International Journal of Current Medical And Applied Sciences, 2019, December, 25(1), 06-12.

ORIGINAL RESEARCH ARTICLE Choice and Timing of Inotrope For Off- Pump CABG. Rajiv Lakhotia1 & L. D. Mishra2 1Associate Professor, 2Director [Academics], Professor and Head, Department of Anaesthesiology, Critical Care & Pain Medicine, Hind Institute of Medical Sciences, Barabanki [UP], India. ------Abstract: - Introduction: Off- pump coronary artery bypass grafting [OPCAB] continues to be in popular practice at many centers. The choice of inotropes for perioperative OPCAB management has been a challenging proposition. Methods: 60 patients requiring multiple grafts with LVEF greater than 40% were included in the study. They were randomized to receive , and as the inotrope during the perioperative period and accordingly divided into 3 groups respectively I, II and III. Phenylephrine bolus doses were used as rescue inotrope to maintain MAP. Composite grafts [T grafts LIMA – Radial] and SVG were used for myocardial revascularization. Average number of grafts was approximately 4. Results : The haemodynamic stability was significantly superior in Group III than in Group I and II. The number of rescue shots of phenylephrine bolus doses to maintain MAP at an acceptable range and the amount of beta –blockers used to control the tachycardia was also significantly higher in Group I & II. The ischaemic episodes as observed by ST variations were also significantly lower in Group III. Conclusion: Adrenaline causes less tachycardia than Dopamine and Dobutamine at equivalent inotropic doses. When Adrenaline increases the HR within physiologic range, it shortens more than , thus increasing the diastolic and preserving the native coronary blood flow better during the procedure [balanced alpha and beta effects]. It provides superior haemodynamics and coronary perfusion [oxygen supply] and thus a beneficial supply / demand [MVO2] ratio to the ischaemic myocardium. Keywords: OPCAB, Inotrope, Chronotrope.

Introduction: Off-pump coronary artery bypass [OPCAB] grafting and Adrenaline and their effects on perioperative continues to be in popular practice at many centers. variables; thereby seeking to determine which The authors felt that an inadequate information was inotrope would serve the goal of better available in the literature which can guide inotrope haemodynamics and superior preservation of use for perioperative management for OPCAB myocardial function during the OPCAB procedure. procedure, especially with regard to choice of a chronotropic inotrope. The clinician s choice from Material & Methods: among inotropes has been a challenging proposition After approval of the institutional ethical committee, with various institutions following different’ protocols. informed consent was obtained from each patient. 60 This prospective randomized study was undertaken to patients requiring multiple graft coronary objectively evaluate three most frequently used revascularization with left ventricular chronotropic inotropes viz. Dopamine, Dobutamine [LVEF] greater than 40% were selected for study. ------Address for correspondence: Dr. Rajiv Lakhotia, Access this Article Online 34, Aakaanksha, ELDECO, Udyaan-2, Rae Bareilly Road, Lucknow , UP, India, Website: PIN --226025. www.ijcmaas.com Email ID- [email protected] How to cite this article: Rajiv Lakhotia & L.D. Mishra : Choice and Timing of Chronotropic Subject: Inotrope For Off- Pump CABG: International Journal of Current Medical Sciences Medical and Applied sciences; 2019, 25(1), 06-12. Quick Response Code

IJCMAAS, E-ISSN: 2321-9335,P-ISSN:2321-9327 Page | 06 Rajiv Lakhotia & L.D. Mishra Patients with left main coronary artery disease in normal position, inferior wall stabilization, [LMCAD], age more than 60 years or any other anastomoses on inferior wall, heart in normal significant co-morbidity viz. renal dysfunction, position, partial clamp for top ends, after proximal neurological dysfunction, previous cardiac surgery, anastomoses, protamine administration, final hepatic dysfunction, cardiothoracic ratio on chest x- assessment of distal anastomoses, sternal closure, ray >60%, associated valvular lesions, significant shifting to ICU. Then a mean value for individual peripheral vascular disease, recent myocardial patient for all parameters was calculated, for the infarction; i.e. patient related factors which could