 SpO2 values below 90 were defined as hypoxemia. The severity of hypoxemia was graded as mild SpO2: 80-89, moderate SpO2: 70-79 or severe SpO270. Coughing or respiratory effort diaphragm movement and limb movement during laryngoscopy and rigid bronchoscopy was graded as mild minor movement that does not effect surgical comfort, moderate effect surgical comfort or severe the bronchoscope has to be removed or any complication by the endoscopist. Postoperative severe restlessness and disorientation with purposeless activity were defined as emergence agitation. All adverse events were recorded by an independent observer. 