 Anesthesia: General anesthesia will be performed in all groups using propofol for induction and rocuronium for intubation and muscle relaxation. Patients will be ventilated to normocapnia by oxygen air desflurane mixture. Sufentanil 5 - 10 mcg will be administered if needed. Paracetamol 1 g i.v. will be administered approximately 30 min before the end of anesthesia and ondansetron 4 mg i.v. will be administered 10 min. before the end of anesthesia. At the end of anesthesia patients will be administered atropine and neostigmine to obtain TOF ration 90. 