Neuromuscular Effects of Vecuronium (ORG NC45) in Infants and Children during N2O, Halothane Anesthesia

Abstract

The authors determined the neuromuscular effects of vecuronium (ORG NC45, Norcuron) during anesthesia with nitrous oxide and 0.9 MAC halothane. To determine potency, they administered vecuronium (15, 20, or 25 micrograms/kg) to 18 infants (less than 1 year old) and 18 children (1-8 years old). They then compared these dose-response relationships with values obtained for adults (greater than 18 years old) under comparable anesthetic conditions. The ED50S (dose producing 50% depression of adductor pollicis twitch tension) of 16.5, 19.0, and 15.0 micrograms/kg for infants, children, and adults, respectively, did not differ significantly. To determine the time course of neuromuscular blockade, the authors administered vecuronium, 70 micrograms/kg, to six infants, six children, and six adults. Onset time (time to maximal effect) was shortest for infants (1.5 +/- 0.6 min, mean +/- SD) compared with that for children (2.4 +/- 1.4 min) and adults (2.9 +/- 0.2 min). Duration (time from injection to 90% recovery) was longest for infants (73 +/- 27 min) compared with that for children (35 +/- 6 min) and adults (53 +/- 21 min). The authors conclude that vecuronium can be used in infants and children in doses similar to those recommended for adults. The time interval for supplemental doses will be longest in infants and shortest in children.