 46 patients received CSE and LPB. Patient demographics were similar in both groups. Although the LPB group demonstrated a statistically significant reduction of VAS scores in the PACU (P<0.05), overall, the addition of a LPB did not significantly reduce the AI when compared to the control group. Other outcomes were similar in both groups (P>0.05). No adverse events attributable to the LPB occurred.
Comments: The addition of a LPB provided better pain control in the PACU, but did not reduce the AI, as measured by the Pulsecor, compared to the control group. We conclude that the addition of a LPB may have limited ability to affect arterial tone in the presence of a continuous infusion of epidural analgesics. Given the known sympatholytic effects of regional anesthesia, it is possible that beneficial effects on AI may be appreciated when comparing regional analgesic to intravenous or oral techniques. However, the use of CSE and LPB represent the standard of care at our institution and further evaluation is not possible at this point in time.
References 1.Bagry H et al. Effect of a Continuous Peripheral Nerve Block on the Inflammatory Response in Knee Arthroplasty. Reg Anesth Pain Med. 2008;33(1):17-23. 2.Gordon DB et al. Opioid Equianalgesic Calculations. Palliat Med. 1999;2:209-219.
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Additional File #2: 2030111194412IRB__28098_Table_1.doc Click here to view Table 2: Postoperative VAS Scores
P- Control (CSE Only) Treatment (CSE with LPB) Value
Time of Follow Up Visit First PACU 2nd PACU POD 1 POD 2 First PACU 2nd PACU POD 1 POD 2 ()
VAS Score 3.35 ± 3.42 1.76 ± 1.62 1.64 ± 1.81 2.66 ± 2.43 1.19 ± 1.77 1.80 ± 1.81 1.47 ± 1.70 1.90 ± 1.69 0.01
Table 1: Perioperative Characteristics
Control (CSE Only, Treatment (CSE with P-Value N=44) LPB, N=46) Age 71.18 ± 5.87 71.2 ± 7.4 0.992 Male/Female 21/23 23/23 0.8337 Height (cm) 168.18 ± 11.02 166.98 ±10.08 0.591 Weight (kg) 78.44 ± 17.04 78.78 ± 17.21 0.927 BMI 27.57 ± 4.68 28.16 ± 5.31 0.580 ASA Class (1/2/3) 1/34/9 1/40/5 0.217 Use of Preoperative Anti-Inflammatory 20 21 0.734 Drugs (Mobic and/or Decadron) Length of surgery 73.25 ± 15.91 73.33 ± 14.25 0.981 (min) Estimated Blood Loss 168.18 ± 32.51 178.04 ± 58.49 0.329 (ml) Received ≥1 Postoperative Blood 11 14 Transfusions Postoperative 188.07 ± 195.20 201.30 ± 179.72 0.739 Drainage (ml) Total morphine from oral opioid use only 47.49 ± 29.64 40.82 ± 25.10 0.251 (mg) Total morphine from 23.30 ± 14.24 19.19 ± 9.82 0.113 PCA use only (mg) Total morphine: PCA and oral opioid use 70.79 ± 37.49 60.00 ± 32.88 0.150 (mg)
Additional File #3: 3030111194412IRB__28098_Table_2.doc Click here to view Table 2: Postoperative VAS Scores
P- Control (CSE Only) Treatment (CSE with LPB) Value
Time of Follow Up Visit First PACU 2nd PACU POD 1 POD 2 First PACU 2nd PACU POD 1 POD 2 ()
VAS Score 3.35 ± 3.42 1.76 ± 1.62 1.64 ± 1.81 2.66 ± 2.43 1.19 ± 1.77 1.80 ± 1.81 1.47 ± 1.70 1.90 ± 1.69 0.01
A63 Title: Femoral Nerve Catheters and Falls in patients undergoing Orthopedic Surgery Presenting Author: Jagan Devarajan MD Presenting Author's Institution: Cleveland Clinic - Cleveland, OH Co-Authors: Tatyana Shuster RN, MSN, C-NP - Cleveland Clinic - Cleveland, OH Loran Mounir Solimin MD - Cleveland Clinic - Cleveland, OH
Abstract: Total knee replacement arthroplasty (TKR) is a common procedure being performed over fifty years for knee pain and decreased functional ability. TKR is associated with considerable pain in the postoperative period which if not treated well will lead to significant discomfort and decreased functional ability of the knee. Various analgesic regimens have been used to control pain following TKR. They include neuraxial analgesia, lumbar plexus block, and femoral nerve block alone or combined with sciatic nerve block and opioid. There is no clear evidence favoring one technique over other though femoral nerve block had been shown to be more successful and associated with fewer side effects. Despite numerous advantages, femoral catheters can produce significant quadriceps weakness resulting in falls. The incidence of falls reported following TKR is from 1-2%. Falls are associated with significant morbidity including fracture of periprosthetic femur, prolonged hospitalization, infection and poor outcomes following surgery. There is paucity of evidence regarding association of femoral nerve catheters and related falls in orthopedic patients and hence this review.
Methods: After obtaining permission from IRB, we collected the details of the patients admitted in orthopedic surgical floors who fell in the past two years. Demographic data like age, sex, BMI were obtained. Past medical history and previous history of falls information were obtained from the patients‘ medical record. Any past history of syncope, giddiness, impaired vision, and preexisting weakness of the legs were collected. H/O alcohol and substance abuse and use of psychotropic medications noted. Time and nature of fall and strength of muscles at the time of fall and hemoglobin were noted.
Results: Total number of patients who fell during two years review was 30 and among them 19 had continuous femoral nerve catheter infusion. The FNC was placed for total knee replacement in 18 patients and one had open reduction and internal fixation of non union of fracture femur. Mean age was 63 years. There were 7 male patients and 15 female patients who had a fall during the postoperative period. All except one had primary total knee replacement arthroplasty. Single shot sciatic nerve block was performed in 5 patients. All patients received ropivacaine 0.1% as continuous infusion at 8-10 ml/hr and no bolus was permitted. 13 had spinal anesthesia for their primary surgery and 8 had general anesthesia. The average blood loss during the surgery was 109 ml but majority of patients had significant decrease in the hemoglobin following surgery. No patients had any previous history of fall. Postoperative confusion was present in 5 patients. Only one patient had dehiscence of the wound and one had fracture of ankle due to fall. Length of hospital stay was increased by 3 days in the patient who required surgery due to dehiscence. Range of movements was not affected in any patient who had fall and they continued physical therapy with supervision during the rest of the stay in hospital. There was no increased length of stay attributed to the falls.
Conclusions: A small minority of patients are at risk of fall due to femoral nerve catheter. However this was not associated with increased morbidity.
A64 Title: Resident knowledge improvement after an advanced regional anesthesia education program Presenting Author: Julie HY Huang MD, MBA Presenting Author's Institution: The Johns Hopkins Hospital - Baltimore, MD Co-Authors: Joseph Hung MD - The Johns Hopkins Hospital - Baltimore, MD Jean-Pierre P. Ouanes DO - The Johns Hopkins Hospital - Baltimore, MD Shawn Sumida MD - The Johns Hopkins Hospital - Baltimore, MD Marie Hanna MD - The Johns Hopkins Hospital - Baltimore, MD
Abstract: Introduction: The purpose of this study was to evaluate the effectiveness of a structured regional anesthesia teaching program in a large academic medical center. These regional anesthesia didactics took place in the setting of a unique resident education program scheduled during two fully protected teaching days a month. More specifically, the curriculum included hands-on cadaver workshops in the anatomy lab, hands-on ultrasound workshops, hands-on nerve stimulator and surface anatomy workshops, and simulator sessions related to complications of regional anesthesia.
Methods: Prior to beginning the formal regional anesthesia teaching program, residents completed a pretest composed of 25 multiple choice questions (MCQ) and a three-section observed standardized clinical examination (OSCE). Seven months later, approximately one month after completion of the regional anesthesia curriculum, the residents were evaluated again with the exact same tests. Pretest and posttest results for both the MCQ and the OSCE were compared by using a paired t-test for statistical means.
Results: Posttest results were significantly improved (P < 0.05) across all clinical anesthesia (CA) years and for both the MCQ (Table 1) and OSCE (Table 2) examinations. Posttest results were also significantly improved (P < 0.05) across all CA years for each of the three sections of the OSCE.
Conclusion: The formal regional anesthesia teaching program developed by the departmental faculty was effective in improving resident knowledge.
Key Words: Education, Regional anesthesia, Pain management.
References 1. Smith HM, Kopp SL, Jacob AK, Torsher LC, Hebl JR. Designing and implementing a comprehensive learner-centered regional anesthesia curriculum. Reg Anesth Pain Med. 2009;34:88-94.
Additional File #1: 1022211173731Abstract2_tables_AS.pdf Click here to view
A65 Title: A Retrospective 30-Month Survey of Sedation and Multimodal Analgesia Practices in a Preoperative Regional Anesthesia Area Presenting Author: Kelly Baird MD Presenting Author's Institution: Wake Forest University - Winston Salem, NC Co-Authors: Robert Couch MS - Wake Forest University - Winston Salem, NC JC Gerancher MD - Wake Forest University - Winston Salem, NC
Abstract: Background: While sedation and preoperative multi-modal analgesia1 in conjunction with regional anesthesia have been widely advocated, compliance with intended practices has not been adequately described. In addition, sedation practices during regional procedures remain controversial2. We performed a retrospective review of our sedation and multimodal analgesia practices for all patients in our regional area over 30 months. Our hypothesis was that the use of sedation would vary to a clinically significant degree by faculty anesthesiologist, while adherence to multimodal analgesia protocols would be highly consistent.
Methods: A computer application for documenting regional anesthesia was added as an integrated module in our operating room information management system (John Galt OR Systems, Winston Salem NC) in March of 2008. The five main documentation components of the Regional Application are 1) general check-in information, 2) pre-procedure Universal Protocol, 3) detailed record of nerve blockade, 4) template driven record of medication administered for multimodal pain management, sedation, and regional analgesia, and 5) automated electronic capture of vital signs. Data from 7/1/2008 to 1/1/2011 required for analysis of our sedation and multimodal analgesia practices was extracted for the fourth component via an ODBC connection to the Oracle database which houses all John Galt data tables.
Results: During this 30 month period, 7407 patients received care in our Regional Anesthesia and Acute Pain Management (RAAPM) area, having 1.8 blocks/patient and 13,688 blocks (figure one). Seven faculty (JC,KC,JG,QM,PN,WR,RW) provided medical direction for the majority of these with 163 patients cared for by other anesthesiology faculty (OA). Average fentanyl use during this period was 149+/-93 mcg, while 3.8+/-3.2 mg of midazolam per patient were used. Sedation practices for each faculty are demonstrated in figure two. Multimodal analgesia practices changed during the 30 month period. (figure three). Intravenous methadone use was 2.6% overall but varied by semester (5.6, 0.8, 1.4, 2.1, and 4.0% respectively).
Conclusions: Our hypotheses that sedation practices varied significantly by clinician was not correct: the variation in sedation was greater for patients than by anesthesiologist. Our hypothesis that multimodal analgesia practices were consistent was not correct. Changes in sedation and multimodal practices appear to follow known systems based effects. For example, a shortage of methadone in the second semester of 2008 prompted removal of this medication from our Acudose Rx (McKesson Health Solutions, CA) and led to a decrease in use of this drug until it was again stocked much later in first semester of 2010. This study has helped us assess our own compliance with multimodal analgesia. In addition, this profile of sedation practices through our RAAPM area documents our practices and may help other clinicians seeking validation of, or comparison with, their own.
References 1. White PF et al. Anesth Analg. 2007;104:1380-1396. 2. Bernards CM et al. Reg Anesth Pain Med. 2008;33:449-460.
Additional File #1: 1022811132512RAAPM_Area_Clinical.pdf Click here to view
Additional File #2: 2022811132721RAAPM_Area__Sedatio.pdf Click here to view
Additional File #3: 3022811132721RAAPM_Area_Multimod.pdf Click here to view
A66 Title: Lumbar plexus block for pain control after hip arthroscopy. A randomized controlled trial. Presenting Author: Matthew C Rade BA Presenting Author's Institution: Hospital for Special Surgery - New York, NY Co-Authors: Jacques YaDeau MD, PhD - Hospital for Special Surgery - New York, NY Tiffany Tedore MD - New York-Presbyterian Hospital, Weill Cornell Medi - New York, NY Enrique Goytizolo MD - Hospital for Special Surgery - New York, NY David Kim MD - Hospital for Special Surgery - New York, NY
Abstract: Introduction: Hip arthroscopy is associated with moderate to severe postoperative pain, with numerical rating scale (NRS, 0-10) pain scores as high as 8 to 10, (1). Many patients receive postoperative opioids that can result in nausea, vomiting and delayed discharge. Lumbar plexus blockade (LPB) has a low complication rate and is superior to opioids for pain control after total hip replacement, (2). No randomized controlled clinical trials address anesthetic or analgesic regimens for patients undergoing hip arthroscopy. This study investigated whether the addition of a LPB to a neuraxial anesthetic reduced postoperative pain.
Methods: Following IRB approval, a prospective randomized controlled trial of 82 patients undergoing ambulatory hip arthroscopy was initiated. All patients received intravenous sedation (midazolam and propofol), ondansetron, ketorolac, and a mepivacaine combined spinal-epidural. Study patients additionally received a LPB using 30 mL 0.25% bupivacaine (with 5 mcg/ml epinephrine), (3). No intraoperative opioids were given; postoperative analgesia was provided with hydrocodone/acetaminophen and oral nonsteroidal anti-inflammatory agents. A blinded investigator interviewed patients at 30 minutes, 1 hour, 2 hours, 3 hours and 4 hours after end of surgery, and via telephone approximately 24 hours postoperatively.
Results: Demographics were uniform between groups, (Table 1). Pain scores were modeled with the General Estimating Equations method. The LPB reduced pain at rest in the recovery room (p = 0.032; NRS pain scores at 30 minutes of 2.8 vs. 4.1), (Figure 1). Trends in secondary outcomes also favored the intervention: reduced analgesic usage in the recovery room (21 vs. 29 mg morphine equivalents), reduced pain with therapy, and higher satisfaction (8.6 ± 1.6 vs. 7.9 ± 2.5); however, these differences were not statistically significant, (Table 1). Adverse events included two falls in the LPB group, without injury.
Discussion: LPB, added to a multimodal analgesic regimen including neuraxial anesthesia, anti-inflammatory drugs and hydrocodone/acetaminophen, reduced pain on the day of hip arthroscopy surgery. A meta-analysis concluded that single- injection LPB reduces pain for 4-8 hours after hip arthroplasty, in keeping with our results, (2). Additional non-significant trends favored the intervention, including reduced pain with therapy, decreased use of analgesics in the PACU and higher patient satisfaction. Study limitations include insufficient power for secondary outcomes. Moreover, control patients in this study did not experience as much pain as suggested from the literature. In conclusion, administration of LPB to hip arthroscopy patients significantly reduces pain on the day of surgery. LPB can be considered for reduction of short-term pain as part of a multi-modal analgesic regimen. The absence of significant improvement in secondary outcomes, and the possibility of side-effects suggest that assessment of risks and benefits of LPB for hip arthroscopy patients should be individualized.
References 1. Lee EM, et al. J Clin Anesth. 2008;20: 462-465. 2. Touray ST, et al. Br J Anaesth. 2008;101: 750-760. 3. Capdevila X, et al. Reg Anesth Pain Med. 2005;30: 150-162.
Additional File #1: 1030111142842Table_1.xls Click here to view
Table 1. Patient Characteristics and Secondary Outcome Measures
Lumbar Plexus Standard Block Overall p- Variablea n=41 n=41 n=82 valueb 35 ± Age, years 37 ± 10.9 33 ± 11.2 11.2 -- Sex, Male/Female (%) 51/49 49/51 50/50 -- 25 ± Body Mass Index 25 ± 3.6 25 ± 4.7 4.2 -- ASA 1/2/3 (%) 63/37/0 63/35/3 63/36/1 -- Total analgesic usage, (mg 25 ± equivalents oral morphine) 29 ± 20.9 21 ± 16.6 19.2 0.051 8.2 ± Patient Satisfaction (0-10) 7.9 ± 2.5 8.6 ± 1.6 2.1 0.187 NRS Pain with Movement at 2 4.2 ± hours (0-10) 4.8 ± 3.0 3.7 ± 2.9 3.0 0.094
a All data is shown as mean ± standard deviation unless otherwise noted
b Independent samples t-test
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A67 Title: The simultaneous manifestation of apoptosis and autophagy in lidocaine treated human pulpal cell Presenting Author: Teo Jeon Shin MD, PhD Presenting Author's Institution: Department of Dental Anesthesiology, Dental Research Institute - Seoul, Seoul Co-Authors: Yeoung-eun Yi D.D.S. - Department of Dental Anesthesiology, Dental Research - Seoul, Seoul Hyun-Jeong Kim MD, PhD - Department of Dental Anesthesiology, Dental Research - Seoul, Seoul Kwang-Suk Seo M.D., Ph.D. - Department of Dental Anesthesiology, Dental Research - Seoul, Seoul
Abstract: In dental practice, lidocaine has been widely used due to its favorable features. However, accumulating evidences suggest the cytotoxic effect of lidocaine in vitro and in vivo. The pulpal cells play important role of maintaining homeostasis within the pulp essential for the response to mechanical or chemical injury. Recent studies have revealed that the amines with structure similar to lidocaine induced autophagic vacoulizations. To date, little is available whether cytotoxic effect of lidocaine to the pulpal cell exists, and if so, which mechanism, either apoptosis or autophagy, is related to the potential cytotoxicity of lidocaine.
First, the third molars were collected from healthy adults (18–30 years of age) and primary pulpal cell culture was performed. We evaluated the change of cell viability after lidocaine treatment to the primary cultured pulpal cell by use of the water- soluble tetrazolium (WST) assay. We examined whether lidocaine triggers apoptosis in pulpal cell line using flow cytometry and immunoblot for caspase-3, and also autophagy using flow cytometric quantification of acidic vesicular organelles in acridine orange stained cells and immunoblotting.
Treatment of lidocaine induced increased cell death in dose and time – dependent manner. Lidocaine triggered apoptosis, as evidenced by the activation of caspase -3 cleavage and disruption of mithchondrial integrity. Interestingly, lidocaine also induced the development of autophagy, as suggested by the fact that fluorescent microscopic images as well as flow cytometry revealed increased formation of autophagic vacoulizations (AVO) in acridine orange stained cells, and western blotting showed increased conversion from microtubule-associated protein 1 light chain 3 (LC) type 1 to type 2.
In summary, we demonstrate that lidocaine exerts cytotoxicic effect in the pulpal cell. The cytotoxicity of lidocaine mainly comes from apoptosis via disrupted mitochondrial function. However, lidocaine simultaneously induced autophagy in the pulpal cell. Autophagy has been reported to be involved in critical biological events, such as cell survival, protection from starvation. Meanwhile, there are also reports that the activation of autophagy paradoxically lead to cell death. In the pulp, the function of autophagy after lidocaine treatment on cell survival remains unclear.
Further study using pharmacological activator or inhibitor of autophagy should be needed to address this issue.
A68 Title: Thick-Plane Four Dimension Ultrasound to Improve Needle Visualization Presenting Author: Christopher P Moore MD Presenting Author's Institution: Virginia Mason Medical Center - Seattle, WA Co-Authors: David B Auyong MD - Virginia Mason Medical Center - Seattle, WA
Abstract: Introduction: Four dimensional (4D) ultrasound (U/S) is used in OB/GYN and cardiology. Case reports show limited practical use in regional anesthesia.[1-3] Nerves are surrounded by echogenic tissues (muscles/adipose) and not anechoic fluid (blood/amniotic fluid). This makes nerves difficult to visualize. Modifications of traditional 3D imaging may improve needle/nerve visualization. Instead of a standard 3D volumetric /multi-planar image, the 3D data can be shown with volume-averaging - a ―thick‖ A-plane U/S beam. For this, the U/S head is ―wobbled‖ over a small angle (5-10 degrees) instead of the entire field (45-75 degrees). [Fig 1] This limited wobbling results in an A-plane image with a ―wider‖ beam facilitating in-plane needling.
Methods: Nine patients requiring nerve block were included. A 7MHz 4D U/S probe produced a 2D and 4D image. The thick-plane 4D image was created by averaging images from a limited degree wobble in real time. Thick-plane 4D and standard 2D views were displayed side-by-side. Data included demographics, block completion time, nerve/needle visibility (subjective and objective), and complications. Objective needle visibility was graded using a grayscale .bmp image and measuring mean pixel intensity on a 0-255 scale in Adobe Photoshop.
Results: All 9 blocks were successful with the thick-plane 4D, with no complications. 5/9 blocks visualized the needle in the thick plane image but not the standard 2D image. [Fig 2] Objective needle visibility with thick-plane 4D improved relative brightness by 1.14x and nerve visibility of 1.6x.[Fig 3] Subjective scores (0-10 scale, 10=best) were: 2D nerve image 5.6 versus 4D nerve image 7.4; 2D needle image 5.0 versus 4D needle image 4.9. In 8 of 9 cases, the 4D nerve image was subjectively better than the 2D image, while the needle quality was comparable. No other significant differences were found in the data.
Discussion: Volume-averaging from thick-plane 4D enhances contrast of structures in-plane and also allows the needle to appear in-plane on an U/S image even when not aligned on the 2D image. This potentially decreases the expertise required for in-plane needling. Also, improved contrast results in a brighter needle and nerve compared to standard 2D. However, volume averaging creates softening of edges in the various structures. Due to wobble within the transducer, frame rate is slower compared to standard imaging. Overall, thick-plane 4D ultrasound aids in identifying the needle and nerve during U/S nerve blocks.
References 1. S. Clendenen et al. Anesth Analg. 2009; 108:1347-1350. 2. N. Feinglass et al. Anesth Analg. 2007; 105:272–274. 3. G. Foxall et al. Reg Anesth Pain Med. 2007;32:516-521.
Fig 1: Diagram of standard 4D ultrasound field with the thick-plane (blue) resulting from a limited degree wobble.
Fig 2: Simultaneous femoral block images with 2D and thick-plane 4D. Standard 2D (left)- no needle present. Thick-plane 4D (right) - needle (arrows) present. A=femoral artery.
Fig 3: Chart of objective brightness of needle and nerve (standard 2D vs. thick- plane 4D ultrasound). Mean brightness (as measured by Adobe Photoshop) of the needle and nerve are charted (1.0= maximum and 0= no brightness). Relative brightness charted of 2D and 4D for the needle/nerve.
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Additional File #2: 2021911180719Fig_2.tif Click here to view
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A69 Title: Significance of Intraarticular Injection in Sacroiliac Joint Instabilities: A Retrospective Study Presenting Author: Foad Elahi MD Presenting Author's Institution: John Stroger Jr. at Cook County Hospital - Chicago, IL Co-Authors: Biji Theckedath MD - John Stroger Jr. at Cook County Hospital - Chicago, IL Asad Khan MD - John Stroger Jr. at Cook County Hospital - Chicago, IL Taruna Penmetcha MD - John Stroger Jr. at Cook County Hospital - Chicago, IL Maria Torres MD - John Stroger Jr. at Cook County Hospital - Chicago, IL
Abstract: Objectives: To evaluate and update the available evidence regarding diagnostic and therapeutic sacroiliac joint injections in the management of sacroiliac joint instability with various pathologies presenting with pain. Also, to identify the long- term response to serial sacroiliac joint (SIJ) injections.
Design: Retrospective study with collection of data from Cerner electronical charting.
Setting and Patients: Pain Management Center/ Anesthesiology Department at the John Stroger Jr., Cook County Hospital, Chicago, IL. Review of electronic documents of over 400 cases who presented to the pain clinic between Jan 2007 and Dec 2010. After applying exclusion criteria, 118 patients were selected in which they underwent diagnostic and therapeutic fluoroscopically guided SIJ injections with a combination of local anesthetic and long-acting corticosteroid ( 5cc Bupivacaine 0.25% and 40 mg Methylprednison).
Measures: Visual Analog Scale pain score and percentage of pain relief were the main tools for outcome measurement. We collected patients' response at 1 hour immediate post procedure, 24-hour nurse telephone follow up, and two and six weeks pain clinic follow up. Response to injection was graded as positive if there was equal or greater than 50% relief of the targeted pain during the local anesthetic phase immediate post procedure and on follow up they should describe pain relief greater than or equal to 50% at the end of at least 2 weeks of follow up.
Results: Upon chart review of 118 patient encounters, we found 81 cases (68.64 %) to be positive responders according to the criteria above, with a mean of 72.75% pain relief in the immediate post procedure (local anesthetic phase) and a mean of 62.46% pain relief after 2 weeks. In the negative responders group 37 cases ( 31.35%) turned out to have a good pain relief ( Mean= 54.51 %) in the immediate post procedure period , on the follow up they demonstrated to be poor responder with a mean of ( 25.49%) pain relief after 2 weeks of injection. This study is incomplete and our statistical data is in process.
Conclusions: In this study, we identified the benefit and significance of SI joint injection in the management of SI joint related pain. SI joint injection has a dramatic immediate pain relief value, as well as great long term relief. Serial SI joint injection in addition to other medical management is an easy procedure with minimal if any complication with great clinically improvement. In this study we did not discuss the selection criteria or clinical findings , however these information in addition to the selection criteria for sacroiliac joint radiofrequency nerve ablation would be the next subject of our retrospective study
A70 Title: Does a Supraclavicular Brachial Plexus Block Induce Greater Changes in Regional Hemodynamics than an Axillary Brachial Plexus Block? Presenting Author: Jiawei Li MPhil Presenting Author's Institution: The Chinese University of Hong Kong - Hong Kong, Hong Kong Co-Authors: Manoj Karmakar MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong Xiang Li PhD - Minhang Hospital of Shanghai - Shanghai, Shanghai Winnie Samy BN - The Chinese University of Hong Kong - Hong Kong, Hong Kong Wing Hong Kwok MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong
Abstract: Background: We have previously demonstrated the hemodynamic changes that occur in the ipsilateral brachial artery after an ultrasound guided (USG) axillary brachial plexus block (BPB). These changes are due to blockade of the sympathetic nerve fibers that accompany the nerves of the brachial plexus and share the same segmental distribution.1, 2 Since the nerves of the brachial plexus are clustered and close to the cervical sympathetic ganglion in the supraclavicular fossa we hypothesized that a BPB at the supraclavicular fossa would induce greater changes in regional hemodynamics than a BPB at the axilla. This prospective, non- randomized, pilot study was designed to test this hypothesis.
Methods: After ethical approval and written informed consent 18 patients scheduled for elective hand surgery under an axillary (n=8, 24-78yrs) or supraclavicular (n=10, 23-61yrs) BPB were recruited for the study. The BPB‘s were performed using ultrasound guidance and 20 ml of Ropivacaine (0.5%, without epinephrine) was injected for the block in each patient. Success of the block was judged by abolition of cold sensation and paralysis of the muscles in the ipsilateral hand and forearm. Regional hemodynamic parameters were measured in the ipsilateral brachial artery using pulsed-wave Doppler ultrasound, before the block (0 min) and at regular intervals for 30 minutes after the block (5min, 10min, 20min, 30min). Measured hemodynamic parameters included Peak Systolic Velocity (PSV, cm/s), End Diastolic Velocity (EDV, cm/s), Time-Averaged Mean Velocity (TAVM, cm/s), diameter (d, cm), Resistance Index (RI), and Pulsatility Index (PI). Blood flow was calculated as the product of TAVM and cross-sectional area, which was derived from the arterial diameter. Paired-sample t-test was used for intra-group comparison of changes in recorded parameters relative to the baseline and independent-sample t- test was used for inter-group comparison. A p value less than 0.05 was considered statistically significant.
Results: The USG BPB was successfully achieved and it was effective for surgical anesthesia in all patients studied. There was a significant increase in PSV, EDV, TAVM, d, and blood flow, and a significant reduction in PI and RI in both study groups (Fig 1). The relative changes in the TAVM, RI, PI and blood flow was significantly greater in the patients who had received a supraclavicular BPB (Fig 2).
Conclusion: An USG supraclavicular BPB causes greater changes in circulatory dynamics in the brachial artery than an USG axillary BPB. A randomized study to confirm these preliminary findings is currently underway at our institution.
References 1. Woollard HH and Norrish RE. Brit J Surg. 1933;21:83-103. 2. Woollard HH and Phillips R. J Anat. 1932;67:18-27.
Additional File #1: 1012711233957Fig1__Regional_hemo.tif Click here to view
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A71 Title: Systematic Ultrasound Identification of Nerves Posterior to the Brachial Plexus during Interscalene Block Presenting Author: Neil Hanson MD Presenting Author's Institution: Virginia Mason Medical Center - Seattle, WA Co-Authors: David Auyong MD - Virginia Mason Medical Center - Seattle, WA
Abstract: Introduction: The interscalene block is used to provide analgesia for shoulder surgery. For in-plane needle approaches, the needle is advanced with a posterior approach in order to avoid the phrenic nerve, located superficially to the anterior scalene muscle (1). This approach to the brachial plexus requires the needle be advanced through the middle scalene muscle. Most descriptions of this posterior, trans-middle scalene approach to the brachial plexus ignore the small branches of the plexus that lie within the middle scalene muscle (2). Our aim was to identify and describe the branches of the brachial plexus that lie posterior to the plexus so they can be recognized and avoided during an ultrasound guided interscalene block.
Methods: Fourteen out of a planned 50 patients undergoing shoulder surgery requiring continuous peripheral nerve blockade (CPNB) were enrolled. Prior to block placement, each patient was scanned by two investigators to characterize any nerve branches within or on top of the middle scalene, measuring proximity to the plexus. Confirmation of the nerves was produced by stimulation, using an insulated Tuohy needle. The current used was increased from 0.1 mA until muscular contraction was elicited to a maximum of 2.0 mA. During stimulation, palpation of the serratus anterior, rhomboids, levator scapulae, and scapula identified the nerve being stimulated.
Results: Thirteen out of 14 subjects had a nerve visible posterior to the plexus at the interscalene level. The mean distance from the nerve to the plexus was 0.56 cm +/- 0.24 and depth from the skin to the nerve was 0.92 cm +/- 0.42. Average depth to C5 from skin on all patients was 0.63 cm +/- 0.23 and 0.95 cm +/- 0.25 for C6. 57% of subjects were male, 43% of subjects were female. Average BMI in these subjects was 25.7 +/-3.0. Of the visible nerves, 54% originated from C5 and 46% from C6. 46% of the nerves had isolated contraction of the levator scapulae (dorsal scapular), 30% resulted in isolated contraction of the rhomboid muscles (dorsal scapular), and 14% resulted in isolated contraction of serratus anterior (long thoracic). The average current used for stimulation was 1.36 mA +/- 0.49.
Discussion: Several branches of the brachial plexus exit dorsally in the neck, including the long thoracic and dorsal scapular nerve. We have characterized these nerves within or superficial to the middle scalene muscle, about 1 cm posterior to the brachial plexus. The nerves usually appear anechoic, surrounded by hyperechoic fascia and are located at a similar depth as the C6 nerve root. Recognizing these nerves during an ultrasound guided posterior approach interscalene block may help to avoid direct needle injury during advancement through the middle scalene muscle. Though described in dissection, these nerves have been mostly ignored in the anesthesia literature as being located in close proximity to the plexus. Potentially, these nerves may be selectively blocked for surgery on the scapula or in the diagnosis/treatment of chronic pain syndromes of the shoulder.
References 1. Kessler J et al. Reg Anesth Pain Med. 2008; 33(6): 545-550. 2. Marhofer P et al. BJA. 2010; 104: 673-683.
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A72 Title: Factors influencing Unexpected Disposition after Orthopedic Ambulatory Surgery Presenting Author: Stavros G Memtsoudis MD, PhD Presenting Author's Institution: Hospital for Special Surgery - New York, NY Co-Authors: Carrie R Guheen MD - Hospital for Special Surgery - New York, NY Yan Ma BS - Weill Medical College of Cornell - New York, NY Cephas P Swamidoss MD, MPH - Hospital for Special Surgery - New York, NY Alison M Edwards MS - Weill Medical College of Cornell - New York, NY
Abstract: Context: Disposition other than discharge to the patient‘s residence after ambulatory surgery represents a financial burden to hospitals, insurers and patients alike. To date, few nationally representative studies exist to identify risk factors for this outcome.
Objective: To analyze if patient characteristics, ambulatory facility type, anesthesia provider and technique, procedure type and temporal factors impact on the outcome of unexpected disposition after ambulatory knee and shoulder surgery.
Design: Population based analysis of data collected for the National Survey of Ambulatory Surgery.
Setting: US hospital-based and freestanding ambulatory surgery centers.
Patients: Patients undergoing ambulatory knee and shoulder surgery.
Intervention: Ambulatory knee and shoulder surgery.
Main Outcome Measure: Unexpected disposition status.
Results: Factors independently increasing the risk for unexpected disposition included: procedures performed in hospital-based versus freestanding facilities (OR 6.83 (CI 4.34; 10.75)), shoulder versus knee procedures (OR 3.84 (CI 2.55; 5.77)), anesthesia provided by non-anesthesiology professionals and certified nurse anesthetists compared to anesthesiologists (OR 7.33 (CI 4.18; 12.84) and OR 1.80 (CI 1.09; 2.99), respectively). Decreased risk for unexpected disposition were found for procedures performed in 2006 versus 1996 (OR 0.15 (CI 0.10; 0.24)) and the use of anesthesia other than regional and general (OR 0.34 (CI 0.18; 0.68).
Conclusions: The decreased risk for unexpected disposition associated with more recent data and with freestanding versus hospital-based facilities may represent improvements in efficiency. However, we found increased risk of adverse disposition in cases in which the anesthesia provider was a certified nurse anesthetist or a non-anesthesiology professional compared to an anesthesiologist. No difference in this outcome was seen when an anesthesia care team provided anesthesia. These findings need to be deliberated by policy- and lawmakers in current debates surrounding considerations for ―opt-out‖ provisions in Medicare reimbursements.
Additional File #1: 1022711080711Factors_influencing.pdf Click here to view
Additional File #2: 2022711080711Factors_influencing.pdf Click here to view
Additional File #3: 3022711080711Factors_influencing.pdf Click here to view
A73 Title: Bilateral total knee arthroplasty: Risk factors for major morbidity and mortality Presenting Author: Cindy Chen MD Presenting Author's Institution: Hospital for Special Surgery - New York, NY Co-Authors: Yan Ma PhD - Hospital for Special Surgery - New York, NY Ya-Lin Chiu MS - eill Cornell Medical College - New York, NY Lazaros Poultsides MD - Hospital for Special Surgery - New York, NY Alejandro Gonzalez Della Valle MD - Hospital for Special Surgery - New York, NY
Abstract: Context: Bilateral total knee arthroplasties performed during the same hospitalization carries increased risk for morbidity and mortality as compared to a unilateral approach. However, no evidence based stratifications to identify patients at risk for major morbidity and mortality are available to date.
Objective: Our objective was to determine the incidence and patient related risk factors for major morbidity and mortality among patients undergoing bilateral total knee arthroplasties.
Design: Population based analysis of data collected for the National Inpatient Sample between the years 1998 and 2007.
Setting: National Inpatient participating US hospitals.
Patients: Included were 42,003 database entries, representing an estimated 206,573 elective bilateral total knee arthroplasties identified by appropriate entry of International Classification of Diseases procedure code 81.54.
Intervention: Elective bilateral total knee arthroplasties.
Main Outcome Measure: Major in-hospital morbidity and mortality.
Results: The incidence for major in-hospital complications and mortality was 9.5%. Risk factors for adverse outcome included advance age (odds ratios for age groups 65-74 and >75 years were 1.88 (1.72; 2.05) and 2.66 (2.42; 2.92) compared to the 45-65 year group), male gender (OR 1.54 (1.44;1.66)), and a number of comorbidities. The presence of pulmonary circulatory disease was the most significant risk factor associated with increased odds for adverse outcome (OR 46.7 (36.98; 60.87)). (Fig. 1)
Conclusions: We identified patient-related risk factors for major morbidity and mortality in patients undergoing bilateral total knee arthroplasties. Presented data can be utilized to aid in the selection of patients for this procedure.
Additional File #1: 1022711201916Figure_1.doc Click here to view
Figure 1. Adjusted odds ratios for major complications/mortality associated with comorbidities in patients undergoing bilateral total knee arthroplasty.
A74 Title: Duration of Motor vs. Sensory Blockade of EXPAREL™ (Bupivacaine Extended-Release Liposome Injection) and Bupivacaine HCl in a Phase 1 Epidural Study Presenting Author: Eugene R Viscusi MD Presenting Author's Institution: Thomas Jefferson University - Philadelphia, PA Co-Authors: Keith Candiotti MD - University of Miami - Miami, FL
Abstract: Introduction: Bupivacaine Extended-Release Liposome Injection (DepoFoam™ Bupivacaine; DB) is an investigational long-acting local analgesic currently being studied for epidural use. This phase 1 study characterized the duration of motor blockade and sensory blockade across a number of doses as compared to bupivacaine HCl.
Materials and Methods: A total of 29 patients received L3-L4 epidural administration via a tested catheter of either bupivacaine HCl 50mg (0.25% in 20mL; n=6) or DB 100mg, 175mg, or 300mg (15mg/mL diluted to 20mL; n=8, 8, and 7 respectively). Motor assessments included median duration of motor blockade, loss of ability to ambulate freely at 4 hours, and median time to recover the ability to ambulate freely for those who had lost this ability. Sensory assessments included sensitivity to pinprick, cold, and thermal thresholds.
Results: The highest median duration of motor block in DB patients was 1 hour, which occurred at the highest dose level (300mg); median duration of motor block in bupivacaine patients was 2.8 hours. A total of 39% of DB patients lost the ability to ambulate freely at 4 hours compared to 80% of bupivacaine HCl patients; among these patients, mean time to recovery was 6.2 hours in both the DB and the bupivacaine HCl patients. All but one DB patient (96%) and all bupivacaine patients (100%) lost sensitivity to pinprick. Median time to onset was 0.3 hours in both groups; median duration of numbness was 36 hours in the DB 300mg group compared to 12 hours in the bupivacaine HCl group. All patients lost sensitivity to cold; median time to onset was 0.3 hours in both groups, with median duration of numbness of 69 hours in the DB 300mg group compared to 12 hours in the bupivacaine HCl group. Thermal threshold analysis showed a dose dependent pattern, with decreasing sensitivity as the dose of DB was increased. A total of 88% of DB patients and 100% of bupivacaine HCl patients experienced at least one adverse event (AE); the most common AE was injection site pain. There were no serious AEs, no deaths, and no withdrawals due to an AE.
Conclusions: In this study, 300mg DB, delivered by the epidural route, provided sensory blockade without prolonged motor blockade compared to standard bupivacaine HCl; safety findings were similar between the two groups. These data support that further studies are warranted
A75 Title: Comparison of thoracic epidural bupivacaine with and without opioid versus intercostal nerve block with bupivacaine infusion via OnQ for post-thoracotomy pain Presenting Author: Jay S Grider DO, PhD Presenting Author's Institution: University of Kentucky - Lexington , KY Co-Authors: Timothy W Mullet MD - University of Kentucky - Lexington, KY Michael E Harned MD - University of Kentucky - Lexington, KY Paul A Sloan MD - University of Kentucky - Lexington, KY
Abstract: Background: Thoracic epidural analgesics have become commonplace for postoperative pain relief following thoracotomy.(1) Recently an intercostal continuous nerve block with local anesthetic via the OnQ catheter system (iFlow Corp) has been utilized to provide analgesia following thoracotomy.(2) The aim of this current study is to compare thoracic epidural local anesthetic infusion (with and without neuraxial opioid) and intercostal nerve extra-pleural local anesthetic infusion on post-thoracotomy analgesia and functional recovery.
Methods: Following IRB approval, 75 consecutive patients presenting for thoracotomy were enrolled in this prospective, randomized, double-blinded clinical trial. Patients entered one of four groups: epidural bupivacaine + opioid (Epi B+O); epidural bupivacaine alone (Epi B); OnQ intercostal catheter with bupivacaine (OnQ); and epidural plus OnQ catheters both with bupivacaine (E+OnQ). Epidural catheters were placed preoperatively at approximately the T6 level. Patients who randomized to a non-epidural group received a sham epidural catheter: their skin was anesthetized and an epidural catheter secured externally to the skin with a sterile dressing. At the conclusion of surgery, all subjects had an extra-pleural intercostal nerve OnQ infusion catheter placed at the level of incision. In addition, prior to chest closure all subjects also received intercostal nerve blocks above and below the surgical incision with single injections of 0.25% bupivacaine. The OnQ and epidural catheter infusions were begun immediately upon entry to the PACU. Epidural analgesics (basal 2 ml/hr with 1 ml q10 min PCA) were 0.25% bupivacaine alone, or 0.25% bupivacaine with 0.01mg/ml hydromorphone; while OnQ intercostal infusions were 0.25% bupivacaine at 8 ml per hour. All patients could receive IV opioid PCA should the catheter system fail to provide adequate analgesia. Visual analog pain scores (VAS) were obtained in PACU, and each morning of post-operative day (POD) one –four. Incentive spirometry results and pain scores during spirometry were also obtained on each POD for the duration of therapy. VAS results were analyzed using the Mann-Whitney U nonparametric test. Incentive spirometry values as a measure of postoperative pulmonary function were compared using the student‘s t-test.
Results: There were no significant differences for sex, age, weight, or ASA classification between groups. Pain scores on arrival in PACU were similar between all groups. There was no difference in mean +/- SD pain scores over POD 1-3 between the OnQ (3.3+/-2.2) and Epi B (3.1+/-2.8) local anesthetic groups, however Epi B+O provided superior analgesia (2.6+/-1.9; p<.05) compared with local anesthetic alone groups. Five patients in the OnQ group required supplementation with IV PCA, while 3 patients in the Epi B+O group required IV PCA. Of the 3 subjects in the Epi B+O group requiring IV PCA, 2 of these resulted from catheter dislodgement (analgesia prior to catheter loss was adequate). Postoperative incentive spirometry of >2L was best in the Epi B+O group (87%), compared (p<.05) with OnQ (78%), E+OnQ (78%), or Epi B (61%). The combination of thoracic epidural bupivacaine with intercostal bupivacaine (E+OnQ) did not provide significantly greater analgesia (3.5+/-1.3; n=9) than either catheter alone.
Conclusions: 1) Intercostal nerve block with continuous bupivacaine using the OnQ catheter system provided excellent postoperative analgesia for thoracotomy. 2) Thoracic epidural bupivacaine with hydromorphone provided superior analgesia and pulmonary function compared with intercostal continuous nerve block following thoracotomy. 3) Intercostal nerve analgesia with the OnQ system was equal to thoracic epidural analgesia when bupivacaine alone was utilized.
References 1) NG A, Swanevelder J. Editorial II Pain relief after thoracotomy: Is epidural analgesia the optimal technique? Br J Anaesth. 2007;98(2):159-162. 2) Wheatly GH, Rosenbaum DH, Paul MC, Dine AP et al. Improved pain management outcomes with continuous infusion of local anesthetic after thoracotomy. J Thor Cardio Surg. 2005;130:464-468.
A76 Title: Predictors of failure of interscalene nerve blocks for shoulder surgery: A 4- year cohort study Presenting Author: Kenneth Jensen MD, BBA Presenting Author's Institution: University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen Co-Authors: Jens Børglum MD, PhD - University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen
Abstract: Aim: To investigate the extent of failures of interscalene nerve blocks for shoulder surgery and potential causes of variation in a large university hospital (Bispebjerg, Denmark).
Methods: Prospective cohort study of 1,326 consecutive interscalene nerve blocks during a 4-year period (2007-2010). A successful nerve block was defined by its ability to (i) provide surgical anesthesia without the need to convert to general anesthesia or use escape blocks, or (ii) provide for effective postoperative analgesia without the need for opioids or escape blocks. Patients were classified according to physical status and baseline demographics, while anesthetists were classified according to level of expertise. This included experts (formal training with > 6 months experience), trainees (formal training with <6 months experience), and novices (no formal training). Formal training consisted of a ultrasonographic nerve block school with anatomy lectures, cadaver workshops, and supervised hands-on education. During 2008, the department changed the nerve localization technique from nerve stimulation (NS) to ultrasound (US) with no change in surgeries, logistics or anesthetic plans. No patient was given long-acting opioids until it was necessary postoperatively.
Results: Complete data sets were available in 1,200 patients. All had the interscalene nerve block placed prior to surgery. 71/633 (11%) in the NS group and 110/567 in the US group had surgery performed in nerve block alone. Failure rates in these subpopulations are listed in tables 1 and 2.
Discussion: By comparable level of expertise, US guidance does not seem to consistently influence failure rates compared to NS guidance. Failure rates of trainees and novices are similar, well above that of experts, suggesting that both formal training and extensive experience are required for optimal performance. In all groups, increased ASA physical status and female sex are related to failure. In the NS group, BMI is related to failure, whereas an inverse relation is evident in the US group. This contradictory finding is interesting and may be explained by nerve- to-skin proximity in the NS group vs. more clearly defined soft tissue and nerves in the US group.
Conclusions: This preliminary study suggests that nerve block failure in shoulder surgery is primarily related to – by decreasing importance - anesthetist level of expertise, block purpose, BMI, ASA physical status and sex. Age and nerve localization technique seem to be less important. Further studies are strongly encouraged to quantify these variations and their implications for anesthesia practice.
Additional File #1: 1012911135447Table_1__Failure_ra.pdf Click here to view
Additional File #2: 2012911135447Table_2__Failure_ra.pdf Click here to view
A77 Title: The Jensen-Borglum motor test. A proposition to expand on the Bromage motor scale for use in regional anesthesia Presenting Author: Kenneth Jensen MD, BBA Presenting Author's Institution: University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen Co-Authors: Jens Børglum MD, PhD - University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen
Abstract: Background: The Bromage motor scale is frequently used for the purpose of assessing motor function following neuraxial anesthesia (1). In this sense, it adequately describes generalized loss of motor function below the waist in a quantitative manner, but it is often used to assess lower extremity nerve blocks as well. However, loss of motor function following regional anesthesia of the lower limb is more complex and is relative to the specific nerves blocked. The femoral nerve is central for motor function, but since the iliopsoas muscle is often unaffected (excluding lumbar plexus block), some basic motor abilities of the lower limb may still be retained. In addition, a high volume femoral nerve block may extend to the lateral femoral cutaneous nerve and, possibly, the obturator nerve (2).
Methods: Following IRB approval, we investigated the applicability of a new motor test in 22 patients with osteoarthritis subjected to a selective proximal triple nerve block for in vivo microdialysis in the knee joint (3). The ultrasound-guided (USG) selective nerve block included block of the femoral, obturator (anterior branch) and lateral femoral cutaneous nerve using lidocaine 2% with epinephrine as local anesthetic. Real-time USG using a high-frequency linear probe on short axis and with an in-plane technique was chosen for all patients. Intravenous adjuvants were not given. The Jensen-Borglum motor test: We applied a variant of the Bromage scale for assessment of motor function. We considered the test positive if patients were able to flex the knee joint but were subsequently unable to extend the knee (suggesting preserved iliopsoas function but impaired quadriceps function). The test was also considered positive if knee flexion was impossible, but considered negative for all other motor abilities.
Results: Surgical anesthesia for the in vivo microdialysis procedure was achieved in 91% of patients, and the Jensen-Borglum motor test was positive in all of these cases. 59% of patients were just able to flex the knees (Bromage scale 2), with 27% unable to flex the knees (Bromage scale 3). Patients with a negative Jensen- Borglum motor test did not achieve surgical anesthesia, suggesting high sensitivity and specificity for assessment of femoral nerve function, compared to that of the Bromage scale.
Conclusions: The Jensen-Borglum motor test adequately predicts successful motor block of the quadriceps muscle and surgical anesthesia for the purpose described. Other authors have proposed a revision to the original Bromage scale as well (4). Arguably, advances in regional anesthesia require new assessments of motor and sensory function, and we suggest that older motor scales be revised according to their specific purpose.
References 1.Bromage PR. Acta Anaesth Scand Suppl. 1965;16:55-69. 2.Marhofer P et a. Anesth Analg. 2000; 90:125-128. 3.Helmark IC et al. Arthritis Res Ther. 2010;12:R126-37. 4.Pue A. Reg Anesth Pain Med. 1998;23:524-525. A78 Title: Motor abilities after multiple nerve blocks on the lower extremity Presenting Author: Kenneth Jensen MD, BBA, Consultant Presenting Author's Institution: University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen Co-Authors: Per-Arne Lönnqvist MD, DMSc, Professor - Institute of Physiology and Pharmacology - Stockholm SE, Stockholm Jens Børglum MD, PhD, MBA, Consultant - University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen
Abstract: Background: It has previously been shown that peripheral nerve blocks (PNB) can result in a superior recovery profile compared with general anesthesia in outpatient knee arthroscopy (1). PNB providing surgical anesthesia of the lower extremity inherently affect motor abilities, especially for the femoral and sciatic nerves. Some degree of hip flexion is retained by the iliopsoas muscle receiving innervation from the lumbar plexus, but quadriceps muscle paralysis and drop foot are often expected side effects to successful sensory blocks involving these nerves. We chose to investigate the implications of motor paralysis in a study on ultrasound-guided (USG) PNB involving the femoral, the lateral femoral cutaneous and obturator nerves (both branches) (―quadruple block‖; 30 patients), and all of the mentioned nerves including the sciatic nerve (―quintuple block‖; 10 patients) (Fig. 1). An equal mixture of bupivacaine 2.5 mg/mL and mepivacaine 1 mg/ml with epinephrine 5 microg/mL was used for all patients. Main characteristics of this study are presented elsewhere (2).