per purpose of study. se affect the perioperative variables and post- Surgical approach was achieved through a standard operative morbidity were excluded from the study median sternotomy under general anesthesia. LIMA design. Further they were screened through Euro was harvested using extra pleural approach Score of risk stratification [1]. Patients with low risk whenever possible. Simultaneously other conduit prediction score were only included in the study were also harvested. After conduit harvesting partial design. They were randomized to receive Dopamine, heparinization in dose of 2 mg/kg unfractionated Dobutamine and Adrenaline as the inotrope during heparin was administered to maintain activated the perioperative period and accordingly divided into coagulation time [ACT] greater than 250 seconds till 3 groups respectively I, II and III, comprising of 20 the completion of revascularization. Radial artery patients each, irrespective of age, sex or body weight. conduits were treated with a dilute solution of NTG, Group I patients received Dopamine, group II Papaverine and . When multiple arterial received Dobutamine and Group III received grafts were planned, proximal end of radial artery Adrenaline as the inotrope during the course of was anastomosed in an inverted Y fashion to the OPCAB surgery. Phenylephrine bolusdoses were used proximal portion of LIMA at the level of 3rd as rescue inotrope to maintain mean arterial intercostal artery. Following pericardiotomy, pressure [MAP]. All patients were on beta-blockers, traction sutures were placed on the pericardial cradle nitrates and calcium channel blockers preoperatively to lift the heart anteriorly. Assessment of target which were continued until the day of surgery. All vessels was done with minimum cardiac patients were premedicated with Tab Diazepam, Inj. manipulation. Right hemi sternum elevation, Fentanyl and Inj. Phenargan intramuscular as per extensive right pleurotomy, and deep vertical right institute protocol. The standard induction protocol pericardiotomy were done to allow cardiac included Inj. Midazolam 0.05mg/kg, Inj. Fentanyl 10 herniation into the right pleural cavity. To assist mcg/kg[narcotic based induction], Inj. Vecuronium further in access to posterior and inferior walls, 0.15mg/kg, supplemented with Isoflurane in an patients were placed in gentle right tilt and head Oxygen/ Nitrous Oxide mixture and ventilated using down position. For exposure of LAD artery a sponge Datex Excel 7600 ventilator through closed circle was placed in the dorsolateral aspect of pericardial system. Inj Vecuronium and Inj Fentanyl infusion was cavity. Mechanical stabilization was achieved using supplemented in maintenance doses until the end of Octopus III [Medtronic Inc, Minneapolis MN] surgery. stabilizer, CO2 Mist Blower [Cardiovations TM, For intraoperative , a combination of leads Ethicon Endo surgery, Inc, Cincinnati, Ohio, USA] II and V5 was continuously displayed and used for ST was used to provide a clear surgical field. segment trend analysis. Invasive beat to beat blood Intracoronary shunts– [Anasto Flo, Baxter Inc, CA 1.5 pressure waveform was displayed through radial mm, 2mm, 2.5mm] were used to minimize ischemia arterial– cannulation. A catheter and reduce bleeding at the anastomotic – site. [Swan Ganz 7F 110cms Edwards Life Sciences. CA, Anastomoses were performed in order of increasing USA] was inserted in situ after induction of general cardiac displacement. Distals were anastomosed anesthesia.– Patient temperature was maintained at using 7-0 prolene running sutures and proximal >360C using a water mattress, prewarmed anastomoses were done using 6-0 prolene intravenous fluids, and an ambient operating room continuous suture technique. After proximal temperature of >200C. Temperature was constantly anastomoses were completed, protamine was monitored via a properly placed nasopharyngeal administered to reverse heparin effects. temperature probe. Haemodynamic instability was defined as fall in mean A cardiopulmonary bypass [CPB] set up was kept arterial pressure [MAP] < 60 mm Hg at any point of ready, but not primed, and the perfusionist team was time requiring intervention viz. physiological e.g. readily available. Intraaortic balloon pump [IABP] intravenous fluids, steep Trendelenburg position; backup was also maintained. Cell saver [Dideco, USA] mechanical e.g. release