Amobarbital and Cardiopulmonary Bypass

Inclusion Criteria: * Age range: 18-65 years old, undergo elective cardiac surgery with extracorporeal circulation. * ASA II-III; * surgical duration is 3-6 hours; * Sign the informed consent form Exclusion Criteria: * BMI less than 18 kg/m2 or greater than 30 kg/m2; * Individuals with a history or potential history of drug abuse or alcohol dependence; * Preoperative use of sedatives or analgesics; * Individuals with severe liver and kidney dysfunction; * Individuals who are allergic or potentially allergic to barbiturates; * Patients with coagulation dysfunction, endocrine disorders, or other conditions that affect hemodynamic status; * Participated in other clinical studies in the past 3 months; * The researchers believe that participants who are not suitable to participate in this study.