Drug:Propofol and sevoflurane The induction dose of propofol is 3-5 mg/kg-1 (mean induction dose: 4 mg/kg-1) follow by propofol infusion (12 mg/kg/h-1 for the first 10 min of general anesthesia, 9 mg/kg/h-1 for another 10 min, and 6 mg/kg/h-1 thereafter; mean maintenance dose: 9 mg/kg/h-1) and a 50:50 mixture of N2O and O2.

Drug:Sevoflurane and Propofol Mask induction is perform with sevoflurane (4-6%) follow by 1.5-2% sevoflurane in a 50:50 mixture of N2O and O2.

The induction dose of propofol is 3-5 mg/kg-1 (mean induction dose: 4 mg/kg-1) follow by propofol infusion (12 mg/kg/h-1 for the first 10 min of general anesthesia, 9 mg/kg/h-1 for another 10 min, and 6 mg/kg/h-1 thereafter; mean maintenance dose: 9 mg/kg/h-1) and a 50:50 mixture of N2O and O2.

The Faces Pain Scale (FPS) (from five face drawings: 0 = no pain, 5 = extreme pain) is used to assess pain severity

Recovery time, defined as the time until eye opening on command or the time of first response to command after anesthesia

Adverse effects during the surgery and after recovery: hypotension, bradicardia, intense coughing, hypersalivation and laryngospasm, nausea, and vomiting.