Methods: Following IRB approval, a total of 40 consecutive patients were enrolled in the study. Duration of motor block and motor abilities using the modified Barthel/100 index (3) were recorded on the first postoperative day.
Results: Duration of motor block was on average 11 hours (range 3-25 hours). Motor abilities for activities of daily living according to the Barthel/100 index were on average 96% (range 68-100%) in the quadruple block group and 90% (range 64-100%) in the quintuple block group (for specific abilities, see Table 1).
Conclusions: Multiple USG PNB of the lumbar plexus have little impact on the motor functions used for activities of daily living in spite of a functional femoral nerve block. Adding a complete sciatic nerve block reduces these motor functions only marginally, suggesting that most patients are able to compensate adequately for the motor paralysis such nerve blocks invariably infer. This could imply that multiple and long-lasting nerve blocks for day-case surgery on the lower extremity are an attractive option for patients that request regional anesthesia, refuse general or neuraxial anesthesia, or in which general or neuraxial anesthesia are not preferable due to contraindications or other anesthetic considerations.
References 1, Hadzic A, Karaca PE, Hobeika P et al. Peripheral nerve blocks result in superior recovery profile compared with general anesthesia in outpatient knee arthroscopy. Anesth Analg. 2005;100:976–981. 2. Børglum J, Jensen K. Ultrasound-guided peripheral nerve blocks providing surgical anesthesia for outpatient knee arthroscopy and anterior cruciate ligament reconstruction. A proof-of-concept study. ASRA Congress 2011 [Abstract]. 3. Shah S, Vanclay F, Cooper B. Improving the sensitivity of the Barthel Index for stroke rehabilitation. J Clin Epidemiol. 1989;42:703-709.
Additional File #1: 1013011123648Figure_1___motor_ab.pdf Click here to view
Additional File #2: 2013011123648Table_1___motor_abi.pdf Click here to view
A79 Title: Cleveland Clinic Experience of Home going peripheral nerve catheter Presenting Author: Ramez R Gharabawy MD Presenting Author's Institution: Cleveland Clinic - Westlake, OH Co-Authors: Wael Ali Sakr Esa MD, PhD - Cleveland Clinic - Cleveland, OH Hesham Elsharkawy MD - Cleveland Clinic - Cleveland, OH Loran Mounir-Soliman MD - Cleveland Clinic - Cleveland, OH Ehab Farag MD - Cleveland Clinic - Cleveland, OH
Abstract: Background: Continuous Peripheral nerve blocks (CPNBs) have an increasingly important role in modern practice, especially in the ambulatory setting. We are reporting our experience of home going peripheral nerve catheters, in term of the incidence of infection, and neurological complications, compared to reported universal incidence.
Method: After Institutional Review Board approval, data were retrospectively gathered. Computer review from Jan. 1, 2009 to Dec. 31, 2010, showed 660 home going catheters were placed, including Supraclavicular, Infraclavicular, Popliteal, and femoral catheters. Technique of placement of the catheters were the same, in the term of ultrasound use, and 19 G stimuplex catheters, with the initial injection of the local anesthetic which varies with the block type. For Supraclavicular, infraclavicular, and popliteal blocks the initial injection was 20 mL of Ropivacaine 0.75%, for Femoral the initial injection was 20 mL of Ropivacaine 0.2%. Discharge instructions to the patients including how to use the home going pumps were given by one of the Acute pain service nurses. The continuous infusion for Supraclavicular, infracalvicular and popliteal was Ropivacaine 0.2% at 8 mL/hr, with 12/mL demand every hour. The infusion for the femoral catheter was Ropivacine 0.1% 8mL/hr with no demand. Follow up phone calls by Acute pain service nurses, recording pain score, any signs of infection, or neurological complication were recorded on daily basis.
Results: Reviewing the computer records of the phone calls and surgeon office visits, we had 6 neurological complications. Three of them were numbness in the distribution of the block that resolved in 24 hours, two were hoarseness of the voice, and one case of ptosis that resolved in 24 hours. All the neurological complications resolved after holding the infusion, with no permanent sequel. We had five superficial infections that was identified, in the form of redness, and tenderness at the catheter site. Patients were instructed to remove the catheter, with complete relief of the infection. Overall there were 6 neurological complications(0.90%), and five superficial infections(0.76%)with no permanent complications.
Discussion: Although the use of CPNBs had been increased over the last few years, and the risk of infection during CPNBs is a major issue, the frequency of infection associated with peripheral nerve catheters remains poorly defined. Recent studies show that between 23 and 57% of peripheral nerve catheters may become colonized, with 0–3% resulting in localized infection. With few case reports of severe infection. Neurological complications associated with CPNBs are rare. Review of the literature showed that neurological symptoms 6 month after the block are 0.6%, most of the symptoms were due to causes unrelated to the block. Our results, 0.76% for the infection, and 0.9% for neurological complication are within the reported data of the complication associated with CPNB.
Conclusions: Our results add to the evidence that major complications from CPNBs are rare. However, minor adverse effects associated with CPNBs may be more common, highlighting the importance of meticulous care during performing the block, and presence of didactic service to follow up the patient.
A80 Title: Older Adults' Pain Medication Usage Following Knee Arthroplasty Presenting Author: Samantha Bremner BSc Presenting Author's Institution: University of Toronto - Toronto, Ontario Co-Authors: Fiona Webster PhD - University of Toronto - Toronto, Ontario Joel Katz PhD - University of Toronto - Toronto, Ontario Judy Watt-Watson PhD - University of Toronto - Toronto, Ontario Colin McCartney MBChB - Sunnybrook Health Sciences Centre - Toronto, Ontario
Abstract: Introduction: Despite advances in pain management techniques, evidence suggests that a high proportion of patients continue to experience moderate to severe pain after knee replacement surgery. Poor postoperative pain control means that patients may fail to rehabilitate adequately and are at risk of other complications such as heart and lung problems. Acute postoperative pain has also been associated with the development of chronic pain. Currently, patients are provided with prescription analgesics to manage their pain after discharge; however, there is little information regarding how patients manage their use of pain medication at home after surgery.
Methods: The study was reviewed and approved by the Research Ethics Boards at the Sunnybrook Health Sciences Centre and University of Toronto. A qualitative descriptive approach was undertaken to investigate pain medication usage in older adults who had recently undergone knee arthroplasty. Using purposeful sampling, 14 participants were recruited at the time of discharge from hospital and subsequently interviewed approximately six weeks later. Interviewing continued until the data collected reached a point of saturation, meaning no new information or themes were being generated. Interviews were transcribed verbatim and coded using constant comparison. Thematic analysis was then conducted to explore how participants practiced and understood pain medication usage in the weeks after orthopaedic surgery.
Results: The participants described using less pain medication than was originally recommended and many stopped taking prescription medication altogether before a renewal was required. Participants described reducing their use of prescription pain medication and many used non-prescription pain management techniques to augment or replace pharmacological methods. Non-prescription methods of pain control included using over-the-counter pain relievers, herbal remedies, ice, rest and exercise. Participants reported adjusting their analgesic usage in response to their level of pain, the side effects experienced, and the risk of becoming ―hooked‖. A number of participants explained that they ―just don‘t like taking pills.‖ Discussion: Participants did not consider modifying pain medication regimes as an issue of adherence, but instead viewed it as self-management. The management of post-operative pain is complex and patient decision-making is often based on personal experiences. In contrast to much of the medication taking literature which focuses on the dichotomy of adherence versus nonadherence, these findings suggest that patients may be adapting their pain medication regimes in response to a number of influences. Consequently, clinicians may need to spend more time addressing patients‘ apprehensions of using prescription analgesics, explaining to patients the importance of adequate postoperative pain control and developing analgesic techniques with less reliance on opioids.
A81 Title: Association of perioperative use of NSAIDs with postoperative myocardial infarction after total joint replacement Presenting Author: Spencer S Liu MD Presenting Author's Institution: Hospital for Special Surgery and Weill Cornell Medical College o - New York, NY Co-Authors: James J Bae MSc - Hospital for Special Surgery - New York, NY Mihai Bieltz MS, MBA - Hospital for Special Surgery - New York, NY Yan Ma PhD - Hospital for Special Surgery - New York, NY Stavros G Memtsoudis MD, PhD - Hospital for Special Surgery - New York, NY
Abstract: Background: Risk to benefit profile of perioperative use of nonsteroidal anti- inflammatory (NSAIDs) analgesics is controversial. Both non-selective and COX2I agents are associated with cardiovascular risk (1), yet are highly effective analgesics with documented benefits. High quality analgesia is particularly important for total joint replacement procedures, as these are painful procedures and rehabilitation may be dependent on quality of analgesia (2). Perioperative use of NSAIDs may be advantageous for total joint replacements if risk of postoperative myocardial infarction (POMI) is not increased. Our patients undergoing total joint replacement routinely receive perioperative NSAIDs beginning just prior to surgery. Thus, we analyzed our electronic medical record database to determine association between NSAID use and POMI.
Methods: Patient admissions undergoing total hip or knee replacement between 3/3/09 and 9/1/10 were identified. POMI was defined as troponin T > 0.1 ng/mL. Perioperative use of NSAIDs (nonselective and COX2I) was identified. Univariate analysis was used to identify covariates to calculate propensity scores to adjust for likelihood of receiving NSAIDs. Propensity scores and covariates identified through univariate analysis were used in logistic regression to determine independent association of NSAID use with POMI.
Results: Of the 10,873 arthoplasty admissions, 97 suffered a POMI (0.9%). Incidence of POMI was 1.8% for the 1042 (10%) admissions that did not receive NSAIDs. Incidence of POMI (Fig. 1) was 1.3% for those (610) that received COX2I (celecoxib) and was 0.8% for the 9,221 that received NSAIDs (meloxicam or ketorolac). Figure 2 displays risk difference between patients with and without NSAIDs. Coavariates identified by univariate analysis for calculation of propensity scores were age, gender, type of procedure, and pre-existing renal insufficiency and ischemic heart disease. After adjustment for NSAID use with propensity scores, logistic regression identified independent risk factors for POMI (Table 3). Both adjusted odds ratios and relative risks indicated that NSAIDs were not significantly associated with risk of POMI (Table 3). Mean duration of NSAID use was 3 days (SD=1.3).
Discussion: These findings suggest that brief perioperative use of NSAIDs carries a favorable risk to benefit profile for postoperative analgesia. Other risk factors for POMI were also identified (age, gender, increased revised cardiac risk index, pre- existing use of beta blockers, and postoperative anemia) and confirmed prior findings.
References 1: Am J Cardiol. 2009 May 1;103(9):1227. 2: Disabil Rehabil. 2010:32:300.
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Additional File #3: 3022511125520Table_3.doc Click here to view Table 3: Association between perioperative nonselective and COX2I NSAID use and POMI adjusted for risk of being on NSAID with propensity score.
Risk factor Odds ration (95% CI) Relative risk (95% CI) Nonselective NSAID (meloxicam or ketorolac) 0.8 (0.4-1.5) 0.8 (0.4-1.5) COX2I (celecoxib) 1.4 (0.5-3.9) 1.4 (0.6-3.6) Preexisting beta blocker use 9.2 (3.2-27) * Preexisting statin use 1.4 (0.3-5.5) Preexisting beta blocker and statin use 8.1 (2.8-24) * Age (per year) 1.07 (1.04-1.1) * Gender (male vs. female) 2.2 (1.4-3.5) * Revised cardiac risk index of 1 vs. 0 3.3(1.9-5.9) * Revised cardiac risk index of > 2 vs. 0 6.7 (3.3-13.4)* Postoperative lowest hemoglobin (per dg/ml) 0.8 (0.6-0.9) * Propensity score 0.4 (0.06-2.4)
*=statistically significant by logistic regression
A82 Title: Determining Minimal Effective Volume of Bupivacaine 0.5% with Epinephrine for Ultrasound Guided Axillary Brachial Plexus Block Presenting Author: Alexandre Takeda MD Presenting Author's Institution: Universidade Federal de Sao Paulo - UNIFESP - Sao Paulo, SP Co-Authors: Leonardo HC Ferraro MD - Universidade Federal de Sao Paulo - UNIFESP - Sao Paulo, SP Andre H Rezende MD - Universidade Federal de Sao Paulo - UNIFESP - Sao Paulo, SP Eduardo J Sadatsune MD - Universidade Federal de Sao Paulo - UNIFESP - Sao Paulo, SP Maria A Tardelli Professor - Universidade Federal de Sao Paulo - UNIFESP - Sao Paulo, SP
Abstract: Background: The axillary block is one of the most commonly used techniques of regional anesthesia for hand surgery. Usually it is obtained with large volumes of local anesthestic, which can result in an increased risk of toxicity. The ultrasound guided block allows volume reduction for interescalene, axillary, femoral and ilioinguinal blocks. Using step-up/step-down model, O‘Donnell and Iohom have demonstrated an effective ultrasound guided axillary brachial plexus block with 1 mL of lidocaine 2% with epineprine per nerve. They concluded this after 5 consecutive cases of successful block with 1 mL per nerve.
Objective: A study to calculate the minimal effective volume of bupivacaine 0.5% with epinephrine for successful axillary brachial plexus block for hand surgery in 90% of the patients (MEV90).
Methods: ASA 1 and 2 adult patients scheduled for ambulatorial hand surgery were included. After given written informed consent signed by patients the axillary brachial plexus block was achieved using ultrasound guidance for needle positioning followed by confirmation with nerve stimulation before local anesthetic injection. This procedure was performed for each nerve (median, radial and ulnar). The study method used was a step-up/step-down sequence model where the dose used for following patients was determined by the outcome of the preceding block. The starting dose of bupivacaine was 5 mL per nerve. In the case of block failure, the dose was increased by 0.5 mL per nerve. Conversely, block success resulted in a reduction in dose by 0.5 mL per nerve. Each of the three nerves was treated as a separate entity. Dose adjustments were made to each nerve individually. The volume dose was increased in 0.5 mL at every 5 consecutive cases regardless of the result of the previous block in order to minimize bias occurrence. A blinded assistant assessed sensory and motor blockade at 5-min intervals up to 30 min. The defined study-stopping rule was when the study achieved 5 cycles of failure/success for each nerve. In order to calculate the MEV90 we obtained a non- linear regression of the exponential decay phase for each nerve. Surgical anesthesia was defined as a motor score of 2 or lower on a modified Bromage Scale, with absent appreciation of cold and pinprick sensation. After that, if block failure was characterized, complementation of the blockade was performed in order to allow surgical procedure. All patients received continuous infusion of propofol to achieve score 3 on Ramsay Sedation Scale.
Results: The study was terminated with a total of 25 patients. All cases where 1 mL per nerve was injected (6 cases for median, 7 for radial and 7 for ulnar) have been successfully blocked. And all cases where 0.5 mL per nerve was injected (4 cases for median, 5 for radial and 5 for ulnar) was considered as failure. The MEV90 calculated for each nerve was: median = 0.58 mL; radial = 0.60 mL; ulnar = 0.62 mL.
Conclusion: This study suggests that using ultrasound guidance along with nerve stimulation it is possible to obtain surgical anesthesia with doses as lower as 1 mL of bupivacaine 0.5% per nerve in the axillary approach of brachial plexus block. However in order to verify the efficacy of the calculated MEV90 further clinical trials are suggested.
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A83 Title: Lumbosacral Spine MRI Findings Associated with Sacroiliac Joint Instability: A Retrospective Study Over Sacroiliac Joint Intervention. Presenting Author: Asad Khan MD Presenting Author's Institution: Cook County Hospital - Burr Ridge, IL Co-Authors: Foad Elahi MD - Cook County Hospital - Burr Ridge, IL Biji Theckedath MD - Cook County Hospital - Burr Ridge, IL Taruna Penmtcha MD - Cook County Hospital - Burr Ridge, IL Maria Torres MD - Cook County Hospital - Burr Ridge, IL
Abstract: Objective: Sacroileitis is an inflammatory process associated with a wide array of pathologies that involve one or both sacroiliac joints. It has been well studied that the SIJ mechanical functionality attributes with lower spine and bilateral hip joints kinesiology. It is characterized by lower back pain, pelvic girdle pain, gluteal pain, restricted range of motion, positive specific clinical signs, and occasionally lower extremity radicular pain. In order to explore, classify, and evaluate the lumbosacral MRI findings accompanied with sacroiliac joint instability; we retrospectively analyzed information regarding imaging data in all of sacroiliac joint injections for the past two years.
Methods: A two-year retrospective study of 400 subsequent cases of sacroiliac joint injections were collected from the Cook County Hospital Cerner electronical database. We discovered that every single case in this study either prior to injection or after injection, there was lumbosacral spine MRI imaging available. This study included evaluating SIJ injection procedure done in the pain clinic for the past 2 years. The cases were classified on the bases of unilateral or bilateral SIJ involvement. Lumbosacral spine MRI finding was evaluated and the findings were classified into: Level of Stenosis, Number of Disc Herniation, Combined Stenosis and Disc Hernation(CSD), Spondylothesis, Spondylosis, Facet Arthropathy, and Degenerative Disc Disease (DDD).
Results: The results of this evaluation revealed that 88% of cases, have at least one MRI findings. Of the 400 subjects we have reviewed 257 found to have SIJ injections (SIJI) on the left side (LT) 83 cases , on the right side (RT) 71 cases, and 73 bilateral (BL). We categorized lumbosacral MRI findings in this series: DDD (59%), Facet Arthropathy (32%), Stenosis (25%), Disc Herniation (19%), CSD (18%), Spondylolisthesis (12%), and Spondylolysis (4%). We found DDD cases to be associated with 65%, 59%, and 52% in left, bilateral, and right SIJI respectively. Facet Arthropathy cases found to be associated with 41% of left SIJI, 31% of right SIJI, and 22% of bilateral SIJI. Lumbar canal stenosis cases accompanied with 30%, 27%, and 19% in right, left, and bilateral SIJI respectively. Disc Herniation cases found with 23% of BL SIJI, 18% of RT SIJI, and 16% of LT SIJI. Combined Stenosis and Disc Hernation cases to be associated with 26%, 14%, and 14% in bilateral, left, and right SIJI respectively. We found L5-S1 Spondylolisthesis cases to be associated with 20% of right SIJI, 11% of left SIJI, and 5% of bilateral SIJI. Interestingly, spondylolysis cases is associated with 4% in all categories. 69% of the entire cases shown a positive response SIJI (more than 50% pain relief after injection). This study is still in process, the final statistical data will be available by the time of publication.
Conclusions: Clinical findings and physical examination is the first step in determining whether SIJ should be considered as a pain generator; therefore we believe SIJ injections is solely based on clinical diagnosis and not imaging findings as it has been proven in medical literature. In this study lumbosacral pathologies is found to be associated with SIJ instability. By pe
A84 Title: Preliminary ultrasound evaluation of the spread of bupivacaine-loaded microspheres Presenting Author: Jesn-Pierre Estebe MD, PhD Presenting Author's Institution: University of Washington - Seattle, WA Co-Authors: Philippe Richebe MD, PhD - University of Washington - Seattle, WA Francois Chevanne BSc - University of Rennes - Rennes, Britanny Claude Ecoffey MD - University of Rennes - Rennes, Britanny Pascal Le Corre PharmD, PhD - University of Rennes - Rennes, Britanny
Abstract: Introduction: To obtain long duration of local anesthetics action, as well as to minimize the systemic toxicity, a biodegradable and biocompatible controlled- release delivery system of has been developed [1, 2]. Ultrasound (US) guidance has become a reliable adjunct for regional anesthesia. However, such drug delivery system had never been evaluated under US-guided injection.
Material and Method: Bupivacaine-loaded microspheres (B-Ms) were produced as previously described (mean size: 5 m) [3]. Two concentrations of spheres were evaluated in the present study: one at concentration previously used in experimental studies (133 mg B + 198 mg Ms / 10 mL)(B-Ms-L) and one at high concentration (665 mg B + 1g Ms / 10 mL)(B-Ms-H). US evaluation was performed with Logiq P5 (General Electric) machine. Injections were performed through a 22G needle (Stimuplex Ultra, B Braun). In the aim to follow the spread of the solution, injections (3 mL) of B-Ms-L and B-Ms-H were performed into a phantom block. Then, in order to follow tissue infiltrations 2 and 6 hrs after injections, injections of both B-Ms concentrations (5 mL) were injected into a piece of fresh meat, and into human cadaver. Saline injections were used as control.
Results: Despite the fact the Ms-solutions are a bit more viscous than saline, all solutions were easily injected through the 22G needle. In the phantom, the spread through the needle during the B-Ms-L injection was surprisingly visible (Fig 1). Then, the spread of B-Ms was seen as snow into the gel (Fig2). B-Ms-H induced a too bright echo to see the frothy spread of spheres into the gel (Fig 3). The same phenomenon of snowing was seen during fresh meat or cadaver injections with B- Ms injections at both concentrations. In comparison, saline injections give a usual black spot picture during liquid diffusion. But, due to the liquid absorption, 2 and 6 hrs after it was impossible to see the difference between pictures performed before and after saline injections. With B-Ms, by using picture of the spread recorded just at the end of injection, it was easy to localize the location of B-Ms 2 and 6 hrs later for the two B-Ms concentrations. Discussion: We could easily see the spread of B-Ms with US. Compare to the catheter, a close location of the B-MS to the nerve probably could guarantee a good level success in the prolongation of the block. The pictures performed at the end of injection might allow a safe follow-up into the tissues. With a specific US training to localized the B-Ms, we could expected in further animal models to correlate the amount B-Ms injected around the nerve and the duration of the block. As evoked for contrast agents, the effect of acoustic power on B-Ms could be evoked. However, as previously reported, B-Ms were suspended by ultrasonication (0.05 MHz / 2 min) before injection without effect on the B release profile. During US- guided injection the probe was set at 6-14 MHz that give less energy into tissue than low frequency but a pharmacokinetics and pharmacodynamics evaluations must be performed.
References 1. Eur J Pharm Biopharm. 2009;72:54-61. 2. Anesth Analg. 2001;93:447-455. 3. Int J Pharm. 2002;15:191-203.
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A85 Title: The effect of local anesthetic solution distribution on block characteristics during interscalene block Presenting Author: Robert S Lang MD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Michael L Kentor MD - University of Pittsburgh Medical Center - Pittsburgh, PA Amy Phelps BS - Duquesne University - Pittsburgh, PA Paul E Bigeleisen MD - University of Pittsburgh Medical Center - Pittsburgh, PA Manuel C Vallejo DMD, MD - University of Pittsburgh Medical Center - Pittsburgh, PA
Abstract: Background: the optimal placement or distribution of local anesthetic solution during interscalene block (ISB) is uncertain. Some authors place local anesthetic deliberately around each visible nerve element, while others simply inject the entire solution into the space between the scalene muscles (1,2). The objective of this study was to determine the distribution of single-injection local anesthetic solution during ISB, and to correlate this distribution pattern with block onset and other characteristics of the block.
Methods: This study was approved by the University of Pittsburgh Institutional Review Board. Patients undergoing ISB for shoulder surgery with ultrasound and nerve stimulator guidance were enrolled after informed consent was obtained. The brachial plexus was imaged with U/S in the interscalene groove. A 5 cm, 22 gauge stimulating needle (B. Braun), connected to a nerve stimulator (B. Braun) was inserted under in-plane ultrasound guidance. The needle was advanced toward the visible nerve fascicles, and when any brachial plexus motor stimulation resulted, a solution of 20 ml of 0.75% ropivacaine was slowly injected. A video of the ultrasound image was retained for later analysis. The degree of anesthesia about the shoulder was evaluated after 5, 10 and 20 minutes had elapsed, using a 3 point score for both motor and sensory blockade. Pain in the PACU was also noted. The patients were called at 24-48 hours to determine block duration. A blinded anesthesiologist, experienced in ultrasound-guided ISB, evaluated the ultrasound video of each block. A six point quantitative distribution score (3) was utilized to rate the degree of distribution of the injected local anesthetic solution about the visible nerves, based on the video. The primary outcome variable was block set up time, as judged by onset of complete sensory and motor function in the nerve areas tested. Other outcome measures were block failure rate, pain scores in the PACU, and duration of analgesia.
Results: Thirty-two patients were recruited for participation in the study. Patient demographics are presented in Table 1. The distribution scores of the sample are noted in Figure 1. Incisional pain in the PACU was reported by only 1 patient, at a level of 1/10. No patients had a failed block. When evaluated according to score of injectate distribution, there was no difference between groups with early (less than 5 minute), intermediate (5-10 minutes), or late (up to 20 minutes) block set up times. The mean block duration was 17.6 (+/-4.8) hrs. There was no significant relationship between duration of analgesia and the injectate distribution score, Figure 2.
Discussion and Conclusions: In this study, differences in apparent distribution of local anesthetic solution about the nerves in the interscalene groove during ultrasound-guided interscalene block did not result in significant differences in block characteristics, including block set-up times, incision pain in the PACU, or duration of analgesia. With a larger sample of patients, the trend towards early set up of the nerve block in the group with higher distribution scores might prove to be significant.
References 1.Reg Anesth Pain Med. 2008;33:253. 2.Reg Anesth Pain Med. 2003;28:340. 3.Reg Anesth Pain Med. 2007;32:130.
Additional File #1: 1030111065636Table_1.doc Click here to view
Table 1: Patient Demographics
Age (years) 49.12 Height (cm) 69.78 Weight (lb) 190.03 Gender Male 22 Female 10 Side of surgery Right 22 Left 10 Type surgery Subacromial Decompression 30 Rotator Cuff Repair 23 Labral Repair 4 Capsule 3 AC 4 Motor response to stimulation Deltoid 21 Brachioradialis 2 Biceps 4 Pectoralis 1 Deltoid/Biceps 5
Additional File #2: 2030111065636Table_2.doc Click here to view
Table 2: Block Characteristics
Distribution Score 1-2 (n=10) 3-4 (n=10) 5-6 (n=12) Set Up Time: Early (5 min) 0 0 3 Intermediate 4 6 5 (10 min) Late (20 min) 6 4 4 Mean duration 17.4 18.7 17.0 (hrs) Incision Pain in 0 0 1 PACU
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Figure 2: Distribution Score Predicting Duration
A86 Title: Fast track arthroplasty using periarticular wound infusion Presenting Author: Sugantha Ganapathy FRCPC Presenting Author's Institution: University of Western Ontario - London, Ontario Co-Authors: Tony Vannelli FRCPC - University of Western Ontario - London, Ontario James Howard FRCSC - University of Western Ontario - London, Ontario David Chess FRCSC - University of Western Ontario - London, Ontario Douglas Naudie FRCSC - University of Western Ontario - London, Ontario
Abstract: Introduction: Total joint arthroplasty results in significant postoperative pain. Periarticular infiltration of a mixture of local anesthetic, morphine, ketorolac and epinephrine continued with infusion of local anesthetic via catheters inserted periarticularly at the end of surgery can provide analgesia without motor blockade. We used this modality of analgesia to facilitate early discharge following THA or TKJA 24-36 hours after surgery.
Materials and Methods: One hundred patients of either sex, aged 40-75 yrs, scheduled for TKJA (50) or THA (50), ASA physical status I-III, received perioperative multimodal analgesia with celecoxib, gabapentin, acetaminophen and periarticular infiltration with 300 mg of ropivacaine in 100 mL mixed with ketorolac 30mg, morphine 10 mg and epinephrine 2.5μ/mL. All patents had spinal anesthesia with 15 mg of hyperbaric bupivacaine. Multi orificial catheters were positioned by the surgeon (3 for TKJA and 2 for the THA one of these was intrarticular. Infusion was with an elastomeric pump delivering 2mL/cath/h of 0.35% ropivacaine for 48 hours. Postoperatively, they were progressed with accelerated pathway of mobilization walking with support the evening of surgery, progressing to walking 5 steps by noon of postoperative day 1. They were discharged home based on good pain control, lack of nausea, hemodynamic stability and lack of surgical complications. All patients had WOMAC scores done preoperative and 30 days after surgery. Patients were seen by home care and the catheters were removed at 48 hours. Plasma ropivacaine levels were measured on arrival in PACU and the morning after surgery.
Results: One hundred patients were scheduled for fast tracking. 78% were discharged the day after surgery and an additional 4 patients were discharged at 36 hours. The plasma ropivacaine levels were below toxic range. Pain scores during rest and ambulation were low. Significant adverse events included postop myocardial infarct on POD 3 at home in 1, postoperative sciatic dysfunction 2, poor pain control 2, dizziness and hypotension 4 and bleeding from surgical site 3. Causes of failure to fast track included low hemoglobin and hypotension 5/22, patient unwillingness3/22, poor pain control 11/22, logistical reasons and more extensive surgery2/22. There were no infections. One catheter broke and a piece left behind in the scar. Patient satisfaction was high. Pain scores and demographics are shown in table 1 and 2. There was no motor weakness of lower limb except in the 2 that had sciatic dysfunction.
Conclusions: Periartiular infiltration and infusion provides goos analgesia with no motor blockade allowing early mobilization and discharge. Patient selection and education are crucial to the success.
References Kerr and Kohen Acta Orthopaedica. 2008;79(2):174–183. Tord Röstlund1 and Kehlet H Acta Orthopaedica. 2007;78(2):159–161.
Additional File #1: 1022811200419table_1_FTA_ASRA.doc Click here to view
Variable THA (50) TKJA (50) DOS rest 0.9(1.6) 1.2(1.7) DOS act 2.7(2) 3.3(2.4) POD 1 rest 1.1(1.5) 1.6(1.7) POD 1 act 2.7(1.8) 3.2(2.2) Post stairs 3.2(1.8) 3.6(2.1) POD2 act 2.4(1.4) 3(2.5) POD 7 act 1.4(1.3) 1.9(1.9) POD 30 act 0.5(0.7) 0.8(1.4)
Table 1:
VAS Pain scores during rest and activity (VRScale 0-10). Values are mean +/-SD
Additional File #2: 2022811200419FTAASRA_table_2.doc Click here to view
Variable THA (50) TKJA (50) Wt in Kg 81.3(19) 92.1(18.5) Ht cm 169(8.7) 172.5(9) ROPI PACU mcg/mL 0.493(0.3) 0.37(0.23) Ropi POD 1 mcg/mL 1.2(0.5) 1.19(0.58) Satis 7.9(2) 6.9(2) Perc eq DOS 3.4(1.5) 3.6(1.5) Perc Eq POD1 2.9(1.4) 2.6(1.5) Perc Eq POD2 2.4(1.4) 2.6(1.5)
Table 2
FTA demography, ropivacaine, satisfaction
A87 Title: Continuous Femoral Nerve Blocks: Varying Local Anesthetic Delivery Method (Bolus vs. Basal) to Minimize Quadriceps Motor Block while Maintaining Sensory Block Presenting Author: Vanessa J Loland MD Presenting Author's Institution: University of California San Diego - San Diego, CA Co-Authors: Matthew T Charous MD - University of California San Diego - San Diego, CA Sarah J Madison MD - University of California San Diego - San Diego, CA Preetham J Suresh MD - University of California San Diego - San Diego, CA NavParkash S Sandhu MD - University of California San Diego - San Diego, CA
Abstract: Background: Because quadriceps weakness is associated with significant functional disability and an increased risk of falls in elderly patients, it is postulated that any nerve block-induced muscular weakness is best minimized during perineural local anesthetic infusion (1). One recent study involving continuous popliteal-sciatic nerve blocks following hallux valgus repair reported increased analgesia without a concurrent increase in motor block by administering local anesthetic in repeated 5 mL hourly boluses compared with a 5 mL/h continuous infusion (2). These results raise the exciting possibility of decreasing the fall risk with a continuous femoral nerve block cFNB) by decreasing muscle weakness while maintaining analgesia. Whether the method of local anesthetic administration for cFNB—basal infusion vs. repeated hourly bolus doses—influences block effects remains unknown.
Methods: Bilateral femoral perineural catheters were inserted in volunteers (n=11). Ropivacaine 0.1% was administered through both catheters concurrently using two electronic portable infusion pumps (ambIT PCA, Summit Medical, West Jordan, Utah): a 6-hour continuous 5 mL/h basal infusion on one side and 6 hourly bolus doses on the contralateral side. All investigators, nursing staff, and subjects remained masked to treatment group assignment: all subjects received both a basal-only infusion and repeated bolus doses (subjects acted as their own controls). The primary end point was the maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle at Hour 6. Secondary end points included quadriceps MVIC at other time points, hip adductor MVIC, and cutaneous sensation (measured as mild discomfort from transcutaneous electrical stimulation) 2 cm medial to the distal quadriceps tendon in the 22 hours following local anesthetic administration initiation.
Results: Quadriceps MVIC for limbs receiving 0.1% ropivacaine as a basal infusion declined by a mean (SD) of 84% (19) compared with 83% (24) for limbs receiving 0.1% ropivacaine as repeated bolus doses between baseline and Hour 6 (paired t- test p=0.91; Fig. 1, *=0.05). Intra-subject comparisons (left vs. right) reflected a lack of difference as well: the mean basal-bolus difference in quadriceps MVIC at Hour 6 was -1.1% (95% CI -22.0 to 19.8%). The similarity did not reach our a priori threshold for concluding equivalence, which was the 95% CI falling within ±20%. There were similar minimal differences in the secondary endpoints during local anesthetic administration (Figs. 2 & 3, *=0.05).
Conclusions: This study did not find evidence to support the hypothesis that varying the method of local anesthetic administration—basal infusion vs. repeated bolus doses—influences continuous femoral nerve block effects to a clinically significant degree. Thus, it is doubtful that when using a continuous femoral nerve block, varying the method of local anesthetic administration will provide an increased sensory-to-motor block ratio and minimize motor block and the risk of falling while optimizing cutaneous analgesia.
References: (1) Ilfeld et al. Anesth Analg. 2010;111:1552-1554. (2) Taboada et al. Anesth Analg. 2008;107:1433-1437.
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A88 Title: Low Dose Bupivacaine-Fentanyl Subarachnoid Block for Surgical Repair of Hip Fractures in Elderly Patients: A Double-Blind Study Presenting Author: Ashish K Khanna MD Presenting Author's Institution: The Cleveland Clinic Foundation - Cleveland, OH Co-Authors: Ehab S.A. Farag MD FRCA - Cleveland Clinic - Cleveland, OH Kanti K Gombar MD - Government Medical College and Hospital - Chandigarh, India Satinder Gombar MD - Government Medical College and Hospital - Chandigarh, India Sudhir K Garg MS - Government Medical College and Hospital - Chandigarh, India
Abstract: Aims and Objectives: Traumatic hip fractures are an important cause of morbidity and mortality in the ever increasing geriatric population. 1 Elderly patients have a reduced physiological reserve and may not be able to compensate for the sudden haemodynamic alterations associated with a subarachnoid block. 2
Materials and Methods: Sixty patients of physical status ASA grade I, II and III, in the age group of 60 - 85 years who were scheduled to undergo elective hip fracture surgery under subarachnoid block were randomized to three groups of 20 patients each to receive 2 mL of 0.5% hyperbaric bupivacaine (Astra IDL) [10mg] (Group I), 2 mL of 0.5% hyperbaric bupivacaine (10mg) with 20µg fentanyl (Group II) or 1.5 mL of 0.5% hyperbaric bupivacaine (7.5mg) with 20µg fentanyl (Group III) in this prospective, double-blind study. Sensory and motor blockade, intraoperative discomfort, post operative analgesia, respiratory and haemodynamic parameters along with side effects and any neurological deficits were assessed for and managed accordingly.
Results: Total duration of analgesia was significantly longer in Group II (253.95±37.546 min), when compared with Group III (170.11±23.044 min) and Group I (219.00± 30.591 min) (p<0.05). Median peak sensory level and two- segment regression time was significantly more in Group I and II as compared to Group II.Incidence of hypotension and the need for vasopressor support was found to be significantly more in Group I and II as compared to Group III.
Conclusion and Discussion: Addition of an opioid to the local anesthetic produces a synergistic effect which allows a reduction in the dose of local anesthetic required and makes it possible to achieve a successful subarachnoid block using otherwise inadequate doses of local anesthetic. The minimum effective dose of bupivacaine was 7.5mg when used in combination with 20µg fentanyl and provided adequate analgesia, anesthesia, rapid motor recovery and better haemodynamic stability in elderly patients undergoing hip fracture surgery.
References 1. Urwin, SC. et al. Br. J. Anaesth. 2000;84:450-455 2. Critchley, LAH. Anaesthesia. 1996;51:1139-1143. 3. Ben-David, B et al. Anesthesiology. 2000;92:6-10.
Additional File #1: 1010911185518Table_ASRA_I.doc Click here to view Table I: Duration of Sensory Block
Group I Group II Group III (n=20) (n=20) (n=18)
Two segment 147.60 ± regression time (min) 135.90 ± 20.893 114.33 ±12.930 16.503 MEAN ± SD
p values:
Two segment Groups regression time
Group I vs. III <0.01
Group II vs. III <0.01
Group I vs. II >0.05
Additional File #2: 2010911185518Table_ASRA_II___III.doc Click here to view Table II: Intra operative Discomfort Level
Group I Group II Group III (n=20) (n=20) (n=20)
Sensory Scale* 17-2-1-0 20-0-0-0 16-1-1-2 0-1-2-3
*0-no distress,1-slight distress(need single dose of anxiolytic), 2-moderate distress(need 2 doses of anxiolytic ), 3-intense distress(required general anesthesia)
p>0.05
Table III: Duration of post operative analgesia
Group I Group II Group III (n=20) (n=20) (n=18)
Time to first request for 172.11 ± 220 ± 30.950 255.85 ± 37.672 post operative analgesia 23.044 Mean ± SD(min)
p<0.05
Additional File #3: 3010911185518Table_IV_ASRA.doc Click here to view Table IV: Incidence of Hypotension and Ephedrine Required
Group I Group II Group III (n=20) (n=20) (n=20)
Hypotension(<90mmHg systolic or >30% fall from 10 (50%) 11 (55%) 4(20%) baseline)
Ephedrine 130 170 55 required(mg)
Data expressed in numbers (%)
p values :
Groups p value
Group I vs. III <0.05
Group II vs. III <0.05
Group I vs. II >0.05
A89 Title: Safety Evaluation of DepoFoam® Encapsulated Bupivacaine in Dogs to Assess Inadvertent Intrathecal Injection Presenting Author: Brigitte M Richard PhD Presenting Author's Institution: Pacira Pharmaceuticals, Inc. - San Diego, CA Co-Authors: Laura R Ott BS, LAT - MPI Research - Mattawan, MI Robert C Switzer PhD - NeuroScience Associates - Knoxville, TN Daryl C Thake DVM, Dipl. ACVP - Midwest ToxPath ScNeuroScience Associatesiences, I - Chesterfield, MO Dean Haan BS - MPI Research - Mattawan, MI
Abstract: DepoFoam bupivacaine (DB) is a sustained-release bupivacaine formulation being investigated for postsurgical analgesia via epidural. A pivotal toxicology study of DB was performed after intrathecal (IT) administration in male dogs. The objective was to address the question whether DB following ―accidental‖ IT administration would have local and/or systemic adverse effects.
Groups of 6 dogs received either DB (45 mg), bupivacaine solution (Bsol) (15 mg), DepoFoam vehicle, or saline. Three (3) dogs were sacrificed on Day 4; the remainder on Day 22. Endpoints included gross observations and clinical pathology, organ weights and histopathology examination of a full tissue list including injection sites. Hematoxylin and eosin (H&E)-stained paraffin sections of spinal cord (SpC) were examined microscopically at 3 sampling sites (cervical, thoracic, lumbar [dosing site]). In addition, portion of the lumbar SpC underlying the injection site was examined for signs of degeneration using a sensitive silver stain method. A grading system for pathological score was used to define gradable lesions (i.e., minimal to severe).
Results were recorded by section of SpC involving white matter (WM) tracts or grey matter (GM). Results revealed no DB-related toxic effects. Due to respiratory arrest during dosing, three dogs receiving Bsol were mechanically ventilated. One of these animals also received 4 mL of atropine sulfate. Impaired limb function was observed on Day 1 in dogs receiving Bsol (6/6) and DB (4/6). In the DB group, the impairment resolved over the next 1 to 3 days. In the Bsol group, the impairment persisted through Day 7 (3/3) and through Day 8 in one of these three dogs. DepoFoam vehicle (1/6) and saline-treated dogs (2/6) also had similar observations, suggesting that the injection procedure may have partially contributed to the incidence of limb impairment. Microscopic findings revealed no treatment-induced degeneration in SpC. Staining for degeneration was observed in all sections of the spinal cord being more evident in WM tracts (dorsal, lateral and ventral funiculi) with lesser amounts present in GM. Microscopic findings, such as axonal/myelin degeneration in WM, focal necrosis of GM, hemorrhage, and/or chronic inflammation observed on Day 4 and/or Day 22, were a result of the IT injection procedure (i.e., penetration of structures by the needle). There were no relevant differences in severity scores among the IT groups (range: 1.83 to 2.71), although the DB group had the lowest severity score (1.83). In summary, the incidence and duration of motor block was greater with Bsol vs. DB. Non specific local irritation, mild hemorrhage and degenerative changes were regarded procedure-related.
This study demonstrates the safety and local tolerance of DB in a clinically relevant model of ―accidental‖ IT injection, and supports the first-time-in-human trial of DepoFoam bupivacaine by epidural administration.
A90 Title: DepoFoam® Encapsulated Bupivacaine Technology – Safety and Tolerability Properties in Rabbits and Dogs Presenting Author: Brigitte M Richard PhD Presenting Author's Institution: Pacira Pharmaceuticals, Inc. - San Diego, CA Co-Authors: Paul E Newton PhD - MPI Research - Mattawan, MI Laura R Ott BS - MPI Research - Mattawan, MI Dean Haan BS - MPI Research - Mattawan, MI Abram N Brubaker PhD - MPI Research - Mattawan, MI
Abstract: DepoFoam bupivacaine (DB; bupivacaine extended-release liposome injection) is in development for prolonged postsurgical analgesia. Dierucoylphosphatidylcholine is unique to DB‘s DepoFoam delivery system (i.e., it is not in the previously approved DepoFoam products DepoDur® (morphine sulfate) and DepoCyt® (cytarabine). Safety and tolerability of DB was tested in the hernia repair model in rabbits and dogs. Studies were conducted in a surgical model in rabbits and dogs to evaluate the potential local and systemic toxicity after local wound infiltration of DB.
Groups of rabbits and dogs (4/sex of each animal) received DB 9 mg/kg, 18 mg/kg, or either 25 or 30 mg/kg, bupivacaine solution (Bsol; 7.5 mg/mL, 9 mg/kg,) or saline after surgery. General anesthesia was induced and an inguinal hernia repair was performed; a polypropylene mesh (1.0 cm x 1.0 cm and 2.0 cm x 3.0 cm in the rabbits and dogs, respectively) was incorporated into the wound closure and sutured in place to mimic clinical practice in herniorrhaphy. All treatments were administered once on day 1 via injection following the surgical procedure. Each dose was divided into eight equal volumes. Four injections were administered in the muscle fascia around the surgical mesh, and four more injections were given in the area surrounding the incision repair. Endpoints included clinical signs, clinical pathology, organ weights and toxicokinetic analysis on day 1. Histopathology examination of a full tissue list was performed on days 3 and 15 including surgical sites. Macroscopic examinations of wound healing were recorded beginning on day 2 through day 15 postdosing.
There was no adverse effect on wound healing in either species. There were no differences in overall incidence or severity of histologic changes in the surgical sites exposed to DB, saline or Bsol except for low severity granulomatous inflammation, which on day 15 only, in 8 of 24 rabbits receiving DB and considered an expected reaction to the liposomes. In dogs, histologic changes at days 3 and 15 were indicative of normal wound healing across the groups. There was no adverse effect on wound healing in either species. The attenuation of Cmax with DB vs. Bsol was two- to six-fold, i.e., Cmax = 107±27.6 vs. 620±89.9 ng/mL (rabbit) and 536±484 vs. 931±396 ng/mL (dog) (n=4, combined sexes). Since toxicity to bupivacaine is Cmax related, this suggests a safety factor of the same magnitude for DB as compared with Bsol at equivalent doses (9 mg/kg). In conclusion, we have established the safety and tolerance of DB in clinically relevant surgical models. The data reported here support phase 2/3 clinical trials designed to investigate the efficacy and safety of DepoFoam bupivacaine after wound infiltration in surgical patients.
A91 Title: Which level to treat? A spinal endoscopic study (epiduroscopy) in patients with low back and radiating pain. Presenting Author: Hemmo A Bosscher MD Presenting Author's Institution: Texas Tech University Health Sciences Center, Lubbock, TX - Lubbock, TX Co-Authors: James E Heavner DVM, PhD, FIPP (Hon) - Texas Tech University Health Sciences Center, Lubb - Lubbock, TX
Abstract: Backround: Precise localization of painful structures in the epidural cavity of patients with low back pain and/or pain radiating to the lower extremities is important for targeted therapeutic intervention.
Objective: The aim of the study reported here was to compare the level where pain was elicited via endoscopic evaluation vs. the vertebral level from where the pain was thought to originate as diagnosed by clinical evaluation (history and physical examination) and MRI.
Methods: Following IRB approval, 130 patients in whom a discrete painful site could be identified were asked if the pain generated by touch of epidural structures with an endoscope, was similar in character and distribution to the pain (concordant pain) for which treatment was planned based on clinical evaluation and MRI reports by qualified radiologists. The radiating pattern of the pain down the leg was used to determine the corresponding nerve root and vertebral level. A level was defined as the region between the midpoints of two pedicles: L3-4, L4-5, L5-S1.
Results: 116 (89%) patients reported maximal concordant pain at a specific level of which 71 (66 %) reported concordant pain at L4 - L5, 14 (12%) at L3-L4 and 22 (19%) at both levels. Only one patient reported pain caudal to L4 – L5; 7 patients reported concordant pain above the level of L3-4. Evaluation of a vertebral level through epiduroscopy, clinical evaluation or MRI was significantly different (Odds ratios, p <0.05). Clinical evaluation diagnosed the level at which pain could be reproduced in 69 of 130 (53%) patients. MRI diagnosed the vertebral levels specifically in 37 (28%) patients. In only 11 patients (8%) did epiduroscopy, MRI and clinical evaluation, agree on the same level of pathology.
Conclusions: The majority of clinically significant epidural pathology in patients with low back pain and or radiating leg pain was found at the L4 - L5 level, followed by L3 - 4. Pathology at other levels was less common. As compared to epiduroscopy, clinical evaluation and MRI may be poor indicators of the correct vertebral level of clinical significant spinal pathology. A92 Title: Measurement of Regional Hemodynamic Parameters in the Upper Extremity Using Pulse-Wave Doppler Ultrasound: A Reliability Study Presenting Author: Jiawei LI Mphil Presenting Author's Institution: The Chinese University of Hong Kong - Hong Kong, Hong Kong Co-Authors: Alan Bourke FRCA, FANZCA - The Chinese University of Hong Kong - Hong Kong, Hong Kong Xiang Li PhD - Minhang Hospital of Shanghai - Shanghai, Shanghai Manoj Karmakar MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong
Abstract: Background: Regional hemodynamic parameters in the upper extremity can be measured using pulsed-wave Doppler ultrasound (US). In this study we sought to assess the interobserver and intraobserver variability in the measured regional hemodynamic parameters, in the brachial and common palmar digital arteries of the upper extremity, using pulse-wave Doppler US.
Methods: After ethical approval and written informed consent, 12 healthy young volunteers (21-34yrs) were recruited. Regional hemodynamic parameters were measured in the left brachial and common palmar digital arteries using pulsed-wave Doppler ultrasound. Measured hemodynamic parameters included Peak Systolic Velocity (PSV, cm/s), End Diastolic Velocity (EDV, cm/s), ratio of PSV and EDV (S/D), Mean Velocity (Vmean, cm/s), Time-Averaged Mean Velocity (TAVM, cm/s), Resistance Index (RI), and Pulsatility Index (PI). The acquired values were from an average of 5 consecutive cardiac cycles. The arterial diameter (d, cm) was measured manually at the end of diastole of the cardiac cycle, which corresponds to the onset of the QRS complex on the ECG tracing (ECG-gating). Blood flow was calculated as the product of TAVM and cross-sectional area. These measurements were performed independently by two observers (AB and JW) and repeated for their reliability. For the inter-observer reliability testing, either observer made two consecutive measurements in each artery (same location). The two observers were mutually blind to their results and the second observer could not start the examination until the first observer had finished all the measurements. For the intraobserver reliability testing, the two observers repeated the same scan after 30 minutes in the same sequence. Intraclass Correlation Coefficient (ICC), and the variation (%) were used for testing the interobserver and intraobserver variability.
Results and Discussion: ICC values were all greater than 0.9 (Table 1, data only provided for the brachial artery) which indicates that there was good intraobserver consistency and interobserver agreement in the hemodynamic measurements made at the brachial and common palmar digital arteries. Measurement variations within and between the observers for all parameters recorded were within 20% (Table 1), which is far less than the hemodynamic changes that occur after a brachial plexus block.
Conclusions: We have demonstrated that pulse-wave Doppler US is a reliable and reproducible method of measuring regional hemodynamic parameters in the upper extremity. Future research should use this method to quantify regional hemodynamic changes after brachial plexus block.
