Influence of isoflurane, sevoflurane, desflurane and propofol on the neuromuscular blocking effect of rocuronium

ABSTRACT

BACKGROUND:Rocuronium is widely used because of rapid onset and intermediate duration of action.The volatile anesthetics potentiate the effect of nondepolarizing muscle relaxants. This study was designed to compare effects of inhalational agents with that of propofol on the muscle relaxation of rocuronium. METHODS:One hundred and thirty-six patients were divided four groups, which were given sevoflurane, isoflurane, desflurane and propofol.Anesthesia was induced with propofol 2 mg/kg and fentanyl 100microg.A ulnar nerve was stimulated with supramaximal stimuli.Anesthesia was maintained with 1.25 MAC inhalational agents or propofol of 7 mg/kg/hr for twenty minutes.Rocuronium 0.1, 0.15 or 0.2 mg/kg was administered.The degree and onset time of maximal depression was recorded.A supplementary dose of rocuronium was given so that all patients received a cumulative dose of rocuronium 0.6 mg/kg. We measured 10% recovery time. RESULTS:The ED50 of rocuronium were 0.157 in the sevoflurane, 0.167 in the isoflurane, 0.169 in the desflurane, and 0.187 mg/kg in the propofol. The ED95 were 0.296 in the sevoflurane, 0.313 in the isoflurane, 0.325 in the desflurane, and 0.407 mg/kg in the propofol.The onset time to maximal depression was prolonged in inhalational agent groups which were administered rocuronium 0.2 mg/kg. The 10% recovery time was delayed in inhalational agent groups than in propofol group. CONCLUSIONS:The inhalational anesthetics had more potent muscle relaxation effect than propofol.We suggest that the dose of rocuronium for adequate muscle relaxation be adjusted according to anesthetics used.