Anesthetic technique will be standardized in all studied. After breathing 100% oxygen for 3 min through a facemask in a supine "sniffing" position, all patients will receive intravenous propofol 2-3 mg/kg and remifentanail 0.05-0.25 µg/kg/min for induction of anesthesia until loss of consciousness defined as decrease of SE less than 50 and the difference between RE and SE is less than 10. Rocrunium 0.6 mg.kg will be administered and complete relaxation will be monitored using a nerve stimulator (TOF-GE, Datex-Ohmeda Division, Instrumentarium Corporation, Helsinki, Finland).