Additional File #1: 1012711030940table1_.tif Click here to view
A93 Title: Minimizing Peaks & Valleys of Postoperative Analgesia in Opioid-Tolerant Surgical Clients Presenting Author: Sheila L. Hoehn MAN, RN, BC Presenting Author's Institution: Mayo Clinic College of Medicine - Mantorville, MN Co-Authors: Abstract Body:
Abstract: Increasing incidence of acute postoperative pain, compiled with the presence of preoperative chronic pain, has become a difficult challenge for nurses in the inpatient surgical setting. The growing use of preoperative opioids nationwide will be evaluated and reviewed in this poster presentation. This escalating occurrence has contributed to the increased incidence of uncontrolled and unrelieved inpatient surgical pain. This challenge is becoming more common as the preoperative usage of opioids for medical and non-medical reasons is consistently rising. This poster will focus on essential assessment skills needed when caring for the surgical patient that is also experiencing long-term chronic pain. Multimodal pain approaches will be highlighted and emphasis on treatment barriers with analgesia management will be reviewed.
A94 Title: Low Dose Hyperbaric Bupivicaine Injected at T12-L1 Provides Adequate Anesthesia With Stable Hemodynamics for Elderly Patients Undergoing TURP Presenting Author: Amr Abdelmonem MD Presenting Author's Institution: University of Cairo - Cairo, Egypt Co-Authors: Ahmed Mukhtar MD - University of Cairo - Cairo, Egypt Patrick McQuillan MD - Penn State University - Hershey, PA Khaled Sedeek MD - Penn State University - Hershey, PA
Abstract: Background: Elderly patients undergoing transurethral resection of the prostate (TURP) may have preexisting cardiac or cerebral dysfunction. Maintaining hemodynamic stability is an important goal for any anesthetic. The objective of this study was to compare the anesthetic efficacy and cardiovascular stability of a subarachnoid injection of 7.5 mg hyperbaric bupivacaine at the level of T12-L1 to 15 mg hyperbaric bupivacaine injected at the level of L3-4 for elderly patients undergoing TURP.
Methods: Fifty patients undergoing TURP were enrolled. Patients were randomized to either of two groups: Group I: Dural puncture was performed in the midline at the T12-L1 interspace. 7.5 mg of hyperbaric bupivacaine (1.5 ml of 0.5% solution) was then injected through a 16 gauge/26 gauge combined spinal-epidural by ―needle through needle‖ technique. Group II: Dural puncture was performed in the midline at the L3-4 interspace. 15 mg of hyperbaric bupivacaine (3 ml of 0.5% solution) was then injected through a 25-gauge spinal needle. Demographic data, prostate size, volume of irrigation fluids, hemodynamic parameters, block characteristics, and complications were recorded.
Results: Demographic data, prostate size, volume of irrigating fluids, complications and duration of surgery were comparable in both groups. Patients in Group I exhibited a more stable blood pressure and heart rate during the study time period (P<0.05). The duration of sensory and motor blockade were shorter in Group I (P <0.05). Patients in Group II demonstrated a significantly higher peak sensory block (T4, P<0.05), shorter mean time to peak sensory block (4.8 ± 1.1 min, P<0.05), and earlier onset of sensory block at T10 (2.6± 0.5 min, P<0.05).
Conclusion: Injection of 7.5 mg hyperbaric bupivacaine at the level of T12-L1 is sufficient to provide adequate sensory block while maintaining hemodynamic stability for TURP. This dose and injection location may offer an additional advantage of decreased duration of motor block in patients undergoing TURP.
A95 Title: Documentation of regional anaesthesia in a university teaching hospital. Presenting Author: Daniel Soltanifar FRCA Presenting Author's Institution: University College London Hospital - London, London Co-Authors: Khalid Syeed FRCA - University College London Hospital - London, London Maria R Capoluongo MBBS - University College London Hospital - London, London Damon Kamming FRCA - University College London Hospital - London, London
Abstract: Introduction: There is currently no national or international consensus on documentation for regional anaesthesia. Keeping good anaesthetic records is important as it enables patients to receive effective continuing care, enables the healthcare team to communicate effectively, allows other doctors to assume the care of the patient at any time, facilitates data collection for research and audit and can be used in legal proceedings(1). With regional anaesthesia becoming increasingly popular and with a recent focus placed on documentation of regional anaesthesia (2), we analysed the quality of record keeping for regional anaesthesia in our institution.
Methods: A retrospective audit of anaesthetic charts was carried out over a 1 month period looking at orthopaedic cases in which regional anaesthesia was performed (excluding neuroaxial techniques). The primary aim of the audit was to assess the extent of documentation, looking specifically at documentation of risks and benefits. The secondary aim was to review documentation of the procedure itself including complications. We cross referenced the charts with the theatre database to see if the data for electronic collection correlated with paper collection.
Results: The results were dramatic. A total of 312 orthopaedic cases were reviewed of which 67 had a documented regional anaesthetic performed. The results are summarised in the charts and tables. Regional anaesthesia was performed in 21 % of cases. Documentation of a discussion concerning consent for the procedure was variable with risks (45%) recorded more frequently than benefits (15%). There was also variability in the information provided for each individual block. The overall level of documentation of the procedure was poor, except for method of location, 85% of cases and volume and concentration of local anaesthetic administered, 93% of cases. Assessment of timing and efficacy of the block again was poor with only 6 % of cases having some form of sensory or motor assessment prior to surgery commencing.
Conclusions: This audit shows a lack of documentation and great variability in what is recorded for regional anaesthesia. There is a very low level of clear documentation of risk and benefit in our institution. We would recommend standard documentation for the recording of regional anaesthesia and the introduction of guidelines which highlight the minimal data set to be recorded would be helpful. Better documentation for regional anaesthesia should improve future audit and research and the measurement of patient outcomes.
References (1) Raising the standard, AAGBI guidelines: a compendium of audit recipes (second edition 2006) section2.4 pp 50-51. (2) Gerancher JC. The three "C's" of documentation in regional anaesthesia: consent, care and compliance. ASRA 35th annual spring meeting 2010.
Additional File #1: 1022411150603Chart_1_regional_ab.docx Click here to view
Additional File #3: 3022411155707chart_2_regional_ab.docx
A96 Title: Minimum Effective Volume of Local Anesthetic in Infraclavicular Block: Ultrasound versus Ultrasound and Neurostimulation. Presenting Author: Diogo Bruggemann da Conceicao MD Presenting Author's Institution: Governador Celso Ramos Hospital - Florianopolis, SC Co-Authors: Pablo Escovedo Helayel MD - Governador Celso Ramos Hospital - Florianopolis, SC Jose Ribamar Filho MD - Governador Celso Ramos Hospital - Florianopolis, SC Getulio Rodrigues de Oliveira Filho MD, PhD - Governador Celso Ramos Hospital - Florianopolis, SC
Abstract: Background and Objectives: The ultrasound-guided blocks offers potential advantages when compared to other forms of nerve location like visualization of local anesthetic spread during the injection, enabling better outcomes and lower incidence of complications. The local anesthetic volume administered is an indirect predictor of systemic toxicity in peripheral blocks. This study aimed to compare the minimum effective local anesthetic volume (MEAV) for the infraclavicular block guided only by ultrasound with ultrasound plus neurostimulation.
Materials and Methods: After approval by the Ethics Committee on Research of the Hospital Governador Celso Ramos and written informed consent, 40 patients of elective surgeries on forearms and hands, ASA I or II were included. Patients were randomly distributed, in two groups: the US (only ultrasound to guide local anesthetic injection) and the UN group (ultrasound combined with neurostimulation). The first patient in each group received a total volume of 30 ml of 0.75% Ropivacaine. The Up and Down method was applied in subsequent patients with a variation of 3 mLs up or down according with the success or failure of the previous block. Evaluation of the effectiveness of the block was made by to the rule of "four Ps" . It was assigned the value 0 (zero) to complete sensory or motor loss and value 1 (one) for the presence of tenderness or motor function. The block was considered complete when all four tests were equal to zero after thirty minutes of the completion of the block. The data received appropriate statistical treatment.
Results: Thirty-nine patients were enrolled in the study. Nineteen patients were in the US group. Twenty were assigned to the UN group. In the US group, the MEAV was 26.36 ml (95% CI, 23.40 to 29.32 ml). In the UN group, the MEAV was 29.40 ml (95% CI, 26.35 to 32.45 ml). The p value between the groups was 0.36. There was no significant difference between the groups for demographic data. Conclusion: There were no statistically significant differences for the MEAV between groups.
A97 Title: First Year Outcomes of a New Pediatric Pain Rehabilitation Center Presenting Author: Genevieve D'Souza MD Presenting Author's Institution: Stanford University - Palo Alto, CA Co-Authors: Christina Almgren CPNP - Packard Children‘s Hospital - Palo Alto, CA Brenda Golianu MD - Stanford University - Palo Alto, CA Julie Good MD,DABMA - Stanford University - Palo Alto, CA Elliot Krane MD - Stanford University - Palo Alto, CA
Abstract: Background: Multidisciplinary outpatient chronic pain rehabilitation programs have been previously evaluated by multiple centers and have shown to have good patient results. (Sherry et al 1999, Eccleston et al 2003). Adolescents and their families reported significant reductions in functional disability, anxiety and somatic focus and improvements in physical conditioning and school attendance. (Eccleston et al 2003)
There is a growing emphasis on a rehabilitative model with an integrated physical, psychological and medical approach to pediatric pain management. (Howard 2003, Lee et al 2002). However, even in the continental US, there are less than 10 such programs fulfilling this need.
At our institution, we felt a need for a similar home hospital or day program for chronic pain treatments. Our multidisciplinary Pediatric Pain Rehab Center (PPRC) was started in January 2010 with a team consisting of 5 pediatric pain physicians, 1 pediatric psychologist, 1 pediatric psychiatrist, 2 pediatric nurse practitioners, 1 physical therapist and 1 occupational therapist. Our support system also included the hospital‘s school teachers and ancillary staff from the Rehabilitation center who did billing and authorizations.
Methods: The program was initiated as a primary outpatient day program for adolescents in the age group of 12 to 18 years of age. A diagnosis of chronic pain with significant functional and social impairment was required with minimal psychological impairment. Patients with conversion disorder and active suicidal ideations/intentions are excluded from the program. Up to 2 adolescents with a diagnosis of chronic pain were enrolled. Initially patients with Complex Regional Pain Syndrome (CRPS) were treated, however, the diagnostic categories were later broadened to include those with Fibromyalgia, Chronic Abdominal Pain (CAP) and Chronic myofascial pain. Participants were prescreened prior to inclusion by all team members. Therapy included a daily check in with the physician/nurse practitioner, 2 hours each of PT and OT, daily psychotherapy with the psychologist and school for up to 4 hours of the day. Participants also received massage therapy and acupuncture as appropriate. Also included were weekly family therapy and weekly team conferences with the family.
In the first year we treated 10 children (8 females and 2 males). They ranged in ages from 12 yrs to 17 yrs old with a mean age of 14.7 yrs. Length of stay was a minimum of 1.5 weeks to one participant who still continues into our second year with 12 weeks of therapy.
Summary: To date, our center has treated 10 adolescent chronic pain patients with positive outcomes. We had one minor complication of a broken catheter that was later determined to be a manufacturing problem, with no long-term sequelae. We diagnosed 2 adolescents with previously unrecognized significant neurological impairment affecting their function which was masked by chronic pain. Our center on inception required monetary sustenance from the hospital for the initial startup. Within the first year, the program has demonstrated self sufficiency even making a profit for the hospital ensuring future continuance of the program.
References Sherry DD, Wallace CA, Kelley C, Kidder M, Sapp L. Short- and long-term outcomes of children with complex regional pain syndrome type I treated with exercise therapy. Clin J Pain. 1999;15:218-223.
Eccleston C, Palermo TM, Williams AC, Lewandowski A, Morley S. Psychological therapies for the management of chronic and recurrent pain in children and adolescents. Cochrane Database Syst Rev 2009; Apr 15;(2):CD003968.
Howard RF. Current status of pain management in children. JAMA 2003;290:2464- 2469.
Lee BH, Scharff L, Sethna NF, McCarthy CF, Scott-Sutherland J, Shea AM, et al. Physical therapy and cognitive-behavioral treatment for complex regional pain syndromes. J Pediatr. 2002;140:135-140.
Additional File #1: 1030111145011genie_1_.pdf Click here to view
A98 Title: Comparison of postoperative analgesia effects between ultrasound-guided ilioinguinal /iliohypogastric nerve block and spinal anesthesia for inguinal hernia repair in adults Presenting Author: Hiromi Araki, medical doctor Presenting Author's Institution: Fujita Health University, School of Medicine, Banbuntane-Hotokuk - Nagoya, Aichi Co-Authors: Takashi Tachibana, medical doctor - Fujita Health University, School of Medicine, Banb - Nagoya, Aichi Yoshihiro Shinoda, medical doctor - Fujita Health University, School of Medicine, Banb - Nagoya, Aichi Yui Ueno, medical doctor - Fujita Health University, School of Medicine, Banb - Nagoya, Aichi Masataka Oishi, medical doctor - Fujita Health University, School of Medicine, Banb - Nagoya, Aichi
Abstract: Introduction: Ultrasound-guided ilioinguinal /iliohypogastric (II/IH) nerve block has been reported to be effective in reducing postoperative pain after inguinal hernia repair in children(1,2). In this study, we compared postoperative pain relief effects, recovery of muscle movement and adverse effects between ultrasound-guided II/IH nerve block and spinal anesthesia for inguinal hernia repair in adults.
Methods: After obtaining IRB approval and informed consents, 30 adult patients undergoing inguinal hernia repair were randomly assigned to receive either II/IH nerve block (II/IH group) or spinal anesthesia (SA group). In both groups, general anesthesia was induced and maintained with propofol while breathing spontaneously via a laryngeal mask airway. In II/IH group, II/IH nerve block was performed using 20ml of 0.75% ropivacaine under ultrasound-guidance after the induction of general anesthesia. In SA group, spinal anesthesia using 3ml of 0.5% isobaric bupivacaine was provided before the induction of general anesthesia. Numeric rating scale (NRS) and incidence of complications were assigned by a blinded investigator at 0, 1, 3, 6, 12, 24, and 48hr postoperatively. Analgesic requirements and time to walking were also recorded.
Results: NRS was significantly lower in II/IH group than in SA group at 6, 12, 24, and 48hr postoperatively, while there were no significant differences at 0, 1, and 3hr. Time to walking was significantly shorter in II/IH group (7.9 ± 4.5hr vs. 23.3 ± 8.0hr). There were no significant differences in the incidence of complication and analgesic requirements. Conclusion: Ultrasound-guided II/IH nerve block provided better quality of postoperative period by reducing postoperative pain and shortening time to walking after inguinal hernia repair.
References (1) Ir J Med Sei. 2007;176:111-115. (2) Br J Anaesth. 2005;95: 226-30.
A99 Title: Thromboprophylaxis and Peripheral nerve blocks for joint replacement Presenting Author: Jacques E. Chelly MD, PhD, MBA Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors:
Abstract: Background: Peripheral nerve blocks including deep and plexus blocks have been shown to facilitate recovery in patients undergoing total joint replacement. However the 3rd edition of the ASRA guidelines for the use of regional anesthesia in patients receiving antithrombotic or thrombolytic therapy1 cautioned their use in patients receiving anticoagulants. This study was conducted to confirm our previously published data on the safety of the combination of peripheral nerve blocks and thromboprophylaxis.2
Methods: Using a similar approach to the one previously reported, we reviewed our IRB approved data base for patients who underwent knee and hip arthroplasty at UPMC Shadyside Hospital in Pittsburgh between December 1, 2005 and December 31, 2009, who benefited from both peripheral nerve block and thromboprophylaxis. Patients who underwent these procedures but received anticoagulant for therapeutic indications were excluded. The type of thromboprophylaxis, the dose, and the date of initiation and duration of therapy along with any bleeding complication were recorded prospectively. All peripheral nerve blocks were performed before surgery. A continuous lumbar plexus and a single parasacral block were performed for the postoperative pain management after a total hip arthroplasty, whereas continuous femoral and continuous gluteal blocks were performed for patients undergoing total knee arthroplasty. The removal of each perineural catheter was done by the nurse assigned to the care of the patient without interruption of the thromboprophylaxis and without consideration for the type of anticoagulant and the time of its administration. After the removal of the perineural catheter, patients were monitored for perineural hematoma.
Results: During the study period, a total of 13, 577 blocks were performed including 3,248 continuous lumbar plexus block, 3,952 continuous gluteal blocks and 2,023 single parasacral blocks. 29% of 7,402 patients received aspirin 325 mg, 29% received warfarin, 27% received fondaparinux and 15% received enoxaparin. In this patient population no major bleeding was recorded.
Discussion: These data confirm those previously published related to the safety of thromboprophylaxis including low molecular heparin drugs in patients benefiting from deep and superficial peripheral nerve blocks for the perioperative management of pain. This study also provides original data on the combination of fondaparinux and peripheral nerve blocks.
References 1. Horlocker TT; Wedel DJ; Rowlingson JC; Enneking FK; Kopp SL; Benzon HT; Brown DL; Heit JA; Mulroy MF; Rosenquist RW; Tryba M; Yuan Ch-S. Regional Anesthesia in the Patient Receiving Antithrombotic or Thrombolytic Therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition). Reg Anes Pain Med. 2010, 35; 64-101 2. Chelly JE, Schilling D. Thromboprophylaxis and Peripheral Nerve Blocks in Patients Undergoing Joint Arthroplasty. J Arthroplast.
A100 Title: Systems Based Practice: Optimizing the Thoracic Epidural in the ICU Presenting Author: Matthew P Harper MD Presenting Author's Institution: Johns Hopkins Hospital - Baltimore, MD Co-Authors: Shawn Sumida MD - Johns Hopkins Hospital - Baltimore, MD Michael Mantinan MD - Johns Hopkins Hospital - Baltimore, MD Artemus Flagg MD - Johns Hopkins Hospital - Baltimore, MD Jpnelon Tsang MD - Johns Hopkins Hospital - Baltimore, MD
Abstract: Background and Objectives: Thoracic epidural analgesia (TEA) is a safe and effective method of post-operative pain management. However, hypotension is a well known adverse effect, which can lead to interruption in TEA use, resulting in the possible loss of epidural catheter function. We utilized a systems-based approach to identify an issue, examine the multiple contributing systems, devise a multi-systems based intervention, implement the intervention, and evaluate the results. Our goal was to prevent premature catheter removal and preserve epidural function in the ICU.
Methods: Quality assurance data was analyzed to determine the incidence of and causes for TEA interruption in the WICU (Weinberg ICU). In August 2009, a multi- systems intervention was implemented, which consisted of 1) APS (acute pain service) Attending began holding periodic education sessions for all WICU registered nurses, advanced practitioners, and ICU fellows. The sessions focused on pain management in the post-surgical ICU patient as well as post-operative epidural management 2) APS direct involvement in managing TEA in the ICU, and 3) a protocol to infuse saline to preserve TEA function in the face of hypotension was implemented for those patients who failed to maintain acceptable blood pressure with lower concentrated local anesthetics infused in the epidural space..
Results: The pre-intervention data was collected by the Acute Pain Service (APS) from June 2008 through August 2009 (15 months) as a part of an ongoing quality assurance project. During this period, there were a total of 269 TEA in the WICU, with 116/269 (43.1%) not used in the ICU or prematurely discontinued. Of the thoracic epidurals not used in the ICU or prematurely discontinued 39/116 (33.6%) of them were due to hypotension Follow-up data have been collected from March 2010, and have been analyzed through September 2010 (7 months). There were a total of 117 TEA in the WICU during the follow-up period. Of these 18/117 (15.4%) were not used in the ICU or discontinued prematurely. Of these epidurals, 3/18 (16.7%) of these were secondary to hypotension.
Conclusions: This study looked at three simple interventions to improve TEA use in the WICU. These included 1) education, 2) APS direct involvement in TEA management, and 3) saline infusion to preserve TEA function. Results show a decrease in thoracic epidural catheters not used in the ICU or discontinued prematurely from 43.1% to 15.4%, and a decrease in thoracic epidurals prematurely discontinued secondary to hypotension from 33.6% to 16.7%. Using a systems-based approach, we were able to identify an area to improve care and we were able to significantly limit the number of thoracic epidurals prematurely discontinued or not used in the ICU.
References 1) Lung function after lobectomy: a randomized, double-blinded trial comparing thoracic epidural ropivacaine/sufentanil and intravenous morphine for patient- controlled analgesia. Bauer C, Hentz JG, Ducrocq X, Meyer N, Oswald-Mammosser M, Steib A, Dupeyron JP. Anesth Analg. 2007 Jul;105(1):238-44. Erratum in: Anesth Analg. 2008 Apr;106(4):1283. 2)Systems Based Practice, ACGME website. 3) Challenge of improving postoperative pain management: case studies of three acute pain services in the UK National Health Service. Powell AE, Davies HT, Bannister J, Macrae WA. Br J Anaesth. 2009 Jun; 102(6):824-31. Epub 2009 Apr 17.
Additional File #1: 1030111171231abstractfigures.pdf Click here to view
A101 Title: Developing Effective Web-Based Regional Anesthesia Education: Case-Based vs. Non-Case-Based Module Design Presenting Author: Sandra L Kopp MD Presenting Author's Institution: Mayo Clinic - Rochester, MN Co-Authors: Hugh M Smith MD, PhD - Mayo Clinic - Rochester, MN
Abstract: Introduction: Benefits of web-based education include: the ability to standardize learning material quality and content, build appropriate learning progressions, utilize interactive multi-media technologies, and individualize delivery of course materials.1,2 To date, web-based curricula have not been studied for regional anesthesia and it is unclear how module design may influence resident learning.1,3 There is also limited data regarding specific learning preferences among anesthesia residents, although educators are increasingly aware that individual learning styles may affect learner performance and therefore should influence curriculum design.4 The goals of this investigation are to characterize learner preference patterns among anesthesia residents and to test the hypothesis that residents with strong active, sensing and visual learner preferences would prefer the interactive case- based module design and subsequently perform better on the post module knowledge assessment.
Methods: After institutional review board approval, forty-three Mayo Clinic Anesthesiology residents participated in this study which involved the completion of two on-line modules, a pre-test and post-test, an Index of Learning Styles (ILS) assessment5, and a participant satisfaction survey. Interscalene and lumbar plexus regional techniques served as the learning content and basis for four web modules constructed using the Blackboard Vista coursework application. One traditional textbook-style (TTS) module and one interactive case-based (ICB) module were designed for both the interscalene and lumbar plexus techniques.
Results: Participants scored higher on the post-module knowledge assessment for both the interscalene and lumbar plexus modules. (Table 1) Post-module knowledge performance scores were independent of both module design and results of the ILS assessment. However, nearly all participants reported a preference for web-based learning and felt that it should be used in anesthesia resident education. Participants did not feel that web-base learning should replace the current lecture- based curriculum.
Conclusions: All residents scored higher on the post-module knowledge assessment but this improvement was independent of the module design and individual learning styles. Although residents believe that on-line learning should be used in anesthesia training, the results of this study do not demonstrate improved learning or justify the time and expense of developing complex case-based training modules. While there may be benefits of web-based education, educators in regional anesthesia should be cautious about developing curricula based upon learner preference data.
References 1. Chumley-Jones HS, Dobbie A, Alford CL. Web-based learning: sound educational method or hype? A review of the evaluation literature. Acad Med. 2002;77:S86-93. 2. Cook DA, Gelula MH, Dupras DM, Schwartz A. Instructional methods and cognitive and learning styles in web-based learning: report of two randomised trials. Med Educ. 2007;41:897-905. 3. Friedman CP. The research we should be doing. Acad Med. 1994;69:455-457. 4. Cook DA. Reliability and validity of scores from the index of learning styles. Acad Med. 2005;80:S97-101. 5. Felder R, Soloman BA. Index of learning styles.
Additional File #1: 1012611122103Table_1_ASRA_2011_A.doc Click here to view
Table 1. Summary of Interscalene and Lumbar Plexus Knowledge Assessment Scores
Total Book Case (N=43) (N=23) (N=20) p value† Interscalene Test Results Pre-Test 12.9 ± 3.62 13.4 ± 3.53 12.3 ± 3.73 0.3301 Post-Test 19.7 ± 2.57 19.6 ± 2.41 19.8 ± 2.80 0.8109 Difference Between The Post and Pre Test 6.8 ± 3.39* 6.2 ± 3.22* 7.5 ± 3.53* 0.2199 Module Time 16.4 ± 4.27 16.3 ± 3.36 16.4 ± 5.22 0.9513
Total Book Case (N=43) (N=20) (N=23) p value
Lumbar Test Results Pre-Test 13.7 ± 3.04 13.7 ± 3.53 13.6 ± 2.62 0.9231 Post-Test 18.1 ± 2.82 18.7 ± 2.60 17.7 ± 2.98 0.2522 Difference Between The Post and Pre Test 4.5 ± 2.56* 5.0 ± 2.76* 4.0 ± 2.34* 0.2510 Module Time 10.0 ± 2.78 8.7 ± 2.24 11.1 ± 2.76 0.0032 Table 1. Summary of Interscalene and Lumbar Plexus Knowledge Assessment Scores
Total Book Case (N=43) (N=23) (N=20) p value†
TTS=Traditional textbook-style ICB=Interactive case-based Data are reported as: mean ± SD † P-value is a Two Sample T-Test eq. variances * Paired T-test p-value is < 0.001 when comparing the pre-test and post-test scores.
A102 Title: Successful Thoracic Paravertebral Block: case series Presenting Author: Sherif Ahmed Abdelhamid MD of anaesthesia Presenting Author's Institution: Medical Research Institute-Alexandria University - Alexandria, Alexandria Co-Authors:
Abstract: Introduction: Thoracic Paravertebral block (TPVB) represents an alternative to general anesthesia for breast surgery. Important benefits of PVB include improved analgesia, decreased incidence of nausea and vomiting, reduced surgical stress response, better pulmonary functions, extended analgesia and improved patient satisfaction. Paravertebral also preserves the benefits of early discharge. However it was noticed that there is a 10-20%1-2 conversion to general anesthesia (GA) due to lack of adequate anaesthesia. This case series describes the use of 2 point TPVB with a catheter for breast surgery to cover more cephalad dermatomes thus increasing the quality and the spectrum of the block and hence obviating the need to convert to GA.
Methods: A total of 30 female ASA II patients aged 40 years or more scheduled to undergo modified radical, simple mastectomy or breast lumpectomy with axillary dissection were consented for a two point thoracic paravertebral block with catheter technique, with sedation for their surgery. Injecting 25 ml of 0.5% bupivacaine with epinephrine 1/200k and 5 ml of 2% lidocaine with epinephrine 1/200 k at T4 after the insertion of a catheter, and 10 ml equal volume of 0.5 % bupivacaine with epinephrine 1/200k and 2% lidocaine with epinephrine 1/200 k at T1 level. Baseline data collected include age, weight, history of chronic opioid use, ASA classification, duration of hospital stay, operative time, onset of blockade, number of sensory blocked dermatomes , duration of block, average pain score at rest and with activity for POD# 0 and # 1, time to require first analgesic, patient satisfaction, and complications.
Results: There were 100% successes with no conversion to GA in all 30 cases. Onset of blockade had a mean of 25.6±3.19 minutes. The dermatomes involved in the sensory blockade ranged between 7-9 dermatomes (C7-T7) with a mean of 8±0.78. Hypotension (more than 20% decrease in baseline BP) occurred in 20 % of cases and was treated with fluid. Operative time had a mean of 101±8.44 minutes. VAS scale was low in all patients (less than or equal 4) till 12 hours. First time patients required analgesia had a mean of 10.8±3.01 hours and hospital stay had a mean of 1.7±0.46 days. Mean visual analogue scale (VAS) changes during the postoperative period. Conclusion: This case series describes the successful use of two-point TPVB with paravertebral catheter placement in patients undergoing breast cancer surgery with no complications. This technique covers more cephalad dermatomes so that the conversion to GA is remote; also, it achieves profound chest wall analgesia that can be extended beyond 24 hours using the catheter while still preserving the ambulatory status of the patient.
Keywords: anaesthesia, regional; thoracic paravertebral block; pain, postoperative; pain
References 1. Karmakar, M. Thoracic Paravertebral Block. Anesthesiology. 2001; 95:771-780. 2. Aditya Kumar, Uma Srivastava, Surekha Saxena, Ashish K. Kannaujia, Namita Saraswat, Abhijeet R Mishra, Sanjeev Sharma J Single Injection Paravertebral Block for Major Cancer Breast Surgery. Anaesth Clin Pharmacol. 2009; 25(3): 281-284. 3. Weltz CR, Greengrass RA, Lyerly HK: Ambulatory surgical management of breast carcinoma using paravertebral block. Ann Surg, 1995; 222: 19-26.
A103 Title: Ultrasound-guided proximal triple block for in vivo microdialysis in the knee joint in 22 patients with severe osteoarthritis Presenting Author: Kenneth Jensen MD, BBA, Consultant Presenting Author's Institution: University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen Co-Authors: Jens Børglum MD, PhD, Consultant - University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen Ida Carøe Helmark MD - University of Copenhagen, Bispebjerg Hospital - Copenhagen NV, Copenhagen
Abstract: Background: In vivo microdialysis in the knee joint both intraarticularly and perisynovially may be applied for scientific or diagnostic purposes (1). Close approximation to the synovial membrane of the catheters requires an undisturbed field around the knee joint which is impossible to achieve by infiltration analgesia. This makes it necessary to consider other options such as general, neuraxial or regional anesthesia (2). We chose to investigate the applicability of a selective ultrasound-guided (USG) block of the femoral, obturator (anterior branch) and lateral femoral cutaneous nerve for this purpose.
Methods: Following IRB approval, a consecutive cohort of 22 patients with severe osteoarthritis were enrolled. A presentation of the microdialysis procedure is published elsewhere (1). Real-time USG using a high-frequency linear probe on short axis and with an in-plane technique was chosen for all patients, and lidocaine 2% with epinephrine was the single local anesthetic used. Time to apply the nerve block, sensory function following block, duration of analgesia and side effects were recorded. No patient was given intravenous drugs during the procedure, and none were asked for.
Results: Successful surgical anesthesia was achieved in 20/22 patients (91%). Five patients required minor regional supplements. Total block duration was on average 7 minutes (range 4-18 minutes). Thermal distinction was impaired at the knee joint in 82% (laterally), 90% (anteriorly) and 100% (medially), respectively. Duration of analgesia was less than 4 hours in 85% of patients (total range, 2-7 hours). Total anesthetic amount used was 24-40 ml per patient. Four patients experienced slight dysarthria or visual disturbances.
Conclusions: A USG proximal triple nerve block is an effective, reliable and attractive option for intraarticular knee examination with the purpose described. The combined USG block procedure was fast, but although neurological side effects were minor and self-limiting, a reduction in the amount of local anesthetic may be preferable in future studies.
References 1.Helmark IC et al. Arthritis Res Ther. 2010; 12: R126-137. 2.Hadzic A et al. Anesth Analg. 2005; 100: 976-981.
A104 Title: Integration of a routine paravertebral blockade into the reconstructive breast service at the Massachusetts General Hospital Presenting Author: Young Ahn MD Presenting Author's Institution: Massachusetts General Hospital, Harvard Medical School - Boston, MA Co-Authors: Katharine Fleischmann MD - Massachusetts General Hospital, Harvard Medical School - Boston, MA
Abstract: Introduction: The integration of a regional block service into a high volume, multidisciplinary hospital program poses unique challenges. Here we describe the full, multidisciplinary integration of a paravertebral block program at the Massachusetts General Hospital, including anesthesia, plastic surgery, the surgical oncology service, and radiology.
Key Members: Patients Regional block team (attending and resident anesthesiologists). Attending and resident surgeons. CNPs on the Surgical Oncology and Plastic Surgery services. Regional nurses/ PACU nurses. Pre-operative Anesthesia Testing Clinic (PATA). Nurses on post-operative surgical floors. Nuclear medicine and Radiology services.
Key Concerns: Appropriate pre- op screening and patient education regarding regional anesthesia. Efficiency and prevention of surgical start delays. Adequate training of and staffing by regional anesthesiologists and regional nurses. Appropriate follow up with patients in the hospital and at home.
Integration and Teamwork, Our Current Model: Planning patients for regional anesthesia begins in the surgical oncologists‘ offices. They provide basic information about paravertebral blocks. The patients are also directed to paravertebral block information on the MGH Cancer Center website. Cases are booked as "block" anesthesia.
The regional block team reviews a list of all scheduled operations two days in advance. Patients are contacted prior to surgery by the block team and thoroughly educated on the paravertebral blocks, risks, and benefits. Patients seen in PATA are given more information about the process in general, as well as the block. The final list of confirmed breast reconstruction patients and OR start times are reviewed by the regional block team and regional/PACU nursing staff one day prior to surgery. If possible, patients needing nuclear medicine injection have it done the evening before. Otherwise, patients are scheduled first in the morning, and the surgical oncologists and radiology staff are readily available. A designated area of the PACU is reserved for these patients pre-operatively.
On the day of surgery, patients are brought "ASAP" to the reserved PACU area. They are re-assessed for the regional procedure and the surgery, and all anesthesia and surgical consents confirmed. An IV is started, sedation given, and the block performed. Patients remain monitored until the OR is ready to accept them. Post-op patients are usually admitted for one night. They are followed up the day after surgery and assessed for resolution of blockade, length of blockade, and overall satisfaction.
Issues: Issues encountered include patients booked without a "block" designation, very infrequent OR start delays due to lack of surgical consent, delays in radiology or difficult block placement, and the need for flexible staffing due to changes in daily volume. These are resolved when reviewing the OR schedule with the team, coordinating with the surgeons, and ensuring that patients arrive on time. We have a thorough database of all cases. Follow-up shows broad acceptance on a multidisciplinary level and an overwhelming satisfaction rate from patients. Further analysis of data suggests significantly decreased length of hospital stays, as well.
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A105 Title: Routine Chest X-Rays are not Required before Interscalene Nerve Blocks Presenting Author: David B Albert MD Presenting Author's Institution: NYU Langone Medical Center Hospital for Joint Diseases - New York, NY Co-Authors: Derek Mason MD - NYU Langone Medical Center - New York, NY Germaine Cuff BSN, MPH - NYU Langone Medical Center Hospital for Joint Diseases - New York, NY
Abstract: Introduction: While it is well described that an Interscalene Nerve Block (ISB) results in phrenic nerve paralysis on the ipsilateral side (1,2), concern exists that this, in the presence of preexisting contralateral hemi-diaphragmatic paralysis, can result in significant respiratory distress after a nerve block is performed. While knowledge of an elevated hemi-diaphragm on the contralateral side, indicating paralysis, would be a consideration as to whether an ISB should be performed, it is not routine for patients to have a Chest X-Ray (CXR) prior to receiving an ISB for shoulder surgery. The frequency of an elevated hemi-diaphragm as an incidental CXR finding is not described in the literature. We undertook a retrospective review of CXRs on patients admitted to the NYU Langone Medical Center for reasons other than orthopedic surgery, to determine the percent of patients who have an undiagnosed elevated hemi-diaphragm to determine if routine CXR should be performed prior to a patient receiving an ISB.
Methods: After obtaining IRB approval, the official report of 1029 random CXRs were reviewed. All X-rays were evaluated by a board certified radiologist specializing in Thoracic Imaging. CXRs were considered positive if the Radiologist documented an elevated hemi-diaphragm and a review of the patients‘ chart did not reveal a pre-existing diagnosis or condition that would explain the findings.
Results: 21/1029 patients were found to have an elevated hemi-diaphragm on routine CXR (2.04%). While the reported incidence was higher on the right (n = 14) than left (n = 7), this did not reach clinical significance.
Discussion: Our data indicate that the incidence of hemi-diaphragmatic paralysis is low (2.04%) Therefore we do not recommend preoperative CXR screening for its presence. However, while it is not a common occurrence it has a place in the differential diagnosis of respiratory distress in the OR or PACU in patients who have received an ISB. Anesthesiologists are in agreement that due to the near 100% incidence of a phrenic nerve block after an ISB the finding of an elevated hemi- diaphragm on a pre-operative CXR would be a consideration prior to performing the block. The literature was lacking when it came to the percent of patients who have an elevated hemi-diaphragm as an incidental finding on CXR. Our review demonstrates a low prevalence (2.04% total, 1.36% right, 0.68% left) and therefore a routine CXR is not justified. Because a small number of our patients will have an elevated hemi-diaphragm on the contralateral side prior to the performance of an ISB, this should be a consideration in the PACU.
References 1. Urmey WF, Talts, KH, Sharrock NE: One Hundred Percent Incident of Hemidiaphragmatic Paresis Associated With Interscalene Brachial Plexus Anesthesia As Diagnosed by Ultrasonography. Anesth Analg. 1991;72:498-503 2. Kessler, j, Schafhalter-Zoppoth, I, Gray, AT: An Ultrasound Study.
A106 Title: Ultrasound-guided nerve blocks providing surgical anesthesia for outpatient knee surgery Presenting Author: Jens Børglum MD, PhD, MBA Presenting Author's Institution: Copenhagen University Hospital: Bispebjerg - Copenhagen, Copenhagen Co-Authors: Per-Arne Lönnqvist MD, Professor, DMSc - Karolinska Institute - Stockholm, Stockholm Kenneth Jensen MD, BBA - University Hospital Copenhagen: Bispebjerg - Copenhagen, Copenhagen
Abstract: Background. Surgical anesthesia for outpatient knee arthroscopy (KA) and anterior cruciate ligament reconstruction (ACL-RC) must address both surgical and tourniquet-related pain. Our aim was to describe the feasibility of using ultrasound- guided (USG) block combinations of the femoral (FN), lateral femoral cutaneous (LFCN) and obturator nerves - anterior branch (ONA) and posterior branch (ONP) - for KA (quadruple block), including an USG block of the sciatic nerve (SN) for ACL- RC (quintuple block).
Methods: The Local Ethics Committee approved the cohort study. Forty prospective patients undergoing either KA (n = 30) or ACL-RC (n = 10) were included. Blocks were performed under aseptic conditions using an equal mixture of bupivacaine 2.5 mg/ml and mepivacaine 10 mg/ml with epinephrine 5 µg/ml. The equipment used was the SonoSite® M-turbo. A linear transducer (6-13 MHz) covered with at sterile sheath (Flexasoft® Conti) was used to scan the FN, ONA, ONP and the LFCN in the proximal thigh (Figures 1A-1C). A curved array (2-6 MHz) was used to scan the sciatic nerve (SN) at the anterior-medial thigh level (Figure 1D). A 22-gauge, 80 mm insulated needle (Stimuplex® B. Braun Medical) was advanced in-plan to the transducer. The physicians performing the quadruple block first blocked the FN, then the ONA and ONP and finally the LFCN. For patients undergoing ACL-RC the quadruple block was performed first and supplemented with a block of the SN; hence the term quintuple block. Intraoperative data collected included: Block characteristics, intraoperative pain (Numerical rating scale (NRS) 0-10) and surgeon and patient satisfaction. Postoperative data collected included: Postoperative pain (NRS 0-10), length of stay (LOS) in the post-anesthesia care unit (PACU), PACU bypass and data concerning physical abilities (Barthel Index7100) and perceived ill health (SF8).
Results: All patients had successful nerve blocks (no supplemental opioids), positive motor and sensory tests within 20 minutes, uneventful surgeries with satisfied patients and surgeons intra- and postoperatively, and minimal pain during and immediately after surgeries (Table 1-2). Average time for performing the quadruple and quintuple blocks were 10 and 16 minutes, respectively. The median total amount of LA used for quadruple block was 40 ml and for quintuple block 60 ml. No adverse effects were observed. Most patients received slight sedative adjuvants (i.v. midazolam 1-2 mg) but remained awake and responsive. Recovery room bypass was 70%. Both multiple block techniques provided adequate analgesia, and mean duration of motor/sensory block was 8/9 hours and 11/15 hours for KA and ACL-RC, respectively (Table 2). Ability of daily living was only marginally reduced; i.e. 4% and 10% for KA and ACL-RC, respectively. Perceived ill health was reduced by approximately 30%.
Conclusions: The novel techniques presented for outpatient knee surgery were found clinically feasible regarding patient factors and hospital logistic issues. The duration of motor block only marginally reduced activity of daily living, but pain when the block effect subsided reduced patients perceived ill health by 30%. The PNBs provide an alternative to general and neuraxial anesthesia and merit further scientific study
Additional File #1: 1012311113046Figure_1___USG_PNBs.doc Click here to view
Figure 1: USG PNBs for KA and ACL-RC.
A: USG block of the femoral nerve (FN).
B: USG block of the lateral femoral cutaneous nerve (LFCN).
C: USG block of the obturator nerve. - anterior branch (ONA), posterior branch (ONP).
D: USG block of the sciatic nerve (SN) – antero-medial approach.
Additional File #2: 2012311113046Table_1___Intra__an.doc Click here to view
Table 1. Intra- and postoperative characteristics of the quadruple and quintuple nerve blocks for KA and
ACL-RC.
Outcome measures Intraoperative conditions PACU conditions
Quadruple Quintuple Quadruple Quintuple
Maximal pain (VAS 0-10) 0 (0-8) 1 (0-4) 0 (0-8) 0 (0-4)
Sedative adjuvants 25/30 (83%) 9/10 (90%) N/A N/A
Surgical satisfaction (1-4) 1.0 (1-2) 1.3 (1-2) N/A N/A
Patient satisfaction (1-4) 1.0 (1-1) 1.0 (1-1) 1.5 (1-4) 1.0 (1-1)
Length of stay (minutes) N/A N/A 0 (0-31) 39 (0-100)
Motor function (Bromage 1-4) N/A N/A 2.0 (1-3) 4.0 (3-4)
Femoral nerve block test N/A N/A 30/30 (100%) 10/10 (100%)
Complete data sets available in 40 patients. Medians with range in brackets where relevant. Maximal pain (NRS 0-10). Satisfaction ratings assessed on a 4-point Likert scale (1=excellent, 4=unacceptable). Motor function according to Bromage was assessed at 20 minutes after nerve block, 1=full motor ability, 4=complete paralysis. Femoral nerve motor function at 20 minutes post-block (positive test = unable to extend the knee following hip flexion). PACU, post-anaesthesia care unit; N/A, not applicable.
Additional File #3: 3012311113046Table_2___Motor_and.doc Click here to view
Table 2. Motor and sensory characteristics after quadruple and quintuple nerve blocks for KA and ACL-
RC.
Characteristics Quadruple Quintuple
Duration of motor block (h) 8 (3-25) 11 (8-16)
Duration of sensory block (h) 9 (3-48) 15 (5-24)
Pain after block subsided (NRS) 5 (1-10) 7 (7-9)
Acceptance of the block experience 27/28 (96%) 7/8 (88%)
19/28 (68%) 5/8 (63%) Completely satisfied 3/28 (11%) 3/8 (38%) Reasonably satisfied
Unsatisfied 2/28 (7%) 0/8 (0%)
Do not wish again 2/28 (7%) 1/8 (13%)
Sensory impressions following block
Feels dead 15/28 (54%) 8/8 (100%)
Pricking sensation 3/28 (11%) 3/8 (38%) Feels numb, swollen or heavy 8/28 (29%) 3/8 (38%) Feels hot or cold
2/28 (7%) 2/8 (25%)
Data obtained from telephone interviews postoperatively. Complete data sets available in 36 patients. Where relevant, medians with range in brackets, or numbers out of totals with percentages in brackets. Pain assessed by a 10-point numerical rating scale. Acceptance of the whole block procedure, assessed as “pleasant” or “tolerable” during telephone interviews.
A107 Title: Femoral Nerve Block Knowledge Survey Presenting Author: Shilpa Reddy MBBS, MRCP, FRCA Presenting Author's Institution: University College Hospital - London, London Co-Authors: Claire Morkane MBBS - University College Hospital – London, London Khalid Syeed MBBS - University College Hospital, London – London, London Damon Kamming MBBS - University College Hospital, London – London, London
Abstract: Introduction: Femoral nerve block use is common in knee and hip fracture surgery with advances in nerve localisation and catheter techniques helping to popularise this technique (1,2). Evidence has shown that fracture management programs involving nerve block use can reduce complications (3) hence nursing and junior medical staff are becoming increasingly involved in the provision of nerve block services (4). Our aim was to assess knowledge regarding femoral nerve block amongst ward staff involved in the care of post-operative orthopaedic patients.
Methods: Junior doctors and ward nurses at a university teaching hospital were interviewed by an anaesthetist and answers were compared to those published by a commonly referenced resource (5). The following questions and model answers were used:
Q1. What is a femoral nerve block? A. Injection of local anaesthetic around the femoral nerve to provide pain relief
Q2. What are its complications? A. Haematoma, infection, nerve damage, intravascular injection
Q3. How long would its effects last? A. 12-24 hours
Q4. List contraindications to its use A. Local anaesthetic allergy, patient refusal, local infection
Q5. When should it be reviewed by a doctor? A. If any of the above complications occur or if effects last more than 24 hours
Q6. Would you like more training on nerve blocks? A. Yes/ No
Results: Forty-eight staffers were interviewed (18 junior doctors and 30 nurses), and answers were categorised into themes by an anaesthetist. Q1. Block description Don‘t know (20, 41.7%), An epidural/spinal (12, 25%), Local anaesthetic into the nerve (9, 18.8%), Local anaesthetic around the nerve (6, 12.5%), Local anaesthetic into the femoral artery (1, 2.1%)
Q2. Complications Paraesthesia (19, 31.1%), Bleeding (14, 23.0%), Don‘t know (9, 14.8%), Nerve damage (7, 11.5%), High motor or sensory block (6, 9.8%), Infection (6, 9.8%)
Q3. How long would its effects last? 0-6 hours (4, 8.3%), 7-12 hours (16, 33.3%), 13-24 hours (0, 0%), > 24 hours (4, 8.3%), Don‘t know (24, 50%)
Q4. Contraindications Don‘t know (30, 62.5%), Local anaesthetic allergy (18, 37.5%)
Q5. When should it be reviewed by a doctor? Ongoing paraesthesia (25, 52.1%), On return to ward (10, 20.8%), Ongoing pain (8, 16.7%), Ward observations unsatisfactory (3, 6.3%), Signs of infection (2, 4.2%)
Q6. Would you like more training on nerve blocks? Yes (40, 83.3%), No (8, 16.7%).
Conclusion: Our study has identified a need for further ward-based training with regard to post-procedure care. Solutions include small group teaching on wards and larger group teaching at staff audit and training days. We aim to re-audit in 3 months time to assess retention of knowledge and success of the training program.
References 1. Enneking FK et al. Lower-limb extremity peripheral nerve blockade. Reg Anesth Pain Med. 2005;30:4-35. 2. Evans H et al. Peripheral nerve blocks and continuous catheter techniques. Anesthesiol Clin North America. 2005;23:141-162. 3. Pedersen SJ et al. A comprehensive hip fracture program reduces complication rates and mortality. J Am Geriatr Soc. 2008;56:1831-1838. 4. Rawal N. 10 years of acute pain services- achievements and challenges. Reg Anesth Pain Med. 1999;24:68-73. 5. www.nysora.com
A108 Title: Contralateral Hamstring Donor-Site Blockade for ACL Reconstruction Presenting Author: Timothy J. Strigenz MD Presenting Author's Institution: University of Wisconsin - Madison, WI Co-Authors: Melanie Donnelly MD - University of Wisconsin - Madison, WI Kris Schroeder MD - University of Wisconsin - Madison, WI
Abstract: Case: DM is a 27-year-old previously healthy female who fell off a trampoline on to her right leg. She heard a pop in her right leg at impact with the ground and had immediate pain and swelling of her right knee. She presented to her physician and an MRI confirmed that she had ruptured her anterior cruciate ligament (ACL) and medial cruciate ligament (MCL) in addition to medial and lateral meniscus tears. She was referred to orthopedics for three months of rehabilitation to regain motion and strength in her right knee. She was then scheduled for a right knee arthroscopy with meniscus repair and ACL reconstruction with a contralateral autologus hamstring graft.
Preoperatively, the patient was offered a right sided single shot femoral nerve block, which she chose to accept. Under ultrasound guidance, thirty milliliters of 0.5% bupivacaine was injected around the right femoral nerve. The patient tolerated this well and was taken to surgery where she underwent a general anesthetic to repair her right knee menisci and reconstruct her right ACL. Because of her existing right MCL tear, a left-sided hamstring tendon was harvested for the ACL repair. The hamstring graft was obtained by making a posteromedial incision over the left pez anserinus insertion, isolating the gracilis and semitendinosus tendons, and harvesting the tendons using a tendon stripper. Before suturing the incision, a 15 cm catheter was threaded up along the path of tendons to level of the musculotendinous junction. Twenty milliliters of 0.5% bupivacaine was injected along this path and the incision was closed in layers. The remainder of the surgery focused on the right knee and was without complication.
Postoperatively, the patient was taken to the outpatient recovery room, where a standard 10 point numerical rating scale was used to record pain levels. Standard post-operative pain medications were available as needed. She was noted to have 3/10 posterior knee pain the right side, which remained consistent through her two- hour recovery. On the graft harvest left side, the patient had 0/10 pain, and this remained so for 24 hours postoperatively based on follow up phone calls by the nursing staff.
Discussion: Pain after ACL reconstruction is not uncommon and is in itself troubling for the patient and can also lead to increased morbidity long term with inability to rehabilitate. Acute anterior knee pain after ACL reconstruction can reliably be managed for up to 24 hours with a single shot femoral nerve block. However, any posterior elements are not covered in the distribution of the femoral nerve. Several techniques have attempted to decrease posterior knee pain associated with ACL reconstruction, including sciatic nerve block, nerve catheters, and intraarticular injection of local anesthetic. These have been proven to be effective but come with their own set of risks. The specific technique of injecting local anesthetic along the path of the hamstring tendons would clearly only be appropriate for ACL reconstruction using hamstring tendon. The posterior injection procedure itself is low risk, can reliably be performed, and may be of moderate to high yield in controlling the pain. However, more investigation is required to ascertain its role in ACL repair.
