High concentration sevoflurane induction of anesthesia accelerates onset of vecuronium neuromuscular blockade

Purpose: To investigate neuromuscular block using accelography after admini stration of vecuronium under sevoflurane 8% induction and maintenance with sevoflurane 2% in adults. Methods: Patients were allocated to three groups: (I) group I anesthesia wa s induced and maintained with propofol and fentanyl (n=15), (2) group II: a nesthesia was induced with propofol and maintained with N2O(66%)-O-2-sevofi urane 2% (n=15), (3) group III: anesthesia was induced with sevoflurane 8% using a vital capacity inhalation induction and maintained with N2O(66%)-O- 2-sevoflurane 2% (n=15), 0.1 mg.kg(-1) vecuronium was used for paralysis th ree minutes after anesthetic induction and reversed using intravenous 0.04 mg.kg(-1) neostigmine with 0.02 mg.kg(-1) atropine when the train-of-four ( TOF) ratio returned to 25%. Results: The onset time from initial administration of vecuronium to maxima l block in the group III was shorter than that in the groups I and II (139 +/- 35, 193 +/- 35 and 188 +/- 47s, respectively: P < 0.05). The clinical d uration from maximal block to 25% recovery of TOF ratio in group II and III was longer than that in the group I (47 +/- 15, 48 +/- 14 and 36 +/- 10 mi n, respectively: P < 0.05). The reversal times from administration of neost igmine to 75% of TOF ratio in groups II and III were longer than that in th e group I ( 196 +/- 53, 208 +/- 64 and 1 36 +/- 28s, respectively: P < 0.05 ). Conclusions: Vital capacity inhalation induction of anesthesia with sevoflu rane accelerates onset and prolongs duration of vecuronium neuromuscular bl ock compared with propofol-fentanyl anesthesia.