of heart to pericardial bed; was used as and when required. pharmacological e.g. phenylephrine bolus [rescue Parameters were recorded at following intervals in shots of 50 mcg], etc. sequence: baseline, induction of anesthesia, skin By convention the distal port of the central venous incision, sternotomy, left internal mammary artery cannula was used for [LIMA] harvesting, pericardiotomy, evaluation of monitoring; the middle port used for vasodilators e.g. target vessels, anterior wall revascularization, lateral NTG, etc.; the proximal port used for inotrope wall stabilization, distal anastomoses on lateral wall, infusion. Thus to account for the dead space of

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proximal port of the central line 0.5 ml of inotrope Persistent ventricular arrhythmias [4] persistent was flushed before starting the infusion. Fall in changes in ST segments more than 1 mm [5] systolic to < 90 mm Hg was classified Progressive increase in mean pulmonary artery as criteria to initiate inotrope infusion. Inotropes pressure [PAP] associated with a fall in MAP. were used as per group to maintain stable Following grafting strategy was adopted. The LAD in following doses : Group I and was always bypassed first. Vessel with more critical Group II, 3-5 mcg/kg/min and Group III 0.01 to 0.03 stenosis, relatively, or without any collaterals, was mcg/kg/min. then bypassed. Thereafter the proximal anastomoses If the [HR] exceeded 90 beats per min, Inj. were completed before performing the distal was administered in bolus doses of 1 mg anastomosis on next target vessel. The guiding followed by 0.5 mg increments if necessary so as to concept was that more cardiac manipulation was maintain the HR < 90 beats/min. The haemodynamic better tolerated with increasingly more parameters were restored to baseline levels [if they revascularization. were less than that] before the surgeon attempted A mean value for all the variables for a particular the next anastomosis. Serum K+ was monitored and patient was determined. Then mean values for the corrected when less than 3.5 m Eq/L. ABG were group along with standard deviation was calculated. monitored and any metabolic acidosis was corrected The analysis of significance for the variables was if observed pH was < 7.35, Following criteria served evaluated using chi-square statistics. For any as guidelines for conversion to CPB: [1] fall in MAP < statistical purpose p value less than 0.05 was 50 mm Hg [2] LV distension with [3] regarded significant. ‘ ’ Observation & Results: Table 1 : Demographic Profile Variables No. Percentage Sex Male 52 86.66 Female 08 13.33 Age [mean] in years 49.85 Previous MI [>3 months] 12 20 Diabetes Mellitus 24 40 Hypertension 38 63.33 COPD 5 8.33 The demographic data of the 60 patients included in the study is summarized in Table No. 1. There were 86.66% male and 13.33% female patients. The mean age of the patients was 49.85 years. 20% patients had suffered previous MI of more than 3 months duration at the time of surgery . 40% patients were known cases of Diabetes Mellitus, 63.33% suffered from Hypertension and 8.33% had previous history of established Bronchitis or Bronchial Asthma. Table 2 : Angiographic Profile Variables No. Percentage Double – vessel disease 12 20.0 Triple – vessel disease 48 80.0 Analysis of Table 2 reveals majority [80%] patients presented with triple vessel disease, while 20% presented with double vessel disease. Table 3 : Surgical Parameters : Variables No. Percentage Total no. of distal anastomoses 233 Graft distribution LAD 60 25.75 Diagonals 26 11.15 Obstuse Marginals 77 33.04 Ramus Intermedius 10 4.29 RCA/PDA / PLB 60 25.75 Mean no. of grafts per patient Conduits used 3.88 LIMA 57 Radial 54 SVG 44 Intramyocardial vessels 5 8.33

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Rajiv Lakhotia & L.D. Mishra

