BACKGROUND: Potent inhalation anesthetics potentiate the neuromuscular blocking effects of non-depolarizing muscle relaxants. Therefore, sevoflurane may increase the safety margin at the end of anesthesia by reducing the muscle relaxant dose requirements. We studied the recovery from rocuronium-induced neuromuscular blockade during sevoflurane- versus propofol-based anesthesia in children. METHODS: Fifty pediatric patients were randomly allocated to maintenance of anesthesia with sevoflurane (n = 25) or propofol (n = 25). Neuromuscular block was maintained with rocuronium and monitored by acceleromyography (TOF-Watch?) using train-of-four (TOF) stimulation every 12 seconds. Anesthetic agent administration was gradually reduced and then stopped toward the end of procedure. At the end of surgery, neostigmine 0.04 mg/kg was administered. Time of tracheal extubation, time of arrival in PACU, amount of rocuronium given were recorded. RESULTS: TOF ratio at the end of surgery was greater in sevoflurane group (73.0 +/- 30.0) than in propofol group (50.0 +/- 37.1)(P < 0.05). The dose of rocuronium administered as supplemental increments in sevoflurane group was significantly smaller than that in propofol group (0.9 +/- 1.6 vs 2.8 +/- 2.4microgram/kg/min)(P < 0.05). Time to extubation (7.3 +/- 2.0 vs 9.0 +/- 2.6 min), and time to arrival in PACU (11.5 +/- 2.9 vs 13.9 +/- 2.6 min) from end of surgery were shorter in sevoflurane group than in propofol group (P < 0.05). CONCLUSIONS: These results support the postulate that the potentiation of neuromuscular block by sevoflurane may provide additional safety for pediatric patients by reducing the muscle relaxant dose requirements.