Study objectives: To compare the neuromuscular and hemodynamic effects of rocuronium and atracurium when administered during a desflurane-based anesthetic.
Design: Randomized, double-blind clinical trial.
Patients: 51 adult ASA physical status I and II patients scheduled for general surgical operations.
Setting: University-based NCI-designated cancer center.
Interventions: Patients received either 0.45 mg/kg rocuronium (n = 28) or atracurium 0.5 mg/kg (n = 23). Induction of anesthesia was accomplished by 2 microg/kg fentanyl intravenously (IV) and 1.5 mg/kg propofol IV and maintained by a nitrous oxide/oxygen desflurane anesthetic.
Measurements and main results: A neuromuscular monitor was used at the adductor pollicis to monitor and record twitch response to train-of-four electrical stimulation. Baseline heart rate (HR) and blood pressure (BP) were measured and again at 2, 5, 10, and 15 minutes after muscle relaxant administration. Patients in the rocuronium group were found to have shorter times to 80%T(1)depression (109 +/- 53 vs. 135 +/- 47 sec), although those differences did not reach statistical significance (p = 0.07). Percent of the first twitch (T(1) ) was significantly lower in the patients receiving rocuronium at 60 seconds (53 +/- 24 vs. 73 +/- 27 sec; p = 0.006) and 90 seconds (25 +/- 22 vs. 47 +/- 29 sec; p = 0.003) than in the patients receiving atracurium. Duration was shorter in rocuronium-treated patients (25% T(1) recovery = 32 +/- 12 vs. 54 +/- 14 min; p < 0.001) than the patients receiving atracurium. Intubation scores were better at 60 seconds after muscle relaxant administration in the rocuronium group. No significant differences in HR or BP were seen between the patients in the two groups.
Conclusions: Rocuronium at a dose of 0.45 mg/kg possesses a fairly rapid onset of neuromuscular blockade and has short:intermediate duration of action when used with a desflurane anesthetic. This quality makes it a desirable drug for operations of relatively short duration. Rocuronium at a dose of 0.45 mg/kg has a faster onset and shorter duration than atracurium, at 0.5 mg/kg, when used with a desflurane anesthetic.