Summarized data in Table 3 reveals that total number of distal anastomoses i.e. the no. of vessels revascularized were 233, out of which 25.75% were on LAD, 11.15% on Diagonal, 30.04 % on circumflex territory [Obtuse Marginals], 4.29% on Ramus Intermedius , and 25.75% were on the RCA / PDA/PLB. Mean number of grafts per patient was 3.88. 8.33% of the target vessels were intramyocardial. Table 4 : Perioperative Complications & Related Variables Variables No. Percentage Use of cell saver 6 10 CPB Conversion 2 3.33 Re-exploration for Bleeding 3 5 Periop MI 1 1.66 Inhospital Mortality 0 0 Post - op AF 8 13.33 In 10% of patients cell saver was used intraoperatively to salvage blood from significant generalized oozing [Table 4] 2 patients [3.33%] [1 from Dopamine group and 1 from Dobutamine group] did not tolerate cardiac displacement and positioning during inferior wall revascularization and had to be converted to CPB. They had fall in MAP, along with a rise in PA pressure and significant ST changes . In these 2 patients grafting was done on a beating heart on CPB without aortic cross clamp. 1 patient out of these two [Dopamine group] suffered lateral wall MI in the postoperative period. 5% patients were re explored for unacceptable postoperative bleeding. 13.33% patients suffered atrial fibrillation [AF] postoperatively. – Table 5 : Perioperative Data Group I Group I I Group III DOPAMINE DOBUTAMINE ADRENALINE 3-5 mcg/kg/min– 3-5 mcg/kg/min– 0.01-0.03 mcg/kg/min– DOSE mcg/kg/min [mean] 4.3  0.73 4.25  0.71 0.018  0.006 HR/min [mean] 87.08  3.65 85.09  3.14 77.03  3.77 SBP mm Hg [mean] 119.06  3.99 113.23  3.38 121  2.45 DBP mm Hg [mean] 75.16  5 72.6  2.9 78.83  3 MAP mm Hg [mean] 89.65  3.93 85.81  2.87 92.67  2.98 PAP mm Hg [mean] 23.33  2.86 22.14  3 22.49  3.11 PCWP mm Hg [mean] 17.2  2.29 16.25  2.64 16.19  2.93 ST changes in mm [mean] 0.88  0.26 0.78  0.24 0.51  0.14 pH [mean] 7.35  0.03 7.37  0.03 7.39  0.02 NaHCO3 in ml [mean] 165  40.87 148.75  35.79 81.25  32.31 Rescue Shots [mean] 2.0  0.94 2.85  0.81 1.07  0.86 [Phenylephrine] Phenylephrine dose in mcg [mean] 105.55  41.61 142.5  40.63 58.33  41.74 Metoprolol dose in mg 2.12  0.58 1.9  0.34 1.11  0.33 Hemodynamic instability [mean] 1.4 0.8 0.1 Run of VPC [mean] 0.65 0.55 0.15 SVT episodes per group 3 2 2 VT/VF per group 2 3 1 Defibrillation 1 1 1 CPB Conversion 1 1 0 No. of grafts [mean] 3.8  0.52 3.9  0.55 3.9  0.44

In hospital mortality was zero. Analyzing Table 5,  3.38 mm Hg for Group II and 121  2.45 mm Hg we observe that the mean dose of Dopamine for Group III; the mean DBP observed for Group I infusion in Group I was 4.3  0.73 mcg/kg/min, was 75.16  5.07 mm Hg , for Group II it was 72.6 the same for Dobutamine in Group II was 4.25   2.9 mm Hg, whereas for Group III it was 78.83  0.71 / mcg/kg/min, whereas the same for 3.02 mm Hg; the mean PAP was 23.33  2.86 mm Adrenaline in Group III was 0.018  0.006 Hg in Group I, it was 22.14  3 mmHg in Group II , mcg/kg/min; mean HR maintained in Group I was whereas it was 22.49  3.11 mm Hg in Group III; 87  3.65 per min, the same in Group II was 85.09 the mean PCWP for Group I was found to be 17.2  3.14 per min, whereas it was 77.03  3.77 per  2.99 mm Hg, it was 16.25  2.64 mm Hg in min in Group III; the mean SBP calculated for Group II and it was found to be 16.19  2.93 mm Group I was 119.06  3.99 mm Hg, it was 113.23 Hg in Group III; the mean ST changes from baseline

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Rajiv Lakhotia & L.D. Mishra was 0.88  0.26 mm in Group I, it was 0.78  0.24 Group III was significantly less than in Group I and mm in Group II, whereas it was 0.51  0.14 mm for Group II [p<0.01] ; whereas the differences in the Group III; the mean pH calculated for Group I was three groups with reference to mean PAP and 7.35  0.03, it was 7.37  0.03 for Group II, mean PCWP were not found to be statistically whereas the same for Group III was 7.39  0.02; significant. The mean pH value was better mean amount of Sodium bicarbonate [NaHCO3] preserved in Group III the difference between administered for Group I patients was 165  40.87 Group III and Group I being statistically significant ml, for Group II it was 148.75  35.79 ml, for [p<0.01]; the mean amount of NaHCO3 required to Group III it was 81.25  32.31ml; mean number of maintain acceptable ABG values was significantly rescue shots of Phenylephrine given were 2.0  less [p<0.01] in Group III than in Group I & Group 0.94 in Group I patients per patient, the same were II. The mean number of rescue shots of Inj. ‘2.85  ’0.8 in Group II, whereas the same in Group Phenylephrine as bolus doses given were least in Group III and most in Group II with Group I in III were found to be 1.07  0.86; mean amount of between and the differences in the three groups Phenylephrine required to maintain acceptable were statistically significant [p<0.01]. Similarly the haemodynamics in Group I was 