Effects of Cisatracurium in Children During Halothane-Nitrous Oxide Anesthesia

Abstract

Study Objective: To determine the neuromuscular blocking effect and recovery profile of cisatracurium besylate in children after administration of a bolus dose that was twice the estimated dose required to produce 95% of the maximum effect (2 × ED 95; 0.08 mg/kg) followed by an infusion during halothane-nitrous oxide anesthesia. Study Design: Open-label study. Setting: Teaching hospital. Patients: 30 male and female (ASA physical status I and II) patients, 2 to 10 years of age, scheduled for elective surgery of low to moderate risk. Interventions: After induction of general anesthesia, patients received cisatracurium 0.08 mg/kg administered over 5 to 10 seconds. For surgical procedures requiring neuromuscular block for at least 60 minutes, a second bolus dose of cisatracurium 0.02 mg/kg was administered after the first response to a train-of-four stimuli (T 1) recovered to 25% of baseline. When T 1 was 5% of baseline after the second dose, a 3 μg/kg/min infusion of cisatracurium was initiated and titrated to maintain 89% to 99% block for the duration of the surgery. For procedures requiring neuromuscular block of less than 60 minutes, one or more maintenance doses of 0.02 mg/kg cisatracurium were administered when T 1 was 25% of baseline after the preceding dose. In 10 patients, recovery was facilitated with edrophonium 1.0 mg/kg administered when T 1 was 26% to 48% of the final baseline. Measurements and Main Results: Evoked muscular response at the adductor pollicis was measured by electromyography. With 0.08 mg/kg, onset time (mean ± SEM) was 4.1 ± 0.4 minutes, and clinically effective duration was 27.3 ± 0.9 minutes. Mean 5% to 95% and 25% to 75% recovery indices were 28.4 ± 2.7 minutes and 11.2 ± 0.8 minutes, respectively. The mean infusion rate necessary to maintain 89% to 99% T 1 suppression for 17 to 145 minutes was 1.7 μg/kg/min. After termination of infusion, the mean 5% to 95% and 25% to 75% recovery indices were similar to those after a single bolus dose, and time to 95% recovery was 30.4 ± 3.0 minutes. After administration of edrophonium, full recovery (T 4:T 1 ≥ 70%) occurred in 1.5 ± 0.4 minutes. No clinically significant changes in heart rate or blood pressure were noted during the first 5 minutes after administration of cisatracurium 0.08 mg/kg. Conclusions: Cisatracurium provided maximal neuromuscular block, cardiovascular stability, and predictable recovery at the doses tested. In view of this finding, cisatracurium should be a useful intermediate-duration neuromuscular blocking drug for children during general anesthesia.