A109 Title: The Contents of the Potential Space of the Sciatic Nerve Presenting Author: Walter H Folger MD, PhD Presenting Author's Institution: Albany Medical College - Albany, NY Co-Authors: Philip O Hansen MD - Albany Medical College - Albany, NY
Abstract: Background: With the advent of ultrasound-guided regional anesthesia, the sciatic nerve can be visualized under the muscles of the thigh. With injection of local anesthesia in close proximity to the sciatic nerve, a ―doughnut‖ of local anesthesia may surround the nerve. This appears as a confined concentric layer around the nerve. A membrane has been identified in a fixed cadaver around the sciatic nerve. This membrane would explain the confinement of the local anesthetic around the nerve in the doughnut. If the local anesthetic is outside this membrane but filling the potential space, then it must be permeable to local anesthetic because this has been the case with successful blocks when a doughnut was not achieved. However, this membrane could delay onset of anesthesia even though it is permeable to the local anesthetic.
Objective: To demonstrate the contents of the potential space containing the sciatic nerve.
Methods: In the first experiment, a transverse incision was made at mid-thigh on a fresh cadaver. The sciatic nerve was transected above the biceps femoris muscle . The nerve end was grasped and pulled proximally from the distal section. The nerve was then lifted upward. Its movement in the surrounding tissues was noted to be contained within a membrane. In the second experiment, the thigh of a fresh cadaver was prepared by multiple injections of saline from proximal to distal after insertion of needles in the sciatic nerve space. This filled the potential space of the sciatic nerve space and dissected the sciatic nerve along its longitudinal length to expose the membrane identified in the first experiment. The membrane covering the sciatic nerve was grasped and pulled away from the nerve. Loose connective tissue and adipose tissue filled the rest of the potential space.
Results: A membrane was identified that surrounds the sciatic nerve that is not connected to the fascia of the muscles forming the boundaries of the sciatic nerve space. Figure 1. Transverse section of nerve showing membrane as nerve is protracted. The nerve moved freely within the membrane. Outside this membrane, between it and the muscles and fascia enclosing the space, was loose connective tissue and adipose tissue. Figure 2. Longitudinal view of sciatic nerve and membrane retracted laterally. The membrane was distensible. The membrane could be easily removed from the sciatic nerve.
Summary: The membrane immediately surrounding the sciatic nerve allows the nerve to move freely when the muscles around it contract. This probably prevents stimulation of the nerve by being stretched by muscular contraction.
Conclusions: 1. The sciatic nerve is surrounded by a thin membrane. 2. The sciatic nerve moves freely within the membrane. 3. Local anesthetic injected within the membrane would be confined. 4. The ―doughnut ‖ sign is seen because of confinement by this membrane. 5. The membrane must be permeable to local anesthetic. 6. The membrane may slow the onset of anesthesia of the sciatic nerve if the anesthetic is outside. 7. The membrane prevents the stimulation of the sciatic nerve during muscle contractions.
A110 Title: Ultrasound-guided injection under the epineural sheath of the sciatic nerve in the popliteal fossa. A cadaver study Presenting Author: Henning L Andersen Medical doctor Presenting Author's Institution: University Hospital of Copenhagen, Frederiksberg - Copenhagen , Denmark Co-Authors: Sofie L Andersen Medical doctor - University Hospital of Copenhagen, Hvidovre - Copenhagen, Denmark Joergen Tranum-Jensen Professor, Medical Doctor - University Hospital of Copenhagen - Copenhagen, Denmark
Abstract: Background and Aims: An epineural sheath surrounding the sciatic nerve in the popliteal fossa has been described by Vloka et al. in 1997. Defining the injection in relation to the epineural sheath may have implications for the pharmacodynamics of sciatic nerve block. We aim to describe the ultrasound characteristics of an injection under the epineural sheath and a safe technique for needle placement with minimal risk of intraneural injection.
Method: Eleven cadaver legs were used for dissection. A catheter or a needle was placed under direct vision by dissection in 6 legs whereas ultrasound guidance was used in 5 legs. 10 mL of polyurethrane was injected. Ultrasound videos and still pictures were recorded during injection. The legs were stored under cool conditions allowing the polyurethrane to harden. The spread of the injectates was verified by dissection and compared to the ultrasound videos and still pictures.
Results: We found the epineural sheath to be a thin, transparent and fragile fascia, surrounding the sciatic nerve like a sock. Ultrasound scan of the sciatic nerve before injecting revealed no definite sign of the epineural sheath. The epineural sheath could only be defined dynamically during injection: • a hyperecchoic fascia-like sheath defining the boundary of the injectate became evident shortly after the injection of small test volumes • the injectate created a half-moon shaped formation covering most of the surface of the nerve and ballooning into the surroundings. Leakage of the sheath appeared in all cases • the nerve was displaced away from the injection site
The injectate never made a complete circumferential spread around the nerve but spread gracefully along the nerve in both directions. For ultrasound-guided injection under the epineural sheath, we placed the needle inplane superficially to the sciatic nerve in short axis view just proximal to the nerve division. Small tangential scratching movements with the needle tip on the nerve surface while injecting small volumes allowed penetration of the epineural sheath. This lifted the sheath from the epineurium, where a small depression between the two major components is often seen. Then the needle tip could be advanced under the sheath and the full volume injected. We found this technique to be safe. Placing the needle profound to the nerve using the same technique involved a greater risk of nerve- or vascular puncture.
Injection outside the epineural sheath resulted in a more irregular spread of the injectate with no sharp boundary and minimal displacement of the nerve. Still, the fluid spread closely along the nerve, but over a shorter distance.
Ultrasound identification of the epineural sheath and estimation of the fluid spread showed remarkable concordance with the dissection results. The intraneural injection showed the most extensive spread along the nerves with coloring of all nerve structures and diffusion into the neighboring nerve components under the epineural sheath.
Conclusion: This study describes the ultrasound characteristics of placing an injection under the epineural sheath of the sciatic nerve. Good coherences were found between the ultrasound visualization of the injected volume and the findings by dissection.
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A111 Title: Approach to Confirming Ultrasound Guided Peripheral Nerve Placement For Post-operative Pain Control Use Presenting Author: Johnetta Washington DO Presenting Author's Institution: National Capital Consortium - Bethesda, MD Co-Authors:
Abstract: Background: Peripheral nerve catheters have become a valued adjunct for pain control both inside and outside the operating room. Useful techniques that employ ultrasound technology have made placement of these catheters more feasible but not without limitations. When catheter use is of most importance outside the operating room initial correct placement is desired. We present an approach to help place and confirm catheter placement by avoiding an initial single injection peripheral nerve block and using simple normal saline for nerve catheter placement.
Implications: Our goals as mentioned are two-fold. First, we address a common technical problem which is difficulty in peripheral nerve catheter advancement into the nerve sheath. Second, common practice is to perform a primary single injection peripheral nerve block prior to placement of the nerve catheter. While this approach is often useful in the settings on intra-operative pain management by providing an initial nerve injection as well as provide a fluid bolus to help expand the neural sheath for catheter placement, ascertaining whether catheter is in appropriate position cannot be assessed until after this initial single injection nerve block wears off. For patients who require prolonged post-operative course, repeat procedures or non-surgical interventions (i.e. - physical therapy) pain control with an initial correctly placed nerve catheter is of most benefit to this population.
One criticism of ultrasound only techniques is the inability to reliably visualize the catheter after it has been placed. For this reason it is even more important to utilize techniques that allow easier placement and earlier assessment of the nerve catheter. Using our simple technique our goal is to help with easing the actual placement of the nerve catheter using normal saline and confirming a functioning catheter sooner by avoiding a primary single injection peripheral nerve block.
Case Report: Patient is a 21-year-old, 67-inch, 72 kg, active duty male soldier injured due to an IED (Improvised Explosive Device), otherwise healthy with exception of extensive right lower leg trauma (ASA II). Due to the nature of his injuries, patient‘s operative course included plans for operating room procedures to include irrigations, debridement and numerous orthopedic procedures. After discussion of pain management options, informed consent was obtained for placement of a continuous lateral sciatic catheter.
Preparation: Procedure was performed in a designated pre-operative block area. Patient was noted to have a VAS of 7/10 in the right lower leg and lateral ankle region. Standard ASA monitors were placed to include pulse oximetry, blood pressure, EKG. Sedation was planned for procedure therefore oxygen via simple face mask at 2L/min was applied. The patient was premedicated with fentanyl 100 mcg IV and midazolam 2 mg IV. In the supine position, the patient‘s right lower extremity was elevated and supported on a stack of blankets to optimize positioning as well as patient comfort. Advantages to this lateral approach include supine position and possible more secure placement of catheter between vastus lateralis and biceps femoris away from the mobile knee joint. ² The sciatic nerve was seen with an intermediate frequency ultrasound probe (GE Medical, Milwaukee, WI) scanning posterior leg from distal knee region to approximately 12-15 cm proximally allowing visualization of the common peroneal and tibial nerves separate and coalescing together as the sciatic nerve (Fig. 1) which was at a depth of approximately 3 cm from skin. Sterile technique was used for the remainder of the procedure. The lateral thigh was cleaned with chlorohexadene prep, sterile clear drape was placed. The ultrasound probe was placed in sterile protectant covering. The region of interest was again identified then the catheter insertion point was marked with sterile marker 3cm from the probe end. Skin was localized using 25- gauge, 2.5-inch needle with syringe of 3 mL of 1% Lidocaine.
Procedure: Using a real time ultrasound guided in-plane technique, an 18-gauge, 10cm Contiplex® insulated tuohy needle was introduced and directed towards the lower aspect of the sciatic nerve sheath. When a distinctive pop was felt after passing through the sheath, gentle aspiration was applied to confirm extra-vascular placement, then a total of 10ml using 2-3 mL increments of 0.9% Normal Saline was injected to expand neural sheath (Fig 2). The catheter was then immediately inserted through the needle, threaded to a 15 cm depth at skin (approximately 5 cm in the sheath). The catheter was tunneled and secured with a clear adhesive dressing. The catheter was then connected to a 30-mL syringe with 0.5% Ropivicaine with Epinephrine 1:400,000 and injected intermittently aspirating between 5 mL aliquots under ultrasound. There was a clear echogenic area surrounding the sciatic nerve (Fig 3). Within 30 minutes of local anesthesia, administration evidence of adequate catheter placement was noted with the patient having motor and sensory changes along with a VAS of 2/10 in the right lower leg and lateral ankle region.
Post-operative Course: The patient underwent general anesthesia for his surgery. He was seen immediately post-op in the PACU for assessment. At that time a continuous infusion Ambit pump with 0.2% Ropivicaine was connected at a rate of 8mL/hr basal with 5 mL 30 min lockout. He continued to endorse significant pain control, VAS 3/10 and used no narcotics while in the PACU. He was followed for 3 days on the ward and continued to have excellent postoperative pain relief. After a more extensive operation on day 4 involving his lower knee and superior leg, he began to have discomfort in his right knee. After informed consent, a right femoral continuous catheter was performed per the above with the difference of using an 18-gauge, 5-cm Contiplex insulated tuohy needle for catheter insertion. He achieved immediate right knee motor and sensory changes along with excellent pain control. He was followed on the wards with both continuous nerve catheters for additional 2 days before being air evacuated to a military installation in the US for definitive surgical management.
Discussion: Ease along with timely placement of a peripheral nerve catheter is necessary in the aforementioned patient populations who require a prolonged post- operative course, repeat procedures or non-surgical interventions. These blocks have been shown to promote better post-operative analgesia and increase patient satisfaction compared to intravenous opiods.¹ Additionally they offer faster functional recovery after surgery.² Peripheral nerve catheter placement can be technically challenging. As mentioned, many providers attempt to place the catheter after performing an initial single injection nerve block. Although the space may be indeed dilated which could help with passing the nerve catheter in the nerve sheath, a primary nerve block has been performed and delays assessment of the actual functionality of the catheter. Borgeat et al used a similar technique where for all patients had a perineural catheter, the initial block was performed through the catheter. ³ With our case report we added the initial step of using a simple 10ml bolus of normal saline through the needle once in the sheath for the benefit of sheath expansion while preserving the catheter for sole use of delivering the local anesthesia.
The case that we present showed a clear benefit to using our technique. Along with visualizing the needle entering the sheath under real time ultrasound, the sheath was dilated allowing easy advancement of the catheter into the sheath and local anesthesia was seen surrounding the nerve. Further confirmation of nerve catheter placement was obtained with patient experiencing significant pain control/VAS score improvement before proceeding to the operating room as well as continued pain control in the both in the PACU and for 6 days post-operative to include a repeat more extensive procedure until his departure for definitive management back in the United States.
References 1) Capdevila X, Barthelet Y, Biboulet P, Ryckwaert Y, Rubenovitch J, D‘Athis F: Effects of perioperative analgesic technique on the surgical outcome and duration of rehabilitation after major knee surgery. Anesthesiology. 1999; 91:8-15. 2) Liu SS, Salinas FV: Continuous Plexus and Peripheral Nerve Blocks for Postoperative Analgesia. Anesth Analg. 2003;96:263-272. 3) Borgeat A, Blumenthal S, Karovic D, Delbos A, Vienne P: Clinical Evaluation of a Modified Posterior Anatomical Approach to Performing the Popliteal Block. Reg Anesth Pain Med. 2004; 29 (3):290-296. 4) Swenson JD, Davis JJ, DeCou JA: A Novel Approach for Assessing Catheter Position After Ultrasound-Guided Placement of Continuous Interscalene Block. Anesth Analg. 2008;106:1015–6.
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A112 Title: A Retrospective Analysis of the Safety of Removal of Continuous Lumbar Plexus Catheters in Postoperative Anticoagulated Patients Presenting Author: Joseph Marino MD Presenting Author's Institution: Huntington Hospital - Huntington, NY Co-Authors: Jay Curtin MD - Huntington Hospital - Huntington, NY Carol Patrick NP - Huntington Hospital - Huntington, NY Cristina Sison PhD - Feinstein Institute - Manhasset, NY George Koutsouras MS - Feinstein Institute - Manhasset, NY
Abstract: Background: Data related to the use of thromboprophylaxis and peripheral nerve blocks remain scarce. Chelly et al reported no bleeding complications in a cohort of 670 patients undergoing total hip replacement benefiting from continuous lumbar plexus blocks and receiving warfarin for thromboprophylaxis (1). At the time of the catheter removal on postoperative day 2 INR was > 1.4 in 36.2%. Although no major bleeding was reported, these data have been considered preliminary and required to be confirmed. The present study was designed to evaluate the incidence of bleeding complications and establish the coagulation status using INR and PT at the time of removal of lumbar plexus perineural catheters in patients receiving warfarin after THR.
Methods: Patients who received a continuous lumbar plexus nerve block for postoperative analgesia and received warfarin after total hip surgery between 2003 and 2010 were included in this retrospective study. The primary outcome measure was the incidence of bleeding complications after perineural catheter removal; secondary outcome measures included patient demographics, coumadin dose, bridge therapy, incidence of deep vein thrombosis, incidence of pulmonary embolism, aspirin use and the PT/ INR value at the time of catheter removal. The removal of each lumbar plexus catheter was scheduled on postoperative day # 3 without consideration of the INR value. Removal was performed by the nurse assigned to the care of the patient. After the removal of the perineural catheter, the nurse was instructed to monitor the patient for clinical evidence of perineural hematoma ( pain at the site, morphologic changes) and neurologic deficits. Serial hematocrits were also followed by the medical staff and any acute decrease would be followed with a diagnostic CT scan. Incidence of DVT was documented with the assistance of lower extremity Doppler ultrasound exams; patients with a suspected PE underwent a diagnostic CT scan.
Results: Three hundred and sixteen patients met the inclusion criteria. Almost all lumbar plexus catheters (97%; 306/316) were removed on the Third postoperative day. At the time of perineural catheter removal, 69% of patients had an INR >1.5. Of that 69%, 50% had an INR between 2.0-3.0; 5% had INR's between 3.0-4.0. There were no adverse bleeding complications or nerve injury after the removal of perineural catheters.
Conclusions: These data confirm data previously reported that it is safe to remove a lumbar plexus catheter placed for postoperative analgesia in patients receiving warfarin therapy for thromboprophylaxis after THR surgery. Combined with the data previously reported these conclusion are now based on 986 patients (1).
References 1) Chelly JE et al. Br J Anesth. 2008;101(2):250-254.
A113 Title: Neuropathic Sequelae of Continuous Popliteal Block (CPB) for Post-operative Pain Control Following Foot and Ankle Surgery Presenting Author: Kathleen A Gartke MD FRCSC Presenting Author's Institution: University of Ottawa - Ottawa, Ontario Co-Authors: Anne CP Lui MSc MD FRCPC - University of Ottawa - Ottawa, ON Monica Taljaard PhD - University of Ottawa - Ottawa, ON Desiree Persaud MD FRCPC - University of Ottawa - Ottawa, ON Rita D Singh MSc MD FRCA - Freeman Hospital - Newcastle Upon Tyne, Tyne and Wear
Abstract: Background and Objectives: Continuous nerve blocks are increasingly popular for postoperative pain control. The reported incidence of neuropathic sequelae has been generally low (0%-3%), although one study reported an incidence of 14%. Our experience suggested that the incidence might be much higher than this following the use of continuous popliteal block(CPB). The objectives of this study were to elucidate the incidence of patient-reported neuropathic sequelae following the use of CPB for pain control following foot and ankle surgery, to characterize these sequelae (including severity) and to identify preoperative /perioperative risk factors.
Methods: A prospective cohort study of N=147 surgical patients undergoing significant foot and ankle procedures was carried out. Preoperative /perioperative questionnaires were completed by the anesthesiologist, detailing patient demographics and anesthetic / surgery details. Patients completed questionnaires at 2 and 6 weeks postoperatively and again at 14 and 34 weeks (3 and 8 months), detailing the nature, location and severity of any abnormal sensations (other than postoperative pain). Neuropathic symptoms were identified using the criteria of the French Neuropathic Pain Group. Patient satisfaction levels were also tabulated and compared with the literature.
Results: Sixty patients (41%) described neuropathic symptoms at 2 weeks; this decreased to 45 (31%) at 6 weeks, 34 (26%) at 14 weeks, and 23 (24%) at 34 weeks. Overall, 81 patients (55.1%, 95% CI 47.1% to 64.1%) reported neuropathic symptoms at some time during the follow-up period, but only 10 patients (7%) had symptoms of sufficient severity that medication (Pregabalin) was prescribed and 6 patients (4%) were referred on to a neurologist or pain specialist. Multivariable logistic regression analyses using Generalized Estimating Equations revealed that the trend over time was significant, but none of tourniquet placement (p=0.3278), tourniquet time (p=0.2890), use of prophylactic antibiotics (p=0.5039), type of anesthesia (p=0.8810), level of anesthesiologist's training (p=0.2479), patient history of chronic pain (p=0.7875) or patient age (p=0.9313) were significantly associated with neuropathy. However, smokers were more likely to report neuropathy (68.4%) than non-smokers (52.9%) (adjusted odds ratio = 2.25, 95% CI 0.96 to 5.33).
Conclusions: The incidence of neuropathic symptoms may be much higher than previously reported. Despite this, patient satisfaction rates are high. Smoking may be a risk factor for the development of neuropathic sequelae following CPB.
A114 Title: Tethering force of epidural catheter connecting devices: comparison of screw type and folding type Presenting Author: Noboru Saeki MD, PhD Presenting Author's Institution: Hiroshima university hospital - Hiroshima, Hiroshima Co-Authors: Ryuji Nakamura MD, PhD - Hiroshima university hospital - Hiroshima, Hiroshima Seiji Kajiyama MD, PhD - Hiroshima university hospital - Hiroshima, Hiroshima Aiko Torikoshi MD - Hiroshima university hospital - Hiroshima, Hiroshima Masashi Kawamoto MD, PhD - Hiroshima university hospital - Hiroshima, Hiroshima
Abstract: Background: Disconnection of epidural catheter from connecting devices causes leakage of anesthetics, moreover may allow contamination into epidural space. The tethering force in screw type epidural connector is well obtained by tightening, yet we had experienced some cases of disconnection. We hypothesized that catheter disconnection is caused by insufficient tethering force due to insufficient tightening torque to a screw type connector, and investigated 1) the differences of tightening torque among anesthesiologists, 2) the relation between tightening torque and tethering force, and 3) compared with other mechanism or folding type.
Methods: Twenty-five anesthesiologists were enrolled. Torque was given and measured using torque gage meter (RX-T-20, AIKO engineering, Osaka). The tethering force of the screw type connectors (Portex®, Smiths medical) tighten at the torque at 40, 60 and 80 mNm, was measured using strength tester (catheter length: 20 mm, speed 400mm/min, MODEL-1840NT, AIKO engineering, Osaka), and was also compared with that of the folding type (Fuse®, Smiths medical and Perifix ONE®,B. Braun). The relationship of torques between the tightening and loosening the connector was also evaluated. The torque given by anesthesiologists (n=25) to screw type connector were estimated as the torque required for loosening the connector.
Results: Tethering force of Smith® tighten at 40, 60 and 80 mNm were, 6.4±2, 9.2±0.5 and 10.2±0.4 N, respectively, while that of Fuse® and Perifix ONE® were 9.2±0.5 and 10.7±0.3 N, respectively (n=6, each). Disconnection of the catheter was seen in 3 out of 6 in Portex® tightened at 40mNm. Torques for loosening the connector tightened at 40, 60 and 80 mNm, were 21.6, 26.3 and 30.3 mNm, respectively. Torque given by anesthesiologists (n=25) was 55.6±25.9 mNm (mean ± SD) with a range from 12 to 136 mNm (n=25).
Conclusion: Tethering force of each connector was comparable when Portex® was tightened at more than 60 mNm. In screw type connector, tightening force given by anesthesiologist may be insufficient to cause of catheter disconnection. Folding type may provide reliable connection.
A115 Title: Ultra-low Dose Naloxone Suppresses p38 MAPK Signal Cascade and Restores the Antinociceptive Effect of Morphine in PTX-treated Rats Presenting Author: Shinn-Long Lin MD, PhD Presenting Author's Institution: Tri-Service General Hospital and National Defense Medical Center - Taipei, Taiwan Co-Authors: Chih-Shung Wong MD, PhD - Cathay General Hospital - Taipei, Taiwan
Abstract: Background: We had previously showed that ultra-low dose naloxone restores the antinociceptive effect of morphine in rats with pertussis toxin (PTX)-induced thermal hyperalgesia by reversing the down regulation of glutamate transporter (GT) expression and suppressing spinal neuroinflammation. In the present study, we examined the underlying mechanisms of this anti-inflammatory effect in PTX- treated rats, particularly on the expression of GTs.
Methods: Male Wistar rats were implanted with an intrathecal catheter and, in some cases, with a microdialysis probe. All rats were injected intrathecally with saline (5 microl) or PTX (1 microg), then, 4 days later, were randomly assigned to receive a single injection of saline, ultra-low dose naloxone (15 ng), or the p38 mitogen- activated protein kinase (MAPK) inhibitor SB203580 (5 microg), followed by morphine injection (10 microg) 30 min later.
Results: Our results showed that PTX injection induced activation of microglia and a significant increase in P-p38 MAPK expression in the spinal cord. Ultra-low dose naloxone plus morphine significantly inhibited the effect of PTX on P-p38 MAPK expression in the spinal cord, while the p38 MAPK inhibitor SB203580 attenuated the PTX-induced mechanical allodynia, thermal hyperalgesia, increase in spinal cerebrospinal fluid excitatory amino acids, and downregulation of GTs. These results show that the restoration of the antinociceptive effect of morphine and GT expression in PTX-treated rats by ultra-low dose naloxone involves suppression of the p38 MAPK signal transduction cascade.
A116 Title: Prospective survey of patient-controlled epidural analgesia with bupivacaine and clonidine after total hip replacement: A pre and post change comparison with bupivacaine and hydromorphone Presenting Author: Spencer S Liu MD Presenting Author's Institution: Hospital for Special Surgery and Weill Cornell Medical College o - New York, NY Co-Authors: Mihai Bieltz MS, MBA - Hospital for Special Surgery - New York, NY Barbara Wukovits RN - Hospital for Special Surgery - New York, NY James J Bae MSc - Hospital for Special Surgery - New York, NY
Abstract: Background: Patient-controlled epidural analgesia (PCEA) with bupivacaine and hydromorphone provides high quality analgesia after orthopedic surgery (1) but is associated with a high incidence of opioid related side effects (15-30%). Epidural clonidine has a different side effect profile (2), but there are no large surveys documenting its use. We performed this prospective survey to evaluate analgesia and side effect profile in total hip replacement (THR) patients before and after systematic change from PCEA with bupivacaine/hydromrphone to bupivacaine/clonidine.
Methods: After IRB approval, 1,000 patients undergoing THR were included. From June 18, 2009 to Sept. 21, 2009, 500 consecutive patients received PCEA with 0.06% bupivacaine and hydromorphone (10 mcg/mL) served as a previously described pre-change control group (1). On July 27, 2010, the standard analgesic regimen was changed to 0.06% bupivacaine and clonidine (1 mcg/mL) without changing the PCEA settings or other aspects of perioperative care. Five hundred consecutive patients were then included as a post-change group until October 28, 2010. All data were prospectively entered and then abstracted from the electronic medical record. Data collection included daily verbal pain scores (VPS), pruritus, nausea, hypotension, need for IV fluid boluses, sedation, and respiratory depression. An online survey to measure staff satisfaction with the changeover was sent to all participating surgeons, anesthesiologists, physical therapists, and physician‘s assistants. Patient satisfaction was measured with Press Ganey scores specific for pain control after total hip replacement before and after the changeover. T test and Fisher exact test were used for analysis.
Results: Patient characteristics were similar between groups (Table 1). Most patients received central neuraxial anesthesia (99%). The clonidine group had lower VPS scores at rest (2.3 vs. 3.7, p<0.001) on POD0 but VPS scores on POD1 were equivalent (Table 2). VPS scores with activity on POD1 were higher in the clonidine group (3.4 vs. 3, p=0.01). Incidences of nausea were equivalent (11- 16%). Incidence of pruritus was less with clonidine (1 vs. 10%, p<0.001). However, incidences of hypotension (49 vs. 18%, p<0.001) and IV fluid boluses were greater with clonidine (51 vs. 24%, p<0.001). No patients suffered from sedation or respiratory depression. 65% of staff completed the online survey and 70% considered clonidine worse than hydromorphone. Patient satisfaction was unchanged (97% vs. 96% rating pain control as ―Good to Very Good‖).
Discussion: The systematic changeover from epidural hydromorphone to clonidine produced mixed results without obvious superiority. Pain control with activity was slightly worse, pruritus was reduced, but hypotension was increased. Based on medical staff preference, we discontinued the systematic change and returned to our previous standard solution of bupivacaine and hydromorphone for PCEA after THR.
References 1: Reg Anesth Pain Med. 2010:35:351-354. 2: Anesthesiology. 1996;85:655-674.
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Table 1: Patient characteristics and surgical procedures
Patient information Bupivacaine/hydromorphone Bupivacaine/clonidine
Age (yr, mean and SD) 64 (12) 65 (12)
Weight (kg, mean and SD) 79 (20) 80 (20)
Height (cm, mean and SD 169 (13) 168 (10)
Gender (Men/Women) 219/281 221/279
Race (% of patients)
White 91 93
Black 4 4
Other 5 3
Length of stay total hip 92 (26) 89 (25) replacement (hrs, mean and SD)
Surgical procedure (% of patients)
Total hip replacement 89 89
Total hip replacement, 11 11 resurfacing
Anesthetic technique (%)
Combined spinal epidural 80 94 (%)
Spinal agent
(%, median dose mg and IQR)
Bupivacaine 0.5% 41, 14.0 (2.5) 41, 12.5 (3.0) Mepivacaine 1.5% 57, 60.0 (7.5) 55, 60.0 (7.5)
Other 2 4
Epidural only (%) 20 5
Epidural agent
(%, median dose mg and IQR)
Bupivacaine 0.5% 4, 75.0 (23.8) 13, 75.0 (12.5)
Mepivacaine 1.5% 6, 240.0 (63.8) 21, 225.0 (75.0)
Mepivacaine 1.5% + - 8, 130.0 (10) Bupivacaine 0.5%
Lidocaine 2% + 78, 343.8 (0) 38, 275.0 (68.8) Bupivacaine 0.75%
Lidocaine 2% 8, 415.0 (142.5) 8, 400.0 (0)
Other 4 12
Intraoperative sedative and analgesics
(% of patients, mean dose and SD)
Midazolam (%, mg) 80, 6 (2) 76, 6 (2)
Fentanyl (%, mcg) 27, 102 (32) 30, 108 (43)
Propofol (%) 98 99
Additional File #2: 2022511131803Table2.doc Click here to view
Table 2: Verbal pain scores, side effects, and duration of patient controlled epidural analgesia
Verbal pain scores at rest Bupivacaine/hydromorphone Bupivacaine/clonidine (0-10, mean and SD) POD 0 3.7 (2.7) 2.3 (1.9)* POD 1 2.5 (1.7) 2.4 (1.7) Verbal pain scores with activity (0-10, mean and SD) POD 1 3.0 (2.3) 3.4 (2.6)* Side effects Nausea POD 0 16 13 POD 1 13 11 Pruritus POD 0 4 1* POD 1 10 1* Hypotension (SBP < 90 mmHg) POD 0 2 3 POD 1 18 49* Lactated Ringers Bolus POD 0 24 51* POD 1 26 23 Analgesic adjuncts (% of patients) Hydrocodone 5 mg/Acetaminophen 1 1 500 mg Hydrocodone 5 mg/Acetaminophen 2 2 325 mg Oxycodone 5 mg/Acetaminophen 325 4 5 mg Meloxicam 91 86 Pregabalin 1 3 Gabapentin 0 2 Duration of PCEA 30.0 (9) 27.5 (10) (hrs, mean and SD) *=significantly different
A117 Title: Needle visualization with ultrasound scan -Is Advanced Needle Visualization™ effective? Presenting Author: Tomoaki Yanaru MD Presenting Author's Institution: Anesthesiology - Fukuoka-shi, Fukuoka Co-Authors: Kenji Shigematsu MD - Anesthesiology - Fukuoka-shi, Fukuoka Kiriko Takahashi MD - Anesthesiology - Fukuoka-shi, Fukuoka Shizuka Sakurai MD - Anesthesiology - Fukuoka-shi, Fukuoka Kiyoshi Katori MD - Anesthesiology - Fukuoka-shi, Fukuoka
Abstract: Introduction: Needle visualization is important for safe ultrasound (US)- guided nerve blocks. Sonosite‘s US- machine has a new software, Advanced Needle Visualization™, to improve visualization of the needles. The aim of this study was to compare the efficacy of needle visualization of the new software using a US training model Blue Phantom (Advanced Medical Technologies, Kirkland, WA).
Methods and Assessment: M-Turbo (Sonosite, Bothell, WA) with a high-frequency linear array probe (HFL-50x/15-6 MHz, Sonosite, Bothell, WA) was used in this study. Needles were inserted into the same plane along the US beam (in plane needle approach). Needles used in this study were 22-guage Tuohy needle (Top, Japan), Stimplex (B Braun Melsungen AG, Germany), Stimplex D (B Braun Melsungen AG, Germany), PM-echo (Hakko, Japan), and Type CCR (Hakko, Japan). All needles were inserted into the phantom at angles of 0, 15, 30, 45-degrees relative to the horizontal plane. The images of needles were recorded with or without Advanced Needle Visualization™. Two other anesthesiologists evaluated the visualization of the needles. Visibility of each needle was scored on a five point scale: excellent= 4, good= 3, normal= 2, poor= 1, invisible= 0.
Results: The visualizations of each needle with or without Advanced Needle Visualization™ were as follows: Tuohy needle 3.0±0.8 vs. 3.9±0.4 (P< 0.05), Stimplex 2.6±0.7 vs. 3.6±0.5 (P< 0.05), Stimplex D 2.4±0.9 vs. 3.6±0.5 (P< 0.05), PM-echo 2.1±1.1 vs. 3.3±0.5 (P< 0.05), and Type CCR 2.4±1.1 vs. 3.5±0.5 (P< 0.05). The visualization of all needles improved with Advanced Needle Visualization™. The needle visualization at each inserting angle were as follows: 0- degree angle 3.2±0.4 vs. 3.2±0.4 (P=0.5), 15-degree angle 2.8±0.4 vs. 3.6±0.5 (P<0.05), 30-degree angle 2.8±0.4 vs. 3.5±0.5 (P<0.05), and 45-degree angle 1.2±0.8 vs. 4.0±0 (P<0.05). The needle visualization at 0-degree did not improve. The needle visualization at an angle of 15-degree or more improved with Advanced Needle Visualization™.
Conclusions: Advanced Needle Visualization™ was effective to improve visualization of all needles. The needle visualization at angle of 15-degree or more improved with Advanced Needle Visualization™.
Additional File #1: 1022811072552fig1.pdf Click here to view
Additional File #2: 2022811072552fig2.pdf Click here to view
A118 Title: Implementation of a Regional Anesthesia Block Nurse Team in the Perianesthesia Care Unit (PACU) Presenting Author: Emily DeBusk BA, RN Presenting Author's Institution: Duke University Medical Center – Durham, NC Co-Authors: J Brandon Winchester MD - Duke University Medical Center – Durham, NC Rebecca Russell BSN, RN, MPW - Duke University Medical Center - Durham, NC Joshua Dooley MD - Duke University Medical Center - Durham, NC Kim Burke BN, RN - Duke University Medical Center - Durham, NC
Abstract: Background: The literature indicates that pre-operative placement of peripheral nerve blocks results in a 30% overall reduction of surgical complications. The historical system of performing peripheral nerve blocks in the OR creates delays to OR start time, which prevents eligible patients from receiving pre-operative nerve blocks. Incidences of wrong sided blocks occur because hurried providers fail to perform a ―time out‖ prior to the block procedure.
Objectives: To provide the opportunity for more patients to receive pre-operative nerve blocks by developing a system in which blocks are done in PACU pre-op holding, preventing delays to OR start times. To prevent wrong-sided blocks by instituting a nurse-initiated ―time-out‖ protocol prior to the block procedure and with each position change
Implementation: A team of PACU nurses was established and trained to assist with nerve block procedures and to monitor for post-procedural complications. Nurses initiate a ―time-out‖ prior to each procedure and position change.
Successful Practice: Since the implementation of the block nurse team, more orthopedic and plastic surgery patients have received pre-operative nerve blocks and both departments have experienced a decrease in delays to OR start times. Since the implementation of the block nurse team, there have been no wrong-sided peripheral nerve blocks.
Implications for Advancing the Practice of Regional Anesthesia: The success of the block nurse team has inspired the creation of regional anesthesia block nursing certification and preceptorship programs. Instituting a dedicated regional anesthesia decreases delays to operating room start times and improves patient flow, which increases the number of pre-operative regional anesthesia procedures that are performed. A119 Title: The CorrectInject® System: Reducing Epidural-Intravenous Misconnections Presenting Author: Michael Block MD Presenting Author's Institution: Hackensack University Medical Center - Hackensack, NJ Co-Authors: Russell J Horn MD - Hackensack University Medical Center - Hackensack, NJ Mark D Schlesinger MD - Hackensack University Medical Center - Hackensack, NJ
Abstract: Background: Medication errors are leading causes of preventable harm in hospitals.1 Device misconnections leading to wrong route medication administration have attracted worldwide attention in patient safety.2 These incidents are believed to occur more frequently than reported since visible harm (which drives reporting) does not always result.3 Nevertheless, reports in the medical and lay press4 highlight that wrong route medication errors persist and have catastrophic consequences in a broad range of clinical settings. The Joint Commission‘s Sentinel Event Alert Number 36 (April 2006), cites 9 cases of tubing misconnections involving 7 adults and 2 infants. Deaths occurred in 8 of these instances and 1 resulted in permanent loss of function.3 The Institute for Safe Medication Practices (ISMP) reports numerous misconnection errors between peripheral and central venous infusion routes, neuraxial routes (epidural and spinal), enteral feeds, and bladder irrigation systems.5 A notable example of patient harm in the United Kingdom (U.K.) is the inadvertent administration of the highly toxic intravenous chemotherapeutic agent, vincristine, into the intrathecal (spinal) space.6 Furthermore, misconnections with accessory devices such as tubing used for noninvasive blood pressure cuffs, oxygen delivery and sequential compression devices are described.7 The US Pharmacopeia, the largest information source of tube misconnection related errors, has received 1600 reports of epidural and intravenous misconnections since 1999.8 In the Labor and Delivery setting, tragic maternal fatalities in the United States (U.S.) and United Kingdom (U.K.) are attributed to these mishaps.9,10 Furthermore, these types of errors result in career ending disciplinary action against providers, loss of reputation for hospitals and greater public fear of the health care system.10
The universal presence of Luer connectors in medical equipment is the leading common root cause of tube misconnection/wrong route administration incidents. Originally designed for attaching hypodermic needles and syringes, these traditionally inexpensive and easy to use [push (slip) or screw (lock)] male-female configurations enable the direct connection of unrelated medical devices. In other words, ―if it can happen, it will happen.‖3 A single patient may interface with up to 40 Luer-containing devices during a hospitalization.7 Given the limited evaluation or effectiveness of risk reduction policies and interventions that attempt to modify clinician work habits to reduce misconnection errors (increased vigilance, isolation of equipment, enhanced labeling, double-checks), development of epidural route- specific Luer alternatives is widely advocated.8 This is exemplified by active legislation in the U.K. (effective April 1, 2012) and in the U.S (California, effective January 2014) prohibiting the use of Luer connectors for epidural administration.11,12
The CorrectInject® epidural safety system is a non-Luer configuration of fittings used for epidural medication delivery systems fulfilling longstanding recommendations for creating connection ―incompatibility by design‖.2 This parallels the anesthesia patient safety advancement of the ―pin index‖ system universal to storage cylinders and delivery hoses of different anesthetic gases in modern day operating rooms.13 This high reliability system (simplified and standardized) prevents inadvertent, lethal misconnections of different anesthetic gases or surgical devices.
Technical Description: The system consists of several unique components. For the purpose of the Clinical Evaluation, three packaging configurations were available: 1. The CorrectInject® Safety System which includes: CorrectInject® Catheter Connector with Cap, CorrectInject® Infusion Adapter, CorrectInject® Filter, CorrectInject® Syringe, CorrectInject® Filter Straw, CorrectInject® White Transport Cap, and 16g epidural catheter. 2. The CorrectInject® Infusion Set which includes: CorrectInject® Infusion Set Adapter and White Transport Cap. 3. The CorrectInject® Syringe Kit which includes: CorrectInject® Syringe, CorrectInject® Filter Straw and White Transport Cap.
All resins and colorants used for the CorrectInject® Epidural Safety System are FDA medically approved materials.
Materials (including fluid path): 1. Polybutylene Terephthalate (PBT) 2. Acrylonitrile Butadiene Styrene (ABS) 3. Acrylic Copolymer 4. Modified Acrylic 5. Polyethersulfone 6. Polycarbonate 7. Polypropylene 8. Polyisoprene Methods: A clinical evaluation by users of the CorrectInject® epidural safety system was initiated at four U.S. institutions: Hackensack University Medical Center (NJ), Alta Bates Summit Medical Center (CA), John H. Stroger Jr., Hospital of Cook County (IL), and Tampa General Hospital (FL). The aims were to determine the system‘s: (1) clinical acceptance and (2) perceived effectiveness for preventing wrong route medication administration into the epidural space. Compatibility of CorrectInject® connectors with other devices (syringe pumps, cassette infusion pumps) was also included in the evaluation. An open-labeled, prospective, controlled study was conducted at four clinical sites across the United States from September 2009 until July 2010. The protocol sample size called for 200 device uses for epidural administration. Eligibility for participation included: obstetrical, surgical, or pain management patients undergoing epidural administration techniques.
Data collection involved the completion of a nine item questionnaire-- ―case report form‖ (CRF) following each use of the CorrectInject® device. Five questions pertained to ease of use and two to error prevention (safety). Included was a rating scale of 1 (very simple) to 5 (very complicated) for ease of use. Space for comments and suggestion was also provided. At the completion of the trial, participating clinicians at each site completed a 16 item system evaluation survey. Ten of these items related to ease of use and six to prevention of error (safety). Questions were in ―yes/no‖ format. Responses were entered into an Excel database by the clinical trial coordinator.
Monitoring of the study included on-site visitations, telephone and email contact by the Smiths Medical clinical trial coordinator. Site initiation training included protocol review and instructions for use. Routine monitoring visits were conducted during the trial period and a closeout meeting took place at the completion of the investigation. Inventory of remaining stock kits were collected and returned at that time and final data sheets collected and entered into the database for analysis.
Results: A total of 202 CRFs were collected from participating sites. 97% of CorrectInject® system usages involved obstetric patients; the remainder involved acute postoperative epidural pain management (Fig. 1).
Figure 1 The majority (91%) of epidural administrations were combined bolus and infusion pump techniques as shown in Figure 2.
Figure 2 Case Report Form Data: There were 15 reports of technical difficulties with the CorrectInject® system (Fig. 3) with 2 occasions of bypassing the system with the replacement of a standard Luer type connector (Fig. 4).
Figure 3
Figure 4 Two such cases involved emergent situations. In one scenario the CorrectInject® connector was noted to be missing upon patient arrival to the operating room. In the other, an urgent epidural bolus was needed with a pre-filled Luer-type syringe with anesthetic medication. In both circumstances, the CorrectInject® epidural connector was replaced with a standard connector. Additional comments referred to the nature of how individual components are packaged and clinician preference for CorrectInject® syringes of different sizes.
System Evaluation: In 99% of cases, clinicians felt that the CorrectInject® system protects against inadvertent administration of non-epidural medications into the epidural space (Fig. 5), while 96% felt the system protects against inadvertent epidural medication to non-epidural routes such as intravenous (Fig. 6).
Figure 5
Figure 6 Yellow color coding on the CorrectInject® connector was felt to be an effective identifier for epidural use by 99% of respondents (Fig. 7).
Figure 7 The weighted mean score for ease of use was 2.4. In 86% of cases, a score of 3 or below was given (Fig. 8). Furthermore, perceived difficulty with the system significantly declined by up to 50% at each site over time (Fig. 9).
Figure 8
Figure 9
Summary: The CorrectInject® system offers patients and clinicians with a novel, non-Luer safeguard against epidural and intravenous misconnections. The findings of this clinical trial support the perceived safety benefits and clinical suitability of the device in this setting (obstetric and pain management epidural bolus/infusion techniques) with potential for broader clinical application. The favorable ―learning curve‖ illustrates the clinical adaptability of the CorrectInject® system for future introduction into routine workflow. Further clinical acceptance of the system is anticipated following packaging and manufacturing modifications. Specifically, integration of the CorrectInject® adapter into the infusion tubing during manufacturing as well as the availability of different CorrectInject® syringe sizes (3, 5 and 10 milliliters) could offer further benefits for users.
The CorrectInject® system provides a practical and effective barrier to epidural- intravenous misconnection errors through ‗incompatibility by design‖. Human error remains a leading and unavoidable cause of patient harm in hospitals despite best efforts and numerous resources that aim to alter clinical practices to reduce harm. Like the pin index system in anesthetic gas delivery, the CorrectInject® system offers the long advocated, system-wide,14 technological solution to eliminate a‖ persistent and potentially deadly‖ root cause of patient harm.
Additional File #1: 1022311132048CI_References.doc Click here to view (attachment was blank) A120 Title: UPMC Regional Fellowship Class 2010-2011: Our experience Presenting Author: Uchenna O Umeh MD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Johnny Lee MD - UPMC - Pittsburgh, PA Jean D Eloy MD - UPMC - Pittsburgh, PA Qing Liu MD - UPMC - Pittsburgh, PA Andrew Lucic MD - UPMC - Pittsburgh, PA
Abstract: Introduction: Over the last few years, there has been an increased interest in the regional anesthesia fellowship. Residents, usually during their CA-2 year begin researching different fellowship programs. By the end of CA-2 and the first half of the CA-3 year, they will have completed interviews and will have to make a decision on where to spend a year for fellowship training. We aim to present our experience as regional fellows with UPMC‘s Acute Interventional Perioperative Pain Service (AIPPS) for the class of 2010-2011.
Our Experience: For the 2010-2011 class, we had a total of 9 fellows, 7 US trained, including one board certified anesthesiologist and 2 internationally trained. The majority of the fellows started on July 1st (7/9), one started on September 1st and the last on October 1st. As fellows, we rotate a month at a time to 6 different hospital sites offering opportunities to gain experience with patients of a level one trauma center, a children‘s hospital, an ambulatory surgery center, and community hospitals with predominantly orthopedic joint replacements, urology, gynecology, general surgery and oncology cases. The blocks performed during each rotation vary according to the site. In addition to performing regional techniques, fellows are closely involved with perioperative management of pain heavily based on the use of continuous techniques. Our yearly curriculum also includes a research month and for those interested, a month of the ―OR‖ rotation with the goal to reinforce skills learned during residency and to preserve technical skills such as arterial line/central line placement, intubation etc. As a group, the 9 fellows did a total of 13,098* blocks (annualized estimate), representing 43.6% of blocks done UPMC system wide.
Discussion: A Pub Med search on the term ―regional anesthesia‖ for the dates 1/1/2000 to 1/1/2001 yielded 1549 results while a comparable search for 1/1/2009 to 1/1/2010 netted 2121 articles. This increase in literature regarding regional anesthesia is a testament to the ever growing complexity of this anesthesia specialty. Coinciding with the growing body of knowledge in the field, more graduates of anesthesia residencies are seeking additional training in regional anesthesia fellowships with the goal to incorporate this knowledge into their future practice and reap the benefits of becoming experts in the field. The trend has been consistent at UPMC as well. In the past 6 years, the regional fellowship at the University of Pittsburgh Medical Center has not only increased from 1 to 9 fellows, but it has also become more competitive. The fellowship‘s popularity and need continues to increase with an anticipated growth to 12 fellows for 2011-2012.
A121 Title: Securing a Continuous Block Catheter: Angles, Planes, Tunnel, Bury,Creases Presenting Author: Walter H. Folger MD, PhD Presenting Author's Institution: Albany Medical College - Albany, NY Co-Authors: Constance Prince MS, FNP - Albany Medical College - Albany, NY
Abstract: Background: Before the patient can be sent home with a nerve block infusion and to maintain a catheter in-hospital, the method of securing the continuous catheter must be settled. Simple principles of physics will point to the most appropriate means of securing the catheter: angles, planes, surface area. Securing the catheter consists of two processes: catheter placement and dressing placement. Bends in the catheter and different planes of catheter alignment increase resistance to movement. Creating a flat surface for adhesion of the dressing increases contact of the dressing to the skin. A coil in the catheter away from the tunnel site allows movement of the proximal end without movement of the distal end in the sheath.
Objective: To demonstrate a technique to stabilize a continuous block catheter for post-operative pain control that will remain secure for one week.
Methods: Catheter placement: The orientation of the needle to the target (the fascial plane of the nerve sheath) is longitudinal. For ultrasound-guided blocks, the probe is SAX (short-axis) to the target, and the needle is out-of-plane to the probe. The needle enters the skin at a right angle and enters the sheath at 45-60 degrees. The catheter follows the line of the sheath and is inserted in the sheath at least three centimeters (one bend; two axes). Then the catheter is tunneled under the dermis at a transverse angle to the path of insertion. It exits the skin at a right angle (third axis; two bends) to the sheath and puncture direction. Dressing placement: Tagaderm is placed below creases, such as, femoral and axillary creases. Mastisol is applied before placing the Tagaderm. The edges are pressed down as the cover is removed from the Tagaderm. The catheter has a small coil away from the puncture and tunnel sites.
Results: Catheter placement: The secured catheter has two bends in three different planes: sagittal, transverse, frontal. The first portion (longitudinal plane) of the catheter is in the fascial plane of the nerve sheath. The second portion (sagittal plane) is in the subcutaneous tissue from the nerve sheath up to the dermis. The third portion (frontal plane) is buried below the dermis at the puncture site until it exits through the skin. Dressing placement: The edges of the Tagaderm remain adherent to the skin. The Tegaderm does not come off flat skin as it does in skin creases. The puncture and tunnel sites can be easily identified to evaluate for inflammation or drainage. Histacryl can tear skin on removal; Mastisol and Tagaderm do not tear the skin. Conclusions: Catheter: 1) Insert the catheter in the longitudinal axis of the fascial sheath. 2) Make two bends in the catheter in three different planes for a tunneled catheter to increase resistance to movement. 3) Coil the catheter away from the puncture and tunnel sites to increase the area of contact of the Tegaderm to the skin. 4) Place a small, single coil away from the tunnel site to resist pulling the catheter out. Dressing: 1) Cover the puncture site and tunnel site with Tegaderm. 2) Avoid placing Tegaderm over tissue creases. 3) Increase adhesion of Tegaderm with Mastisol. 4) Focus on securing the edges of the Tagaderm dressing.
