Influence of gender on enhancement of neuromuscular blocking effects of cisatracurium or rocuronium by sevoflurane

Abstract

Objective To investigate the influence of gender on the enmcement of neuromuscular blocking effects of cisatracurium or rocuronium by sevoflurane. Methods Two hundred and forty ASA Ⅰ or Ⅱ patients, aged 20-60 yr, weighing 45-85 kg, scheduled for elective surgery under general anesthesia were assigned into 2 groups ( n = 120 each): cisatracurium group and rocuronium group. Each group were divided into 4 subgroups according to gender and anesthetics ( n = 30 each): female propofol group, male propofol group, female sevoflurane group and male sevoflurane group. Anesthesia was induced with midazolam, propofol and fentanyl. After loss of consciousness, the laryngeal mask was inserted and the patients were mechanically ventilated. Propofol groups received target-controlled infusion (TCI) of propofol (target plasma concentration 2-6 μg/ml), and sevoflurane groups inhalation of sevoflurane. Cisatracurium 0.15 mg/kg or rocuronium 0.6 mg/kg was injected intravenously 5 min after propofol infusion or after the end-tidal concentrion of sevoflurane was maintained at 1.71% (1 MAC) for 5 min. Neuromuscular block was assessed with accelerograph F (TOF-watch SX). Train-of-four (TOF) stimulation of ulnar nerve was used. The onset time, duration of peak effect and times for recovery of T1 to 25% and TOF ratio (TOFR) to 25% were recorded.Results Compared with propofol groups, the time for recovery of TOFR to 25 % for rocuronium, and the duration of peak effect and times for recovery of T1 to 25 % and TOFR to 25% for cisatracurium were significantly prolonged in female sevoflurane group, the onset time of rocuronium was significantly shortened, while the duration of peak effect and times for recovery of T1 to 25% and TOFR to 25% for rocuronium and cisatracurium were significantly prolonged in male sevoflurane group ( P ＜ 0.05 or 0.01 ). The times for recovery of T1 to 25% and TOFR to 25% for rocuronium and onset time of cisatracurium were significantly shorter in female than in male during sevoflurane anesthesia (P ＜ 0. 05 or 0.01 ). Conclusion The enhancement of rocuronium-induced neuromuscular block by sevoflurane is stronger in male than in female,but there is no gender variation in the enhancement of cisatracurium-induced neuromuscular block by sevoflurane. Key words: Anesthetics, inhalation; Atracurium; Androstanols; Sex factors; Neuromuscular blockade