Duration and recovery profile of cisatracurium after succinylcholine during propofol or isoflurane anesthesia

Study Objective: To determine the duration and recovery profile of maintenance doses of cisatracurium besylate following succinylcholine, and during propofol or isoflurane anesthesia. Design: Randomized, open-label study. Setting: Operating suite of a university-affiliated medical center. Patients: Forty ASA physical status I and II adult patients having elective surgery with general anesthesia lasting longer than 90 minutes. Interventions: Following a standardized induction sequence, a baseline electromyogram (EMG) was obtained. An intubating dose of intravenous (IV) succinylcholine 1.0 mg/kg was administered. Ventilation was maintained with a face mask until the first twitch (T-1) of the evoked train-of-four (TOF) reached 10% of control when tracheal intubation runs performed. Spontaneous recovery from neuromuscular blockade was allowed to occur until the first twitch returned to 25% of control. Patients then were randomized to receive cisatracurium as follows. Group 1: 0.025 mg/kg [0.5 X 95% effective dose (ED95)]; Group 2: 0.05 mg/kg (ED95); Group 3: 0.05 mg/kg (ED95); and Group 4: 0.1 mg/kg (2 x ED95). Anesthesia for Groups 1 and 2 were maintained with isoflurane 1% to 2%, 66% nitrous oxide (N2O) in oxygen (O-2), and in Groups 3 and 4, anesthesia was maintained with propofol 80 to 160 mu g/kg/min, 66% N2O in O-2. The TOF-evoked EMG was recorded at 10-second intervals. The time for the evoked EMG to spontaneously return to 25%, 50%, and 75% of the original baseline was recorded. Measurements and Main Results: There were 10 patients in each of the four groups. The duration of action of cisatracurium 0.05 mg/kg (ED95) after an intubating dose of succinylcholine is 24.5 +/- 10 minutes and 21.3 +/- 9 minutes during anesthesia maintained with isoflurane and propofol, respectively. Doubling the dose of cisatracurium resulted in approximately twice the duration of action (40.2 +/- 7 min) during propofol anesthesia. Following a dose of cisatracurium 0.025 mg/kg (0.5 x ED95), the T-1 of the EMG-evoked response did not decrease below 25% in 7 of 10 patients. Conclusion: Following succinylcholine, the duration of action of a single dose of cisatracurium 0.05 mg/kg is 20 to 25 minutes during anesthesia maintained with propofol or isoflurane. The duration and recovery profile of cisatracurium is dose dependent during propofol and isoflurane anesthetics. Cisatracurium 0.025 mg/kg is an inadequate maintenance dose following recovery from succinylcholine and it fails to provide adequate surgical relaxation. (C) 2000 by Elsevier Science Inc.