title: Sevoflurane exposure time and the neuromuscular blocking effect of vecuronium.
abstract: OBJECTIVE
  To determine the effect of sevoflurane exposure time on the duration of vecuronium neuromuscular blockade.
  
  
  METHODS
  In 40 adult patients anesthesia was induced with 1.5-2 mg x kg(-1) propofol and 3-5 microg x kg(-1) fentanyl and the trachea was intubated without the aid of muscle relaxant. Patients were randomized into four groups of 10. In group 1, 0.05 mg x kg(-1) vecuronium was administered with N2O and anesthesia was maintained by propofol infusion and fentanyl. Vecuronium was administered with sevoflurane 2% in 30 patients, commencing at the same time (group 2) and at 30, and 60 min after sevoflurane (groups 3, 4). Adductor pollicis force of contraction to train-of-four ulnar nerve stimulation was recorded. Times from vecuronium injection to 95%, maximal block, and recovery times to 25% recovery were recorded.
  
  
  RESULTS
  There were no differences in times to 95% and maximal block in the four groups. Recovery times were longer in groups 3 and 4 than in groups 2 and 1 (P < 0.01). Times to 5% recovery were 15.0 +/- 3.7, 17.8 +/- 4.8, 28.2 +/- 9.9, and 29.5 +/- 9.5, and to 25% recovery were 22.3 +/- 5.2, 27.2 +/- 6.4, 42.3 +/- 16.3, and 50.5 +/- 16.4 in groups 1, 2, 3, and 4 respectively. No differences were found between group 1 and group 2 nor between group 3 and group 4.
  
  
  CONCLUSIONS
  Sevoflurane produced time-dependent potentiation of vecuronium. After 30 min exposure, 25% recovery was prolonged by 89% and after 60 min by more than 100% compared with the control group.
authors.affiliation: Department of Anesthesia, Ain Shams University, Cairo, Egypt. kader2a@hotmail.com
authors.forename: A A
authors.initials: AA
authors.lastname: Ahmed
authors.forename: M
authors.initials: M
authors.lastname: Kumagai
authors.forename: T
authors.initials: T
authors.lastname: Otake
authors.forename: Y
authors.initials: Y
authors.lastname: Kurata
authors.forename: Y
authors.initials: Y
authors.lastname: Amaki
mesh_terms: D000328:Adult; D000368:Aged; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D008875:Middle Aged; D009469:Neuromuscular Junction / Q000187:drug effects*; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D000077149:Sevoflurane; D013997:Time Factors; D014673:Vecuronium Bromide / Q000494:pharmacology*
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D003473:Neuromuscular Nondepolarizing Agents; D000077149:Sevoflurane; D014673:Vecuronium Bromide