A122 Title: Early weight-bearing ambulation under modified femoral nerve block for minimally invasive total knee arthroplasty Presenting Author: Shigeo Ishiguro MD Presenting Author's Institution: Oyamada Memorial Spa Hospital - Yokkaichi City, Mie Prefecture Co-Authors: Kiyoyuki Yoshioka MD - Mie University - Tsu, Mie Prefecture Naoki Asano MD - Mie University - Tsu, Mie Prefecture Masahiro Yagihara MD - Mie University - Tsu, Mie Prefecture Ken Amitani MD - Mie University - Tsu, Mie Prefecture
Abstract: Starting a weight bearing ambulation in early postoperative period of total knee arthroplasty is crucial in avoiding its complications and obtaining preferable outcomes. However, early ambulation is a demanding task as it would be prerequisite to spare practical motor and sensory functions of lower extremities under the proper anesthetic managements. Although, femoral nerve block can provide enough postoperative analgesia after total knee arthroplasty, it is often accompanied by severe motor paresis prior to fallings.
We devised modified femoral nerve block to spare voluntary knee extension ability and clinically applied it to the patients who receive minimally invasive total knee arthroplasty. In our cutting edge nerve blockade technique, main targets of the sensory nerves are saphenouse nerves and distal branches of anterior subcutaneous nerves which branched out from femoral nerve trunks. All the patients at bed rest rated analgesia of 0 to 3 by visual analogue score. In addition, rectus femoris muscle was not affected at all and surgically-invaded vastus medialis oblique muscle was completely anesthetized. Patients were able to not only actively raise their extremities with their knee in extension but also flex their knee in the air without pain aggravation. This enabled the patients to walk around without giving way in the recovery room on day 0.
Our anesthetic approach has a possibility to become a new choice for minimally invasive surgery in total knee arthroplasty to bring more preferable postoperative outcomes.
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A123 Title: Ultrasound-Guided Anterior Approach to Sciatic Nerve Block: A New Technique Using the Intrafasicular muscle plane as a target. Presenting Author: Barry G Thorneloe MD BSC BSN Presenting Author's Institution: University of Alberta - Edmonton, Alberta Co-Authors: Derek Dillane MB MMedSci FFARCS - University of Alberta - Edmonton, Alberta
Abstract: Introduction: The anterior sciatic nerve block remains one of the least used by anesthesiologists. Increasing obesity, unreliable landmarks and difficulty identifying the nerve on ultrasound continue to be issues. The sciatic block can be used for anesthesia (surgical conditions) and post-operative analgesia (pain relief) in knee and below the knee surgery. Therefore, there is a significant group of patients who would benefit from this block being used more routinely. If the anterior sciatic nerve block could safely be done by visualizing other, more easily identifiable, anatomic structures on ultrasound, it would eliminate the need to rely on sonographic visualization of the sciatic nerve. To that end, we wish to test the hypothesis that ultrasound will readily identify the plane between the muscle groups where the sciatic nerve exists, without necessarily seeing the sciatic nerve itself. Furthermore, by using this plane as a landmark and target for local anesthetic deposition, the sciatic nerve will consistently be blocked.
Background: Increasing obesity, unreliable landmarks and difficulty identifying the sciatic nerve on ultrasound continue to present barriers for sciatic nerve blockade. The anterior approach (in contrast to the posterior approach) negates having to turn patients lateral or prone and allows for concomitant femoral nerve blockade.1 These benefits make the anterior approach to the sciatic nerve block advantageous for the patient and anesthesiologist.
Classic anterior approaches to sciatic nerve block described by Beck (1963) and Chelly (1999) place the needle at the level of the lesser trochanter; which has been shown to be a physical impediment to reaching the nerve2, despite internal and external rotation3. Furthermore, the landmarks which these approaches employ can be difficult to locate, particularly in the obese population.4,5 Even with the advent of ultrasound, the depth and variation in sciatic nerve appearance and position can be challenging to overcome. Recently, Tsui et al. showed that turning the ultrasound probe longitudinally from transverse, allows for easier identification of the sciatic nerve as a ―cable‖ rather than an oval.6 However, this technique is limited in its ability to see/avoid blood vessels and to ensure circumferencial spread of local anesthetic without having to turn the probe back to the transverse configuration. Therefore, as more patients come for knee and below knee surgery, the ability of anesthesiologists to offer an anterior sciatic nerve block that does not rely on visualization of the sciatic nerve yet remains easy and safe to do is of the clinical importance.
The sciatic nerve is known to course through a fascial plane between the adductor and gluteal muscle groups. Identification of the muscle groups and the fascial plane between them would give the anesthesiologist a new sonographic landmark and target for deposition of local anesthetic. The low frequency (2-5 MHz) ultrasound probe has been shown to be efficacious at looking at deep anatomical structures, including the anatomy surrounding the sciatic nerve.7 To date, there are no studies which evaluate the utilization of the fascial plane between the adductor and gluteal muscle groups as a potential target for the anterior sciatic nerve block.
Objective: In this study I propose to perform a prospective feasibility study to measure the success and safety of an anterior approach to ultrasound-guided sciatic blockade where the fascial plane between the adductor and gluteal muscles groups is used as a target, as opposed to the sciatic nerve specifically.
Hypotheses: This anterior approach to ultrasound-guided sciatic blockade where the fascial layer between the adductor and gluteal muscles groups is used as a target, will be easier and as efficacious as when the sciatic nerve, itself, is used as the target.
Study Population: This will be a prospective observational and feasibility study of a total of 20 patients undergoing surgery of the lower limb where a sciatic nerve block is intended as an adjunct to operative and post-operative analgesia. It will involve all patients coming for knee/ below knee surgery.
Inclusion criteria: • Consenting adult patients > 18 years • Scheduled for elective and emergency surgery at or below the knee
Exclusion criteria • Pre-existing neurological deficit • Local infection • Allergy to local anesthetic • Long-term opioid intake • Patient refusal
Methods: Following Institutional Ethics Board approval and informed consent, 20 patients undergoing lower limb surgery will be enrolled in this study. A volunteer imaging study was conducted prior to the clinical study. The fascial plane between the adductor magnus and gluteus maximus was visualized in all volunteers. The visible human visualization software was utilized to confirm the sciatic nerve consistently resided in the fascial plane between the adductor magnus and gluteus maximus. In addition, it was used to determine the optimal level to anteriorly approach the sciatic nerve to minimize injury to blood vessels and other structures, as well as, the mean medial distance of the sciatic nerve at that level.8 The nerve blocks will be performed or supervised by experienced anesthesiologists from the Acute Pain Service. Single injection, anterior approach sciatic nerve blocks will be performed on the anterior aspect of the upper thigh using ultrasound and nerve stimulation guidance as previously described. The local anesthetic injected will consist of a mixture of 0.25% bupivacaine and 1% ropivacaine administered on a mg/kg basis. All nerve blocks will be performed in awake patients, as per current safety prerequisites. Standard monitoring and sedation will be used throughout the duration of the nerve block procedure.
The primary outcome will be block success. Success will be measured by assessing sensory and motor blockade on a 3 point scale (0 - paralysis/anesthesia; 1 - paresis/hypoesthesia; 2 - no block) both pre and post-operatively. This scale has been previously used in the literature more measuring efficacy of sciatic nerve blockade. Secondary outcomes will include length of time taken to perform the nerve block (including any pre-scanning prior to the actual performance of the block) and incidence of acute complications associated the nerve block. These secondary outcomes will be used as surrogates for ease of ultrasound-guided anterior sciatic block using intrafascial landmarks.
Analysis: This is a prospective observational and feasibility study. Successful identification of the fascial plane between the adductor magnus and gluteus maximus will be reported. The number of needling attempts to stimulate the sciatic nerve and the thresholds used will also be reported. Lastly, the success of nerve blockade will be reported as per the previously mentioned sensory and motor block 3-point scale.
References 1. Ota J, Sakura S, Hara K and Saito Y. Ultrasound-guided anterior approach to the sciatic nerve block: A comparison with the posterior approach. Anesth Analg. 2009;108:660-665. 2. Ericksen ML, Swenson, JD and Pace NL. The anatomic relationship of the sciatic nerve to the lesser trochanter: Implications for anterior sciatic nerve block. Anesth Analg. 2002;95:1071-1074. 3. Vloka JD, Hadzic A, April E and Thys DM. Anterior approach to the sciatic nerve block: The effect of leg rotation. Anesth Analg. 2001;92:460-462. 4. Van Elstraete AC, Poey C, Lebrun T, and Pastureau, F. New landmarks for the anterior approach to the sciatic nerve block. Anesth Analg. 2002;95:214-218. 5. Chantzi C, Sarateas T, Zogogiannis J, Alevizou N and Dimitriou V. Ultrasound examination of the sciatic nerve at the anterior thigh in obese patients. Acta Anaesthesiol Scand. 2007;51:132. 6. Tsui BCH and Ozelsel TJP. Ultrasound-guided anterior sciatic nerve block using a longitudinal approach: "Expanding the view". Reg Anesth Pain Med. 2008;33:275- 276. 7. Chan VWS, Nova H, Abbas, S, Perlas A, McCartney CJL and Xu DQ. Ultrasound examination and localization of the sciatic nerve. Anesthesiology. 2006;104:309- 314. 8. Visible Human Visualization Software, courtesy Ecole Polytechnique Ferale de Lausanne, online website.
A124 Title: Utility of Tetracaine as a Long-Acting Spinal Anesthetic: Should We Let it go Silently? Presenting Author: Nagle Pamela MD Presenting Author's Institution: Wake Forest University Baptist Medical Center - Winston-Salem, NC Co-Authors: George L Smith MD - Wake Forest University Baptist Medical Center - Winston-Salem, NC John C Gerancher MD - Wake Forest University Baptist Medical Center - Winston- Salem, NC
Abstract: For years, tetracaine has been used in our institution as the subarachnoid anesthetic block (SAB) of choice for procedures of lengthy duration-not an uncommon event in an academic center. The recent decision to cease production of tetracaine has forced us to re-evaluate our use of the drug. Our computerized operating room information system (ORIS) allowed us to gather this data efficiently and analyze the results in order to review our practice and define case-specific issues and characteristics that will help to define our practice moving forward. As the vast majority of our tetracaine SABs are placed in orthopedic procedures involving the hip and knee, our study focuses specifically on this group.
The query of our institution‘s ORIS from January 2008 through February 2011, focused on quantification of the total use of tetracaine per month, the use of tetracaine versus other agents in this orthopedic population and then the case- specific data involving both length of procedure and timing of drug dose. The total use of tetracaine anesthetics per month allows us to assess our clinical practice relevant to the shortage/discontinuation notices and explore the implications of human behavior in these results. These results demonstrate the ‗response times‘ in change of practice to such notices and may impact our future handling of similar shortages. Next, we calculated the length of the of procedures and plotted this versus the drug chosen for SAB (subarachnoid block) in order to support or refute our belief of the true necessity for a longer-acting SAB and our precision with predicting the necessity should the data support our practice. In the following sections, we discuss our application of this data to assess practice patterns and plan future best practices. Finally, we assess the current data from our study and discuss it in context of the academic discussion that tetracaine remains important in clinical practice.
A125 Title: A prospective, randomized trial, comparing analgesic efficacy and postoperative functional recovery of either single shot sciatic nerve block or posterior capsule infiltration combined with femoral block for total knee arthroplasty. Presenting Author: Ben Safa FRCPC Presenting Author's Institution: Sunnybrook Health Sciences Centre - Toronto, Ontario Co-Authors: Lynn Haslam RN - Sunnybrook Health Sciences Centre - Toronto, Ontario Jeffrey Gollish FRCPC - Holland Orthopedic and Arthritic Institute - Toronto, Ontario Colin McCartney FRCPC - Sunnybrook Health Sciences Centre - Toronto, Ontario
Abstract: Background: Many methods of pain relief have been implemented in an attempt to provide safe and effective analgesia to patients following total knee arthroplasty (TKA). Overall, the literature has strongly supported the use femoral nerve block, the addition of sciatic nerve block has been more controversial. This study will evaluate the hypothesis that a single shot sciatic nerve block compared to posterior capsule infiltration or placebo would yield significant benefit in patients having TKA who are receiving multimodal analgesia in conjunction with femoral nerve block.
Methods: This interim analysis was performed following recruitment of 52 out of the total 96 patients required for the study. In a randomized, double-blind fashion, patients undergoing TKA received either femoral-sciatic, femoral-posterior capsule local anesthetic infiltration, or femoral-sham nerve block/sham infiltration after a standardized spinal anesthetic. Multimodal analgesia including acetaminophen, celecoxib and gabapentin was initiated preoperatively and continued for three day postoperatively. Patient-controlled analgesia (hydromorphone) was continued for 48 hours. Controlled-release oxycodone 10 mg every 8 hours was started the first morning after surgery. Once the PCA was discontinued, oxycodone 5 mg every hour as needed was available. Pain scores (at rest and with movement) and opioid consumption were recorded for 72 hours. The timed up and go test (TUG) and range of motion were performed as functional outcome measures.
Statistics/Sample Size: Power analysis indicated that with a total of 96 patients entering this two treatment parallel-design study to detect a 30% reduction in pain score with a power of 80% and an α of 0.05. Demographics, opiate, and TUG scores were calculated using t-test analysis. Pain scores were analyzed using the t-test and Mann-Whitney U test. Outcomes such as range of motion, pain scores were analyzed using a repeated measure ANOVA looking at the interaction of group over time for the various scores. A p value of .05 was considered significant. Results: There were no significant differences found between groups for age, body mass index, or gender distribution. There were no reported surgical or anesthetic complications. Pain scores across all groups were relatively low. At the twelve hour mark, mean pain scores were 4.18, 3.37, 4.69, respectively for Groups A, B, and C. There are no significant differences in pain scores between treatment groups (table 1)and no differences in opioid consumption over the first 72 hours (table 2). The TUG analysis showed no significant difference (p=0.48). There were no significant time or pain score differences between groups in the TUG test or in knee flexion/extension (table 3).
Discussion and Conclusion: In patients undergoing primary total knee replacement who receive a spinal anesthetic, a single shot femoral nerve block and a multimodal analgesic regimen; the addition of a single shot sciatic nerve block or the infiltration of local anesthetic into the posterior capsule of the knee block may not add any further analgesic benefit in the post operative period. Full recruitment and final analysis of the data will be required to adequately answer these questions.
Additional File #1: 1022811104732Table_1.doc Click here to view
Table 1
Pain on movement – Mean pain score across all groups
10 9 8 7 6 VAS Mean 5 (0-10) 4 Group A 3 2 Group B 1 Group C 0
Pain Score Intervals
Additional File #2: 2022811104732Table_2.doc Click here to view
Table 2
Morphine equivalents – Mean opioid usage across all groups
100.0 90.0 80.0 70.0 60.0 Morphine 50.0 Group A Equivalents 40.0 Group B 30.0 Group C 20.0 10.0 0.0 24 h 48 h 72 h
Cumulative Opioid Consumption
Additional File #3: 3022811104732Table3.doc Click here to view
RANGE OF MOTION (MEAN) Group Group Group Table 3 A B C Baseline (Pre-Op) Flexion 90 112.50 113.33 Extension -2.38 1.05 -0.07 Pain Pre Test 1 0.3 1.6 Pain Post Test 3.1 2.9 3 POD #1 Flexion 66.27 68.73 69.64 Extension 2 0.5 2.06 Pain Pre Test 3.26 3.8 3.7 Pain Post Test 5.6 5.2 5.4 POD #2 Flexion 77.82 79.10 77 Extension 0.94 1.41 3.43 Pain Pre Test 1.75 2.7 2.5 Pain Post Test 4.37 4.8 5.4 POD #3 Flexion 86.46 86.05 87.07 Extension 0.15 0.11 1.64 Pain Pre Test 2 3 1.6 Pain Post Test 4.58 5 4 TIMED UP & GO (POD #3) Mean Time (seconds) 34.62 39.18 27.17 Pain Pre TUG 2.3 3.2 2 Pain Post TUG 3.6 3.7 2.9 A126 Title: Dermatome Distribution of Sensory and Temperature Anesthesia following an Epidural Test Dose at the T10-T11 Thoracic Epidural Interspace Presenting Author: Aali Shah MD Presenting Author's Institution: Northwestern University, Feinberg School of Medicine - Chicago, IL Co-Authors: Mark C Kendall MD - Northwestern University, Feinberg School of Medicine - Chicago, IL Robert J McCarthy PharmD - Northwestern University, Feinberg School of Medicine - Chicago, IL Antoun Nader M.D. - Northwestern University, Feinberg School of Medicine - Chicago, IL
Abstract: Introduction: Thoracic epidural analgesia is effective in perioperative pain relief for uterine artery embolizations.1 The major sensory fibers from the uterus accompany the sympathetic nerves, which enter the nerve roots of the spinal cord at T11 and T12.2 A test dose of 3-5 mL of 1.5% lidocaine with 1:200,000 epinephrine is frequently used to rule out intravascular and intrathecal catheter placement. The purpose of this study was to investigate the extent of sensory and temperature dermatome distribution for thirty minutes following a 5mL test dose.
Methods: Following IRB approval, 95 ASA I-III female patients (>18 y/o) undergoing uterine artery embolization received a thoracic epidural for postoperative pain relief. Low thoracic epidural catheters were placed using loss of resistance to air technique at the intended T10-11 vertebral interspace. All patients received a test dose of 5mL lidocaine with 1.5% with epinephrine 1:200,000. The extension of sensory discrimination (pin prick) and loss of temperature discrimination (ice) was recorded at 5 minute intervals up to thirty minutes following the injected test dose. The testing distribution pattern extended from T4- L3. Correct epidural catheter placement was confirmed under fluoroscopy.
Results: Ninety-five patients completed the study. The patients age 45(40-45), height (in) 64(63-66), weight (kg) 78(66-98) were recorded. At the T10 dermatome level, 70% of subjects demonstrated analgesia to ice and 63% to pinprick at 15 minutes and 85% achieved complete analgesia at the T10 dermatome level. The caudal extent of analgesia increased to 24% for ice and 30% for pin prick at the L1-L3 dermatome by the 30 min testing interval. Cephalad spread extended to the T4 dermatome in 30 to 40 percent of subjects. (Figure)
Discussion: The loss of temperature discrimination to ice occurs before the loss of sensory discrimination to pin prick in the first twenty minutes following test dose injection. The extent of the dermatome distribution to the loss of temperature discrimination to ice and loss of sensory discrimination to pin prick was similar; T10 dermatome was the most frequent dermatome to achieve analgesia. Using a 5mL test dose, only eighty-five percent of patients achieved complete analgesia at T10. Our study is the first to report the assessment of dermatome distribution after an epidural test dose in uterine artery embolization patients receiving thoracic epidural analgesia for postoperative pain control.
References 1. Masui. 2005 Feb; 54(2):156-159. Japanese 2. Katz VL. Reproductive Anatomy: Gross and Microscopic, Clinical Correlations. In: VL Katz et al., eds. Comprehensive Gynecology. 5th ed. Philadelphia: Mosby Elsevier, 2007:200–201.
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A127 Title: Simulating the Brachial Plexus- An Ultrasound Phantom Presenting Author: Michael A Long MD Presenting Author's Institution: University of Alabama Birmingham - Birmingham, AL Co-Authors:
Abstract: Background: Ultrasound-guided peripheral nerve block techniques are gaining wide spread acceptance as a ―new‖ standard approach to regional anesthesia. These techniques are often significantly different from older anatomical approaches and require new knowledge and technical skills. As new learners advance their practice, ultrasound simulation models are helpful in acquiring basic knowledge and skills such as ultrasound manipulation, image identification, machine operation and needle advancement. Studies suggest simulation models improve learner comfort level, psychomotor skills, and possibly reduce common errors. These models also provide learners a safe, non-threatening, learning environment without the risk of injuring patients.
Objective: To create a low-cost, easily made, brachial plexus ultrasound phantom for simulating ultrasound-guided supraclavicular nerve blocks.
Methods: We built a brachial plexus ultrasound phantom using penrose drains, IV tubing, foley catheter and gelatin. A supraclavicular nerve bundle was simulated by adding 4-5 pieces 5‖ cut IV tubing into a 3/4‖ penrose drain with the ends tied off. Vein was simulated by filling a 5/8‖ penrose drain with water. A large foley catheter acts as a small, non-compressable artery. Subcutaneous tissue was simulated with Metamucil and highly concentrated gelatin dissolved in hot water. Objects were layered within the gelatin. A standard ultrasound machine and nerve stimulating needle were used to perform a simulated in-plane supraclavicular nerve block.
Results: The created phantom simulates the supraclavicular nerve bundle, venous, and arterial structures within a particulate gelatin. The model is low cost and simple to build. All the materials are readily available in most operating suites and local grocery stores. Assembly requires no more than a microwave and refrigerator and all materials can be recycled into new phantoms. This phantom closely approximates supraclavicular structures and is easily modified to increase image complexity and needle advancement.
Conclusions: Our brachial plexus phantom has the potential to improve patient safety and physician education. We plan to integrate the simulation into regional education programs and evaluate its effectiveness.
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A128 Title: Efficacy of pregabalin for the treatment of postoperative pain: a meta- analysis Presenting Author: Brandon Togioka MD Presenting Author's Institution: Johns Hopkins University - Baltimore, MD Co-Authors: Jean-Pierre Ouanes DO - Johns Hopkins University - Baltimore, MD Shawn Sumida MD - Johns Hopkins University - Baltimore, MD Kanupriya Kumar MD - Johns Hopkins University - Baltimore, MD Kyaw Mon MD - Johns Hopkins University - Baltimore, MD
Abstract: Introduction: The use of pregabalin for the treatment of postoperative pain has been described but the overall efficacy is unclear. We performed a meta-analysis of available randomized trials.
Methods: This study qualified for exemption from The Johns Hopkins IRB. The National Library of Medicine's PubMed database was searched for the time period 1966 to December 20107 with the textwords pregabalin and postoperative pain. Data were collected from each article and results were recorded. A random effects model was used. All statistical analyses were performed with RevMan 4.2.7 (The Cochrane Collaboration, 2004).
Results: Our search resulted in a total of 8 studies which met all inclusion criteria. Pregabalin doses ranged from 50 to 600 mg/day. Pregabalin treatment was associated with a significant decrease in VAS pain scores at 12 hours (weighted mean difference [WMD] = -0.85; 95% confidence interval [CI]: -1.48 to -0.23, p = 0.007) but not at 24 (WMD = 0.02; 95% CI: -0.86 to 0.90, p = 0.97) or 48 (WMD = -0.36; 95% CI: -0.74 to 0.02, p = 0.06) hours. Pregabalin was associated with a significant increased risk in dizziness (Odds ratio [OR] = 2.14 [95% CI: 1.06 to 4.31]) but was not associated with any increase in odds of postoperative nausea and vomiting (OR = 0.73 [95% CI: 0.50 to 1.06]) or sedation (OR = 1.28 [95% CI: 0.67 to 2.44]).
Discussion: The use of pregabalin appears to provide some analgesic efficacy at 12 hours after surgery but did not provide improved analgesia beyond this period. An increase in dizziness with pregabalin use may be expected.
A129 Title: Analgesic Efficacy of Intravenous Magnesium Infusion: a meta-analysis Presenting Author: Grace Kong MD Presenting Author's Institution: The Johns Hopkins University - Baltimore, MD Co-Authors: J. Gabe Tsang MD - The Johns Hopkins University - Baltimore, MD Brandon Togioka MD - The Johns Hopkins University - Baltimore, MD Kanupriya Kumar MD - The Johns Hopkins University - Baltimore, MD Jean-Pierre Ouanes DO - The Johns Hopkins University - Baltimore, MD
Abstract: Objective: Intravenous magnesium has been administered as an adjunct agent (typically as an intraoperative bolus and infusion) for postoperative analgesia. However, how intravenous magnesium may affect analgesia or other opioid-related side effects. We have performed a systematic review to further examine this issue.
Method: This study qualified for exemption from the Johns Hopkins IRB. Systematic literature searches of the National Library of Medicine‘s PubMed and EMBASE databases were conducted using terms related to postoperative use of IV magnesium. Only randomized controlled trials comparing perioperative IV magnesium infusion were considered. Data on pertinent study characteristics and relevant outcomes were extracted from accepted articles. There was no restriction on language for inclusion. Meta-analysis was performed using the Review Manager 4.2.10 (The Cochrane Collaboration, 2004). A random effects model was used.
Results: The literature searches yielded 14 articles which met all inclusion criteria. There were a total of 412 subjects in the magnesium group and 412 in the no magnesium group. We found that use of perioperative IV magnesium was associated with a decreased VAS pain scores at 4-6 hours [weighted mean difference (WMD) = -0.69 (95% confidence interval [CI]: -1.15, -0.23), p = 0.003],12 hours [WMD = -0.67 (95% CI: -1.01, -0.32), p = 0.001], and 24 hours postoperatively [WMD = -0.43 (95% CI: -0.79, -0.06), p = 0.02]. We found that use of perioperative IV magnesium was not associated with a decrease in postoperative nausea and vomiting (odds ratio = 0.62, 95% CI: 0.37, 1.03, p = 0.06)
Conclusions: Our pooled analysis examining the analgesic efficacy of perioperative IV magnesium infusion revealed that IV magnesium was associated with a decrease in visual analog pain scores at 4-6, 12 and 24 hours after surgery. When compare to the no magnesium group, the use of IV magensium was not associated with any changes in odds of postoperative nausea and vomiting. The results should be interpreted with caution and certainly further examination with larger RCT is warranted as the overall number of subjects A130 Title: Structured regional anesthesia course in Egypt and implementation of regional anesthesia program improves trainees‘ regional anesthesia practice: a performance review Presenting Author: Julie HY Huang MD, MBA Presenting Author's Institution: The Johns Hopkins Hospital - Baltimore, MD Co-Authors: Sherif Abdel Hamid MD - Alexandria Research Institute - N/A, N/A Magda AboOllo MD - Alexandria Research Institute - N/A, N/A Marie Hanna MD - The Johns Hopkins Hospital - Baltimore, MD
Abstract: Introduction: We previously found that a structured, hands-on course in regional anesthesia was beneficial in teaching anesthesia trainees at the Alexandria Research Institute in Egypt and improved trainees‘ knowledge in regional anesthesia and postoperative pain management. (Abstract presented at ASRA spring meeting 2010). To follow up on knowledge retention and long-term improvement in clinical practice among those trainees, we reviewed the associated clinical outcomes of 88 patients who received regional anesthesia perioperatively.
Methods: In November of 2009, a US-trained regional anesthesiologist gave a structured, hands-on course in regional anesthesia and pain management at the Alexandria Research Institute in Egypt. Evaluation of the trainees showed overall statistical improvement in all post-instruction scores (p < 0.0001) compared to pre- instruction, regardless of training level. A structured follow-up program was initiated and adopted by the institution in Egypt. In the follow-up program, data were collected on every regional anesthesia technique performed in the institution as part of the transfer knowledge program to improve regional anesthesia practice. From June through December 2010, 88 patients received regional anesthesia from the anesthesia trainees, and data on these cases were collected to assess quality outcomes. Baseline data collected included age, weight, gender, surgical procedure, history of chronic opioid use, ASA classification, duration of hospital stay, type of procedure (epidural/caudal, spinal, nerve block, or combined spinal-epidural), specific block type, drug used for block, position, technique used, duration of block, average pain score at rest [by visual analog scale (VAS)] on postoperative days (PODs) 0 and 1, average pain score with activity (by VAS) on PODs 0 and 1, patient satisfaction, and complications. Analyses were performed to characterize implementation of regional techniques and associated clinical outcomes.
Results: Of the 88 patients, 38 (43%) cases used epidural/caudal, 31 (35%) used spinal, 17 (19%) used peripheral nerve blocks, and 2 (2%) used combined spinal- epidural (Fig. 1). Types of peripheral nerve blocks implemented during this period included thoracic paravertebral blocks (7 cases), ankle (3 cases), superficial cervical plexus (3 cases), supraclavicular (2 cases), transverses abdominus (1 case), and axillary (1 case; Fig. 2). The pain score was low in all patients at rest on POD 0 with mean score 2.3±0.7 on a VAS scale of 0–10. A performance review of the anesthesia trainees showed 99% success of regional anesthesia technique implemented with minimal complication rate (1/88 cases with an incomplete block). No other complications were reported.
Conclusions: Prior analyses showed benefit in teaching a structured regional anesthesia course to trainees in an international setting. The performance review after the first 6 months confirms successful use of regional techniques in 88 cases with a low complication rate (1%). A second report showed similar successful outcomes for 30 cases in which two-point injection parvertebral blocks were used for breast cancer procedures. Based on these results, outreach teaching efforts should continue to promote regional anesthesia and pain management education across this country and the entire globe.
Key Words: Education, Regional anesthesia, Pain management.
Additional File #1: 1022211175222Abstract_1_fig_ASRA.pdf Click here to view
A131 Title: The effect of supraclavicular block levels of local anesthetic on the Bispectral Index Presenting Author: Kelly P Byrne MBChB Presenting Author's Institution: University of Alberta - Edmonton, Alberta Co-Authors: Derek Dillane MB MMedSci - University of Alberta - Edmonton, Alberta Ban Tsui MD - University of Alberta - Edmonton, Alberta
Abstract: Background: There are mixed reports in the literature as to the effect of lidocaine on the bi-spectral index. One case report of inadvertent lidocaine overdose during the course of a general anesthetic, reported a BIS level of 0, which was attributed to the systemic effects of lidocaine(1). Another study showed a reduction in propofol requirements for induction and maintenance of anesthesia when patients were given IM lidocaine or bupivacaine when compared to placebo and titrated to a BIS value between 40 and 50(2). This data is somewhat contradicted by 2 other studies, one showing an effect of lidocaine only when given epidurally rather than when given IV during general anesthesia(3) and one showing an effect of lidocaine on the BIS reading during general anesthesia only when surgery is undertaken(4). There is a good physiological basis for lidocaine to have an effect on the bi-spectral index, as it causes inhibition of neuronal transmission, both peripheral and in the central nervous system. In this study, the subjects are free of confounding factors such as general anesthesia and sedation, and one would expect measurable levels of lidocaine following the supraclavicular block, which is near major vascular structures and thus associated significant systemic uptake. Therefore, if lidocaine does affect the bispectral index, one would expect to see this effect.
Methods: Consent was obtained from 21 consecutive patients presenting for hand and forearm surgery. They all underwent supraclavicular brachial plexus block without any form of sedation. Initially, 1.5% lidocaine was used for the first 6 patients in the study. However, after reports of early post-operative pain in the day surgery unit, this was changed to a mixture of 1.5% lidocaine and 0.125% bupivacaine for the remaining patients. There were no further reports of early post- operative pain in the day surgery unit. Patients underwent the block with routine hemodynamic monitoring and BIS monitoring. The BIS number was then monitoring for the next 30 minutes while the patient awaited transfer to the operating room.
Results: Dose of lidocaine received was between 4-8mg/kg and the dose of bupivacaine was between 0.375-0.625mg/kg. 3 patients had clinical symptoms of local anesthetic toxicity with circum-oral tingling and light-headedness. This was not correlated with dose received, and in one case was associated with likely partial intravascular injection. There was no significant change seen in the BIS number following institution of the block. There were transient decreases in the BIS number, associated with the patient drifting off to sleep. When roused the BIS number returned to normal.
Discussion: Lidocaine when used by itself, or in combination with bupivacaine has no effect on the BIS number in the awake patient. It does not provide a reliable marker of impeding local anesthetic toxicity or change with symptoms of LA toxicity. Even small doses of bupivacaine when used with lidocaine significantly prolong the clinical effect of a supraclvicular block.
References 1. Gaughen CM, Durieux M. Anesth Analg. 2006;103:1464-1465 2. Senturk M, Pembeci F, et al. Br J Anaesth. 2002;89:849-852. 3. Hodgson PS, Liu SS. Anesthesiology. 2001;94(5):799-803. 4. Hans GA, Lauwick SM, et al. Br J Anaesth. 2010;105(4):471-479.
A132 Title: Combined Spinal-Epidural Analgesia Versus Epidural Analgesia in Labor: Analgesic Quality and Implications. Presenting Author: Miguel Plaza Lloret, Consultant Presenting Author's Institution: Consorcio Hospital General Universitario de Valencia Co-Authors: Oscar Diaz Cambronero, Consultant – Consorcio Hospital General Universitario de Valencia – Valencia, Valencia Nuria Garcia Gregorio, Consultant – Consorcio Hospital General Universitario de Valencia – Valencia, Valencia Maria Vila, Consultant - Consorcio Hospital General Universitario de Valencia – Valencia, Valencia Carlos Errando Oyonarte, Consultant - Consorcio Hospital General Universitario de Valencia – Valencia, Valencia
Abstract: Introduction: The combined spinal-epidural labor analgesia technique (CSEA) has attained widespread popularity in obstetric anesthesia worldwide. The onset of analgesia is rapid and reliable, and maternal satisfaction is high. To explore the effects of walking epidural analgesia and CSEA on obstetric and neonatal outcomes, we performed a prospected study.
Objective: To compare whether quality of analgesia, duration of labor and several maternal and fetal outcomes are affected depending on the anesthesia technique chosen, i.e., CSEA and epidural analgesia with levobupivacaine or ropivacaine.
Material and Methods: Prospective, randomized, double-blinded study. Health pregnant patients at term (singleton pregnancy) were assigned to the CSEA or epidural analgesia group. Group CSEA received 0.25% levobupivacaine 1 mL plus 0.7 mL saline plus fentanyl 0.5mg/mL (0.3mL); group epidural-L received 0.25% levobupivacaine in incremental x mL boluses until a T10 sensory level was reached; group epidural-R received 0.2% ropivacaine in incremental boluses until a T10 sensory level was reached. In both epidural groups, 2% lidocaine 3mL was used as test dose. Analgesia was continued with 0.125% levobupivacaine at an infusion rate of 4 to 12 mL/h as needed. Modified Bromage motor scores and the capacity of ambulation or sitting in a chair when the patient intended to do this were recorded each hour until delivery. Pain VAS 1/10, arterial pressure, HR, SaO2, and cardiotocography were recorded. Duration of labor and type of delivery were registered. After delivery newborn Apgar score was measured at 1 and 5 min. Afterwards the patients were requested about analgesic quality perceived with score graduation 1/5. Results: 150 patients were included, with 50 patients in each group. Analgesia started earlier in the CSEA group (8 min) compared with epidural groups (10 min) p<0.05. Patients in the CSEA group reported better perceived analgesia quality than those in the epidural groups. There were no other differences among groups.
Conclusions: CSEA for labor provided good and rapid analgesia, with no adverse effects in other labor outcomes as type of delivery and newborn Apgar scores, compared with standard epidural analgesia.
A133 Title: ASRA Checklist Improves The Management of Simulated Local Anesthetic Systemic Toxicity Presenting Author: Alison D Dragnich MD Presenting Author's Institution: Virginia Mason Medical Center - Seattle, WA Co-Authors: Joseph M Neal MD - Virginia Mason Medical Center - Seattle, WA Robert L Hsiung MD - Virginia Mason Medical Center - Seattle, WA Michael F Mulroy MD - Virginia Mason Medical Center - Seattle, WA Brian B Halpern RN - Virginia Mason Medical Center - Seattle, WA
Abstract: Introduction: Following the aviation industry‘s lead, anesthesiology educators have embraced the concept that management of rare events such as severe local anesthetic systemic toxicity (LAST) can be learned through simulation and optimized through the use of checklists. The American Society of Regional Anesthesia and Pain Medicine (ASRA) created a treatment checklist as part of its 2010 Practice Advisory on LAST.(1) We hypothesized that trainees given the ASRA checklist would provide superior medical management during a simulated episode of LAST as compared with those without this tool. Our secondary aim was to validate the effectiveness and usability of the ASRA checklist.
Methods: With IRB approval, anesthesiology residents and fellows participated in a simulated episode of severe LAST. The simulation script was standardized and run using SimMan (Laerdal). Subjects were block randomized by training level. For our primary outcome, three observers graded the subjects‘ performance based on their completion of 28 predefined tasks, such as appropriate treatment of local anesthetic-induced arrhythmias or correct dosages for lipid emulsion therapy. The subjects‘ non-technical performance was evaluated by two observers using a validated 16-point ANTS (anaesthetists‘ non-technical skills) tool.(2) Observers noted whether those receiving a checklist subsequently used it fully or partially. Subjects were asked to rate their impressions regarding the general use of checklists, and to comment upon the specific qualities of the ASRA checklist. Knowledge retention was assessed 2-months later by a 12-question multiple choice test. Statistical significance for the primary outcome (P < 0.05) was defined as one standard deviation difference between group mean scores. Eleven subjects per group were necessary to assess the primary outcome. Statistics are presented as mean (SD).
Results: The Checklist Group (n = 12) and the No Checklist Group (n = 13) included 23 residents and 2 fellows. Subjects given the checklist rendered medical management that was superior to that rendered by those not given the checklist: 21.4 (2.5) vs. 14.4 (3.0) correct items, respectively, P < 0.001. The total ANTS score did not differ between groups, although subjects randomized to receive the checklist surpassed subjects without a checklist with regard to Decision-Making: 5.4 (1.8) vs. 4.0 (1.4) summed observer points, respectively, P = 0.04. However, subjects who fully used the checklist (n = 7) had higher ANTS total score, and Situation Awareness and Decision-Making sub-scores vs. those who received but only partially used the checklist (n = 5) (P = 0.001). (Table 1) Post-test scores were higher in the Checklist Group vs. the No Checklist Group: 7.0 (1.5) vs. 5.7 (1.4) correct answers, respectively, P = 0.04.
Subject rating of the ASRA checklist is presented in Table 2. Subject performance during the simulation exercise suggested the need for two major refinements to the current ASRA checklist—1) enhanced emphasis that treating LAST-related cardiac arrest differs from standard ACLS, and 2) the need to consider cardiopulmonary bypass earlier in the resuscitation sequence.
Conclusions: Compared to subjects without access to the ASRA checklist, those receiving it demonstrated superior medical management, selectively improved non- technical performance, and better knowledge retention. The high number of non- users and the subjective comments suggest that some subjects were uncomfortable relying on checklists, even though using the checklist resulted in superior performance. This study validates the usefulness of the ASRA checklist and makes suggestions for its future refinement.
References 1. Neal et al. Reg Anesth Pain Med. 2010;35:152. 2. Fletcher et al. Br J Anaesth. 2003;90:580.
Additional File #1: 1030111182626Abstract_Table_1.doc Click here to view
Table 1. Comparison of ANTS Performance As A Function Of Checklist Use
Fully Partially Used
Used Checklist Checklist (n = 5) (n = 7) P Value
Task Management Mean (SD) 7.4 (0.8) 5.6 (2.5) 0.096
Median 8 6
Team Working Mean (SD) 7.7 (0.8) 7.2 (0.8) 0.292
Median 8 7
Situation Awareness Mean (SD) 7.6 (0.8) 5.2 (0.8) <0.001
Median 8 5
Decision-Making Mean (SD) 6.7 (0.8) 3.6 (1.1) <0.001
Median 7 4
Total (average total score) Mean (SD) 14.7 (0.8) 10.8 (2.1) 0.001
Median 15 11
ANTS = Anaesthetists‘ Non-Technical Skills
P values are from t-tests
2 raters scored each sub-component and the scores are summed; total score is the average of the raters‘ total scores
Components are scored as follows: 4 points for Good, 3 points for Acceptable, 2 points for Marginal, 1 point for Poor
Additional File #2: 2030111182626Abstract_Table_2.doc Click here to view
Table 2. Subject Reported Value of ASRA Checklist
No
Checklist Checklist
(n = 12) (n = 13) P Value
Checklists (in general) are useful tools in medicine
Agree 4 (33.3) 2 (15.4) 0.378
Strongly agree 8 (66.7) 11 (84.6)
In emergency situations, I should be able to respond appropriately from memory alone
Strongly 1 (8.3) 1 (7.7) 1.000 disagree Disagree 3 (25.0) 4 (30.8)
Neutral 3 (25.0) 2 (15.4)
Agree 5 (41.7) 5 (38.5)
Strongly agree 0 (0.0) 1 (7.7)
I feel ill at ease relying on a checklist Strongly 2 (16.7) 3 (23.1) 1.000 disagree Disagree 7 (58.3) 7 (53.8)
Neutral 3 (25.0) 2 (15.4)
Agree 0 (0.0) 1 (7.7)
I am confident that the ASRA checklist includes all essential information to treat LAST Neutral 2 (16.7) 0 (0.0) 0.467
Agree 7 (58.3) 10 (76.9)
Strongly agree 3 (25.0) 3 (23.1)
The SINGLE word that would BEST describe your feelings regarding using the checklist to manage your patient (or would describe, had you received a checklist) Comfortable 0 (0.0) 3 (23.1) 0.040
Confident 0 (0.0) 2 (15.4)
Confused 0 (0.0) 1 (7.7)
Neutral 1 (8.3) 0 (0.0)
Supported 10 (83.3) 6 (46.2)
Weak 0 (0.0) 1 (7.7)
Once I received the ASRA checklist, I used it to managed this simulated patient Agree 5 (41.7) 0 (0.0)
Strongly agree 7 (58.3) 0 (0.0)
I found the ASRA checklist useful in this situation Agree 3 (25.0) 0 (0.0)
Strongly agree 9 (75.0) 0 (0.0)
If I had received the ASRA checklist, I would have used it to manage this simulated patient Agree 0 (0.0) 2 (15.4)
Strongly agree 0 (0.0) 11 (84.6)
I wish I had received the ASRA checklist Agree 0 (0.0) 1 (7.7)
Strongly agree 0 (0.0) 12 (92.3)
number (percentage)
P values are from t-tests
A134 Title: Magnetic resonance imaging of continuous epidural infusions and bolus doses with epidural catheters Presenting Author: Christopher J Voscopoulos MD Presenting Author's Institution: Emory University School of Medicine - Atlanta, GA Co-Authors: Amit M Saindane MD - Emory University Hospital - Atlanta, GA Puneet Sharma PhD - Emory University Hospital - Atlanta, GA Michael Byas-Smith MD - Emory University Hospital - Atlanta, GA
Abstract: Introduction: Magnetic resonance imaging (MRI) is considered the gold standard for diagnosis of epidural pathology. We estimate that more than 8 million epidural catheters are placed annually in the United States. Unexplained neurological deficits require urgent neuroradiological evaluation along with attentive bedside clinical evaluation. However, despite advances in diagnostic techniques and in medical treatment, almost half of survivors are left with neurologic deficits. In the early hours following compression of the spinal cord, clinical signs may be vague. This poses an immense difficulty for clinicians, as early recognition is the most important clinical factor in preventing permanent neurological deficits. Though it has been reported that continuous thoracic analgesic infusions can give the false appearance of pathological changes, the larger problem is a lack of baseline normal anatomic variants in which to compare pathology against. The purpose of this study was to develop an MR imaging sequence to accurately assess the spinal MR findings associated with uneventful continuous and bolus dosed epidural infusions so that radiologists, anesthesiologists, pain medicine specialists, and surgeons can make better clinical decisions when faced with possible epidural catheter placement pathology.
Methods: A total of 10 patients with uncomplicated T6-T9 thoracic epidurals were enrolled in our study. Five patients were 40 years of age or younger, and 5 patients were 60 years of age or older. Upon a patient‘s normal date for epidural catheter removal, patients were bolused with 10 cc of sterile normal saline into their epidural catheters at a constant rate of 1 cc/15 seconds while real time MR imaging was undertaken. The MR imaging was performed on a Siemens Trio 3-Tesla MR unit. The imaging protocol consisted of a standard clinical sagittal T1-weighted (TR/TE = 16/8.3 ms), T2-weighted (TR/TE = 4500/118 ms), and T2-weighted fat-saturated (TR/TE = 3000/87 ms) sequences through the thoracic spine. High temporal and spatial resolution dynamic sagittal T2-weighed imaging of the thoracic spine was obtained using a cardiac-gated TrueFISP (True fast imaging with steady state precession; minimum TR/TE 2.82/1.19; in plane resolution of 1.4 mm and temporal resolution of 430 ms) sequence during the injection of 10 cc of saline solution into the epidural space using the existing epidural catheter. The rate and distance of anesthetic dispersal from the injection site was calculated based on temporal and spatial information from the TrueFISP sequence. The volume of fat within the epidural space was calculated by manual segmentation of the T1-hyperintense portion of the epidural space which demonstrated loss of signal on fat-saturated images.
Results: We are currently under the process of final data acquisition and analysis. Our preliminary data is very promising.
Discussion: When faced with suspected epidural pathology and the use of MR imaging will be implemented, we believe the description of our imaging method, and the description of normal anatomy with this method, provides for the ability of practitioners to make better clinical decisions regarding the need for urgent or emergent intervention in this patient population. A135 Title: Ultrasound Guided Continuous Saphenous Nerve Block Presenting Author: Gregory Franklin DO Presenting Author's Institution: Oregon Health and Science University - Portland, OR Co-Authors: Jay Tokeshi MD - Oregon Health and Science University - Portland, OR Matthew Abrahams MD - Oregon Health and Science University - Portland, OR Jean-Louis Horn MD - Oregon Health and Science University - Portland, OR
Abstract: Introduction: The saphenous nerve, a terminal branch of the femoral nerve, supplies sensory branches to cover the medial aspects of the leg. It is often combined with a sciatic nerve block to provide complete anesthesia or analgesia of the leg, ankle, or foot. Traditionally, a continuous infusion to cover the saphenous nerve is performed with a femoral nerve catheter and results in unnecessary quadriceps femoris muscle weakness.1 We describe a technique to place a catheter in the subsartorial space distal to the emergence of the motor branches of the femoral nerve based on an ultrasound guided single shot technique described by Horn et al.2 We also reviewed the course of twelve patients who underwent painful ankle surgery with combined sciatic and saphenous catheters.
Methods: Our institutional review board approved the review of anesthetic records of patients who underwent combined saphenous and sciatic nerve catheter placement. We placed all blocks under sterile conditions, with standard monitors, supplemental oxygen, and light conscious sedation using a stimulating nerve block catheter kit (Stimucath, Teleflex, Asheboro, NC). After the placement of a sciatic nerve catheter under ultrasound (US) guidance, we scanned the medial thigh with a high - frequency linear array US transducer (HD11XE with L4-12, Philips NV, Bothell, WA) to identify the vastus medialis muscle 2-5 cm proximal to the patella. We then moved the transducer posteriorly to identify the sartorius muscle and saphenous nerve. We anesthetized the skin with 1% lidocaine and advanced a 17- gauge Touhy needle using an in-plane technique, placing the tip of the needle deep to the sartorius muscle. We then opened the subsartorial space with 5 mL of normal saline and threaded a 19-gauge catheter 5 cm past the needle‘s tip (Fig. 1). We then injected five to 10 mL of ropivacaine 0.5% under US visualization and secured the catheter. We infused 0.2% ropivacaine (3 mL/hr) through the saphenous catheter to provide continuous analgesia. We reviewed patient charts for initial success rate as assessed by loss of sensation to cold in the saphenous nerve distribution, PACU pain score, side effects and success of the continuous infusion.
Results: We identified twelve patients in whom saphenous nerve catheters were placed between 3/2009 and 10/2010. Ten were placed pre-operatively, and two were placed post-operatively as ―rescue‖ blocks. All blocks were successful. The two patients with rescue blocks experienced the most significant reduction in pain score upon catheter dosing. All patients received a working popliteal catheter (all placed preoperatively). On post operative day 1, 3 patients experienced insufficient analgesia and were started on intravenous PCA infusions. No patients demonstrated quadriceps femoris weakness.
Conclusions: US-guided saphenous nerve catheter placement at the distal thigh is feasible. This approach can provide prolonged analgesia for procedures involving the medial ankle, while maintaining quadriceps femoris strength. Further study is needed to compare such selective distal approaches to traditional proximal techniques.
References 1. Benzon HT, Sharma S, Calimaran A. Anesthesiology. 2005;102(3):633-638. 2. Horn JL, Pitsch T, Salinas F, Benninger B. Reg Anesth Pain Med. 2009;34: 486- 489.
Additional File #1: 1030111143315Final_Saphenous_Ima.pdf Click here to view
Additional File #2: 2030111143315Final_Saphenous_Ima.pdf Click here to view
A136 Title: Cadaveric evaluation of ultrasound guided transversus abdominis plane block Presenting Author: Jonathan Brookes FRCA Presenting Author's Institution: University of Western Ontario - London, Ontario Co-Authors: Laura Morris BSc. - University of Western Ontario - London, Ontario Sugantha Ganapathy FRCPC - University of Western Ontario - London, Ontario Marjorie Johnson PhD - University of Western Ontario - London, Ontario Danielle Stothart MD - University of Western Ontario - London, Ontario
Abstract: Introduction: The transversus abdominis plane block (TAPB) has been shown to provide good analgesia for lower abdominal surgery, and the recent innovation of the ultrasound guided TAPB has lead to improved efficacy. Innervation of the lower abdominal wall is from spinal nerves T10 to L1, and above the umbilicus from T7 to T9, with a small contribution from T6. Previous anatomic studies in cadavers have shown that single injections of dye in the midaxillary line do not result in evidence of spread to T9 nerves or higher following TAPB (1). This would explain why anesthesia of the upper abdominal wall has not been reliably achieved by a single injection in the mid axillary line. Further studies have shown (2) that when using a multiple injection technique it is possible to deliver injected dye as high as the T7 nerves, albeit in only 43% of cases and at the expense of sparing of L1 nerves. The current study was designed 1) To assess spread of injectate following a 2 injection technique in the TAP to cover spinal nerves T7-L1 using a total of 30mL of injectate. 2) To investigate the existence of previously postulated anatomical barriers to spread of dye in the subcostal region.