105.55  41.61 mean dose of Inj. Phenylephrine administered to mcg, in Group II it was 142.5  40.63 mcg, whereas maintain stable haemodynamics was found to be the same was only 58.33  41.74 mcg in Group III least in Group III and most in Group II with Group I patients; mean dose of Metoprolol required in in between and the differences within the groups Group I patients to maintain acceptable HR was were statistically significant. Even the mean dose 2.12  0.58 mg, it was 1.9  0.34 mg for Group II, of Inj. Metoprolol administered to maintain HR whereas the same required for Group III patients within acceptable range was significantly less was 1.11  0.33; episodes of haemodynamic [p<0.01] in Group III than in Group I & II. The instability were observed as mean of 1.4 times mean occurrences of haemodynamic instability per patient in Group I, the same was 0.8 in Group were significantly less in Group III than in Group I II, whereas it was only 0.1 per patient in Group III; & II [0.1 per patient as compared to 1.2 and 0.8 the run of premature ventricular contractions respectively]; the mean number of episodes of run [PVCs] was a mean of 0.65 per patient in Group I, of PVCs also were found to be significantly less in 0.55 per patient in Group II and 0.15 per patient in Group III than in Group I & II. group III; 3 episodes of SVT in the group of 20 patients were observed during study in Group I, Discussion: the same was observed to be 2 episodes in Group II The gold standard of surgical revascularization has and 2 episodes in Group III; 2 episodes of been challenged by the development of balloon malignant ventricular arrhythmias were observed angioplasty catheters. Evolutionary strategies in in Group I of which one required to be defibrillated Cath Lab , has generated renewed interest in and one procedure was converted to CPB, in OPCAB surgery with its potential benefits, viz. Group II, 3 episodes of malignant ventricular avoiding‘ the’ complications associated with CPB, arrhythmias were noted of which one episode yet offering the patient the benefit of long term required defibrillation and one procedure was graft patency that greatly exceeds that of current converted to CPB, whereas in Group III only 1 endovascular technologies [2]. However a less episode of malignant ventricular arrhythmia was optimal operative field and limited access may observed which was defibrillated. None was result in incomplete procedures[3]. However, in converted to CPB in Group III. The mean number of our study, we achieved complete myocardial grafts anastomosed in Group I were 3.8  0.52, it revascularization, albeit, the patients were was 3.9  0.55 in Group II and 3.9  0.44 in selected, so necessitated for the objective of the Group III. study. Calafiore et al documented that arterial A study of Table 5 reveals that the mean increase revascularization of all the arteries of the heart is in HR in Group I & II as compared to Group III was possible without the use of CPB in selected statistically significant [p<0.01] in infusion doses patients, with results similar to those done with which provided acceptable haemodynamics CPB[4]. The procedure of OPCAB requires a period intraoperatively. There was significant increase in of temporary occlusion of the target coronary mean SBP in Group I and Group III compared to artery, this along with cardiac displacement, Group II [p<0.01]; mean DBP was significantly causing myocardial ischemia accompanied by greater [p<0.01] in Group III than in Group I and haemodynamic instability and arrhythmias [5]. Group II; the mean value of MAP was also greater The challenge for the anesthesiologist is to in Group III than in Group I & II [p<0.01], also the facilitate and contribute to the evolutionary increase in mean MAP in Group I compared to process of OPCAB; inotrope management being Group II was statistically significant [p<0.01]; the one such domain. difference in ST changes from baseline value in

