Comparison of Midazolam/Ketamine with Methohexital for Sedation During Peribulbar Block Michael K. Rosenberg, MD, Charles Raymond, MD, and Patrick D. Bridge, MS Department of Anesthesiology, Sinai Hospital, Farmington Hills, Michigan nesthesiologists are often required to perform Baseline and serial values were recorded for blood retrobulbar blocks (RBB) or peribulbar blocks pressure, heart rate (HR), and arterial oxygen satura- (PBB) for ophthalmic surgical procedures, as tion while the patients breathed room air. A change in 11/29/2018 on BhDMf5ePHKbH4TTImqenVHV1elE1c3IGZ1dvGW5knoLqnAcYzsVVpRTf7ypEaWeP by http://journals.lww.com/anesthesia-analgesia from Downloaded A well as to simultaneously sedate patients. Drugs that systolic blood pressure (SBP) or HR of >20% above or Downloaded have been utilized for sedation include methohexital below baseline was noted. Patient movement requir- (l-3), alfentanil (2,4), midazolam (31, and propofol ing restraint and respiratory depression/obstruction requiring intervention (jaw lift or intermittent positive from (3,5). Patient movement and/or respiratory problems http://journals.lww.com/anesthesia-analgesia during block placement may increase the incidence of pressure breathing) were also noted. In the postanes- complications, such as optic nerve and vessel damage, thesia care unit (PACU), the following were recorded: retrobulbar hemorrhage, central nervous system com- time-to-home readiness (PACU time), occurrence of plications, and globe perforation (6). postoperative nausea and/or vomiting, and confusion and/or hallucinations. So that the anesthesiologist can focus on performing For data analysis, descriptive measures were calcu- the block, and thus avoid complications (7,8), it is lated and presented as frequencies, percentages, and important that a sedation technique be used which is by mean + SEM. Pearson’s x was used to determine BhDMf5ePHKbH4TTImqenVHV1elE1c3IGZ1dvGW5knoLqnAcYzsVVpRTf7ypEaWeP associated with minimal patient movement or respi- group differences in movement during PBB block. ratory difficulty. In this study we describe a low-dose Fisher’s exact test was used to determine group dif- midazolam/ketamine sequence and compare it with a ferences in respiratory depression. An independent commonly used methohexital technique. t-test was used to determine the differences in group means for PACU time. P < 0.05 was accepted as significant. Methods After approval by our research committee, 40 patients Results undergoing cataract extraction with intraocular lens There were no significant demographic differences implant were randomly assigned to one of two between groups. Five patients (25%) in Group I and groups. All patients received intravenous (IV) seda- two (10%) in Group II had an increase in SBP ~20% tion and a PBB (single-stick technique), both adminis- above baseline. Six patients (30%) in Group I and five on tered by a single anesthesiologist. Each patient was (25%) in Group II had an increase in HR >20% above 11/29/2018 monitored and received oxygen by nasal cannula dur- baseline. The group differences were not significant. ing sedation and block placement. There were no decreases in SBP or HR >20% below For sedation, Group I (n = 20) patients received baseline in either group. methohexita10.5 mg/kg (maximum dose 50 mg) by IV The occurrence of patient movement and/or respi- bolus injection. The block was performed 90 s later. ratory depression/obstruction and the PACU times Group II (n = 20) patients received midazolam 0.025 are listed in Table 1. There were significant differences mg/kg (maximum dose 2 mg) titrated over 5 min. for the occurrence of patient movement and respira- This was followed by ketamine 0.2 mg/kg (maximum tory problems (Group I > Group II). There was no dose 15 mg) IV. The block was performed 2.5 min after postoperative nausea and/or vomiting or postopera- ketamine administration. tive confusion/hallucinations in either group. Accepted for publication March 13, 1995. Discussion Address correspondence to Michael K. Rosenberg, MD, Sinai Surgery Center, 28500 Orchard Lake Rd., Farmington Hills, MI Why another technique for sedating patients during 48334. RBB/PBB? In busy ambulatory practices, the same 01995 by the International Anesthesia Research Society 0003.2999/95/$5.00 Anesth Analg 1995;81:1734 173 174 BRIEF COMMUNICATION ROSENBERG ET AL. ANESTH ANALG