Neuromuscular effects of rapacuronium in pediatric patients during nitrous oxide-halothane anesthesia: Comparison with mivacurium

Abstract

Purpose: To describe neuromuscular effects of rapacuronium in pediatric patients during N2O-halothane anesthesia and compare them with mivacurium in children. Methods: 103 pediatric patients, seven days - 12 yr, received rapacuronium or mivacurium during N2O-halothane anesthesia. Onset and recovery of block were measured using EMG (Datex). Block was compared between groups based on drug treatment and age. Children 0.7 occurred later after 2 mg·kg-1 than 1 mg·kg-1 in these patients (P < 0.05). There was no difference in T25 among neonates, infants and toddlers for 1 mg·kg-1 or 2 mg·kg-1 doses. Rapacuronium, 3 mg·kg-1, produced maximum block 1.5 min earlier than did mivacurium, 0.2 mg·kg-1 (P < 0.001). There was no difference in block at 60 sec, maximum block or time to maximum block between 2 and 3 mg·kg-1 rapacuronium for children > two years of age. Maximum block occurred 1.0 ± 0.5 min after 2 or 3 mg·kg-1 when T1 was 0.2 ± 1.1% of baseline. T25 and T4/T1 > 0.7 occurred 10 to 11 min later after this dose of rapacuronium than after mivacurium. Conclusion: Rapacuronium produces block earlier than mivacurium. Recovery from rapacuronium block is dose related and slower than that following mivacurium during halothane anesthesia.