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The average number of distals per patient in our We observed that superior MAP and better DBP, study was 3.88. Manish et al reported an average the mean HR was significantly lesser with of 3.2 distal anastomoses per patient in their series Adrenaline and significantly less amount of of 500 patients [6]. The present series had no post- Metoprolol [] was used operative strokes. Manish et al also reported zero intraoperatively to control the HR within post-operative stroke rate in their study[6]. 3.33% acceptable range. It– is consistent with the [2 cases] were converted to CPB during our study. available literature which states Epinephrine Tugtekin et al reported 3.2% conversion to CPB causes less tachycardia than Dopamine [13] or [7]; all the patients in their study had LVEF <30%, Dobutamine [14] at equivalent inotropic doses. although the study was only for anterior vessels. 1 With Adrenaline HR is increased, systole is patient suffered perioperative MI [1.66%] in this shortened and strengthened, myocardial work and study. In another study it was reported 1.2%, thus MVO2 are increased but within physiological although 12.4% patients had preoperative range of HR, it shortens systole more than diastole, LVEF<25% in their study [6]. The authors so that the duration of diastolic perfusion is better observed 13.33% incidence of post-operative AF in preserved [15]. This tilts the demand [MVO2] / their study; which is consistent with incidence supply [coronary perfusion] ratio favourably to the reported by various authors, as 12.5 to 29% in ischaemic myocardium, preserving the native OPCAB [5,8,9]. coronary blood flow better during the procedure The in hospital mortality in the present study was [balanced alpha & beta effects]; which accounts for zero. It was reported as 0.8% in a study which significantly less ST changes from base line included 12.4% patients with LVEF<25% [6]. observed in patients on Adrenaline infusion during Cartier s study reported 1.1% mortality in their OPCAB. It is known that Adrenaline increases study due to various reasons viz. multiorgan coronary perfusion pressure through its alpha failure,’ malignant arrhythmia and even aortic effects [15]. Kaplan [15] suggested a sustained dissection [10]. effect can be obtained with a continuous infusion Significantly less ST changes in the group of of Adrenaline in the range of 0.03 to patients receiving Adrenaline infusion suggests 0.1mcg/kg/min for average sized adult patient in that perioperatively myocardial function the post CPB period to tackle episodes of preservation was superior in that group when haemodynamic instability. We had similar results compared to Dopamine or Dobutamine in the in a dose range of 0.01 to 0.03mcg/kg/min during equivalent inotropic doses used. OPCAB surgery. Grundeman et al [11] stated that cardiac Steen et al demonstrated usefulness of Adrenaline displacement during OPCAB surgery causes a infusion in cardiac surgical patients after CPB [16]. major drop in , despite elevation of Adrenaline [0.04 mcg/kg/min] was compared with right ventricular and unchanged LV Dopamine and Dobutamine in doses of 5 to 15 preload; whereas Porat et al [12] stated that mcg/kg/min at a constant preload and was shown cardiac displacement caused right heart to produce superior haemodynamics in terms of dysfunction precipitating haemodynamic , MAP, HR, while systemic vascular instability. We also believe that due to the resistance [SVR] did not change , and no geometric changes precipitating restrictive filling arrhythmias occurred with Adrenaline. This is pattern of LV, added to it, the malorientation of the consistent with our observation during OPCAB annular apparatus, precipitates mitral procedure; where episodes of haemodynamics regurgitation [MR] which contributes to higher instability and run of PVCs were significantly less pulmonary pressures and right heart dysfunction in Adrenaline group. Due to superior maintenance leading to decreased and of systemic and thus perfusion pressure the haemodynamic instability. Observations in the amount of Phenylephrine doses were also Group III also suggest that apart from geometric significantly less in group of patients receiving reasons, other variables viz. preservation of Adrenaline. optimum heart rate, rhythm, coronary perfusion Though Hilsted at el [17] demonstrated increases pressure, after load and preload, all contribute in lactate free fatty acids, etc. with Adrenaline use towards determining the filling pattern of LV and in diabetic patients; we observed a significantly subsequent MR and unstable haemodynamics. less acidosis and significantly less amount of Adrenaline proved superior in this setting NAHCO3 requirement, relatively, in patients evidently due to balanced alpha and beta receptor receiving Adrenaline infusion when compared to stimulation. those receiving Dopamine or Dobutamine during Several studies [4,6,7] have quoted perioperative OPCAB. We seek to explain this observation by use of inotropes during OPCAB, but we did not improved peripheral as well as target organs come across any literature suggesting guidelines perfusion and fewer incidences of ischemic for inotrope management for OPCAB procedure. manifestations as a result of superior