MIDAZOLAM/KETAMINE VS METHOHEXITAL FOR SEDATION 1995;81:1734 Table 1. Measured ParametersDeveloped During The midazolam/ketamine technique required a Sedation and Peribulbar Block Placement longer time from the initiation of sedation until place- Midazolam/ ment of the block (approximately 7.5 min compared to Methohexital ketamine 90 s for the methohexital group). (n = 20) (n = 20) In conclusion, we found our low-dose mida- Patient movement 9 (45%) 2 (10%) zolam/ketamine sedation sequence superior to a (P = 0.013) methohexital technique regarding patient movement Respiratory depression/ 6 (30%) 1(5%) and respiratory depression/obstruction. This is partic- obstruction (P = 0.046) ularly advantageous when the same anesthesiologist Time-to-home readiness 62 t 5.9 63 ? 5.3 is both sedating the patient and performing the block, min min as he or she can focus more completely on block placement and hopefully avoid ocular complications. anesthesiologist often administers the IV sedation and performs the PBB/RBB. A technique with minimum potential for patient movement and respiratory diffi- References culties minimizes the need for airway intervention 1. Gilbert J, Holt JE, Johnston J, et al. Intravenous sedation for and allows the anesthesiologist to focus on performing cataract surgery. Anaesthesia 1987;42:1063-9. the block. This, in turn, should help prevent block 2. Yee JB, Schafer PG, Crandall AS, Pace NL. Comparison of methohexital and alfentanil on movement during placement of complications such as globe perforation (7). We feel retrobulbar nerve block. Anesth Analg 1994;79:320-3. that a low dose midazolam/ketamine technique ac- 3. Ferrari LR, Donlon JV. A comparison of propofol, midazolam, complishes this goal. and methohexital for sedation during retrobulbar and peribul- In this group of elderly patients, many of whom had bar block. J Clin Anesth 1992;4:93-6. 4. Stead SW, Northfield KM. Effects of alfentanil analgesia for cardiovascular disease, there may have been some ophthalmic nerve blocks [abstract]. Anesthesiology 1990;73: reluctance to use ketamine, with its sympathomimetic A769. effects (9). In our series, increases in SBP and HR 5. Beatie CD, Stead SW. Effects of propofol sedation for ophthal- >20% above baseline actually occurred in more mic nerve blocks [abstract]. Anesthesiology 1991;75:A28. methohexital patients than midazolam/ketamine pa- 6. Morgan CM, Schatz H, Vine AK, et al. Ocular complications associated with retrobulbar injections. Ophthalmology 1988;95: tients. Therapeutic intervention was not necessary in 660-5. any patient in either group. 7. Grizzard WS, Kirk NM, Pavan PR, et al. Perforating ocular A significant advantage of the midazolam/ injuries caused by anesthesia personnel. Ophthalmology 1991; ketamine technique is that most of the patients are in 98:1011-6. 8. Kuker JS, Belmont JB, Benson WE, et al. Inadvertent globe verbal communication throughout the block proce- perforation during retrobulbar and peribular anesthesia. Oph- dure. This allows for eye opening on command, which thalmology 1991;98:519-26. is necessary for safe block placement. Also, if patients 9. Backer CL, Tinker JH, Robertson DM. Myocardial reinfarction following local anesthesia for ophthalmic surgery. Anesth begin to move, they usually cease on command, which Analg 1980;59:257-62. prevents the movement from becoming disruptive. 10. Hejja I’, Galloon S. A consideration of ketamine dreams. Can Methohexital patients are usually unresponsive to ver- Anaesth Sot J 1975;22:100. bal command during block placement. Movement 11. Garfield JM. A comparison of psychologic responses to ket- therefore requires holding the patient’s head, restrain- amine and thiopental-nitrous oxide-halothane anesthesia. Anaesthesiology 1972;36:329. ing the patient, and/or interrupting block placement. 12. Corssen G, Reves JG, Stanley TH. Dissociative anesthesia. In: Postoperative hallucinations have been described Intravenous anesthesia and analgesia. Philadelphia: Lea & with ketamine (10,ll). We saw no hallucinations or Febiger, 1988:99. confusion in our midazolam/ketamine patients. This 13. White PF, Way WL, Trevor AJ. Ketamine: its pharmacology and therapeutic uses. Anesthesiology 1982;56:119. effect is likely dose related (12) and modified by the 14. Johnson M. The prevention of ketamine dreams. Anaesth Intens concomitant use of benzodiazepines (12-14). Care 1972;1:70. .