Effect of Noise Isolation on the Incidence of Moderate to Severe Postoperative Pain

Inclusion Criteria: * Between the ages of 18 and 70, both male and female. * American Society of Anesthesiologists Classification 1-3 * Patients undergoing elective major abdominal surgery under general anesthesia(Surgery time ≥ 2h) * Voluntarily accept patient controlled intravenous analgesia and signed informed consent Exclusion Criteria: * Patients with previous severe disease * Patients with hearing abnormalities * Patients requiring mechanical ventilation or undergoing epidural catheters or other types of regional anesthesia after surgery * Patients with chronic preoperative pain and/or long-term analgesic use * Patients who could not cooperate with the study for any reason