Clinical Research Directory

Inclusion Criteria: 1. ASA I \~ II level; 2. BMI22-30kg/m2; 3. Those who intend to undergo laparoscopic cholecystectomy; 4. Age 18\~65 years. Exclusion Criteria: 1. Has been allergic to the drugs used in this study; 2. Patients with a history of chronic use of alcohol, smoke or other sedative drugs; 3. Patients took opioids and other analgesics before surgery; 4. Emergency operation; 5. Stress, anxiety resulting in secretion of catecholamine; 6. Patients with neuropsychiatric disorders, coma, depression, cognitive impairment and Alzheimer's disease; 7. Patients with epilepsy, autonomic nervous dysfunction and other diseases with abnormal EEG results; 8. SBP\< 85 mmHg or HR\< 45次/min; 9. Has implanted pacemaker; 10. Patients were unwilling or disable to finish whole study; 11. Patients with acute upper respiratory infections, liver or kidney failure and severe cardiopulmonary dysfunction.