A comparison of intubating conditions and duration of activity of cisatracurium and atracurium in Filipinos for surgery at the Philippine General Hospital: A prospective, randomized, double-blind study

ABSTRACT

BACKGROUND: Cisatracurium , an R-cis, R-cis isomer of atracurium, is a benzoquinolinium non-depolarizing muscle relaxant with intermediate duration of action that has the advantage of minimal histamine release compared to the parent compound atracurium. Similar studies have described cisatracurium to have cardiovascular stability up to 7 times the ED95 dose. However, few have been conclusive owing to concomitant use of agents that can cause potential histamine release and hemodynamic effects. This study was specifically designed to minimize these variables. The promise of the clinical advantages of the use of cisatracurium merits investigation against its parent compound atracurium in the Filipino population especially in terms of hemodynamic stability when utilized intraoperatively. The study was conducted to evaluate the onset of action, conditions for intubation, duration of neuromuscular block and side effects of cisatracurium compared to atracurium among Filipino surgical patients METHODOLOGY: A prospective, randomized, double-blind study was performed in eighty one (81) healthy patients of ASA Physical Status 1 and 2 undergoing elective surgical procedures treated with either 0.15 mg/kg cisatracurium (3 x ED 95) n=39 or 0.5 mg/kg atracurium (3 x ED 95) n=42 administered over 5 seconds intravenous bolus under adequate anesthesia, before surgical stimulation. We compared the time course of the neuromuscular block and determined whether the muscle relaxants caused cutaneous and systemic evidence of histamine release. Induction of general anesthesia commenced with the use of propofol-fentanyl in oxygen. Stabilization of the Neuromuscular junction was achieved prior to the administration of the muscle relaxants with the use of tetanic stimulation of 50 Hz; for 5 seconds followed by single twitch stimuli for 2 minutes. Neuromuscular transmission was assessed by recording the mechanical twitch response to train-of-four nerve stimulations every 10 seconds. Cutaneous manifestations, blood pressures and heart rates were recorded periodically. RESULTS: Time to 95 percent block were 77.09-155.99 seconds with cisatracurium. and 64.60 - 128.21 seconds with atracurium. The administration of either muscle relaxant resulted in complete neuromuscular block in all patients providing good to excellent intubating conditions. The time to spontaneous recovery (T4T1 ratio 80 percent) were noted to be within the range of 63.48 - 103.48 minutes for cisatracurium whereas those treated with atracurium recovered within the range of 74.76 - 92.64 minutes and none necessitated reversal from the muscle relaxants. One patient from the cisatracurium group and two from the atracurium group were noted to have cutaneous flush. CONCLUSION: When given a dose of 3 x ED 95, except for onset, cisatracurium group did not differ significantly from the atracurium group with regard to onset, duration, intubating conditions, and hemodynamic stability.