Methods: Exploratory dissection of three embalmed cadavers was performed to find the superior interdigitations of the transversus abdominis muscle with the diaphragm (fig1). Experimentation with different dyes was carried out to determine a dye that was both easy to inject and remained in the correct anatomical space following injection. Different needles and injection sites were assessed to discover the optimal combination to attain the desired spread using seven cadavers. All TAPBs were carried out with ultrasound guidance. Once the optimal combination had been determined, TAPBs were carried out using the dye on a further 6 cadavers to assess the extent of spread of dye and its retention within the TAP.
Results: There was no barrier to spread of injectate within the TAP in the vicinity of the costal margin. Trials with varying needles showed a 12.5cm Tuohy to be optimal. A two injection technique was found to be ideal. A needle was inserted close to the anterior axillary line to advance cephalad in the TAP, parallel to the costal margin while hydro dissecting with 20 mL of dye. A second needle was advanced caudad in the TAP while hydrodissecting with 10mL of dye below the umbilicus. With this technique spread to L1 was noted in 100% of cadavers. Spread to T7/8 was noted in 78% of cadavers, and only to T9 in the remaining 22%.
Discussion: A modified TAPB technique using two injections, one directed cephalad and the second directed caudad can deliver injectate from T7/8 to L1 predictably in cadavers. This need to be validated clinically. Embalmed cadavers pose specific problems of differing degrees of rigidity and hydration.
References Tran T. et al Br. J. Anaesth. 2008;102:123-127 Barrington M et al. Anaesthesia. 2009,64:745-750.
Additional File #1: 1021511142146fig_for_TAP_abst_AS.doc Click here to view
Cephala d
7th rib
Diaphrag m Transversu s Inter- abdominis digitation muscle of transvers T7 nerve us abdomini s and diaphrag Cauda m l
Figure1: Dissection at the costal margin revealing Transversus abdominis interdigitating with diaphragm.
Additional File #2: 2021511142146ASRA_tap_anatomy_Ta.doc Click here to view
Table 1: Nerves covered with the current technique
Subject Nerves reached Additional information
#8, 68 yr old male T7-L1
#9, 73 yr old male T8-L1
#10, 79 yr old female R T8-L1 side
#10, 79 yr old female L T8-L1 side
#11, 69 yr old female R T9-L1 side
#11, 69 yr old female L T9-L1 side
#12, 91 yr old male T8-L1 2 extra mL was injected
#13, 67 yr old female R T7-L1 side
#13, 67 yr old female L T8-L1 side
A137 Title: Injection of fluid through into the epidural space prior to epidural catheter insertion: a meta-analysis Presenting Author: Kyaw Mon MD Presenting Author's Institution: Johns Hopkins University - Baltimore, MD Co-Authors: J. Gabe Tsang MD - Johns Hopkins University - Baltimore, MD Jamie Murphy MD - Johns Hopkins University - Baltimore, MD Jean-Pierre Ouanes MD - Johns Hopkins University - Baltimore, MD Shawn Sumida MD - Johns Hopkins University - Baltimore, MD
Abstract: Background: Fluid such as saline or local anesthetic are commonly injected into the epidural space following identification of the epidural space (typically with the loss- of-resistance technique) as some clinicians believe that expansion of the epidural space may result in fewer complications (e.g., accidental vascular catheter insertion, paresthesias) or greater ease in epidural catheter insertion. However, the overall efficacy of fluid injection into the epidural space following identification of the epidural space is unclear. We have performed a meta-analysis to further examine this issue.
Methods: This study qualified for exemption from the Johns Hopkins IRB. Systematic literature searches of the National Library of Medicine‘s PubMed and EMBASE databases were conducted using terms related to local anesthetic, saline, and epidural. Only randomized controlled trials comparing injection of fluid (i.e., saline or local anesthetic) to no injection into the epidural space after identification of the epidural space were included for analysis. Data on pertinent study characteristics and relevant outcomes were extracted from accepted articles. There was no restriction on language for inclusion. Meta-analysis was performed using the Review Manager 4.2.10 (The Cochrane Collaboration, 2004). A random effects model was used.
Results: The literature search yielded 5 articles which met all inclusion criteria. There were a total of 528 subjects for the fluid group and 420 for the no fluid group. We found fluid injection into the epidural space (vs. no fluid injection) following identification of the epidural space was associated with a reduced risk of venous cannulation [Relative risk (RR) = 0.54, 95% confidence interval (CI): 0.35, 0.84; p = 0.0006] but there was no difference between the groups with regard to transient paresthesias [RR = 0.84, 95%CI: 0.40, 1.74; p = 0.63] or ease of epidural catheter placement [RR = 0.97, 95%CI: 0.90, 1.05; p = 0.50].
Conclusions: Our pooled analysis examining the analgesic efficacy of fluid injection into the epidural space (vs. no fluid injection) following identification of the epidural space revealed that injection of fluid into the epidural space following identification of the epidural space may result in a lower risk of venous cannulation but without a decrease in transient paresthesias. Injection of fluid prior to insertion of the epidural catheter does not appear to improve the ease of epidural catheter placement. The results should be interpreted with caution and certainly further examination with larger RCT is warranted as the overall number of subjects is relatively small.
A138 Title: Achilles Heel of Ambulatory Sports Practice - Achilles Tendon Repair Under Peripheral Nerve Block Presenting Author: Lauren J. Fisher DO Presenting Author's Institution: Beth Israel Deaconess Medical Center - Boston, MA Co-Authors: Milica Markovic MD - Beth Israel Deaconess Medical Center - Boston, MA Lars Richardson MD - Beth Israel Deaconess Medical Center - Brookline, MA Jonathan Fisher MD - Beth Israel Deaconess Medical Center - Boston, MA
Abstract: Background: There is little consensus among anesthesiologists regarding the optimal anesthetic for Achilles tendon repair. Many practitioners perform peripheral nerve block for postoperative pain relief, and general anesthesia (GA) for the surgery itself given the typical prone position of the patient and inaccessibility to the airway intraoperatively. At our institution, we have been performing many of these procedures under peripheral popliteal nerve block with monitored anesthesia care (MAC) with great success. The use of a regional block technique eliminates the need for airway instrumentation, allows the patient to position him/herself comfortably on the OR table, allows for less overall medication, and promotes faster OR times since the patient does not have to be induced or awakened from GA. The objective of our study is to demonstrate the feasibility and safety of this technique, as well as to investigate the impact on the OR utilization times.
Methods: Retrospective medical record review of all patients undergoing Achilles tendon repair surgeries at a Level 1 Trauma Center from 1/1/2005 to 12/31/2010. Anesthesia records were abstracted using a structured tool to record demographics, type of anesthesia, key time intervals, and complications. Microsoft Excel and SPSS 17.0 were used to analyze the data using descriptive statistics. Student‘s t-test and Fisher exact test were used to compare groups.
Results: 228 patients underwent Achilles repair; 224 patients were included in analysis; 4 patients were discarded given incomplete data. Sixty-seven patients received peripheral nerve block + MAC for their repair; 84 received GA alone; 69 received combined GA + peripheral nerve block, and 4 repairs were performed under neuraxial anesthesia. No patients receiving peripheral nerve block + MAC required conversion to GA.
Patients were placed into one of two groups for analysis: either peripheral nerve block technique (popliteal nerve block + MAC) or non-peripheral technique (including GA, GA + peripheral nerve block, and neuraxial technique.) Overall mean age was 41.8 (SD 11.5), and 79.5% were male. There was no difference in age, sex, or ASA classification between the two groups (p=0.16,0.37,0.36).
Key time intervals were analyzed between the groups. Significant differences were seen between the groups in the time interval between entering the OR and incision (p 0.03), total surgery time (p<0.001), end of surgery to leaving OR time (p<0.001), total OR time (p<0.001), and the total anesthesia case time (A to D time) (p<0.001).
Conclusions: Achilles tendon repair under peripheral technique is feasible. None of the 67 patients under peripheral technique required conversion to GA. Additionally, the peripheral technique resulted in significantly shorter time between entering the OR and surgery start, surgery duration, end of surgery to leaving OR, and overall OR and Anesthesia time. The performance of Achilles tendon repair under peripheral nerve block + MAC anesthesia may have implications on OR utilization, providing shorter intraoperative times and the ability to schedule more cases in a given day. Further prospective studies may prove peripheral nerve block + MAC to be the optimal anesthetic technique for Achilles Tendon repair.
Additional File #1: 1022811205128Achilles_demographi.doc Click here to view
Peripheral Technique Non Peripheral P value Technique N 67 157 Age 40.2 (SD+11.6) 42.5 (SD+11.4) 0.16 % Male 83.6% 77.7% 0.37 ASA 0.36 I 64.2% 54.1% II 32.8% 40.8% III 3% 5.1%
Additional File #2: 2022811205128Achilles_times_tabl.doc Click here to view
Time Interval Peripheral Technique Non Peripheral P value (Hour:min) Technique Entering OR to Surgery 0:25 0:21 0.03* Start (SD 0:18) (SD 0:10) Surgery End to Leaving 0:04 0:10 <0.001* OR (SD 0:04) (SD 0:07) Surgery Duration 0:39 1:11 <0.001* (SD 0:15) (SD 0:46) Total OR Time 0:59 1:51 <0.001* (SD 0:22) (SD 1:05) Total Anesthesia Time 1:30 2:23 <0.001* (SD 0:29) (SD 1:02)
A139 Title: Proximal Approach to a Suprascapular Nerve Block Presenting Author: MariJo Wienkers MD Presenting Author's Institution: Virginia Mason Medical Center - Seattle, WA Co-Authors: David Auyong MD - Virginia Mason Medical Center - Seattle, WA
Abstract: Ultrasound identification of the proximal suprascapular nerve as it arises from the upper trunk has yet to be described. The origin of the suprascapular nerve from C5 or upper trunk of the brachial plexus is well known. The suprascapular nerve exits before the brachial plexus drops posterior to the clavicle. After leaving the plexus laterally and posterior, it is passes deep to the omohyoid/trapezius muscles, reaching the suprascapular notch1. Suprascapular nerve blocks have been described at the notch, a posterior landmark of the scapula, with both landmark and ultrasound techniques2,3. The suprascapular nerve supplies motor innervation to the infraspinatus/supraspinatus and sensory innervation to the shoulder joint, capsule, and variably, the overlying skin4.
A 28-year-old male presented with shoulder pain due to overuse. Management with oral analgesics was ineffective in providing relief. A 15mHz linear ultrasound probe was used to identify the brachial plexus at the interscalene level. The plexus was scanned caudad and the anechoic suprascapular nerve was identified arising from the superior portion of the upper trunk.[Fig 1] The nerve exited from the plexus laterally as the probe was slid just posterior to the clavicle. A 21G needle was inserted in-plane [Fig 2] from posterior to anterior and 3mL of 0.25% bupivacaine was injected, surrounding the nerve.[Fig 3] The patient had immediate analgesia of the shoulder, without concomitant brachial plexus block. The patient was still able to abduct his arm. He experienced some weakness with abduction, likely from blockage of the supraspinatus muscle. Block duration was 8 hours.
Identification of the suprascapular nerve can be achieved by visualizing the nerve as it exits the upper trunk by scanning caudally from the interscalene to the supraclavicular image. The proximal approach suprascapular nerve block at this level is used to provide for shoulder analgesia. This approach is useful because it is very similar the commonly used supraclavicular nerve block. It is significantly shallower than a posterior/suprascapular notch approach, making needle insertion under ultrasound easier. This proximal approach may be useful in patients requiring ipsilateral arm function, sparing of the phrenic nerve, or diagnosis of chronic shoulder pain syndromes. Also, the location of the suprascapular nerve as it exits puts it as risk for injury with in-plane lateral-to-medial approaches to the supracalvicular block. Therefore, it may be prudent to identify and avoid this nerve during routine supraclavicular nerve blocks.
References 1. Martinoli C, et al. Brachial plexus and nerves about the shoulder. Semin Mus Rad. 2010;14:523-546. 2. Moore DC. Block of the suprascapular nerve. Regional Block. 4th ed. Springfield, IL: CC Thomas Co; 1979:300-303. 3. Harmon D, Hearty C. Ultrasound-guided suprascapular nerve block technique. Pain Phys. 2007;10:743-746. 4. Ritchie ED et al. Suprascapular Nerve Block for Postoperative Pain Relief, Anesth Analg. 1997; 84:1306-1312.
Fig 1: Supraclavicular view with labels. The suprascapular nerve exits the upper trunk at this level and appears hypoechoic.
Fig 2: Probe and needle position for a proximal approach to a suprascapular nerve block.
Fig 3: Needle and local anesthetic surrounding the suprascapular nerve.
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A140 Title: Ultrasound-Guided Transversals Fascia Plane Block in Iliac Crest Bone Graft Surgery Presenting Author: Meera Harris MB BCHir, MPharm Presenting Author's Institution: University of Cambridge - Toronto, Ontario Co-Authors: Ki Jinn Chin MBBS, MMed, FANZCA, FRCPC - Toronto Western Hospital - Toronto, Ontario Danielle Factor MBBS - Guy's and St Thomas's NHS Foundation Trust - London, - Vincent Chan MD, FRCPC - Toronto Western Hospital - Toronto, Ontario Brent Graham MD, MSc, FRCSC - Toronto Western Hospital - Toronto, Ontario
Abstract: Introduction: Iliac crest bone graft (ICBG) harvesting is associated with a significant amount of acute pain in the first 24 hours after surgery. While the transversus abdominis plane (TAP) block has been described as a method of providing analgesia for ICBG harvesting, it may not be the most suitable technique as it only blocks the L1 dermatome 50% of the time. The transversalis fascia plane (TFP) block is a novel ultrasound (US)-guided technique that reliably blocks the L1 dermatome. We report our preliminary experience with the TFP block for analgesia for ICBG harvesting.
Methods: Following institutional ethics board approval, we retrospectively reviewed patients who had undergone anterior ICBG harvesting in conjunction with distal forearm surgery between 1 November 2009 and 30 April 2010. All patients received a single-shot brachial plexus block for anesthesia of the primary surgical site, and either general anesthesia (GA) or spinal anesthesia (SA) for the ICBG harvest site. Patients who had spinal anesthesia were routinely sedated intraoperatively with IV midazolam, fentanyl, and propofol . Patients then received an US-guided TFP block depending on whether an anesthesiologist with necessary expertise was available. Needle tip position for TFP block was confirmed by injecting 1-3 mL of 5% dextrose solution, and followed with an injection of 20 mL of 0.5% ropivacaine with 5mcg/ml of epinephrine.
The following outcomes were analyzed: 1) total intraoperative dose of opioid (expressed as IV morphine equivalents), 2) total dose of opioid administered in the postoperative care unit (PACU), 3) admission pain score in PACU, 4) discharge pain score in PACU.
Results: We identified 27 patients in total, 11 of who received a single-shot US- guided TFP block prior to surgery. Anesthesia for ICBG harvesting was provided by GA in 16 patients and by SA in 11 patients. Patients who received a TFP block had a trend to lower intraoperative opioid requirements (8.9±6.6 vs. 10.5±8.7 mg IV morphine) and lower admission pain scores in PACU (1.3±1.8 vs. 2.3±2.7), as well as significantly lower PACU opioid requirements (2.0±3.7 vs. 8.3±8.2 mg IV morphine, P=0.026). In the subset of patients who had a GA, significantly lower PACU opioid requirements (3.2±4.3 vs. 9.2±7.5 mg IV morphine, P=0.08) and discharge pain scores (1.1±2.0 vs. 4.0±2.6, P=0.03) were observed in those who received a TFP block compared to those who did not.
Discussion: This small retrospective review supports the analgesic efficacy of the TFP block in ICBG harvesting. We are presently conducting a randomized controlled trial to verify these findings and to further define the clinical characteristics of the block.
References 1. Foot Ankle Int. 2005;26:147-151. 2. Reg Anesth Pain Med. 2010; 35(6): 520-524. 3. Anaesth Int Care. 2010; 38: 1-9. 4. Can J Anesth. 2009; 56: 618-662.
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Additional File #2: 2020811193256TFP_block_table_1.pdf Click here to view
A141 Title: Pre Procedure Ultrasound In Obstetric Neuraxial Analgesia: When is it Worth the Effort Presenting Author: Steven T Fogel MD Presenting Author's Institution: University of Missouri - Columbia, MO Co-Authors: Jonathan L Hill DO - University of Missouri - Columbia, MO Wade Davis PhD - University of Missouri - Columbia, MO Ge Bin MD, MS - University of Missouri - Columbia, MO Nichols A Michael CRNA - University of Missouri - Columbia, MO
Abstract: Introduction: Recently, there has been increased interest in the use of ultrasonography (US) for neuraxial analgesia and anesthesia. Grau et al, as well as other authors, have shown that pre-procedural US can reduce the number (#) of attempts at placing epidural catheters (EPID) in difficult patients (pts) as well as improving the learning curve of EPID in the obstetric (OB) pt population.1-3 We sought to determine the benefit, if any, of pre procedure US in our OB pt population and wish to report our preliminary results. Specifically, we hypothesized that among pts with poor landmarks (barely palpable or non-palpable), US would reduce the # of needle sitings (separate needle punctures required for successful EPID) and/or attempts (# needle passes required at each siting for EPID) compared to pts who did not have US. Among pts with good landmarks (prominent or palpable), there would be no differences between groups.
Methods: This is an ongoing, non-blinded, prospective randomized trial. All enrolled pts were randomly assigned to either the Ultrasound Group (USgrp) or No Ultrasound Group (NOgrp) by drawing a card in a sealed opaque envelope. Pts in the USgrp had pre-procedure US exam of the lumbar spine performed by a single investigator (STF). EPIDs were performed by all members of the OB Anesthesia Team, including attending physicians, anesthesiology residents under direct supervision of an attending physician and CRNAs. The following data were collected: Quality of pt's spinal landmarks (prominent, palpable, barely palpable, non-palpable), # of needle sitings, # of attempts, time for performance of US in the USgrp (TUS), time for performance of EPID (TEPID), total time TT (TT=TUS+TEPID in USgrp or TT=TEPID in NOgrp), failure rates and pt satisfaction with EPID (1 to 5 Likert scale). Wilcoxon two-sample test was used for comparing two groups. P<0.05 was considered significant.
Results: Figures 1 & 2. Forty-two pts have been enrolled thus far. Among pts with poor landmarks there was a significant difference between groups in the # of needle sitings: median (range) 1(1.0 – 3.0) vs. 3(1.0 - 4.0) USgrp vs. NOgrp p=0.0017. There were also significant differences in # attempts (USgrp < NOgrp) p=0.0011. There was no significant difference in TEPID (sec) median (range) 70 (34 – 212) vs. 462 (26 – 902) USgrp vs. NOgrp p=0.068. There were no significant differences in # sitings or attempts between groups among pts with good landmarks. No significant differences between groups were found for TT or pt satisfaction among pts with poor landmarks. Among pts with good landmarks TT was greater in the USgrp than NOgrp p=0.0193. There was one failure in the NOgrp.
Discussion: Our results thus far suggest that US reduces the # of required needle sitings and attempts for EPID in pts with poor landmarks. It does not seem to be of significant benefit in pts with good landmarks. Continued study is required.
References 1. Acta Anaesthesiologica Scandinavica. 2001;45:766-771. 2. Can J Anaesth. 2003;50:1047-1050. 3. Int J Obstet Anesth. 2010;19(4):373-378.
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A142 Title: Prospective, Blinded, Randomized Evaluation of Dexamethasone Efficacy as Adjunct to Bupivacaine in Transversus Abdominus Plane (TAP) Block Presenting Author: Chien-Hsiang Chow MD Presenting Author's Institution: St. Elizabeth's Medical Center - Waltham, MA Co-Authors: Arvind S Murthy MD - St. Elizabeth's Medical Center - Boston, MA Ali K Daha MD - St. Elizabeth's Medical Center - Boston, MA Ingolf A Tuerk MD, PhD - St. Elizabeth's Medical Center - Boston, MA Andrew L Sternlicht MD - St. Elizabeth's Medical Center - Boston, MA
Abstract: Introduction: The Transversus Abdominis Plane (TAP) block has gained popularity for provision of post-operative analgesia in lower abdominal procedures, providing effective pain control for up to 18 hours. O‘Donnell et al. demonstrated the efficacy of the TAP block for post-operative analgesia following prostatectomies (1). Other studies report that the addition of dexamethasone (dex) to local anesthetics improves analgesia from brachial plexus peripheral nerve blocks (2, 3). However, there are no published reports studying adjuncts for TAP blocks to prolong the duration of analgesia. The purpose of this study is to investigate the efficacy and safety of dex added to local anesthetic in prolonging analgesia following TAP blocks in patients undergoing robot-assisted laparoscopic prostatectomy.
Materials and Methods: After obtaining IRB approval, 50 male patients undergoing robotic-assisted laparoscopic prostatectomy by a single surgeon at our institution are to be enrolled for this study. The sample size was chosen based on an anticipated difference of a minimum 25% change in the mean duration of analgesia, based on data from other peripheral nerve block studies with dex. At 80% power, 21 patients per treatment arm need to be analyzed. We assume a 15% dropout rate in the analysis population. After informed consent was obtained, patients were randomized into two treatment arms, 0.125% bupivacaine 80 cc plus 4mg dex (40 cc and 2mg dex on each side of the abdomen), or 0.125% bupivacaine 80 cc plus 1 cc of sterile saline. Visual analog scales (VAS) and dermatomal level of sensory block were used for data collection in standardized time intervals. Time to first additional analgesic administration, and total intraoperative and post-operative narcotic use were recorded. Pending data analysis of treatment effect from this study, we plan to continue the study and enroll patients undergoing other abdominal surgeries. In this second portion of the study, patients undergoing bilateral TAP blocks for post-operative analgesia will receive blinded dex on only one side of their abdomen allowing patients to serve as their own control.
Results: As of date of submission 21 patients have been enrolled into Phase 1 of the study. Time to first request for analgesia following TAP blockade has ranged from 121 minutes to 1118 minutes (n=17, mean 493 min, median 431 min). No adverse events have been reported in the study to date.
Discussion: Our analysis remains blinded at present, however we expect that complete data from Phase 1 of the study will be available for presentation at the meeting. The mean duration of blockade cannot be compared with previous studies since the volume and concentration of local anesthetics administered are different. It is hoped that the development of the model of study in Phase 2 will allow powered analyses of efficacy of adjunctive pharmacotherapy with small numbers of patients. Using the model developed in Phase 2 of the study, we hope that future research may investigate the efficacy of other anesthetic adjuncts to the TAP block.
References 1. O‘Donnell, BD, et al. Reg Anesth Pain Med. 2006; 31-91. 2. Viera, PA, et al. Eur J Anesth. 2010 Mar;27(3):285-288. 3. Parrington, SJ, et al. Reg Anesth Pain Med. 2010; 35(5):422-426.
A143 Title: Machine Learning Predicts Need for Postoperative Femoral Nerve Block Presenting Author: David A Edwards MD, PhD Presenting Author's Institution: University of Florida College of Medicine - Gainesville, FL Co-Authors: Patrick J Tighe MD - University of Florida College of Medicine - Gainesville, FL Sarah Laduzenski MD - University of Florida College of Medicine - Gainesville, FL Neil J Ellis MD - University of Florida College of Medicine - Gainesville, FL Andre P Boezaart MD, PhD - University of Florida College of Medicine - Gainesville, FL
Abstract: Background: Machine Learning Classifiers (MLCs) are mathematical algorithms which classify large amounts of data into useful information. Currently MLCs are used in the complex and computationally intensive analysis of handwriting recognition, automated voice recognition, fraud detection, email spam filtering, targeted marketing by large web-based marketplaces, and most recently, crime fighting. This technology has thus far not been widely adopted in Medicine. However, with the advent of electronic medical records and electronic databases, combined with the rapid expansion of medical knowledge, MLCs may offer vital assistance as decision support tools. Here, we tested several MLCs to determine whether they could correctly classify patients at risk for severe pain following ACL reconstruction.
Methods: In this study of a retrospective sample of 349 patients, we tested the feasibility of using MLCs to predict who would require a femoral nerve block (FNB) for pain control following anterior cruciate ligament repair. To simulate a pre- operative decision support paradigm, we used only information routinely available prior to the start of surgery (sex, smoking history, opioid use, for example). We hypothesized that commonly used MLCs, namely, support vector machines, naive Bayesian analysis, multilayer perceptron, and decision trees, would perform comparably to a traditional logistic regression-based analysis with a limited dataset. MLCs were compared with several measures of classifier performance including area under the receiver operating curve, kappa statistic, and percent correct prediction in both training and 10-fold cross validation.
Results: MLCs correctly classified between 77.4% and 96.3% of instances during training, and between 65.9% and 77.7% of instances with 10-fold cross validation. The highest ROC was found for SVM in training at 0.996, but with ADTree at 0.7 following cross-validation. For both training and testing stages, SVM produced the greatest kappa statistic at 0.902 and 0.242. While SVM produced the highest F- measure in training stage at 0.962, simple logistic regression and BayesNet tied for highest F-measure with cross-validation at 0.72 (see table).
Conclusion: Our results suggest that, even when matching untuned classification models with suboptimal data sets, MLCs offer results that are at least comparable to traditional statistical models. Future studies should include formalized datasets that also include quantitative sensory and psychosocial evaluations. This should improve the predictive ability of MLCs to predict severe postoperative pain. MLCs can serve as cognitive aids in an era of rapid growth of medical information.
Additional File #1: 1022511154040ASRA___Edwards_Tabl.doc Click Stage BayesNet MLP SVM ADTree SLR here to view Training ROC Area 0.737 0.778 0.996 0.772 0.657 Kappa statistic 0.295 0.320 0.902 0.301 0.228 Percent Correctly Classified 77.4% 79.7% 96.3% 79.1% 77.7% F-Measure 0.744 0.754 0.962 0.747 0.72
10-Fold Cross- ROC Area 0.691 0.688 0.671 0.7 0.645 Validation Kappa statistic 0.2169 0.1703 0.242 0.179 0.228 Percent Correctly Classified 75.1% 74.5% 65.9% 74.2% 77.7% F-Measure 0.716 0.7 0.677 0.702 0.72 A144 Title: Long Term Lead Migration Rates in Occipital Nerve Stimulator Patients Presenting Author: Eric G Cornidez MD Presenting Author's Institution: Mayo Clinic Arizona - Phoenix, AZ Co-Authors: Terrence Trentman MD - Mayo Clinic Arizona - Phoenix, AZ Michael Ivancic MD - Mayo Clinic Arizona - Phoenix, AZ Ann Chang Brewer BS - Mayo Clinic Arizona - Phoenix, AZ Richard Zimmerman MD - Mayo Clinic Arizona - Phoenix, AZ
Abstract: Introduction: Occipital nerve stimulation (ONS) may provide relief for refractory headache disorders. Lead migration is considered the most common and troublesome complication of ONS, but little is known about the rate of lead migration among long-term uses of the therapy. The purpose of this study is to document lead migration rates among patients treated long term with ONS.
Methods: After IRB approval, we retrospectively reviewed the medical records of all non-industry sponsored study patients who were implanted with occipital nerve stimulator systems at Mayo Clinic in Arizona. Those who gave verbal consent participated in a brief phone interview regarding their occipital nerve stimulation experience. Lead migration rates were documented based on the phone interview and review of the patients‘ medical records.
Results: Twenty-six patients underwent ONS implantation during the study period, which covered 8.5 years (2002 – 2010). Twelve of the patients could not be contacted for various reasons, and 14 participated in the phone interview. Of the 14 patients, 10 have used their stimulators long term (59 ± 27 months) and have undergone 8 revision surgeries in a combined duration of 589 months of ONS therapy. Of the 12 non-interviewed patients, our chart review revealed 15 lead revision surgeries in a combined duration of 648 months of ONS therapy. Eight of these patients required at least one revision (one patient required 5 revisions and another required 3 revisions) due to lead migration. When combining all of our 22 patients with long-term ONS therapy, 14 required at least one revision surgery in the duration of 1237 months of therapy.
Discussion: Lead migration is a significant complication of ONS. Our migration rate is somewhat higher but comparable to the reported rate of migration of spinal cord stimulators (11.7-23.0%)1-4. This may be secondary to the fact that occipital nerve stimulator leads are placed in the highly mobile neck region.
Conclusion: Further studies of ONS anchoring and other techniques to minimize the risk of lead migration are indicated. References 1. Sundaraj S.R., et al. Spinal Cord Stimulation: a seven-year audit. J Clin Neurosciences. 2005;(3)12:264-270. 2. Kumar K, et. al. Spinal Cord Stimulation in Treatment of Chronic Benign Pain: Challenges in Treatment Planning and Present Status, A 22-Year Experience. Neurosurgery. 2006;(3),58:481-494. 3. Cameron T. Safety and Efficacy of Spinal Cord Stimulation for the Treatment of Chronic Pain: a 20-year literature review. J Neurosurg (Spine 3). 2004; 100:254- 267. 4. Turner J, et. al. Spinal Cord Stimulation for Patients With Failed Back Surgery Syndrome or Complex Regional Pain Syndrome: A Systematic Review of Effectiveness and Complications. Pain. 2004;108:137-147.
Additional File #1: 1021611153258Contacted_ONS_Migra.xls Click here to view
Table 1. Contacted Occipital Nerve Stimulation Patients Patient Diagnosis Duration of Implant Lead Notes (Months) Revisions 50F Post-traumatic 48 0
42F Migraine 16 1 Awaiting revision for lead migration 46F Hemicrania 85 2 continua
31F Migraine 70 1 Worse scores due to seasonal migraines 27F NDPH 71 0
45F Cluster 42 1
48M Post-traumatic 24 0 Headaches resolved with move to higher elevation 37F Migraine 69 0
53M Cluster 102 1
42F Migraine 62 2 Doesn’t help pain, just other symptoms (nausea, photophobia)
Additional File #2: 2021611153258Non_Contacted_ONS_M.xls Click here to view
Table 2. Non-Contacted Occipital Nerve Stimulation Patients Patient Diagnosis Duration of Implant (Months) Lead Revisions Notes (from most recent clinical record)
60F Migraine, Occipital Neuralgia 94 2 Unable to contact - No longer efficacious after 2 yrs
47F Migraine 19 0 Unable to contact -efficacious until explanted for infection, lost to follow up
40M Unknown 48 1 Unable to contact - satisfied with lead revision, lost to follow up
51M Occipital Neuralgia 105 1 Unable to contact - new headache onset
41F Trigeminal Autonotic Cephalgia 73 5 Unable to contact - poor headache control. Needs revision
34F Migraine 32 0 Unable to contact - no longer efficacious
57F Cluster 72 0 Unable to contact – not efficacious
50F Migraine, Occipital Neuralgia 95 1 Unable to contact - not efficacious
59M Cluster 13 0 Unable to contact - efficacious at last note
57F Cluster 33 1 Unable to contact - efficacious until battery depleted. Insurance denied coverage.
28F Migraine 1 1 Explanted not efficacious - deceased
33F Migraine 63 3 Efficacious at last note - deceased
Total 648 15
Additional File #3: 3021611153258Combined_ONS_Migrat.xls Click here to view Table 3: All Occipital Nerve Stimulator Patients Patient Diagnosis Duration of Implant (Months) Lead Revisions Notes
50F Post-traumatic 48 0
42F Migraine 16 1 Awaiting revision for lead migration
46F Hemicrania continua 85 2
31F Migraine 70 1 Worse scores due to seasonal migraines
27F NDPH 71 0
45F Cluster 42 1
48M Post-traumatic 24 0 Headaches resolved with move to higher elevation
37F Migraine 69 0
53M Cluster 102 1
42F Migraine 62 2 Doesn’t help pain, just other symptoms (nausea, photophobia)
60F Migraine, Occipital Neuralgia 94 2 Unable to contact - No longer efficacious after 2 yrs
47F Migraine 19 0 Unable to contact -efficacious until explanted for infection, lost to follow up
40M Unknown 48 1 Unable to contact - satisfied with lead revision, lost to follow up
51M Occipital Neuralgia 105 1 Unable to contact - new headache onset
41F Trigeminal Autonotic Cephalgia 73 5 Unable to contact - poor headache control. Needs revision
34F Migraine 32 0 Unable to contact - no longer efficacious
57F Cluster 72 0 Unable to contact – not efficacious
50F Migraine, Occipital Neuralgia 95 1 Unable to contact - not efficacious
59M Cluster 13 0 Unable to contact - efficacious at last note
57F Cluster 33 1 Unable to contact - efficacious until battery depleted. Insurance denied coverage.
28F Migraine 1 1 Explanted not efficacious - deceased
33F Migraine 63 3 Efficacious at last note - deceased
Total 1237 23
A145 Title: Ultrasound-Guided Parasacral Approach to the Sciatic Nerve Block in Children Presenting Author: Jennifer Dillow MD Presenting Author's Institution: University of New Mexico School of Medicine - Albuquerque, NM Co-Authors: Randy Rosett MD - University of New Mexico School of Medicine - Albuquerque, NM Sally Vender MD - University of New Mexico School of Medicine - Albuquerque, NM Firoz Vagh MD - University of New Mexico School of Medicine - Albuquerque, NM James Hruschka MD - University of New Mexico School of Medicine - Albuquerque, NM
Abstract: Background and Objectives: The parasacral approach to sciatic nerve blockade has the potential for safe and effective use in children, but it has never been studied in the pediatric population. A potential advantage of the parasacral approach over other sciatic block techniques is increased reliability in blocking the posterior cutaneous nerve of the thigh. The ischium and inferior gluteal vessels are excellent landmarks for identification of the sciatic nerve in this location even in the obese patient. The aim of this study was to assess the efficacy of an ultrasound guided parasacral sciatic nerve block in children.
Methods: Nineteen patients between the ages of 1 and 16 years, who were having lower limb surgery and a peripheral nerve block for post-operative pain were prospectively enrolled. A parasacral sciatic block was performed using both ultrasound guidance and nerve stimulation. All patients received 0.5 ml/kg of Ropivacaine 0.2% up to a maximum of 20 ml. Patient demographics, block time, the lowest current of nerve stimulation and type of stimulation, identification of gluteal arteries, and amount of narcotic given during the case were recorded. Post- operatively, pain scores, the success or failure of the block, the estimated time the block lasted, and complications were recorded.
Results: The mean age of the patients was 10 ± 4 years. The time required to perform the block was 5 ± 3 minutes. The block was performed using the parasacral approach in 95% of the cases. In one patient, ultrasonographic landmarks could not be identified, and a sciatic nerve block was performed successfully in the popliteal fossa. The lowest current with positive stimulation was 0.3 ± 0.1 mA. The gluteal artery was identified between the ischium and sacrum in 16 of 19 cases. The success rate was 100%. The pain scores in the PACU for all patients in the first hour were zero, except one patient that had a pain score of 3/10 at 30 minutes. His pain improved to 0/10 after one dose of Fentanyl and distraction techniques were employed. The blocks were effective for 17.3 ± 5.4 hours based on either increasing pain scores or parental interview. There were no complications identified.
Conclusions: The parasacral approach is an effective alternative to other approaches of sciatic nerve blockade for providing post-operative pain relief in children having lower extremity surgery.
Additional File #1: 1022611170319Data_Table_1.doc Click here to view
Table 1: Patient and Block Demographics – Parasacral Approach to the Sciatic Nerve Block in Children
Patient Age Weight Surgery Block Gluteal Stimulation Fentanyl Estimated time- min Vessels in the OR Length of Identified (mcg/kg) Block- hrs 1 6 y 15.5 kg Foot tibialis 3 Yes Plantar flexion None 16.5 tendon transfer @0.4 2 8 y 25 kg Foot sural artery 2 Yes Plantar flexion 1 11 flap @0.2 3 7 y 22 kg Reconstruction 3 Yes Plantar flexion 1 12 cleft foot @0.28 4 16 y 50 kg Triple 4 Yes None 0.5 19 arthrodesis 5 9 y 44 kg Foot metatarsal 2 Yes Plantar flexion 1 22 osteotomy @0.2 6 16 y 85 kg Achilles tendon 4 Yes Dorsiflexion None Unknown repair @0.5 7 12 y 56 kg ORIF Ankle 5 Yes None 2 Unknown 8 12 y 23 kg Foot Polydactaly 4 Yes Dorsiflexion 1 22 Reconstruction @0.3 9 10 y 60 kg Ankle n/a * No n/a * 1 23 Osteotomy 10 10 y 34 kg Tibia malleolar 3 Yes Plantar flexion 2 20.5 osteotomy, @0.3 tendon transfer 11 12 y 72 kg ORIF Ankle 3 Yes Plantar flexion 0.75 21 @0.49 12 10 y 43 kg Resection tarsal 8 Yes Eversion @0.3 1 9 coalition 13 5 y 32 kg Foot osteotomy 2 Yes Plantar flexion 0.75 30 @0.3 14 11 y 41 kg Excision 8 Yes Plantar flexion None 14 accessory @0.4 navicular bone 15 8 y 33 kg Removal implant 8 No Dorsiflexion 0.75 20 tibia @0.3 16 5 y 24 kg ORIF Ankle 7 No Plantar flexion None 13 @0.3 17 16 y 83 kg Fusion great toe 11 Yes Plantar flexion 1 17 @0.3 18 16 9 kg Foot Polydactaly 4 Yes Dorsiflexion 1 12 mos Reconstruction @0.4 19 15 y 63 kg ORIF distal 3 Yes Plantar flexion 1.5 18 tib/fib @0.2 *Ultrasonographic landmarks could not be identified and a popliteal block of the sciatic nerve was performed.
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A146 Title: Randomized Study of Ultrasound Guidance vs. Nerve Stimulation for Popliteal Fossa Block of the Sciatic Nerve Presenting Author: Leslie Thomas MD Presenting Author's Institution: Ochsner Clinic Foundation - New Orleans, LA Co-Authors: Nicholas E Forth MD - Ochsner Clinic Foundation - New Orleans, LA Bobby Nossaman MD - Ochsner Clinic Foundation - New Orleans, LA
Abstract: Background: The use of the ultrasound in regional anesthesia has increased since the advent of high-frequency imaging technology. Reliable data comparing ultrasound and neurostimulation techniques for sciatic nerve block in the popliteal fossa in a residency training program is somewhat limited. The primary objective of this study was to compare time from the start of the procedure to the onset of adequate sensory and motor anesthesia between techniques in a teaching program. Secondary objectives that were investigated included the reliability of the block, the incidence of adverse events, and patient satisfaction scores.
Methods: After obtaining approval from the IRB and written informed consent, patients were enrolled in this prospective randomized study. Patients were ASA physical status I-III scheduled to undergo outpatient lower extremity (foot and ankle) surgery. Patients were randomized to receive a popliteal block using either nerve stimulation (NS) or ultrasound guidance (UG). The local anesthetics used in both groups consisted of 20 mL 1.5% Mepivacaine with 3mcg/mL epinephrine and 20 mL 0.75% Ropivacaine with 3mcg/mL epinephrine injected via a stimulating needle. The start time began after the patient was positioned, skin prepped, ultrasound/nerve stimulator equipment was prepared, and the Stimuplex needle was in the hand of the anesthesiologist. All time assessments were made by a research assistant blinded to the technique. Complications were recorded including vascular puncture, paresthesia, pain on injection, and failure to achieve adequate sensory/motor anesthesia.
Results: The use of US, when compared to NS, did not significantly change the procedural times (P = 0.9), onset of adequate sensory blockade (P = 0.43), or onset of adequate motor blockade (P = 0.15). The incidences of side effects were also not different between the two groups. PACU fitness discharge times were not statistically different between the two groups (P = 0.77). Finally, the incidence of postoperative neuritis was uniformly low (n < 5 in both groups; P = 0.87) and that patient satisfaction scores (P = 0.22) were uniformly high in both groups. These results are statistically significant, and furthermore suggest that in an accredited residency program with regional fellowship trained staff that there was no benefit from either technique in regards to onset time. Discussion: We found statistically significant data that enlightened us that the time from procedure start to adequate sensory and motor block was not different depending on technique used. Moreover, these times were found to be both clinically and financially relevant, as the cost of nerve stimulation vs. ultrasound. Differences in reliability of the block, and incidence of adverse events were unchanged. Finally, there were high procedural success rate, high patient satisfaction scores and low postoperative neurological complications rates. These findings suggest that anatomic differences of the nerve have a more important role in the onset of blockade rather than the medical tool utilized to perform the block. These findings also suggest that both techniques are safe and effective and may assist health-care personnel in the performance of this block in a busy tertiary medical center.
A147 Title: Formula to Estimate Epidural Depth in Parturients Presenting Author: Mayank Gupta MD Presenting Author's Institution: John H Stroger Jr. Hospital of Cook County, Chicago - Chicago, IL Co-Authors: Sudha Lukka MD – John H Stroger Jr. Hospital of Cook County - Chicago, IL Mahoua Ray MD - John H Stroger Jr. Hospital of Cook County - Chicago, IL Rajesh Sharma MD - John H Stroger Jr. Hospital of Cook County - Chicago, IL Ned Nasr MD - John H Stroger Jr. Hospital of Cook County - Chicago, IL
Abstract: Back ground & Objectives: The prevalence of obesity in women of reproductive age is increasing, therefore the placement of the epidural catheters could be technically challenging for the anesthesia providers. Frequently encountered difficulties in obese parturients may be secondary to obscure anatomical landmarks, difficulty in positioning and altered tissue consistency resulting in false loss of resistance due to hormonal changes. Knowledge of estimated lumbar epidural space depth (LESD) in relation to body mass index (BMI) may reduce the incidence of difficulties encountered in these patients. The purpose of this study was estimation of the LESD in relation to BMI in obese parturients, to review whether the prior knowledge of estimated LESD helps in increasing the success rate, and also to see if we can validate the results of the study conducted by Clinkscales et al done in Michigan parturients.
Methods: The study was conducted at John H Stroger Jr Hospital of Cook County, Ill., following approval by our Institutional Review Board (IRB). This study was a retrospective anesthesia chart review of all the parturients who underwent epidural catheter placements between 2006 and 2008. Variables included for data collection were the maternal age, mode of delivery, height, weight, lumbar vertebral interspace used for catheter placement, number of attempts needed for placement of catheter, centimeter depth from the skin to the lumbar epidural space. Pearson regression analysis was used to observe the relationship between epidural depth, BMI, weight, height and age.
Results: A total of 1025 pregnant patients were found to have epidural catheters. Of these, 367 patients were excluded from the study due to incomplete documentation. (Table 1) In Pearson regression analysis there was a strong relationship between BMI and LESD (R2 0.434) the relation between BMI and LESD becomes less prominent at a BMI greater than 50 (Table 2 & Fig 1.). The mean LESD is 1cm to 2cm increased in each BMI subgroup when compared to the recent study conducted by Clinkscales et al in Michigan parturients (Fig 2). We could not find any significant relationship between maternal age and LESD (p > 0.05). The mean LESD is 6.74 cm at the L3-L4 vertebral space (Table 3). This study yielded a formula to calculate lumbar epidural space depth (LESD) relative to BMI. The equation is ―LESD= 2.691+ (BMI X 0.128)‖.
Conclusions: A BMI has a strong correlation with LESD. The observed increase in the mean BMI in the subgroups may be the consequence of having African Americans as the major group of patient population in our hospital. According to the study of Richard C. D‘Alonzo, the African-American group had LESDs that were deeper compared with the other ethnic groups regardless of BMI. The prior knowledge of estimated LESD can help in increasing the success rate of epidurals in parturients.
References 1. C P Clinkscales et al. An observational study of the relationship between lumbar epidural space depth and BMI in Michigan parturients. Int J Obstet Anesth. 2007; 16: 323–327. 2. R C D‘Alonzo et al. Ethnicity and the Distance to the Epidural Space in Parturients Reg Anesth Pain Med. 2008;33(1):24-9.
Additional File #1: 1022611134342Epidural_Tables___F.doc Click here to view
Mean Std Deviation Ht 64.13 2.811
Wt 189.11 48.890 BMI 32.254 7.7346 Age 25.65 6.575 Depth 6.83 1.508 Table-1
BMI Subgroup N Mean LESD & Std Dev 20-30 1 312 6.02+/-1.14 30-40 2 256 7.16+/-1.24 40-50 3 75 8.39+/-1.22 50&higher 4 23 9.17+/-1.63 Table-2
Lumbar vertebral N Mean LESD &Std space Deviation L1-L2 3 8.00+/-1.73
L2-L3 125 6.90+/-1.58 L3-L4 420 6.74+/-1.51 L4-L5 103 7.00+/-1.38
L5-S1 15 7.23+/-1.35 Table-3
Fig-1
Fig-2
A148 Title: Social Network Model of Perioperative Pain Service Communications Presenting Author: Michael Kushelev MD Presenting Author's Institution: University of Florida - Gainesville, Fl Co-Authors: Steven D Lucas MD - University of Florida - Gainesville, Fl Kayser F Enneking MD - University of Florida - Gainesville, Fl Patrick J Tighe MD - University of Florida - Gainesville, Fl
Abstract: Introduction: Lapses in effective communication contribute to many adverse perioperative events. Many instruments including checklists, anesthesia information management systems, and standardized handoffs have attempted to improve perioperative communication. However, none of these tools quantifies the local complexity of the perioperative communication network. Social network mapping uses a network-science approach to quantify the complexity and node-based flow of information. Here, we describe the initial construction of an elementary social network involving our perioperative pain service.
Methods: A list of all entities involved in the daily operations of the Regional Anesthesiology and Perioperative Pain Medicine (RAPPM) service were identified, each considered a potential communication node. Next, we then listed all routine communication linkages between these entities, thus defining ―edges‖ between nodes. Edges reflected which communications would commonly take place in an average 24-hour period within the perioperative environment. Based upon the ensuing social network, Degree, Page Rank, Authority, Clustering, and Eigenvector Centrality were then computed for each node based upon their edges within the construct (Gephi 0.7, Gephi Consortium, Paris, France). Comparisons of network analysis attributes by provider role were conducted using the Kruskall-Wallis test (JMP 8.0.2, SAS Institute, Cary, NC).
Results: The resulting RAPPM Communications Network is shown in Figure 1. This elementary iteration included 45 nodes and 80 edges. (Table 1) The on-call CA-1 exhibited the highest degree centrality at 12, closely followed by the two RAPPM attending anesthesiologists at 11 each, with significant differences amongst each provider role (p=0.0006). Similar results were found for the PageRank of these entities, with the on-call CA-1 at 0.12 and 0.10 for the RAPPM attendings (p=0.0008). The on-call CA-1, RAPPM CA-2, and the RN assigned to the RAPPM service exhibited the highest network authority with scores of 0.06, 0.05 and 0.05, with significant differences across each provider type (p<0.0001). Pediatrics, neurosurgery, psychiatry, and chronic pain medicine consulting services, the FSC block room RN, orthopedic anesthesia attending, and both RAPPM attendings exhibited the highest clustering coefficients each of 0.5. The RAPPM CA-3, as well as RAPPM RN, had the highest Eigenvector Centrality scores of one. There were significant differences across the provider types for both Clustering (p=0.0007) and Eigenvector Centrality (p<0.0001). A comparison of attributes by provider role is found in Figure 2.
Conclusions: Social network mapping, applied to our RAPPM service, offered unique insights into the complexity, redundancy, and potential failures of our perioperative communications. Our data suggested that the importance of a node did not necessarily relate to the healthcare experience of that node. Future efforts will need to incorporate native data into the simulated network constructs.
References Bastian M, Heymann S, Jacomy M (2009). Gephi: an open source software for exploring and manipulating networks. International AAAI Conference on Weblogs and Social Media.
