Methods : Seventy-five patients were studied with the use of LT size 4. N2O (66%) and isoflurane were used to maintain anesthesia. Initial intracuff pressure and volume were recorded for airway sealing during ventilation. Time-course changes of the intracuff pressure followed by recording every 10 min. If the intracuff pressure reached 100 cmH2O, the cuff was deflated to the initial intracuff pressure and the volume of deflated air and postoperative airway complications were recorded.