Monitoring consisted of noninvasive blood pressure, Electrocardiogram (ECG) , pulse oximetry, and BIS. All subjects received a standard dose of 2 mcg/kg fentanyl approximately 20 min before induction of general anesthesia. a standard BIS® monitor strip was applied before fentanyl administration and induction of general anesthesia. Induction was performed in all patients with 2m/kg propofol, 0.2 mg/kg cisatracuruim, followed by direct laryngoscopy and tracheal intubation. Therefore, when BIS reached > 65 , sevoflurane was started immediately at the predetermined dose.