When general anesthesia is performed for surgery, tracheal intubation is performed. In order to ventilate after performing tracheal intubation, air is injected into the cuff attached to the tube to fill the gap between the tracheal tube and the patients's inner surface of trachea.

Even though, 20 to 30 cm H2O is known to be the appropriate pressure to prevent air leaks while preventing ischemic damage of tracheal mucosa. So, Researchers want to observe clinical differences in pressure at both ends of the safety zone of the cuff pressure.

Patients who are scheduled for elective surgery/ general anesthesia are randomized to two groups.

l : cuff pressure - 20cmH2O ll : cuff pressure - 30cmH2O

After tracheal intubation with routine method, cuff pressure is continuously monitored with manometer. The anesthesia during surgery is maintained with 0.8 MAC of desflurane and continuous remifentanil. Clinical outcomes (sore throat, hoarseness and postoperative pain) are evaluated after 0 minutes, 2 hours, 4 hours, and 24 hours after surgery.

Inclusion Criteria:

• patients undergoing total hip replacement arthroplasty that require general anesthesia

Exclusion Criteria:

• a patient who disagrees with the study
• tracheal stenosis
• operation time > 3 hours or < 1 hour 30 minutes
• difficult airway
• drug abuse, alcoholism