Additional File #1: 1030111151748Figure_1_RAPPM_Netw.pdf Click here to view
Additional File #2: 2030111151748Figure_2_for_Networ.pdf Click here to view
Additional File #3: 3030111151748Table_I_for_ASRA_Ab.xls Click here to view Node Label Degree PageRank Authority Clustering Coefficient Eigenvector Centrality AOD NT 1 0.01 0.03 0.25 0.06 AOD ST 2 0.02 0.04 0.50 0.19 Charge RN NT 1 0.01 0.03 0.17 0.06 Charge RN ST 2 0.02 0.04 0.33 0.19 Chronic Pain Medicine Team 2 0.02 0.04 0.50 0.65 FSC Attending 1 2 0.03 0.03 0.00 0.01 FSC Attending 2 2 0.03 0.03 0.00 0.01 FSC BR RN 2 0.03 0.04 0.50 0.07 FSC Ortho Surgery Attending 1 0 0.00 0.00 0.00 0.00 FSC Ortho Surgery Attending 2 0 0.00 0.00 0.00 0.00 FSC RAPPM CA-3 3 0.03 0.04 0.14 0.07 FSC Resident 1 1 0.02 0.03 0.00 0.06 FSC Resident 2 1 0.02 0.03 0.00 0.06 General Surgeon 1 0 0.00 0.00 0.00 0.00 General Surgery Anesthesia 1 0 0.00 0.00 0.00 0.00 Medicine 1 0.01 0.03 0.33 0.60 Neurosurgery 1 0.01 0.03 0.50 0.60 NTBR RN 2 0.02 0.04 0.08 1.00 Oncologic Anesthesia 1 0 0.00 0.00 0.00 0.00 Oncologic Surgeon 1 0 0.00 0.00 0.00 0.00 Ortho Anesthesia Attending 7 0.06 0.04 0.50 0.07 Ortho Anesthesia Resident 1 2 0.02 0.04 0.10 0.19 Ortho Anesthesia Resident 2 2 0.02 0.04 0.25 0.19 Ortho Surgeon 1 0 0.00 0.00 0.00 0.00 Ortho Surgeon 2 0 0.00 0.00 0.00 0.00 Pediatrics 1 0.01 0.03 0.50 0.60 Peds Anesthesia 1 0 0.00 0.00 0.00 0.00 Peds Surgeon 1 0 0.00 0.00 0.00 0.00 PPM RN 3 0.03 0.05 0.12 0.67 Psychiatry 1 0.01 0.03 0.50 0.60 RAPPM Attending: FSC 5 0.06 0.00 0.00 0.00 RAPPM Attending: North Tower 11 0.10 0.03 0.50 0.01 RAPPM Attending: South Tower 11 0.09 0.00 0.50 0.00 RAPPM CA-1 12 0.12 0.06 0.00 0.30 RAPPM CA-2 3 0.03 0.05 0.00 0.12 RAPPM CA-3 2 0.02 0.04 0.05 1.00 RAPPM Fellow FSC 3 0.04 0.03 0.00 0.01 RAPPM Fellow NT 4 0.04 0.04 0.00 0.65 RAPPM Fellow ST 4 0.04 0.03 0.00 0.01 STBR RN 3 0.03 0.05 0.00 0.25 Thoracic Anesthesia 1 0 0.00 0.00 0.00 0.00 Thoracic Surgeon 1 0 0.00 0.00 0.00 0.00 Trauma/CCM 1 0.01 0.03 0.33 0.60 Urologic Anesthesia 1 0 0.00 0.00 0.00 0.00 Urologic Surgeon 1 0 0.00 0.00 0.00 0.00
A149 Title: How useful is transversus abdominis plane block for intraoperatory analgesia Presenting Author: Miguel Plaza Lloret, Consultant Presenting Author's Institution: Consorcio Hospital General Universitario de Valenica – Catarroja, Valencia Co-Authors: Oscar Diaz Cambronero, Consultant - Consorcio Hospital General Universitario de Valenica – Valencia, Valencia Nuria Garcia Gregorio, Consultant - Consorcio Hospital General Universitario de Valenica – Valencia, Valencia Maria Vila Montañes, Consultant - Consorcio Hospital General Universitario de Valenica – Valencia, Valencia Rosa Lopez Rincon, Consultant – Hospital General de Albacete – Albacete, Albacete
Abstract: Background and Aims: There have been published many recent studies evaluating the efficacy of TAP block for postoperatory analgesia. Transversus abdominis plane (TAP) block is a new regional anesthetic technique whose aim is to block anterior branches of thoracolumbar nerves originating from T6-L1,which inervates anterior abdominal wall, by introducing local anesthetic into the neurovascular plane between the internal oblique and the transverses abdominis muscles. Ultrasound (US) is a useful device to identify anatomical landmarks. We aim to evaluate its analgesic efficacy in the intraoperative (IO) period for laparoscopic surgery (cholecistectomy and apendicectomy)
Methods: Forty-three adult patients (ASA I to II) undergoing laparoscopic surgery were randomized in two groups. Group A (n=23): Standard care based on opioid analgesia. Intravenous (i.v.) fentanyl during IO and subcutaneous (s.c.) meperidine in the PO. Group B (n=20): After induction a bilateral TAP block was performed (introducing levobupivacaine 100 mg in each side).
Fentanyl 1mcg/kg i.v. was given if arterial blood pressure (ABP) or cardiac frequency (CF) or both rise >20% from basal values (ABF and CF at 5 min post induction). Meperidine 50mg s.c. was given if visual analogue scale (VAS) pain scores was >4. Each patient was assessed at 30 min and 24 h after surgery. Both groups received acetaminophen and non-steroidal anti-inflammatory drugs in the postoperative period.
Results: In our preliminary results, US-guided TAP block significantly reduced intraoperative fentanyl consumption. Postoperative VAS pain scores were reduced in group 2 at 30 min.
Conclusions: US guided TAP block is a useful technique in the IO and PO pain management of patients undergoing laparoscopic surgery.
A150 Title: Octreotide and Peripheral Neuropathy: A New Adjunct for Therapy? Presenting Author: Nihir Waghela MD Presenting Author's Institution: University of Chicago - Chicago, IL Co-Authors: Dalia ElMofty MD - University of Chicago - Chicago, IL
Abstract: Introduction: Carcinoid tumors arise from the neuroendocrine cells of the bronchial system, the gastro-intestinal tract and less frequently pancreas, ovaries, testis and prostate. Malignant carcinoid syndrome is a constellation of symptoms mediated by overproduction of numerous humoral factors such as serotonin, bradykinin, prostaglandin, and histamine. Two of the most common manifestations of this disease are flushing and diarrhea. The mainstay of treatment is the somatostatin analog octreotide. Paraneoplastic syndromes have been implicated in patients with carcinoid including Lambert-Eaton myasthenic syndrome, paraneoplastic polyneuropathy. This case report describes a patient who experienced improvement in her sensorimotor neuropathy while being treated with octreotide for her malignant carcinoid syndrome.
Case Report: The patient is a 50-year-old female diagnosed with metastatic carcinoid tumor in 1989 for which she had not undergone treatment until 2008. She was diagnosed with type II diabetes in 2007. Approximately 3 years ago, she complained of worsening diarrhea with up to six stools per day and hot flashes. She noted progressive weakness and difficulty walking. She reported paresthesias in her upper and lower extremities. Focused physical exam revealed wide-based ataxic gait and 4/5 strength upper and lower extremities. Patellar reflex could not be elicited. She had significant allodynia in her hands. Her medications include gabapentin 900 mg tid, fentanyl patch 100 mcg q 72 hr, hydromorphone 4 mg q 3- 4 hr prn, triamterene/hydrochlorothiazide 37.5/25 mg qday,sitagliptin 100 mg qday, glipizide 10 mg qday, and vitamin B12 1000 mcg qday. Patient was started on octreotide 30 mg IV qmonth. Patient reported with initiation of therapy, she noted improvement of her allodynia and increase in activity. She subsequently was able to wean her oral opiate requirements.
Discussion: Octreotide is a long-acting octapeptide that binds to somatostatin receptors with pharmacologic properties similar to those of the natural hormone somatostatin. Octreotide has also been implicated in the treatment of chronic pain. Adler et al reported in 2009 that glial cell line-derived factor (GDNF) exerts anti- allodynic effect via somatostatinergic mechanisms. Intrathecal octreotide has also been implicated for treatment of chronic pain. Yu-Chuan et al reported in 2001 that intrathecal sandostatin significantly relieved thermal hyperalgesia behaviorally in rats and dose-dependently reduced spinal Fos-LI neurons expression evoked by stroking stimulation, which may reflect mechanical allodynia in rats with sciatic constriction injury. We report a case of a 50-year-old patient with a history of metastatic carcinoid syndrome whose symptoms of allodynia may have improved from monthly sandostatin injections. Further research is warranted to determine the anti-allodynic effects of octreotide.
References Yu-Chuan, T et al. J Int Assoc for the Study of Pain. 2002;99:407-413. Adler, J et al. Pain Med. 2009;10:1229-1236. Rudnicki, S et al. Muscle and Nerve. 2000;23:1800-1818.
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A151 Title: Local inflammation contributes to the loss of local anesthetic efficacies in sciatic nerve block – an animal study Presenting Author: Qing Liu MD, PhD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Michael s Gold PhD - University of Pittsburgh - Pittsburgh, PA Jacques E Chelly MD, PhD, MBA - University of Pittsburgh Medical Center - Pittsburgh, PA
Abstract: Background: Inflammation-induced decreases in the efficacy of local anesthetic- induced nerve block have been well documented in the dental literature in association with acute pulpitis. This serves to both limit the utility of local anesthetics in the presence of inflammation and increase the likelihood of toxicity as a result of the greater doses of anesthetic needed to obtain the same degree of nerve block. Interestingly, the decrease in local anesthetic efficacy described in dentistry is comparable for both local and regional anesthetic approaches arguing that the inflammation-induced decrease in pH cannot account for changes observed in the presence of inflammation. Thus, we hypothesize that the local inflammation contributes to loss of local anesthetic efficacies in sciatic nerve block.
Methods: A rodent model of inflammation was used by injecting CFA (Freund‘s adjuvant) in the rats‘ hind paws. Sciatic nerves were harvested 24 hours after the injections. Compound action potentials with rapidly conducting A- waves and slowly conducting C-waves were recorded from the nerves with or without inflammation, in the presence of 0.5%, 1%, 2% and 5% lidocaine. The lidocaine dose response curve was then fitted with a Michaelis-Menton equation to demonstrate the effects of local inflammation on the abilities of lidocaine to block A and C-waves.
Results: The current study shows that lidocaine dose-dependently block both A and C-waves recorded in non-inflammed sciatic nerve. The blockade was not observed in the inflamed sciatic nerve, except when 5% lidocaine was used, suggesting that local inflammation significantly decreased the ability of lidocaine to block compound action potentials in sciatic nerves.
Discussion: Our data demonstrated that local inflammations contribute to the loss of local anesthetic efficacy in sciatic nerve blocks. Higher doses of local anesthetics were needed to achieve the same degree of nerve block, which would increase the risks of local anesthetic toxicity. Further studies to understand the changes in the voltage-gated sodium channel (VGSC) subunits in the axons of the afferents innervating the site of inflammation will elucidate the biochemical mechanisms underlying the inflammation-induced local anesthetic failure.
A152 Title: Flexible Ultrasound Arm Presenting Author: Rajnish Gupta MD Presenting Author's Institution: Vanderbilt Medical Center - Nashville, TN Co-Authors: Eric R Briggs MD - Vanderbilt Medical Center - Nashville, TN
Abstract: The use of real-time ultrasound imaging for procedures in medicine is rapidly becoming commonplace. However, challenges with this technique persist, including the frequent need for two sets of hands. The proceduralist must manipulate the ultrasound probe with one hand and then fix and maintain a stable image while advancing a needle with the other. This leaves the proceduralist unable to handle other equipment or syringes. Ideally, the proceduralist could utilize a stabilizing arm for the ultrasound probe to fix the probe in position, so that both hands could be utilized to focus on the procedure, eliminating the need for a second person.
The concept of a stabilizing ultrasound arm is not a new one. A collaborative effort at Dartmouth involving physicians and the engineering department produced the ultraStand™, sold by Wellan Medical, Inc. However, the distal flexible portion of the ultraStand™ has a fixed resistance, making rapid fine adjustments of the ultrasound probe difficult. Our proposed solution is a stabilizing ultrasound arm that provides free range of motion and extreme flexibility while manipulating the probe during image acquisition, and that can be instantly locked into position while maintaining compression on the tissues once the optimal image is obtained. The distal probe attachment will serve the dual role of securing the ultrasound probe and housing a tensioning/releasing mechanism for the flexible arm, making it readily accessible to the proceduralist.
This project is in the earliest stages of development. We are working closely with a team of biomedical engineering students at Vanderbilt and have developed an early prototype utilizing rudimentary ball and socket type joints with a central tensioning cable that, when engaged, applies friction to the joints, fixing the arm in position. Other components in development include the tensioning lever/distal probe attachment and a proximal attachment used to secure the arm to a patient's bed or other stable structure. Proposed mechanisms for the tensioning system could include a closed pneumatic system, closed hydraulic system, or internal cable system utilizing either electric motors or a preloaded/spring-wound tensioning lever. Patent pending.
A153 Title: Does a Supraclavicular Brachial Plexus Block Induce Comparable Hemodynamic Changes in the Proximal and Distal Arteries of the Upper Extremity? Presenting Author: Jiawei Li MPhil Presenting Author's Institution: The Chinese University of Hong Kong - Hong Kong, Hong Kong Co-Authors: Manoj Karmakar MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong Xiang Li PhD - Minhang Hospital of Shanghai - Shanghai, Shanghai Winnie Samy BN - The Chinese University of Hong Kong - Hong Kong, Hong Kong Wing Hong Kwok FANZCA - The Chinese University of Hong Kong - Hong Kong, Hong Kong
Abstract: Background: Supraclavicular brachial plexus block (BPB) causes venodilatation1 and an increase in blood flow velocity through the brachial artery of the ipsilateral upper limb.1 However, there are limited data on regional hemodynamic changes after an ultrasound guided (USG) BPB2 and there are no data comparing the hemodynamic changes in the proximal and distal arteries of the upper extremity, which this study was designed to investigate.
Methods: After ethics approval and written informed consent, 10 patients (23- 61yrs) scheduled for elective hand surgery under a supraclavicular BPB were recruited for this study. The BPB‘s were performed using a combination of ultrasound guidance and nerve stimulation. 20 ml of Ropivacaine (0.5%, without epinephrine) was injected posterolateral to the subclavian artery in the supraclavicular fossa in each patient. Success of the block was judged by abolition of cold sensation and paralysis of the muscles in the ipsilateral hand and forearm. Regional haemodynamic parameters were measured in the ipsilateral brachial and common palmar digital arteries using pulsed-wave Doppler ultrasound, before the block (0 min) and at regular intervals for 30 minutes after the block (5min, 10min, 20min, 30min). Measured haemodynamic parameters included Peak Systolic Velocity (PSV, cm/s), End Diastolic Velocity (EDV, cm/s), Time-Averaged Mean Velocity (TAVM, cm/s), diameter (d, cm), Resistance Index (RI), and Pulsatility Index (PI). Blood flow was calculated as the product of TAVM and cross-sectional area, which was derived from the arterial diameter. Paired-sample t-test was used to compare the changes in recorded parameters relative to the baseline and between the two arteries. A p value less than 0.05 was considered statistically significant.
Results: The Supraclavicular BPB was successfully achieved and it was effective for surgical anesthesia in all patients studied. After the block, there was a visible increase in the diameter of the arteries on Color and Power Doppler imaging and this was more evident in the common palmar digital artery. In the Doppler spectral waveform, the protodiastolic reflux disappeared and there was an elevation of the diastolic curve with time in both arteries. There was also a significant increase in PSV, EDV, TAVM, d, and blood flow, and a significant reduction in PI and RI in both the arteries studied (Fig 1). The relative change in each of the recorded hemodynamic parameters tended to be higher in the common palmar digital artery (Fig. 1) but statistical significance was only achieved for the relative increase in the diameter of the common palmar digital artery which was greater than that in the brachial artery (p<0.05 at all studied time points).
Conclusions: Supraclavicular BPB alters the pattern of blood flow in the brachial and common palmar digital arteries of the ipsilateral upper extremity. It also causes vasodilatation, reduction in vascular resistance, acceleration of blood flow and an increase in blood flow. These changes tend to be more profound in the distal artery.
References 1. Shemesh D et al. Ultrasound Med Biol. 2006;32:817-822. 2. Laskowski IA et al. Ann Vasc Surg. 2007;21:730-734.
Additional File #1: 1012811001023Fig1__regional_hemo.tif Click here to view
A154 Title: Quantitative Evaluation of the Echotexture of the Median Nerve in the Young and the Elderly Presenting Author: Xiang Li PhD Presenting Author's Institution: Minhang Hospital of Shanghai - Shanghai, Shanghai Co-Authors: Manoj Karmakar MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong Jiawei Li Mphil - The Chinese University of Hong Kong - Hong Kong, Hong Kong Tony Gin MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong
Abstract: Background: We have previously demonstrated using computer-assisted grey scale analysis that the echo intensity (EI) of the median nerve is significantly greater in the elderly than in the young.1 However there are no data on the echotexture of a peripheral nerve. This study was designed to objectively investigate the differences in the echotexture of a median nerve (MN) in the young and the elderly.
Methods: After ethical approval and written informed consent 10 healthy young volunteers (< 30yrs, Group Y) and 10 elderly patients undergoing lower limb surgery (> 60 yrs, Group E) were recruited for this study. Ultrasound scans were performed in the mid-forearm with the subject in the supine position. The arm was abducted and the forearm was externally rotated with the palm of the hand facing the ceiling. The median nerve was scanned in the mid-forearm using a standardized protocol. A high-frequency linear array transducer (13-6 MHz) and a Micromaxx (SonositeTM Inc, Bothell, WA) US System with video recording capabilities was used for the scan. The recorded data were transferred to a personal computer using the Site-Link Manager software (SonositeTM Inc., Bothell, WA) and Adobe Premier Pro software (Adobe Systems Inc, San Jose, CA) was used to capture a still image (TIFF format, 720 x 480 pixels and 8-bit gray levels) for off cart data processing. The still image was then ―normalized‖, a simple digital image processing technique during which the gray-scale values of all pixels in the images are evenly adjusted to two reference points (pure black=0; pure white=255). The EI of the MN was measured using the standard histogram function in Adobe Photoshop (Adobe Systems Inc, San Jose, CA). The cross-sectional area (CSA) of the MN was determined using the measurement function in Image-Pro® Plus 6.2 (IPP). For echotexture analysis the noise in the image was reduced using the median filter of IPP. The default median value (128) of the gray-scale range (0-256) was used as the common threshold. The grayscale image was thereby converted to a binary image. The white area index (WI) and black area index (BI) of the MN was also determined using IPP.2 Independent-samples t test was used for statistical analysis. A p value less than 0.05 was considered statistically significant.
Results: Data on the CSA, EI, BI and WI of the MN in the young and the elderly are presented in Table 1. The CSA of the MN was significantly larger (p=0.002) in the young. The EI and WI in the elderly was significantly greater (p=0.002 and p=0.037 respectively) than that in the young. The BI in the young was also significantly higher (p=0.037) than that in the elderly.
Conclusions: This is the first study to quantitatively evaluate the echotexture of the MN in the young and elderly. We have demonstrated that there are significant differences in the echotexture of the MN between the young and the elderly. This may be due to age related changes in the relative proportion of neural fascicles and connective tissue in the MN. Our finding may also explain why the MN appears smaller, brighter and whiter in ultrasound images of the elderly patients.
References 1. Li X et al. Brit J of Radiol. 2011;In Press. 2. Maurits NM et al. Ultrasound Med Biol. 2003;29:215-225.
Additional File #1: 1012711224716table_1__echotextur.tif Click here to view
A155 Title: Quantitative Evaluation of the Changes in Echogenicity of the Sciatic Nerve During an Ultrasound Guided Sciatic Nerve Block Presenting Author: Xiang Li PhD Presenting Author's Institution: Minhang Hospital of Shanghai - Shanghai, Shanghai Co-Authors: Manoj Karmakar MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong Jiawei Li Mphil - The Chinese University of Hong Kong - Hong Kong, Hong Kong Tony Gin MD - The Chinese University of Hong Kong - Hong Kong, Hong Kong
Abstract: Background: During an ultrasound-guided (USG) peripheral nerve block, the nerve often appears brighter and is also better visualized after the local anesthetic injection.1 However, there are no data quantifying this observation, which this study was designed to investigate.
Methods: After local research ethical approval and written informed consent, 11 adults, ASA Ι-Ш, <80 yrs who were scheduled to undergo orthopedic lower limb surgery under a combined USG sciatic nerve block (SNB) and a lumbar plexus block were recruited for this study. Patients were positioned in the lateral position with the side to be blocked uppermost and with both the hips and knees flexed. A MicroMaxx (Sonosite Inc, Bothell, WA) US System with a low-frequency transducer (C60e, 5-2 MHz) was used for the scan. In the subgluteal space the sciatic nerve appears as an oval hyperechoeic structure between the hyperechoeic epimysiums of the gluteus maximus and the quadratus femoris muscle.2 Once the ultrasound (US) image was optimized, the settings in the US machine were kept constant to avoid any changes in echogenicity of the sciatic nerve due to changes in system settings. The USG SNB was performed in the subgluteal space by a single investigator using a technique that we have previously described.2 After negative aspiration through the block needle, 25–30 ml of lidocaine 1% and ropivacaine 0.25% with epinephrine 1:400 000 was injected over 2–3 min while observing the distention of the subgluteal space and distribution of the local anesthetic (LA) in real-time. Ultrasound images during the block was recorded as multiple video loops and still images were captured from these loops at three time points, A (before the LA injection), B (during the LA injection) and C (3 minutes after the LA injection). The echo intensity (EI) and cross sectional area (CSA) of the sciatic nerve were measured using Adobe® Photoshop CS2 and Image-Pro® Plus 6.2 respectively. One-way repeated measures ANOVA with Scheffe‘s test was used to compare the differences in the EI and CSA of the sciatic nerve at the three time points studied. A p value less than 0.05 was considered statistically significant. Results: All the SNB‘s were successful. Changes in the EI and CSA of the sciatic nerve during the USG SNB are shown in Figure 1. CSA of the sciatic nerve at time B and C was comparable and significantly smaller than that at time A, p=0.003 and p=0.019, respectively. The EI of the sciatic nerve at time B and C was also comparable and significantly greater than that at time A, p<0.0005 and p=0.019, respectively.
Discussion: This is the first study to quantitatively evaluate the sonographic changes during an USG SNB. Using computer-assisted gray-scale analysis we have demonstrated that there is a significant increase in EI and a reduction in the CSA of the sciatic nerve during an USG SNB. Factors such as: change in reflection coefficient, change in sciatic nerve density, and posterior acoustic enhancement may account for the observed phenomenon and may explain why the sciatic nerve appears brighter and is also better delineated after the LA injection.
References 1.Saranteas T et al. Acta Anaesthesol Scand. 2007;51:387-388. 2.Karmakar MK et al. Br J Anaesth. 2008;100:533-537.
Additional File #1: 1012711225519Fig_1_0.tif Click here to view
A156 Title: Assessing the Efficacy of a Regional Anesthesia Workshop for Anesthesiology Residents Presenting Author: Hanni E Monroe MD Presenting Author's Institution: University of North Carolina - Chapel Hill, NC Co-Authors: Randall Coombs MD - University of North Carolina - Chapel Hill, NC Natalie Miller BA - University of North Carolina - Chapel Hill, NC Andrey Bortsov MD, PhD - University of North Carolina - Chapel Hill, NC Victoria Salo-Coombs BSN - University of North Carolina - Chapel Hill, NC
Abstract: Introduction: With the increasing popularity of regional anesthetic techniques comes a mandate that residents obtain these skills during residency. There are significant limitations to the apprenticeship model of on-the-job training. Many different methods of supplemental education in regional anesthesia have been described in the literature, but none have been shown to be superior to any others. The objective of this study was to evaluate the educational value of a one-day regional anesthesia workshop. The primary outcome measure was the ability of the workshop to increase the residents‘ comfort level in independently performing regional nerve blocks.
Methods: Twenty-eight anesthesia residents participated in a 4 hour regional anesthesia workshop, which reviewed nerve blocks of the upper and lower extremities, and use of ultrasound needle localization. Prior to the workshop, each resident completed a survey assessing their comfort with their ability to independently perform 13 different nerve blocks. At the conclusion of the workshop and at 3 months post-workshop, the residents were again asked to complete similar surveys. Additionally, the post-workshop survey addressed resident satisfaction with the workshop and areas for future improvement. Paired sample t-test was used to compare pre- and post-workshop comfort levels. P-value < 0.05 was considered significant.
Results: Twenty-eight residents completed the workshop. 100% of participants completed the pre- and post- questionnaires, as well as the 3-month f/u questionnaire. There was a statistically significant increase in residents‘ comfort level immediately post-workshop for 11 out of 13 blocks evaluated, which was sustained in 5 of 13 blocks at the 3 month follow-up survey. Senior residents (CA-2 and CA-3, n=17 (61%)) had higher baseline comfort scores when compared to junior residents (PGY-1 and CA-1, n=11 (39%)). When all blocks were considered together, junior residents demonstrated a statistically significant increase in comfort level with independently performing nerve blocks immediately post workshop and at 3 month follow-up. Senior residents had a statistically significant increase in comfort level immediately post workshop, but not at 3 month follow-up. 100% of participants found the workshop to be beneficial, especially with regard to improvement in anatomic and landmark knowledge.
Conclusions: The workshop did increase the comfort level of the participating residents immediately upon its completion for the majority of blocks evaluated. This increased comfort was sustained long term for approximately half of those blocks. The increase in comfort was more pronounced for residents with less experience at baseline. The workshop was an effective teaching tool. Future workshops might be most effective when targeted at learners with less baseline experience in regional anesthesia. Regional anesthesia workshops can provide an important adjunct in the education of resident anesthesiologists.
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A157 Title: Review of regional anesthesia literature from 1992-2010 Presenting Author: J. Gabe Tsang MD Presenting Author's Institution: The Johns Hopkins University - Baltimore, MD Co-Authors: Brandon Togioka MD - The Johns Hopkins University - Baltimore, MD Christopher Wu MD - The Johns Hopkins University - Baltimore, MD
Abstract: Objective: The clinical use of regional anesthesia (RA) has seemingly grown more popular in recent years. This review intends to determine whether this trend is reflected in the literature, and what types of regional anesthesia articles are have been published.
Methods: This study qualified for exemption from The Johns Hopkins IRB. The top five non-subspecialty anesthesiology journals and the top rated regional anesthesia subspecialty journal as ranked by 2006 Impact Factor were obtained from the ISI Web of Knowledge, Journal Citation Report (Thomsen Reuters, New York, NY). Each issue published from these journals from a period of January 1992 through June 2010 was examined. Articles excluded from analysis included letters to the editors, editorials, meeting abstracts, and book reviews. Data was grouped into four, five year periods: block A 1992-1996, block B 1997-2001, block C 2002-2006, and block D 2007-2010.
Results: Chosen for review from the top five non-subspecialty anesthesiology journals were the top 4 by impact factor (2006): Anaesthesia, Anesthesia & Analgesia, Anesthesiology, and British Journal of Anaesthesia. Regional Anesthesia and Pain Medicine was the subspecialty journal chosen for review. The total percentage of RA articles published over the past 19 years appears relatively stable for each journal. There are virtually no RA guideline/advisory articles published until block C onward (two in A&A, 14 in Regional Anesthesia and Pain Medicine). Regional Anesthesia and Pain Medicine publishes a greater proportion of technique (―how to‖) papers (from 10.0-13.6% of their total RA articles published), compared to Anesthesia & Analgesia and Anaesthesia (0.8-4.0, and 0-2.2%, respectively). Neuraxial blocks are the region most studied in all the journals. The proportion of articles dedicated to it is decreasing though, with an increase in articles regarding upper and lower extremity blocks, more obvious in Regional Anesthesia and Pain Medicine and Anesthesia & Analgesia (16.2-35.0%, and 9.0-29.2%, respectively). Ultrasound use for RA is increasing in the literature, with large numbers showing up in block D. Epidural and spinal blocks remain the most studied type of block in Anesthesia & Analgesia and Anaesthesia throughout all time periods. In Regional Anesthesia and Pain Medicine, there is a decline in the neuraxial type blocks with a concordant increase in single shot and peripheral nerve catheter articles (59% vs. 20.4% in block A, compared to 23.3% vs. 39.4% in block C).
Discussion: Despite there being no obvious change in proportion of RA articles being published in any of the reviewed journals, the content of the articles appear to be changing. The use of ultrasound in the literature seems only to be picking up in more recent years, despite having been first described for RA use in 1994. It would be interesting to see if there would be any significant changes in the data set, should block D be a full five year tally. Further analyses of the other top five non-subspecialty journals would be useful to determine if the trends seen here are shared.
A158 Title: Optimal angle and site of needle insertion for ultrasound-guided nerve blocks Presenting Author: Jenna K Masters MD Presenting Author's Institution: Virginia Mason Medical Center - Seattle, WA Co-Authors: David B Auyong MD - Virginia Mason Medical Center - Seattle, WA
Abstract: Introduction: Needle visualization is important for performing safe and successful ultrasound guided regional anesthesia. One of the major determinants of in-plane needle visualization is the angle of needle insertion, as needles perpendicular to the propagated ultrasound waves appear more bright. Previous studies show that needle visibility on ultrasound decreases with steeper angles in phantom and animal tissue models.1,2 We set out to determine the maximal insertion angle for needle visualization, depending on depth of target.
Methods: Three needles (17g Arrow Tuohy, 22g B Braun Stimuplex A , 21g Pajunk Uniplex) were inserted into beef tissue at angles from 0 to 35 degrees in 5 degree increments. Ultrasound .bmp images were recorded and angle calculation software was used to measure insertion angle to within 1 degree. Adobe Photoshop highlighted the needle image (magic wand tool) and the needle mean RGB pixel intensity (0-255) was measured. Then, subjective ratings of the needle images by blinded reviewers (all presented at 0 degrees) were recorded. Reviewers rated the image on both a continuous variable [clarity of needle: 0-10 scale] and binary variable [I am comfortable the needle image to advance it near critical structures: Yes/No].
Results: All three needle types had consistent pixel intensity from angles 0 to 15 and the maximum slope of the decline in pixel intensity occurred between 15 and 20 degrees. There was a sharp decrease in pixel intensity across all needles for insertion angles of >25 degrees. (Fig. 1) Subjective scores revealed that subjects were uncomfortable with needle images at rates of 11% at 20 degrees and 33% at 25 degrees and 61% at 30 degrees. Using the above data, we then calculated the insertion point of the needle, in relation to the ultrasound probe to keep at needle at <25 degrees insertion angle. This suggested insertion point results in a needle angle that allows for best visibility of targets at depths of 1 to 5cm. (Fig. 2)
Conclusions: The results from our study suggest that in-plane needle insertion angle be <25 degrees to allow for optimal needle visibility and clinical confidence in needle position. To achieve an insertion angle of <25 degrees, the target should be placed in the center of the ultrasound probe and image. Then, the needle should be inserted at a distance from the center of the ultrasound probe that is equal to the twice the depth of the target. Traversing more tissue with the needle could be assumed to increase patient discomfort, but this has not been shown in studies comparing ultrasound to stimulator techniques.3 Also, starting further away from the intended nerve target could put other critical structures within the path of the needle. Therefore, an effective pre-scan of the needle path is warranted.
References 1 Schafhalter-Zoppoth et al. Reg Anesth Pain Med. 2004;29(5) 480-488. 2 Maecken, T et al. Reg Anesth Pain Med. 2007; 32(5) 440-447. 3 Casati et al. Anesthesiology. 2007;106:992-996.
Figure 1: Objective Needle Visibility Scores: X-Axis=RGB Mean Pixel Intensity (0=none, 255=maximum). Y-axis= Needle angle.
Figure 2: Calculation of needle insertion distance from target according to depth. Clinically, the needle should be inserted away from the target at a distance approximately double the
Additional File #1: 1030111194604Needle_Visibility_a.TIF Click here to view
Additional File #2: 2030111194604Needle_Visibility_a.TIF Click here to view
A159 Title: Intrathecal but Not Intravenous Oxytocin Inhibits the Visceromotor Reflex to Distention of the Rat Urinary Bladder Presenting Author: Mitchell P Engle MD, PhD Presenting Author's Institution: University of Alabama-Birmingham - Birmingham, AL Co-Authors: Meredith T Robbins PhD - University of Alabama-Birmingham - Birmingham, AL Timothy J Ness MD, PhD - University of Alabama-Birmingham - Birmingham, AL
Abstract: Background: Oxytocin (OXY) is a neuropeptide produced in the paraventricular nucleus that has recently been recognized as an important component of the descending analgesic systems. Little is known about the role of OXY in modulating noxious visceral information. The present study was undertaken to determine if intravenous (i.v.) or intrathecal (i.th.) OXY produce antinociception to noxious visceral stimulation.
Methods: The effects of i.v. or i.th. OXY on the abdominal visceromotor reflex (VMR) to graded urinary bladder distention (UBD) was measured in urethane anesthetized rats. The ability of an oxytocin antagonist (OTA) to inhibit the effects of OXY was also investigated. In addition, the effect of i.th. OTA on endogenous OXY was also studied.
Results: Intravenous OXY at doses of 0.5 mcg/kg or 40 mcg/kg did not inhibit the VMR to UBD. However, i.th. OXY doses of 0.15 μg or 1.5 μg inhibited the VMR to UBD by 37% or 68% respectively. Time to peak inhibition was approximately 30 minutes and the peak effect was sustained for greater than 60 minutes. The effect of OXY on the VMR could be both reversed and prevented by the i.th. administration of an OTA. Interestingly, the i.th. administration of OTA alone did not affect the VMR.
Conclusions: Intrathecal, but not intravenous OXY produces a dose-dependent antinociception to noxious urinary bladder distention. The site of action is likely the spinal cord because high doses of i.v. OXY failed to inhibit the VMR. The effect of i.th. OXY is OXY receptor specific since its effect was both prevented and reversed with OTA. The lack of effect with i.th. OTA alone indicates that endogenous OXY release from supraspinal sites is not likely to be involved in the modulation of acute visceral pain. To our knowledge, these studies provide the first published evidence that the i.th. delivery of OXY may be an effective pharmacological tool for the treatment of visceral pain associated with the urinary bladder. A160 Title: So you bent the epidural needle . . . Presenting Author: Richard L Shih MD Presenting Author's Institution: Virginia Mason Medical Center - Seattle, WA Co-Authors: Lucy S. Hostetter MD - Virginia Mason Medical Center - Seattle, WA Christopher M. Bernards MD - Virginia Mason Medical Center - Seattle, WA
Abstract: Background: Epidural blocks are frequently placed using 17 or 18-gauge needles, allowing passage of continuous catheters. During block placement, needles can be subjected to substantial axial forces resulting from interaction with firm interspinous ligaments and contact with bony spine structures. These forces can cause bending of the needle tip, which obstructs passage of the epidural catheter, and (more rarely) needle shaft fracture (Ref. 1), which can cause significant morbidity and/or necessitate surgical removal. In our study, we measured the amount of axial force required to bend the tips of different epidural needles.
Methods: Sample lots (five each) of 17, 18 and 19g Tuohy and Sprotte epidural needles were obtained from two manufacturers (Arrow®, Pajunk®). Each needle was fitted into a custom-built apparatus (Fig. 1) designed to isolate the needle tip during application of axial force. A fixed rate of progressive axial force was then applied while a dynamometer measured the force applied to the needle tip. The buckling force, defined as the force required to bend the needle tip (Fig. 2), was measured and recorded. Mean buckling force, standard deviation and standard error of the mean were calculated for each needle group.
Results: The means and standard errors of the measured buckling forces are presented in Table 1. There was remarkable needle-to-needle variability in measured buckling forces for the Pajunk® 18g Tuohy and 19g Sprotte needles (standard deviations 32.5N and 20.4N, respectively). No difference between the buckling force for the 18 and 19g Pajunk® needles (p = 0.4) was found despite the differing gauge and needle type. The Arrow® 17g Tuohy needles had significantly lower buckling forces than the Pajunk® 18g Tuohy (p = 0.01) and the Pajunk® 19g Sprotte (p = 0.01) needles. The Arrow® needles also had notably less needle-to- needle buckling force variability (standard deviation 2.47N) than the Pajunk® needles. All needle tips bent such that epidural catheters could not be passed through the tip.
Discussion: Bending and fracture of epidural needles are highly undesirable complications of neuraxial block placement. Our investigation demonstrates significantly different buckling forces for needles of differing manufacturers. No difference in buckling force was found between one manufacturer‘s needles of differing gauge and needle type. Our study also discovered a remarkable difference in needle-to-needle buckling force variability between needles of differing manufacturers. Interestingly, the needle used almost exclusively at our institution for placement of continuous neuraxial and continuous peripheral nerve blocks (Arrow® 17g Tuohy) had the lowest measured mean buckling force but also the lowest needle-to-needle buckling force variability. Our findings warrant further testing with larger samples of needles with differing manufacturers, gauges, and needle types.
Additional File #1: 1030111132846Tables_and_Referenc.doc Click here to view Table 1
Needle Type (gauge) Buckling Force (N) ± SEM
Arrow® Tuohy (17) 15.1 ± 1.1
Pajunk® Tuohy (18) 44.4 ± 14.5
Pajunk® Sprotte (19) 56.8 ± 9.1
Additional File #2: 2030111024541Figure_1__Apparatus.pdf Click here to view
Additional File #3: 3030111024541Figure_2__Bent_Tuoh.pdf Click here to view
A161 Title: Weight-Based Volume of Injection Influences the Cranial to Caudal Spread of Local Anesthetic Solution in Ultrasound-Guided Transversus Abdominis Plane Blocks in Canine Cadavers Presenting Author: Sean M Bruggink MD Presenting Author's Institution: University of Wisconsin School of Medicine and Public Health - Madison, WI Co-Authors: Carrie A Schroeder DVM - University of Wisconsin School of Veterinary Medic - Madison, WI Tracy L Baker-Herman PhD - University of Wisconsin School of Veterinary Medic - Madison, WI Kris M Schroeder MD - University of Wisconsin School of Medicine and Public Health - Madison, WI
Abstract: Objective: To determine if the volume of local anesthetic solution affects the cranial to caudal spread, and subsequently which ventral nerve root segments are affected, in ultrasound guided transversus abdominis plane (TAP) blocks in canine cadavers.
Study Design: Prospective Experimental Study.
Animals: 20 adult beagle cadavers weighing 9.3 ± 1.4 kg (mean ± SD).
Methods: TAP blocks were preformed bilaterally via ultrasound guidance by two experienced clinicians. A 1:1 solution of methylene blue/Bupivacaine 0.25% was prepared and was injected using ultrasound guidance at volumes of 0.25, 0.5, 0.75 and 1.0 mL/kg. The cadavers were dissected 24 hours post-injection to determine the spread of injectate solution within the transversus abdominis fascial plane
Results: The transversus abdominis fascial plane was adequately visualized by ultrasound, injected, and dissected in 38 beagle hemi-abdominal walls. The dermatomal spread, defined as the number of ventral nerve roots saturated by injected solution, was 2.9 (± 0.7), 3.4 (± 1.1), 4.0 (± 0.7), and 4.2 (± 1.2) in the 0.25, 0.5, 0.75 and 1 mL/kg groups respectively (Figure 1). The most frequently stained nerve roots were T13-L3, L1-L3, T13-L3 and T13-L4 in the 0.25, 0.5, 0.75 and 1.0 mL/kg groups respectively. The group with the greatest spread of solution was the 1 mL/kg group with an average spread from L1 to L4.
Conclusions: This anatomic study in beagle cadavers suggests that the volume of injected local anesthetic influences the cranial to caudal spread within the transversus abdominis plane during ultrasound guided TAP block. Although there was a large variance in the spread of injectate, the most logical volume of injection appears to be 0.75 mL/kg. This volume covers most of the ventral roots innervating the abdomen while sparing nerves to the lower extremities. Additionally, this study along with previous studies by our group, suggest that TAP blocks could be easily preformed as an anesthetic adjunct in canines presenting for routine abdominal surgery, such as exploratory laparotomy or ovariohysterectomy. Currently, TAP blocks are rarely performed in veterinary medicine. Clinicians performing this block could potentially adjust the volume of injected local anesthetic to augment the spread of analgesic coverage for the given surgical procedure. Studies on human cadavers with a similar design could help determine the optimal volume of injectate in human patients.
Additional File #1: 1022011122121Figure_1.pdf Click here to view
A162 Title: Does ultrasounded-guided interscalene block directed at avoiding the phrenic nerve with concomitant low volume injection reduce the incidence of diaphragmatic paralysis? Presenting Author: Aaron Y Sieradzan MD Presenting Author's Institution: Emory University School of Medicine - Atlanta, GA Co-Authors: Armin Oskouei MD - Emory University School of Medicine - Atlanta, GA
Abstract: Introduction: Many standard anesthesia texts report 100% diaphragmatic paralysis after interscalene brachial plexus block based upon Urmey‘s 1991 study titled ―One Hundred Percent Incidence of Hemidiaphragmatic Paresis Associated with Interscalene Brachial Plexus Anesthesia as Diagnosed by Ultrasonography.‖ For the 13 patients enrolled in their study, each received an interscalene block based upon the paresthesia technique, and a mean of 43.3 mL of local anesthetic was injected. We sought to investigate if avoiding the phrenic nerve as well as using lower volumes of local anesthetic will decrease the incidence of hemidiphragmatic paralysis.
Methods: We selected 20 consecutive patients that were scheduled for shoulder surgery that would normally have received combined general anesthesia and interscalene single shot block under our standard protocol. In the preoperative area, we used ultrasound to first identity the phrenic nerve. We then performed ultrasound guided interscalene blocks, taking care to avoid the phrenic nerve and injected 7-10mL of Ropivicaine 0.5% on the first pass. We then compared each patient‘s baseline diaphragmatic excursion values with their excursion values measured at 5 and 10 minutes after the block (measured under ultrasound as per Urmey et al 1991).
Results: Hemidiaphragmatic paresis was observed in 4/20 patients (20%) using our needle placement technique, combined with lower volumes of local anesthetic. VAS scores were less than 3 in 19/20 (95%) patients post-operatively and in 17/20 (85%) patients 8 hours after injection. Upon 24-hour follow up, 19/20 (95%) of patients reported pain satisfaction scores as either "somewhat satisfied" or "very satisfied." None of the patients had any significant respiratory compromise or dyspnea.
Conclusions: In contrast to Urmey‘s 1991 study, where 100% of patients experienced hemidiaphragmatic paresis, we only observed a 20% occurrence of diaphragmatic impairment with use of our specific needle placement strategy and low volumes of local anesthetic. We were also still able to provide adequate post-op analgesia and patient satisfaction scores. If patients have respiratory compromise and present for shoulder surgery, consider using this technique.
Additional File #1: 1012611171847interscalene_abstra.doc Click here to view
A163 Title: Prospective, Blinded, Randomized Evaluation of Dexamethasone Efficacy and Safety as Adjunct to Bupivicaine in Transversus Abdominus Plane (TAP) Block Presenting Author: Chien-Hsiang Chow MD Presenting Author's Institution: Steward-St. Elizabeth's Medical Center - Brighton, MA Co-Authors: Arvind S Murthy MD - Steward-St. Elizabeth‘s Medical Center - Brighton, MA Ali K Daha MD - Steward-St. Elizabeth‘s Medical Center- Brighton, MA Ingolf A Tuerk MD - Steward-St. Elizabeth‘s Medical Center- Brighton, MA Andrew L Sternlicht MD - Steward-St. Elizabeth‘s Medical Center - Brighton, MA
Abstract: Introduction: The Transversus Abdominis Plane (TAP) block has gained popularity for provision of post-operative analgesia in lower abdominal procedures, providing effective pain control for up to 18 hours. O‘Donnell et al. demonstrated the efficacy of the TAP block for post-operative analgesia following prostatectomies(1). Other studies report that the addition of dexamethasone(dex) to local anesthetics improves analgesia from brachial plexus peripheral nerve blocks(2,3). However, there are no published reports studying adjuncts for TAP blocks to prolong the duration of analgesia. The purpose of this study is to investigate the efficacy and safety of dex added to local anesthetic in prolonging analgesia following TAP blocks in patients undergoing robot-assisted laparoscopic prostatectomy.
Materials and Methods: After obtaining IRB approval, 50 male patients undergoing robotic-assisted laparoscopic prostatectomy by a single surgeon at our institution are to be enrolled for this study. The sample size was chosen based on an anticipated difference of a minimum 25% change in the mean duration of analgesia, based on data from other peripheral nerve block studies with dex. At 80% power, 21 patients per treatment arm need to be analyzed. We assume a 15% dropout rate in the analysis population. After informed consent was obtained, patients were randomized into two treatment arms, 0.125% bupivicaine 40 cc plus 4mg dex (20 cc and 2mg dex on each side of the abdomen), or 0.125% bupiviciane 40 cc plus 1 cc of saline. Visual analog scales(VAS) and dermatomal level of sensory block were used for data collection in standardized time intervals. Time to first additional analgesic administration, and total intraoperative and post-operative narcotic use were recorded. Pending data analysis of treatment effect from this study, we plan to continue the study and enroll patients undergoing other abdominal surgeries. In this second portion of the study, patients undergoing bilateral TAP block procedures for post-operative analgesia will receive blinded dex on only one side of their abdomen allowing patients to serve as their own control.
Results: As of the date of submission 20 patients have been enrolled into Phase 1 of the study. Time to first request for analgesia following TAP blockade has ranged from 121 minutes to 1118 minutes (n=17, mean 493 min, median 431 min). No adverse events have been reported in the study to date.
Discussion: Our analysis remains blinded at present however we expect that complete data from Phase 1 of the study will be available for presentation at the meeting. The mean duration of blockade cannot be compared with previous studies since volume and concentration of local anesthetic is different. It is hoped that the development of the model of study in Phase 2 will allow powered analyses of efficacy of adjunctive pharmacotherapy with small numbers of patients. Using the model developed in Phase 2 of the study, we hope that future research may investigate the efficacy of other anesthetic adjuncts to the TAP block.
References 1) O‘Donnell, BD, et al. Reg Anesth Pain Med. 2006;31;91. 2) Viera, PA, et al. Eur J Anesth. 2010 Mar;27(3):285-288. 3) Parrington, SJ, et al. Reg Anesth Pain Med. 2010; 35(5):422-426.
A164 Title: Risk-Benefit Analysis of pediatric neuraxial regional analgesia: a 6 year retrospective analysis of adverse events incidence after epidural catheter placement in a major teaching institution. Presenting Author: Hansen P Jared MD Presenting Author's Institution: University of Chicago - Chicago, IL Co-Authors: Magdelena Anitescu MD, PhD - University of Chicago - Chicago, IL
Abstract: Background: The use of epidural catheters for post-operative pain control in the pediatric population is widespread. However, the overall rate and type of adverse events occurring with their use is unknown as many current publications are case reports or focus on a single type of event. Due to differences in anatomy, cognitive ability, as well as the fact that many pediatric epidurals are placed under general anesthesia, results from studies of adult complication rates may not generalize to the pediatric population.
Methods: Following IRB approval, we retrospectively analyzed our single institution database of all pediatric continuous epidural catheters placed over a period of 6 years (1/13/2004-1/21/2010). Anesthesia records and all daily progress notes from the time of epidural placement until discontinuation of the epidural catheter were reviewed and the presence of all documented adverse events was recorded.
Funding: This study did not require funding from an outside source.
Results: 171 patients receiving continuous epidural anesthesia for post-operative pain were included in the study. There were 63 (36.8%) which complained of pain in PACU and in POD #1 which responded well to epidural rate and solution adjustment as well as infrequent (2-3 times per day) prn short acting opioids. The majority of complaints recorded were related to minor side effects such as pruritus 24 (13.9%) patients, nausea/vomiting 19 (11%), unilateral block 9 (5.3%) patients and excessive motor block 8 (4.7%) patients. Hardware malfunctioning such as catheter dislodgement and epidural catheter leak were reported in 22 (12.9%) patients. There were no major complications such as epidural abscess, epidural hematoma, nerve injury or death in the population studied. Serious complications defined as excessive sedation or dural puncture were reported in 6 (3.5%) patients.
Conclusions: Continuous epidural analgesia is frequently used in the pediatric population for the management of post-operative pain. Since many of the catheters are placed under general anesthesia in this patient population, the accidental misplacement of an epidural catheter with subsequent major side effects, may not be recognized until in the postoperative period. In our analysis we identified only a minority of major complications which were immediately recognized and treated. Our study shows that epidural analgesia is a safe and effective method of treatment of perioperative pain in children. However, prospective studies may be necessary to further evaluate favorable risk-benefit analysis of postoperative pediatric epidural analgesia.
References Ivani G, Mossetti V. Continuous central and perineural infusions for postoperative pain control in children. Curr Opin Anaesthesiol. 2010 Oct;23(5):637-642. Llewellyn N, Moriarty A. The national pediatric epidural audit. Paediatr Anaesth. 2007 Jun;17(6):520-533.
Additional File #1: 1022811152546Peds_Epidural_Adver.pdf Click here to view
A165 Title: Combined Ultrasound and Neurostimulation Guided Low-dose Lumbar Plexus Block Versus Intrathecal Morphine for Total Hip Arthroplasty Within an Established Analgesic Clinical Pathway Presenting Author: Jenna A Hansen MD, MS Presenting Author's Institution: Stanford University School of Medicine - Stanford, CA Co-Authors: T. Edward Kim MD - Stanford University School of Medicine - Palo Alto, CA Seshadri Mudumbai MD - Stanford University School of Medicine - Palo Alto, CA Edward R Mariano MD, MAS - Stanford University School of Medicine - Palo Alto, CA
Abstract: Background: The analgesic clinical pathway for total hip arthroplasty at our institution consists of preoperative intrathecal morphine, intraoperative periarticular ropivacaine 300 mg, and postoperative oral and parenteral opioids as needed with scheduled NSAIDs. To minimize side effects and need for postoperative monitoring, we introduced an ultrasound-guided low-dose lumbar plexus block to replace intrathecal morphine in this pathway. For quality assurance purposes, we compared the efficacy of these two regional analgesic techniques in this setting.
Methods: With IRB approval, we retrospectively reviewed the total joint database from November 30 to December 31, 2011 for patients who had undergone total hip arthroplasty under general anesthesia and received either intrathecal morphine or low-dose lumbar plexus block. In the spinal group, patients received bupivacaine 0.75% with morphine 200 mcg via a 27 gauge pencil point needle using a standard midline approach using sterile technique. In the block group, with patients in the prone position, a 2-5 MHz 60 mm curvilinear array transducer in axial orientation and perpendicular to the spine was used to identify the psoas muscle in short axis. Under sterile conditions, a 10 cm 18 gauge stimulating Tuohy-tip needle was directed in-plane anteromedially into the psoas muscle. An evoked quadriceps motor response was used as additional confirmation of needle tip location near the lumbar plexus before injecting 20 mL of ropivicaine 0.2% with 2.5 mcg/ml epinephrine. The primary outcome was opioid consumption in the first 24 hours postoperatively. Secondary outcomes included opioid use intraoperatively and on postoperative days 1 & 2, pain scores, and side effects as determined by anti- emetic and diphenhydramine use.
