Naotaka Kishimoto, Shinichi Koyama, Noboru Nagata and Junichiro Kotani
Background: We examined the optimal concentration of sevoflurane to prevent cardiovascular depression after induction of general anesthesia with remifentanil and propofol.
Methods: Seventy-five adult patients were randomized to one of three groups (n = 25). Midazolam (0.025 mg/kg) and remifentanil (0.5 ?g/kg/min) were administered to all patients, followed by propofol (1.0 mg/kg) and rocuronium (0.6 mg/kg) after 2 min. The lungs were ventilated manually with sevoflurane and oxygen via a tightly fitted face mask. The trachea was intubated when end-tidal sevoflurane concentration reached 1%, 1.5%, and 2% in each group, respectively. Three min after the start of administration, remifentanil was decreased to 0.25 ?g/kg/min. The effect-site concentration of remifentanil was 6.0 ng/ml for 4 min after it was started. Hemodynamic variables were recorded from before induction of anesthesia to 15 min after tracheal intubation.
Results: There were no serious adverse events such as severe bradycardia or asystole. Relative change of mean arterial pressure after induction of general anesthesia in the end-tidal sevoflurane 1% group was smaller than that of the end-tidal sevoflurane 1.5% and end-tidal sevoflurane 2% groups.
Conclusion: An end-tidal sevoflurane concentration of 1% was sufficient when general anesthesia was induced with an effect-site concentration of remifentanil of 6.0 ng/mL and propofol of 1 mg/kg.