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Rajiv Lakhotia & L.D. Mishra hemodynamic stability and less incidence of Journal of Cardiothoracic and Vascular Anesthesia, arrhythmias as observed in our study. Vol 17, No. 4, 2003: pp 452 – 458 7. Tugtekin SM, Gulielmos V, Cichon R, et al : Off – pump Conclusion: surgery for anterior vessels in patients with severe Adrenaline causes less tachycardia than Dopamine dysfunction of the left . Ann Thorac Surg 70 : and Dobutamine at equivalent inotropic doses. 1034 – 1036, 2000 When Adrenaline increases the HR within 8. Cohn WE, Sirois CA, Johnson RG : Atrial Fibrillation physiologic range, it shortens systole more than after minimally invasive coronary artery bypass grafting : A retrospective, matched study. J Thorac diastole, thus increasing the diastolic perfusion, Cardiovasc Surg. 117 : 298 – 301, 1999 preserving the native coronary blood flow better 9. Kalman JM, Munawar M, Howes LG, et al: Atrial during the procedure (balanced alpha and beta Fibrillation after coronary artery bypass grafting is effects). It provides superior haemodynamics and associated with sympathetic activation. Ann Thorac coronary perfusion (oxygen supply) and thus a Surg. 60 : 1709 – 1715, 1995 beneficial supply / demand [MVO2] ratio to the 10. Cartier R, Bouchard D, Martineau R., Couturier A. ischemic myocardium. Systemic coronary surgery in the beating heart. We conclude that Adrenaline is the superior Experience in 250 cases. Ann Chir 53[8] : 693 – 700, chronotropic inotrope compared to Dopamine and 1999 11. Grundeman PF, Borst C, Herwaarden JAV, et al Vertical Dobutamine for perioperative management of displacement of the beating heart by the Octopus OPCAB surgery. tissue stabilizer : Influence on coronary flow. Ann Thorac Surg 65 : 1348 – 1352, 1998 References: 12. Porat E, Sharony R, Ivry S, et al : Hemodynamic changes and right heart support during vertical 1. Nashef S.A.M, Roques F., Michel P., et al. European displacement of the beating heart. Ann Thorac Surg system for cardiac operative risk evaluation [Euro 69 : 1188 – 1191, 2000 SCORE]. Eur J Cardiothorac Surg 1999; 16 : 9-13 13. Stephenson LW, Blackstone EH, Kouchoukos NT. 2. Akipnar B, Guden M, Sagbas E, et al: Off-pump Dopamine vs epinephrine in patients following cardiac coronary artery bypass grafting with use of the surgery. Randomized study. Surg. Forum 27 : 272, Octopus 2 stabilization system. Heart Surg Forum 3: 1976. 282 286, 2000 – 14. Butterworth JF, Prielipp RC, Zaloga GP, et al : Is 3. Dickes MS, Stammers AH, Pierce ML, et al : Outcome dobutamine less chronotropic than epinephrine after analysis of coronary artery bypass grafting: minimally coronary bypass surgery? Anesthesiology 73[ Suppl invasive versus standard techniques. Perfusion 14: 461 3A] : A 61, 1990. 472, 1999 – 15. Joel A. Kaplan, Anita V Guffin in treatment of

4. Calafiore AM, Teodori G., Giammarco GD, et al : perioperative Left Ventricular Failure, Chapter 32, Multiple arterial conduits without cardiopulmonary Cardiac Anesthesia, 3rd edition. Ed. Joel A. Kaplan, M. bypass: Early angiographic results. Ann Thorac Surg D., W. B. Saunders Company, Pennsylvania, 1979, p. 67 : 450 – 456, 1999 1062 – 1064. 5. van Dijk D., Nierich AP, Jansen EWL, et al : Early 16. Steen PA, Tinker JH, Pluth JR, et al : Efficacy of outcome after off-pump versus on pump coronary dopamine, dobutamine and epinephrine during bypass surgery : Results from a randomized study. emergence from cardiopulmonary bypass in man. Circulation 104: 1761 1766, 2001 – Circulation 57 : 378,1978. 6. Manish Mishra, Shipra Shrivastava, Ajay Dhar, et al. A 17. Hilsted J, Richter E, Madsbad S, et al : Metabolic and Prospective Evaluation of Hemodynamic Instability cardiovascular responses to epinephrine in diabetic during Off-pump Coronary Artery Bypass Surgery. autonomic neuropathy. N, Engl J Med 317 : 421, 1987

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