Results: Twelve patients met the inclusion criteria: 6 in the spinal group and 6 in the block group. Morphometric and surgical data were similar between groups. The spinal group required less opioid use in the first 24 hours (p<0.05; Fig. 1). Intraoperative opioid use and worst pain scores for the first 24 hours were lower for the spinal group (p=0.004 and p<0.05, respectively). There were no further differences in other secondary outcomes.
Conclusions: Based on this small retrospective study, spinal analgesia with intrathecal morphine may provide superior pain relief in the first 24 hours after surgery compared to single-injection, low-dose lumbar plexus block. Prospective research comparing higher concentrations of local anesthetic or continuous lumbar plexus blocks with or without intrathecal opioids is warranted. The efficacy of periarticular local anesthetic also deserves further investigation.
Additional File #1: 1020711144739Opioid_Requirements.pdf Click here to view
Additional File #2: 2020711144739Worse_Pain_Figure.pdf Click here to view
A166 Title: Place of ultrasonography-assisted method for difficult epidural access in pregnant women, performed by resident in anesthesiology Presenting Author: Karim Benmiloud MD, CA-1 Presenting Author's Institution: Hopital du Valai – Sion – Sion, Valais Co-Authors: Jean-Cyrille Pitteloud MD – Hopital du Valais – Sion – Sion, Valais Patrick Ravussin MD, PhD, Pr - Hopital du Valais – Sion – Sion, Valais
Abstract: Background and Aims: In our regional hospital, residents in anesthesiology, are in first line to practice epidural anesthesia procedure for pregnant women (approx 1260 each year). Sometimes like in literature, for specific patient (especially obese), it is more difficult to perform well. We decided to use ultrasound (US) as a mean to improve our efficiency in epidural access for difficult cases, presumed or real after failed attempts.
Methods: During 15 months (12/2009-02/2011), one resident (PGY-1 who previously performed > 50 efficient epidural procedures) used a sonosite Micromaxx US system equipped with a 2-5 Mhz curved array probe (Sonosite Inc. USA) in the lumbar region, to identify the midline, the intervertebral space and the distance from skin to epidural space. Once the best image of the intervertebral space L3-L4 or L4-L5 was visualized and frozen in the center of the screen, skin was marked with a dermographic pen to represent the center of the right and left lateral extremities of the probe both in transverse and longitudinal plane. The site of puncture was determined by the intersection of the line connecting two vertical points with the line connecting two horizontal points.
Results: During this period we used US for prepuncture landmarks in 13 patients (after obtaining their informed consent), with an average maternal age of 29,5±7yr. Seven of these pregnant women had pre-pregnancy BMI-level ≥ 30. Eleven reached the WHO criteria for obesity at the end of pregnancy, with a mean BMI level at 34,4(28-41). In this serie we used US landmarks, with a 84,61% success rate of insertion at the first «US assisted »attempt. We reach 100% success rate with second attempt for the two cases failed at first puncture. Changing angle of the needle during procedure was quoted as second attempt. In four cases we used US landmarks as first line option due to inability to feel the lumbar spinous processes at palpation. Epidural space depth (in cm) measured at Ultrasonography (UD=5,51±0.45) was very close to the depth measured by the needle insertion (ND=5,57±0.43).
Discussion: It is well known that palpation is inaccurate to identify lumbar interspinous spaces. US measurement of epidural space was described for the first time 30 years ago. Since this time, US was used with good success for prepuncture landmarks in epidural and spinal anesthesia. It has been shown that US decreased the number of attempts, and intervertebral spaces punctured. (without specificity of population studied) For our cases, 61,5% of patients have poor bony surfaces landmarks, and in 38,5% we couldn‘t recognize any lumbar spinous process by palpation. Our data are too small at times, but it seems that a high percentage of success in this population could be reached after more practice.
Conclusions: US may have a place in obstetrical anesthesia, especially for obese women, decreasing the high risk associated with airway management in case of emergency cesarean section. Further studies seem necessary for « US assisted » catheter insertion to become « gold standard » for presumed difficult epidural access. « Live procedure » or « US guided » epidural catheter insertion appears to be the best technique for success but requires more time to be competent .
A167 Title: Predictors for Neurologic Sequelae After Regional Anesthesia Presenting Author: Vivian Hui Yun Ip MBChB, MRCP, FRCA Presenting Author's Institution: University of Alberta Hospital - Edmonton, AB Co-Authors: Ban CH Tsui MSc, MD, FRCPC - University of Alberta Hospital - Edmonton, AB
Abstract: Introduction: Neurological deficit is a recognized complication after regional anesthesia.(1) Although the risks are relatively low, this can be devastating and debilitating. Patient, surgical, and anesthetic risk factors may all contribute to peripheral nerve injuries after surgery.(2) We conducted a qualitative systematic review to identify the independent predictive factors for developing post-operative neurologic sequelae following regional anesthesia. This is to enable better risk assessment and patient selection prior to the performance of regional techniques.
Methods: Systematic search was conducted through MEDLINE (January 1950 to July 2008) and EMBASE (January 1980 to July 2008), and relevant reference lists for all studies investigating the risk factors for temporary or permanent post- operative neurological deficits in adults. All studies meeting the inclusion/exclusion criteria were independently reviewed, critically appraised, and data extracted by the authors.
Results: We identified 15 eligible studies for final analysis. This included a total of 2,725,195 patients. (Table 1) For peripheral nerve blocks, pain at injection site and a high tourniquet pressure (>400mmHg) were identified as predictors for development of post-operative neurological complications. Two studies found paresthesia during block procedure as an independent risk factor for developing post-operative neurological deficits although this finding was contradicted by two other studies comparing the paresthesia technique and trans-arterial approach or nerve stimulator techniques. For neuraxial blocks, associative factors include paresthesia during block procedure, pain on injection, spinal stenosis, pre-operative valgus deformity for knee arthroplasty, previous laminectomy or pre-existing neuropathy. Interestingly, many factors which were thought to be associated with postoperative neurologic sequelae such as diabetes, the use of vasoconstrictor, long-bevelled needle and the number of needle passes have not shown any significant correlation.
Discussion: Qualitative analysis of the studies shows a wide range of predictive factors for post-operative neurological impairment. Important predictive factors can be helpful in risk assessments, and patient selection for regional techniques or help identifying those who may be predisposed to develop post-operative neurological complications. More vigorous studies with robust statistics and validated designs are needed to investigate this field of interest.
References (1) Reg Anesth Pain Med. 2009;34:534-541. (2) Anesth Analg. 2001;93:1606-1611.
Additional File #1: 1011411204619Table_1_RV.doc Click here to view
Table 1. Table showing the number of different studies and the risk factors found for post- operative neurological deficits.
Type of block Number of Number of Risk factors Studies patients
Upper limb 6 2641 Paresthesia during needle placement
Long tourniquet time
Combined 2 4907 Tourniquet pressure >400mmHg upper and lower limb
Neuraxial 6 2,613,917 Pre-existing neuropathy
Spinal stenosis
Paresthesia during puncture
Previous laminectomy
Pre-existing valgus deformity (TKR)
Neuraxial and 1 103,730 Paresthesia during puncture peripheral block Pain during injection
A168 Title: Persistent Motor Weakness with intact sensation following combined lumbar plexus and sciatic nerve blocks Presenting Author: Benjamin Vaghari MD Presenting Author's Institution: Thomas Jefferson University - Philadelphia, PA Co-Authors: Kishor Gandhi MD, MPH - Jefferson Medical College - Philadelphia, PA Andrew Ng MD - Thomas Jefferson University - Philadelphia, PA Manoj K Karmarkar MD - The Chinese University of Hong Kong - Shatin, NT, Hong Kong
Abstract: Introduction: We present a case of a healthy 21-year-old male presenting 2 days after surgery with persistent motor weakness and intact sensation of the leg following a combined lumbar plexus and sciatic nerve block.
Case Description: 21-year-old, 5‘11, 78 kg, healthy male presented for left anterior cruciate ligament repair. We performed a left lumbar plexus block via traditional landmarks approach with nerve stimulator guidance (1-2). 30mL 0.5% Ropivacaine was injected incrementally at low pressure with negative blood aspiration and intravascular symptoms or paresthesia. Left sciatic nerve was visualized with ultrasound (Philips HD11 XE) at left subgluteal region. 21G 100mm insulated stimulator needle was advanced in-plane with ultrasound (Linear array 11-3 MHZ) and nerve stimulator guidance (Figure 1). Plantar flexion twitch was obtained at 0.5mA and diminished at 0.35mA with nerve stimulator. 20ml 1.5% Mepivacaine was injected incrementally at low pressure with negative blood aspiration and intravascular symptoms or paresthesia. Patient was alert and awake during both nerve blocks. Tourniquet was applied to the left proximal thigh and inflated to 250 mmHg for 105 minutes. An arthroscopic leg holder (MED metric LH1000) was utilized for limb stabilization for approximately 115 minutes during the case (Fig. 2). The case proceeded uneventfully. On postoperative day (POD) 2, patient was admitted to the hospital for persistent left lower extremity weakness. Physical examination revealed weak hip flexors/extensors and weak plantar flexion and dorsiflexion. Left lateral anterior thigh and left calf sensory was diminished. Vibration, propioception, patellar and ankle reflex remained intact. Lumbar plexus magnetic resonance imaging was negative for psoas or epidural hematoma (Fig. 3). Patient was evaluated by Neurology and Physiatry in the hospital.
Recommendations were made for the patient to undergo intensive physical therapy. On POD 8, patient regained significant obturator and sciatic nerve motor function. He had improved plantar flexion, dorsiflexion, ankle inversion and eversion. Lateral femoral cutaneous and femoral nerves sensory distribution improved. However femoral nerve motor distribution remained weak. Patient was discharge with home physical therapy on POD 12. Patient regained full motor at week 4 after nerve block. EMG conducted at 4 weeks showed no neuropathy with completely normal conduction.
Discussion: This patient presented with conflicting sensory and motor symptoms. In light of normal EMG‘s, we believe that there may be surgical factors that resulted in patient morbidity. The combination of tourniquet inflation, circumferential leg holder, and positioning during surgery (hip hyperflexion, hip external rotation, and knee extension) may have caused neurapraxia as seen in the patient (3-4). It is recommended that proper documentation and subspecialty consultation routinely follow care of patients with neurological injury.
References 1. Capdevilla X, Macaire P, Dadure C, et al. Anesth Analg. 2002; 94:1606-1613. 2. Morau D, Lopez S, Biboulet P, et al. Reg Anesth Pain Med. 2003:28:309-314. 3. Noordin S, McEwen JA, Kragh JF Jr, et al. J Bone Joint Surg Am. 2009. 91:2958- 2967. 4. Kim TK, Savino RM, McFarland EG: et al. Am J Sports Med. 2002. 30:619-629.
Additional File #1: 1021011091515Figure_1.doc Click here to view
Figure 1: Ultrasound Guided Subgluteal Sciatic nerve block
Local Anesthetic
Sciatic Nerve
Additional File #2: 2021011091515Figure_2.doc Click here to view
Figure 2: LH1000TM Arthroscopic Leg Holder (MEDmetric Corporation) used for leg stabilization.
Additional File #3: 3021011091515Figure_3.doc Click here to view
Figure 3: MRI of Lumbar plexus on post operative Day 4 & 12.
Post Operative Day 4 Post operative day 12
A169 Title: Epidural Complication Rates at a Major Anesthesia Teaching Hospital: A randomized three month retrospective review Presenting Author: Christopher Annis MD Presenting Author's Institution: University of Chicago - Chicago, IL Co-Authors: Magdalena Anitescu MD - University of Chicago - Chicago, IL Raed Rahman DO - University of Chicago - Chicago, IL
Abstract: Objective: Neuraxial analgesia is frequently used perioperatively for effective pain control. However, use is limited by a perceived unfavorable risk-benefit ratio. The purpose of this abstract is to present a randomly selected, retrospective snapshot of data collected over a 3-month time period of all non-obstetrically placed epidurals, evaluating for incidence and magnitude of adverse events.
Methods: Following IRB approval, a random 3-month period over a 3-year interval (2/1/2008 – 2/1/2011) was selected. All adult patients under the Acute Pain Service were included in the analysis. From the database created, patients who underwent epidural catheter placement for postoperative analgesia were identified. Charts were reviewed and selected adverse events were noted. Placement and subsequent use in non-obstetric surgical patients was reviewed for each post- operative day during the reviewed period. Reported adverse events were recorded as major (dural puncture, epidural hematoma, epidural abscess, transient/permanent nerve injury, meningitis/positive culture tip) and minor (vasovagal/hypotensive/arrhythmia episodes, non-functioning or disconnected catheters, or positive test dose).
Results: From the 85 patients undergoing epidural analgesia for postoperative pain control, 35(41.2%) events were reported. Minor events were reported in 32(37.6%) patients while only 3(3.52%) reported a major complication (two accidental dural punctures, one positive culture catheter tip) (Fig.1). No dural puncture cases became symptomatic for Postdural Puncture Headache. While concerning for epidural abscess, the positive tip culture was ultimately considered inadvertent contamination with no treatment necessary (Fig.2). From the 32 patients who reported minor side effects, 15(17.6%) were associated with hardware malfunctioning (catheter accidentally removed by patient(9), disconnected cap(2) and catheter mal-functioning(4). The remaining 17 patients had either a hypotensive episode(12), pruritus(2), vasovagal syncope with placement(1), positive test dose(1) or bradycardia(1) (Fig 3). All side effects were thoroughly followed up with daily evaluations and appropriate treatment. No episodes of epidural abscesses/hematomas, intrathecal placement, transient/permanent nerve injury, or meningitis were found.
Conclusions: Concern over potential complications is valid as the incidence of adverse events is not zero. Moreover, significant devastating neurological complications associated with neuraxial instrumentation can range from 0.04% to 0.1% (1,2). Our study, albeit limited by its retrospective nature, showed a low incidence epidural-related complications during the period studied. While this is a limited review of the available data, there were no major complications reported of the non-obstetrically placed epidurals and represents a trend of safety and vigilance.
References 1. Brull, R et al. Neurological Complications After Regional Anesthesia: Contemporary Estimates of Risk. Anesth Analg. 2007;104(4):965-974. 2. Cameron, M et al. A Review of Neuraxial Epidural Morbidity: Experience of More Than 8,000 Cases at a Single Teaching Hospital. Anesthesiology. 2007;106:997- 1002
Additional File #1: 1022411222337Epiduralcomplicatio.xls Click here to view
Total Epidurals Epidural Hematoma Epidural Abscess Permanent Nerve Injury Meningitis Dural Puncture Positive culture of epidural tip 85 0 0 0 0 2 1
Major adverse events 90 85 80 70 60 50 40 30 20 10 0 0 0 0 2 1 0 Total Epidural Epidural Permanent Meningitis Dural Positive Epidurals Hematoma Abscess Nerve Injury Puncture culture of epidural tip
Additional File #2: 2022411222337Epiduralcomplicatio.xls
Minor adverse events 90 85 80 70 60 50 40 30 20 12 9 10 2 1 1 2 1 4 0
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Additional File #3: 3022411222337Epiduralcomplicatio.xls Click here to view
Epidurals Major adverse events Minor adverse events 85 3 32 Total adverse events 90 85 80 70 60 50 40 32 30 20 10 3 0 Epidurals Major adverse events Minor adverse events
Series1
A170 Title: Why do we Recommend Therapeutic Medial Branch Blocks after Cervical Spine Operations? A descriptive study with three case scenarios. Presenting Author: Foad Elahi MD Presenting Author's Institution: John Stroger Jr. Cook County Hospital - Chicago, IL Co-Authors: Maria Torres MD - John Stroger Jr. Cook County Hospital - Chicago, IL Taruna Penmethca MD - John Stroger Jr. Cook County Hospital - Chicago, IL Andrzej Stazskeiwickz MD - John Stroger Jr. Cook County Hospital - Chicago, IL
Abstract: Background: Immediate post operative acute neck pain, cervical neck muscle spasm, toticollis, anterocollis, retrocollis, warrant using long term cervical collar which might finally cause disuse atrophy , persistent chronic pain are among the most common short and long term complications after most of surgical procedures on the cervical spine. Numerous factors can contribute to inadequate pain management immediately post operative, including lack of sufficient surgeons training, fear of surgical field being violated by an intervention, indeed potential side effects associated with injections as well as lack of appropriate patient follow up are among those. Currently no interventional pain procedure recommendation exists for the patients.
Objective: The objective of this study was to determine if a therapeutic medial branch block is a rational treatment for patients with postoperative neck pain after cervical spine operations in order to prevent long term complications.
Study Design: Descriptive analysis of authors‘ findings with Retrospective chart audits.
Setting: Review of charts of all patients who underwent cervical spine operations due to multiple etiologies during a time period of 9 years by senior author.
Methods: We reviewed 100 charts of the cervical spine surgeries. Patients with persistent postsurgical pain were not routinely treated with therapeutic medial branch blocks. A positive treatment response with sufficiently satisfied with the relief identified.
Results: Of the 100 operations performed, 30 were microscopic one level discectomy, 11 were artificial disc operations, 46 were C5-C6 one level cage, and 13 were fusions with cage and plate. Three cases undergone diagnostic / therapeutic medial branch block on unilateral cervical C3- C7, on post operative day 12 after all other modalities of pain management were being failed. All three cases on 3 months, 6 months, and 12 months follow up still complaining of cervical pain and discomfort. All other cases recovered from surgery with no obvious chronic pain issue. In this study we describe in detail the pain generators after common surgical interventions, present in detail those three cases presentation, and review the literature about the importance of proper pain management post cervical spine surgeries. We would describe the rationale behind early intervention along proper medical management.
Limitations: This study is retrospective and observational mainly by senior surgeon, and therefore does not represent a high level of evidence.
Conclusion: This observational study would support early interventional pain procedures like median branch block alongside the medial management of post operative pain.
A171 Title: Combining the Old with the New in Regional Anesthesia Presenting Author: Philip O Hansen MD Presenting Author's Institution: Albany Medical Center - Albany, NY Co-Authors: Rafel Proban MD - Albany Medical Center - Albany, NY Walter Folger MD - Albany Medical Center - Albany, NY
Abstract: Background: With the use of ultrasound regional training has been relegated to placing the probe on the extremity looking for the nerve and ignoring the surrounding structures. So while the ultrasound has been hailed as an advance in regional anesthesia, residents are not using it to learn anatomy. They are looking for the tree (the nerve) without understanding its place in the forest (the extremity). We want to emphasize the use surface anatomy in conjunction with the ultrasound image to learn both anatomy and how the blocks are performed.
Objective: To combine anatomical landmarks in the longitudinal plane with ultrasound images in the transverse plane to produce a 3-dimensional picture for regional anesthesia.
Methods: The components of the extremity are reviewed from pictures. The bones, muscle, fascial planes, blood vessels, and nerves are identified. Emphasis is placed on the spatial relation of structures to the nerve. Without U/S landmarks are identified tactilely based on ease of palpation: bones >tendons>fascia>muscles. Next, lines of orientation are drawn, the probable puncture site is marked, and then the longitudinal plane is established. The ultrasound probe is placed on the extremity and verbally the resident identifies the structures on U/S before insertion of the needle.
Results: After pictorial review the actual physical palpation and mapping of the structures is purposeful and reinforces the spatial relations of the structures. For example, in a lateral popliteal block, the patella and lateral epicondyle of the tibia are palpated first, then the tendons of the hamstring muscles and iliotibial band followed by the vastus lateralis and short head of the biceps femoris muscles. palpation systematically maps out the space containing the sciatic nerve. Now the placement of the U/S is deliberate with the knowledge that the nerve is likely at the predicted site. If the nerve is not readily identified, scanning is purposeful as the resident can visualize the approximate course of the nerve in a 3 dimensions.
Summary: Visualizing the relationship of landmarks and structures to the nerve target markedly improves the understanding of a block procedure. Since both anatomical landmarks and ultrasound images are two-dimensional planes, a three- dimensional picture of the anatomy is formed by combining the two techniques rather than using either in isolation. A thorough understanding of the relationship of surface features to deeper structures is invaluable in performing U/S guided nerve blocks. Instituting this teaching method early in regional training will not only improve the resident‘s precision and speed when performing blocks, but will also enhance their understanding of where catheters should be placed in relation to the nerve.
Conclusions: 1.The longitudinal plane of surface landmarks and the transverse plane of ultrasound are both 2-dimensional. 2. Surface landmarks frame the region of space where the nerve can be found. 3. Mapping out the anatomy facilitates accurate placement of the puncture site. 4. Ultrasound effectively adds depth perception to surface picture. 5. Combining the two planes creates a 3-dimensional picture.
A172 Title: Psychometric Characteristics of the Korean Version of the Roland-Morris Disability Questionnaire Presenting Author: Jee Y Moon MD Presenting Author's Institution: Department of Anesthesiology and Pain Medicine - Seoul, Seoul Co-Authors: Pyung-bok Lee MD, PhD - Seoul National University Bundang Hospital - Sungnam-si, Gyonggi-do Yongchul Kim MD, PhD - Seoul National University Hospital - Seoul, Seoul Sooyoung Park MD, PhD - Seoul National University Hospital - Seoul, Seoul
Abstract: Background and Objectives: The Roland-Morris Disability Questionnaire (RDQ) and the Oswestry Disability Index (ODI) are widely used questionnaires which measure functional disability from low back pain (LBP). The Korean ODI was validated and; the Korean RDQ was not. We validated the Korean RDQ in patients with chronic LBP and compared responsiveness between the RDQ and the ODI in patients with chronic lumbar facet joint pain.
Methods: After careful review of the prefinal version of the Korean RDQ, some minor modifications of the translations were performed by the expert committee. Then, cross-cultural adaptation of the Korean RDQ was performed in 221 patients with chronic LBP. Among them, 30 patients were reliability tested by using Cronbach‘s alpha coefficient and the intraclass correlation coefficient (ICC). Validity was evaluated using an 11-point numerical rating scale (NRS) and the Korean ODI. For responsiveness, the receiver operating characteristic (ROC) curve analysis of the RDQ and the ODI was compared in 52 patients with lumbar facet joint pain using an anchor-based method (the 7-point global perceived effect scale).
Results: The test-retest reliability (ICC = 0.989) and the internal consistency (Cronbach's alpha = 0.879) were satisfied in the Korean RDQ. There was a positive correlation between the RDQ and the NRS (r = 0.59, P < 0.001). The assessment of the concurrent validity showed a strongly positive correlation between the RDQ and the ODI (r = 0.76, P < 0.001). For responsiveness, the Korean RDQ with the higher area under the ROC curve showed a better overall responsive performance than did the ODI in patients with lumbar facet joint pain after medial branch radiofrequency neurotomy (P < 0.01)(Fig. 1).
Conclusion: Our study indicates that the Korean RDQ is valid for measuring disability in a Korean population, and is responsive to the patients‘ progress.
Additional File #1: 1102610233035Figure_2.tif Click here to view
A173 Title: The Effect of Femoral and Sciatic Nerve Catheters and Single Shot Nerve Blocks for Below the Knee Amputations Presenting Author: Luke Stoltzfus MD Presenting Author's Institution: University of Wisconsin Hospitals and Clinics - Madison, WI Co-Authors: Adin-Christian Andrei PhD - University of Wisconsin - Madison, WI Brooke Anderson MSN, RN - University of Wisconsin Hospitals and Clinics - Madison, WI Kristopher Schroeder MD - University of Wisconsin Hospitals and Clinics - Madison, WI Melanie Donnelly MD - University of Wisconsin Hospitals and Clinics - Madison, WI
Abstract: Objectives: Peripheral nerve blocks and continuous peripheral nerve catheters can assist with intraoperative and post-operative pain management, but there is conflicting data regarding the impact of these techniques on post-operative outcomes. We performed a retrospective review of 26 patients at our institution, all of whom underwent BKAs with continuous peripheral nerve catheters, single shot femoral, or sciatic nerve blocks, or general anesthesia alone. Our outcomes included post-operative opioid requirements, post-operative sedation scores, post- operative pain scores, post-operative antiemetic use and time to discharge.
Methods: Following IRB approval, a chart review was performed on all patients undergoing BKAs at our institution between 11/2008 and 11/2009. All femoral and sciatic nerve single shots and catheters were placed preoperatively and run as infusions in the post-operative period. Femoral nerve catheters were placed with combined ultrasound and nerve stimulation methods and sciatic nerve catheters were placed with a subgluteal approach utilizing nerve stimulation alone. Linear regression models were applied to relate age, gender, and BMI to post-op pain, opioid use (days 1, 2, 3), average sedation (days 1, 2, 3), pain (dynamic) and time to discharge. Pairwise comparisons of the post-op day zero average sedation in the general, single shot and peripheral nerve catheter groups were carried out based on Wilcoxon's rank-sum test. Unadjusted and adjusted (for gender, BMI and age) logistic regression models were used to relate anti-emetic use to the anesthetic type.
Results: Between 11/2008 and 11/2009, 31 patients underwent below the knee amputation at our institution. Of these patients, 5 were excluded from the study due to placement of an epidural (2), bilateral BKAs (1), simultaneous surgery on opposite leg (1) and post-operative death (1). Among the 26 study patients, 14 had femoral and sciatic nerve catheters, 5 had femoral or sciatic nerve single shot blocks and 7 had general anesthesia without regional intervention. No significant differences were observed between the three study groups in terms of post- operative opioid requirements, post-operative pain scores, post-operative antiemetic use, and time to discharge. Post-operative sedation scores on day zero (POD 0) were higher for patients undergoing general anesthesia alone versus those with femoral and sciatic nerve catheters (P = 0.03).
Discussion: Although our study identified no significant difference in outcomes among the three groups, except for POD 0 sedation scores, there are several limitations. First, our sample size was not large enough to detect subtle differences among the study groups. Second, preoperative opioid use has recently been shown to increase post-operative opioid consumption following amputations and preoperative opioid consumption data was unavailable in our study. Moreover, selection of patients for regional anesthesia versus general anesthesia might have reflected concerns over post-operative pain control due to chronic opioid use. These patients would be expected to have higher preoperative opioid requirements, which could result in an underestimate of the effect of regional interventions on post- operative opioid consumption.
A174 Title: Manual Vacuum Aspiration Under Paracervical Block Versus Conventional Surgery Under General Anesthesia in First Trimester Abortion Presenting Author: M Yousri K Amin MD Presenting Author's Institution: Alexandria University – Alexandria Outside USA Co-Authors: Mohamed R Gaber MD – Alexandria University – Outside USA Ibrahim A Medhat MD - Alexandria University – Outside USA Tawfik T Abdelsalam MD - Alexandria University – Outside USA Abdelmoneim A Fawzy - Alexandria University – Outside USA
Abstract: Background: The objective of the study was to evaluate manual vacuum aspiration(MVA) versus conventional surgical treatment of first trimester abortion (D&C,E&C).
Methods: The study was carried out on 200 patients with different types of first trimester abortion, divided randomly into 2 groups: G1:(100 patients) subjected to MVA under Paracervical block(PCB). G2:(100 patients) subjected to conventional dilation or evacuation and curettage (D&C or E&C)under general anesthesia(GA). Both groups were evaluated: Intra-operative (operative time &complications) and post-operative(need for analgesia, duration of hospital stay & complications)
Results: The clinical data on maternal age, parity, duration and type of abortion, showed insignificant difference in both groups. Also, the operative time, the intra- and post-operative complications revealed the same results. On the other hand, Larengeal spasm as a complication of GA was recorded in 3%in G2.There was also, a marked significant increase for the need of postoperative analgesia,65% in G2(GA),than in 8% of G1(PCB). As regards to the hospital stay, there was marked significant reduction in G1, as 76% of the patients discharged after 2 hours, while 82% in G2 were discharged after 24 hours.
Conclusions: MVA under PCB is a safe and quick method for treatment of first trimester abortion. It is highly recommended to be used in developing countries, as it is safe, reduces time and maternal morbidity, and saves hospital resources.
A175 Title: Perioperative Peripheral Nerve Catheter(s) for Above-knee Amputations Presenting Author: Melanie J Donnelly MD Presenting Author's Institution: University of Wisconsin - Madison, WI Co-Authors: Matthew Piske MD - University of Wisconsin - Madison, WI Kristopher Schroeder MD - University of Wisconsin - Madison, WI
Abstract: Introduction: Patients having limb amputation may have severe perioperative pain resulting in large opioid requirements. This can contribute to over-sedation, nausea, vomiting, and prolonged hospital stay. Recently we have begun offering femoral and/or sciatic nerve catheters to patients having an above-knee amputation (AKA). Typically, these are placed 1 day prior to the scheduled operation, but may be placed the day of the operation. While it appears that patients do have improved pain control, this brief investigation was undertaken to objectively measure our results.
Methods: We looked retrospectively at a small series of 7 patients from July 2010 - November 2010 undergoing AKA. Four patients had intravenous patient-controlled analgesia for perioperative pain control, and three patients had femoral and/or sciatic peripheral nerve catheters (PNC) placed at least one day preoperatively. We compared pain scores (0-10 VAS) preoperatively, in the recovery room (PACU), and 48 hours post-operatively. We also collected data for total opioid requirements intra-operatively, in the PACU, and 48 hours post-operatively.
Results: Patients in the PNC group used only 20.0 mg intravenous (IV) morphine equivalents during the first 48 hours after surgery versus 366.8 mg IV morphine equivalents for the group without nerve catheters. Narcotics that were used included intravenous hydromorphone, oral oxycodone, and long acting oxycodone. Pain scores were lower in the PACU, and during the first 48 hours, in the peripheral nerve catheter group. All three patients receiving PNC‘s received transgluteal sciatic catheters, and two of them received femoral catheters. One of those patients did not receive a femoral catheter due to a fresh surgical wound in the groin. All sciatic and femoral infusions used 0.2% ropivacaine at 6-8 mL/hour with a bolus function. All catheters were left in place at least into post-operative day 2.
Discussion: Though the data certainly cannot be viewed as conclusive given our small sample size, the pain scores and opioid requirements for the first 48 hours post-operatively were reduced in the PNC group. Other medications used for pain such as gabapentin, pregabalin, or acetaminophen, have not been accounted for in this analysis. These objective findings confirm our clinical suspicions and are encouraging. There is very little literature on use of peripheral nerve catheters, placed by anesthesiologists, in patients having above knee amputations. A recent publication by Borghi et al.(1) examines pain control for a combination of above and below knee amputations. That study began as a randomized trial, but became observational due to the severe pain experienced by those who did not receive peripheral catheters. That finding alone illustrates the usefulness of PNC‘s for pain control in patients receiving amputations. In order to scientifically answer this question a large scale randomized trial must take place.
References: 1. Borghi, B, et al. Anesth & Analgesia. 2010;111(5):1308-1315.
Additional File #1: 1022711081936Table_1.doc Click here to view
Table 1. Averages for pain scores and opioid use in both groups
Mean total Mean Mean total Pain Scores 48 Mean total intraoperative recovery recovery hours post – opioid for opioids* room pain room operatively 48 hours scores opioids* post- (peak/low) (peak/low/mean) operatively*
Group 31.2 mg 6.0/5.0 15.5 mg 7.7/1.5/4.5 366.8 mg Without Nerve Catheter
Peripheral 20.0 mg 4.7/0 3.3 mg 3.7/1.0/2.5 20.0 mg Nerve Catheter Group
*IV morphine equivalents
A176 Title: The Usefulness of Three-phase Bone Scan and Thermography for Making the Diagnosis of CRPS-I Presenting Author: Park Sang Hyun, Professor Presenting Author's Institution: Department of Anesthesiology and Pain Medicine, Jeju National Un - Jeju, Korea Co-Authors:
Abstract: Background: Complex regional pain syndrome (CRPS) is a painful and disabling disease, yet the diagnosis of this can be difficult to confirm by purely objective measures. Therefore, we performed three-phasic bone scans and thermography as a work up in order to determine their predictive value and usefulness for making the diagnosis of CRPS.
Methods: 44 patients who had been diagnosed with CRPS type-1, according to the modified criteria, were evaluated. All the patients were examined by performing a three-phasic bone scan and thermography as part of a work-up for diagnostic confirmation. The diffuse increased tracer uptake in the delayed image (phase III) was estimated by the positive findings. The findings were considered positive for CRPS if the thermographic findings showed temperature asymmetries between the affected and non-affected extremities of more than 1.00℃.
Results: A review of the three-phasic bone scan for 44 patients indicated that 16 patients (36.4%) had diffusely positive scans, and thermographic abnormalities were noted in 35 of 44 patients (79.5%).
Conclusions: The use of thermography in clinical settings can play an important role in the diagnosis of CRPS. However, a three-phasic bone scan alone cannot provide a completely accurate diagnosis, so it is imperative that the three-phasic bone scan data be integrated with the clinical evaluation and the other relevant tests.
Key Words: CRPS, thermography, three-phasic bone scan.
A177 Title: Peripheral Nerve Blocks for Lower Extremity Surgery in High-Risk Surgical Patients Presenting Author: Paul Choi MD Presenting Author's Institution: New York Medical College - Westchester Medical Center - Valhalla, NY Co-Authors: Donna Vernon MD - New York Medical College - Westchester Medical Cen - Valhalla, NY Paul Wilson MD - New York Medical College - Westchester Medical Center - Valhalla, NY Jian Hou MD - New York Medical College - Westchester Medical Center - Valhalla, NY
Abstract: Introduction: Studies have shown that when compared to general anesthesia, regional anesthesia offers the following postoperative benefits: decreased incidence of nausea and vomiting, increased postoperative analgesia and decreased length of hospital stay. However, few studies have been performed to evaluate the effectiveness and safety of providing lower extremity anesthesia and unilateral sympathectomy by peripheral nerve blocks to high risk surgical patients who are undergoing lower extremity surgery, where other forms of anesthesia may not have been as effective, safe or even contraindicated.
Objective: The purpose of this study is to demonstrate that a unilateral sympathectomy anesthetic approach is a safe and effective anesthetic alternative in high-risk patients undergoing lower extremity surgeries who are not good candidates for general or neuraxial anesthesia.
Methods: We performed a retrospective chart review of 22 surgical patients who underwent regional anesthesia induced unilateral sympathectomy for lower extremity surgery at Westchester Medical Center (Table 1.1). A combination of regional blocks were used consisting of either a femoral or lumbar plexus block for anesthesia of the anterior, medial and lateral lower extremity while a sciatic or popliteal block was performed for anesthesia of the posterior lower extremity. Selected patients charts were reviewed for sex, age, co-morbidities, anticoagulation medications, intra-operative hemodynamic stability, fluid resuscitation, type of regional anesthetic technique used, length of hospital stay, and presence of any postoperative complications.
Results and Discussion: Table 1.1 shows that many of the patients had significant cardiovascular co-morbidities. Most notably, ten patients had heart failure, six patients had ICDs and/or pacemakers in place, six patients had atrial fibrillation, CAD was present in eleven patients, PVD and DM were present in thirteen patients, and four patients had TIA/CVA. In addition, three patients had pulmonary hypertension, while nine of the patients had some form of COPD. Table 1.1 lists all other relevant co-morbidities. Perioperatively, it can be seen in Table 1.1 that only two patients required 1-2 Units of PRBCs due to intra-operative blood loss and anemia. No other blood products were given. Intra-operative crystalloid infusion ranged from 400 ml to 3700 ml, with a mean of 1300 ml. The groups‘ perioperative SBP (95 mmHg to 190 mmHg) and DBP (45 mmHg to 90 mmHg) and HR (58 to 110) ranges were all very similar to their baseline / preoperative values. The groups‘ average estimated blood loss was approximately 250 ml with a maximum EBL of 600 ml.
Conclusion: The 22 patients in this case series analysis posed a significant challenge for safe and effective anesthetic management. This limited retrospective case series analysis demonstrates that peripheral nerve blocks done for lower extremity surgeries on patients who are high-risk and are not good candidates for general or neuraxial anesthesia, are safe and effective as an anesthetic option. As shown, regional anesthetic techniques provide for vitally essential intra-operative hemodynamic stability and are low risk for post-operative complications.
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A178 Title: The Use of Ultrasound Imaging for Performing the Lumbar Plexus Block in a 9-year-old Patient Presenting Author: Gaurav Rajpal MD Presenting Author's Institution: University of Pittsburgh Medical Center - Pittsburgh, PA Co-Authors: Ruttum David MD - University of Pittsburgh Medical Center - Pittsburgh, PA Cladis P Franklyn MD - University of Pittsburgh Medical Center - Pittsburgh, PA Chelly E Jacques MD, PhD, MBA - University of Pittsburgh Medical Center - Pittsburgh, PA
Abstract: Introduction: Lumbar Plexus block provides effective analgesia for hip, thigh and knee surgery. Especially in children, where depth of the lumbar plexus varies with age, external landmarks do not accurately predict lumbar plexus depth. We did a lumbar plexus block for a 9-year-old male pre-operatively for Femoral Varus Osteotomy procedure under Ultrasound guidance.
Case History: A 9-year-old, 27 kg patient with Perthes disease came to the hospital for Femoral Varus Osteotomy procedure. The surgeons consulted the pain service for perioperative pain management. The patient and parents were offered a lumbar plexus block pre-operatively which was agreeable to them. The patient was given general anesthesia and intubated without muscle relaxants. The patient was placed in left decubitus position with the operative hip superior. External landmarks were marked, the iliac crest and the saggital plane identified. The curved array ultrasound probe with a low frequency was placed in the saggital plane and spinous process was identified in line with the iliac crest. The transducer was then moved laterally toward the operative side until hyperechoic transverse process is seen. The transducer was then turned perpendicular to the saggital plan. The lumbar plexus was identified next to the transverse process. After sterile preparation, draping and putting an ultrasound sleeve on to the transducer, the transducer was placed in the similar position as was used to identify lumbar plexus. With the bevel directed medially, a 10 cm, 18 gauge insulated needle was inserted in a lateral to medial direction. The needle was connected to a nerve stimulator initially set at 1.5mA, 0.1 ms and 2 Hz, the needle was directed at the lumbar plexus until quadriceps femoris contraction and patellar motion was elicited with an electric current of 0.5mA. 10ml of 0.2% ropivacaine was injected through the needle. The depth of the plexus from the point of insertion of needle was 7cm and a 22 gauge catheter was threaded 5 cm past that point. The catheter was secured with steri strips and a transparent tegaderm was used to tape on top of that.
The surgeons then proceeded with the surgery which went uneventful. The patient got 100mcg of fentanyl intraoperatively. Post-operatively, the lumbar plexus catheter was connected to a local anesthetic infusion of 0.2% ropivacaine for postoperative pain control at the rate of 4ml/hr. The patient was ordered roxicodone 2.5mg Q4H prn, toradol 12mg Q6H prn, acetaminophen 275mg Q6H and dilaudid 0.125mg Q1H prn. The patient did not request any rescue doses of dilaudid for next 24 hours as the patient was rating his pain scores in the range of 2-5/10 in the following 24 hours. The pain medications were adjusted the following day, the rate of nerve block infusion increased to 5ml/hr, dose of acetaminophen increased to 400mg Q6H. The catheter was removed postoperative day 3. The patient and the family were very satisfied with the pain management.
Conclusions: The sonographic identification of the lumbar plexus in children is a feasible option to blind technique as the depth of the plexus varies with age and external landmarks do not accurately predict lumbar plexus depth. The lumbar plexus performed under ultrasound guidance provides effective analgesia for hip and thigh surgery in children.
A179 Title: Safety and Efficacy of Fluoroscopic guided Epidural Blood Patch in iatrogenic dural puncture: an eight year retrospective review in a teaching institution Presenting Author: Raed Rahman MD Presenting Author's Institution: University of Chicago Medical Center – Chicago IL Co-Authors: Magdalena Anitescu MD, PhD - University of Chicago Medical Center - Chicago, IL
Abstract: Background: A post-dural puncture headache (PDPH) can arise as a result of inadvertently puncturing the dura mater during epidural catheter placement for post-operative pain control, labor analgesia or epidural steroid injections. It can also be a consequence of diagnostic or therapeutic spinal fluid instrumentation or spinal fluid. The epidural blood patch (EBP) is currently considered the gold standard treatment for severe, refractory and debilitating PDPH. However this procedure carries the risk of aggravating the headache by another accidental dural puncture. We hypothesize that performing EBP with fluoroscopic guidance is associated with minimal side effects and excellent pain relief in patients with refractory PDPH.
Methods: Upon obtaining IRB approval, we identified all patients in our institution who underwent at least 1 blood patch in an 8-year interval (May, 2002-September, 2008). The charts of all those patients were retrospectively reviewed and data regarding the presence, intensity and quality of the PDPH symptoms, procedure techniques, number of procedures performed per patient, complications related to the procedures or conditions as well as effectiveness of the procedures to relieve the PDPH symptoms were recorded and analyzed.
Results: From the total of 105 patients undergoing an EBP in the interval described, 6 had their procedure done without fluoroscopic guidance. From the remaining 99 patients, 15 were excluded due to incomplete documentation in medical records. 82 (98%) of the 84 remaining patients reported headache relief (either qualitatively or quantitatively). 2 (2%) of the 84 patients had 0% relief. In the 56 patients reporting quantitative pain relief the VAS scores decreased from 8.4/10 to 1.2/10. In this subpopulation, 53 (94%) reported 70%-100% pain relief with the procedure while the remaining 3 (6%) reported only 20-30% pain relief. From all the patients included in the study, only 1 patient had a vasovagal syncope after completion of the EBP which resolved with supportive treatment. No other complications were recorded. Patients were not followed in the pain clinic unless their persistent symptoms required an additional blood patch (6 patients).
Conclusions: Although the EBP is considered the gold standard in treating PDPH symptoms, it‘s use is limited by fear of symptom worsening with additional accidental dural tear. By performing the procedure under direct fluoroscopic guidance, this complication can be decreased significantly while providing increased patient satisfaction. Our study, despite its limitations (retrospective review, limited documentation), showed that patients had profound pain relief with the procedure performed under fluoroscopy while the rate of complications was insignificant. This pilot study suggests that fluoroscopic guidance for EBP might be of significant benefit for patient with PDPH and can be offered early in the course of the treatment of the positional headache with known etiology. However, prospective studies may be necessary to elucidate this hypothesis.
References 1. Apfel CC , Saxena A, OS Cakmakkaya, R Gaiser, E George, and O Radke. Prevention of Postdural Puncture Headache after Accidental Dural Puncture: A Quantita.
Additional File #1: 1022411095946ASRA2011abstractgra.doc Click here to view 84 Included Patients
Quantitative Relief Qualitative Relief No Relief (56 patients) (26 patients) (2 patients)
A180 Title: Examination of Medline Publications from Academic Anesthesiologists in the United States from 2006-2008 Presenting Author: Christopher L Wu MD Presenting Author's Institution: Johns Hopkins University - Baltimore, MD Co-Authors: Robert Hurley MD, PhD - University of Florida - Gainesville, FL Kevin Zhang MD - Johns Hopkins University - Baltimore, MD Jamie Murphy MD - Johns Hopkins University - Baltimore, MD Phebe Ko MD - Johns Hopkins University - Baltimore, MD
Abstract: Background: Traditional academic medicine is based on a model in which research and education are integral to the primary mission of excellent clinical care, a number of regulatory and financial pressures are challenging academic medicines ability to meet it missions. We undertook a systematic search to examine publication output for the entire US academic anesthesiology community over a 2 year period.
Methods: The FAMOUS database of the AAMC was used to obtain the names and demographic information for all registered faculty in anesthesiology departments in the United States. A search of the Medline database from July 2006 to June 2008 was performed using each of the names and the resulting publications were then stratified based on the author order, academic rank, degree and institution.
Results: Examination of the FAMOUS database revealed 6954 faculty who held positions at 108 US academic anesthesiology programs between July 1, 2006 and June 30, 2008. Approximately 50% were at the Assistant Professor level and over slightly 80% had an MD degree only. There were a total of 6044 unique publications. The majority of unique publications were original articles (76%), followed reviews (16.8%) and case reports (7.3%). Professors published at a rate twice that for Associate Professors (3.4 vs. 1.8 publications [over 2 years]/faculty), who in turn published at a rate twice that for Instructors (1.8 vs. 0.8 publications [over 2 years]/faculty). Faculty with a PhD degree published at a higher rate than those with MD and PHD degrees (3.8 vs. 2.6 publications [over 2 years]/faculty) or MD (3.8 vs. 1.1 publications [over 2 years]/faculty) degrees. Faculty members had an average of 0.7 publications/year over the 2-year period with the median number of publications = 0. Only 14 of the 108 institutions had more than half of their faculty publish in the two year study period. Approximately 65% of faculty had no publications whereas the top 1% of authors was responsible for 17% of all publications. The top 5% of authors were responsible for 48% of all publications and the top 20% of authors accounted for 87.6% of all publications.
Conclusions: In anesthesiology, higher academic rank is associated with higher rate of publishing in peer review journals. However, these publications are not normally distributed; a relatively small minority of faculty published the majority of manuscripts making academic departments vulnerable. Although there are other forms of scholarly activity, publication of peer-reviewed manuscripts remains one of the most common barometers of academic achievement. Further investigation to enhance the academic productivity of low publishing faculty is needed.
A181 Title: Ultrasound-Guided Continuous Suprascapular Nerve Block after Surgery for Frozen Shoulder Presenting Author: Jens Børglum MD, PhD, MBA Presenting Author’s Institution: Copenhagen University Hospital: Bispebjerg - Copenhagen NV, Copenhagen Co-Authors: Michael R. Krogsgaard MD, PhD – Copenhagen University Hospital: Bispebjerg - Copenhagen NV, Copenhagen Kenneth Jensen MD, BBA – Copenhagen University Hospital: Bispebjerg – Copenhagen NV, Copenhagen
Abstract: Background: Frozen shoulder is an extremely painful condition. There is marked synovitis of the glenohumeral joint and thickening of the shoulder capsule. No curative treatment has so far been proved effective. However, capsulotomy and subsequent physiotherapy have shown promising results. Physiotherapy must begin as quickly as possible to improve range of motion, attenuate inflammation, and prevent fibrous developments. The sensory part of the suprascapular nerve (SSN) supplies the scapula and the acromioclavicular joint, and contributes 70% of the nerve supply for the superior and posterior part of the shoulder. Our aim was to provide continuous blockade of the SSN for postoperative pain management by using ultrasound (US) guidance to insert a perineural catheter in the suprascapular notch.
Methods: Following surgery, a perineural catheter was placed under US guidance in the scapular notch below the superior transverse ligament (TSL) where the SSN runs (Fig. 1). The catheter set was a Contiplex Tuohy needle 18G (150 mm) and a 0.85 x1000 mm (20G) catheter (B. Braun, Germany). The ultrasound machine was a Flex Focus 400 Anesthesia (BK Medical), and the transducer was a 1.8-6 MHz curved array. The transducer was placed parallel to the scapular spine, and the needle inserted at the medial end of the transducer (Fig. 1). The needle was advanced under US guidance through the supraspinatus muscle towards the inferior-lateral endpoint in the scapular notch below the TSL (Fig. 2). A bolus of 5 mL ropivacaine 2 mg/mL was administered before the catheter was advanced 1 cm past the needle tip. Correct placement of the catheter was confirmed under US guidance when the injectate of 1 mL ropivacaine 2 mg/mL expanded beneath the transverse scapular ligament (Fig. 2). The catheter was connected to an elastomeric pump containing 300 mL ropivacaine 2 mg/mL, infusion rate 5 mL/hour. During the following 25 days, postoperative pain (VAS 0-10), range of motion (ROM) (Fig. 3), physical well-being, emotional outlook, and eventual adverse events were recorded. Results: With a well functioning catheter in place, VAS remained 0 to 2 under the prescribed physiotherapy and exercise. The first catheter provided for a continuous block for 10 consecutive days. When unintentionally displaced during low-impact passive and guided active mobilization, severe pain (VAS = 7) was quickly manifest but disappeared when a new catheter was inserted for the following 11 days. Motor abilities, judged by the Modified Barthel Index/100, were only reduced by 5% on the first postoperative day, and perceived ill health, judged by the Short Form-8- Index, was not affected by pain, loss of energy or emotional and social problems. Most importantly, development in ROM, judged by passive external and internal rotation, continued to improve during a total of 25 days (Fig. 3).
Conclusion: This case report represents the first study in which an US-guided placement of a perineural catheter provides an effective continuous block of the SSN and allows for effective and virtually pain-free physiotherapy following capsular release. Our results highlight the importance of focusing on the postoperative period and the value of an US-guided SSN block.
Figure 1. Ultrasound-guided block of the suprascapular nerve
Model photo: Ultrasound transducer and needle orientation for the placement of a catheter providing for continuous blockage of the suprascapular nerve (inside circle). The transducer is placed parallel to the scapular spine. The recommended needle insertion point is at the medial end of the transducer, and the needle is advanced under real-time ultrasound guidance towards the inferior-lateral endpoint at the scapular notch beneath the transverse scapular ligament (TSL), thus providing a tunnel through the supraspinatus muscle (SPM). TP = trapezius muscle. Coracoid process = CP.
Figure 2. Transverse view of the suprascapular fossa
Ultrasonographic image of the suprascapular fossa and scapular notch roofed by the transverse scapular ligament (TSL). The injectate of local anaesthetic (LA) has been placed below the TSL lifting it as the injectate expands the tissue in the scapular notch. The catheter is subsequently advanced through the needle (arrow) into this expansion. Trapezius muscle = TP. Suprraspinatus muscle = SPM.
Figure 3. Development in range of motion (ROM)
Development in ROM pre- and postoperatively. Continuous line = passive external rotation. Dotted line = passive internal rotation. On day 0, the patient had the operation. On day 11, the second perineural catheter was inserted; the catheter was discontinued on day 22.