Dose-response relationship and infusion requirement of cisatracurium besylate in infants and children during nitrous oxide-narcotic anesthesia

Abstract

Background: To determine the effect of age on the dose-response relation and infusion requirement of cisatracurium besylate in pediatric patients, 32 infants (mean age, 0.7 yr; range, 0.3-1.0 yr) and 32 children (mean age, 4.9 yr; range, 3.1-9.6 yr) were studied during thiopentone-nitrous oxide-oxygen-narcotic anesthesia. Methods: Potency was determined using a single-dose (20, 26, 33, or 40 μg/kg) technique. Neuromuscular block was assessed by monitoring the electromyographic response of the adductor pollicis to supramaximal train-of-four stimulation of the ulnar nerve at 2 Hz. Results: Least-squares linear regression analysis of the log-probit transformation of dose and maximal response yielded median effective dose (ED50) and 95% effective dose (ED95) values for infants (29 ± 3 μg/kg and 43 ± 9 μg/kg, respectively) that were similar to those for children (29 ± 2 μg/kg and 47 ± 7 μg/kg, respectively). The mean infusion rate necessary to maintain 90-99% neuromuscular block during the first hour in infants (1.9 ± 0.4 μg · kg-1 · min-1; range: 1.3-2.5 μg · kg-1 · min-1) was similar to that in children (2.0 ± 0.5μg · kg-1 · min-1; range: 1.3-2.9μg · kg-1 · min-1). Conclusion: The authors conclude that cisatracurium is equipotent in infants and children when dose is referenced to body weight during balanced anesthesia.