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

Study Objective: To determine the duration and recovery profile of maintena nce doses of cisatracurium besylate following succinylcholine, and during p ropofol 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 elec tromyogram (EMG) was obtained. An intubating dose of intravenous (IV) succi nylcholine 1.0 mg/kg was administered. Ventilation was maintained with a fa ce mask until the first twitch (T-1) of the evoked train-of-four (TOF) reac hed 10% of control when tracheal intubation runs performed. Spontaneous rec overy from neuromuscular blockade was allowed to occur until the first twit ch returned to 25% of control. Patients then were randomized to receive cis atracurium 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 isof lurane 1% to 2%, 66% nitrous oxide (N2O) in oxygen (O-2), and in Groups 3 a nd 4, anesthesia was maintained with propofol 80 to 160 mu g/kg/min, 66% N2 O 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 orig inal baseline was recorded. Measurements and Main Results: There were 10 patients in each of the four g roups. The duration of action of cisatracurium 0.05 mg/kg (ED95) after an i ntubating dose of succinylcholine is 24.5 +/- 10 minutes and 21.3 +/- 9 min utes during anesthesia maintained with isoflurane and propofol, respectivel y. Doubling the dose of cisatracurium resulted in approximately twice the d uration 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 r esponse did not decrease below 25% in 7 of 10 patients. Conclusion: Following succinylcholine, the duration of action of a single d ose of cisatracurium 0.05 mg/kg is 20 to 25 minutes during anesthesia maint ained with propofol or isoflurane. The duration and recovery profile of cis atracurium is dose dependent during propofol and isoflurane anesthetics. Ci satracurium 0.025 mg/kg is an inadequate maintenance dose following recover y from succinylcholine and it fails to provide adequate surgical relaxation . (C) 2000 by Elsevier Science Inc.