Objective To observe and evaluate the protective effect of desflurane post-conditioning on myocardial injury during cardiopulmonary bypass and its influence on patients'postoperative recovery.Methods A total of 200 patients in need of cardiac surgery were selected as the experimental subjects,who were aged from 20 to 65 years old,and divided into ASA Ⅱ-Ⅲ and NYHA Ⅱ-Ⅲ by endotracheal intubation and extracorporeal circulation method under general anesthesia.The patients were randomly divided into desflurane post-treatment group(experi-mental group,group D)and control group(group C)after selection.With the successive opening of the aorta and superior vena cava,group D were given 5%desflurane by inhalation with mechanical ventilation.While group C inhaled pure oxygen without inhaling desflurane.The depth of intraoperative anesthesia was maintained between 40～50 during the operation.Radial artery blood was collected from patients in 24 h before surgery(T0),immediately after intubation(T1),and 1 h(T2),6 h(T3),12 h(T4)and 24 h(T5)after aortic opening to achieve the determi-nation of troponin I(cTnI)and creatine kinase isoenzyme MB(CK-MB).On the premise of obtaining the informed consent of the patient,about 50 mg of right atrial appendage tissue was collected before aortic intubation(T1.5)and 1 hour after aortic opening(T2)to determine the apoptosis rate.Results(1)cTnI in group C at the time of T2,T3,T4 and T5 was apparently higher than group D(P<0.05).(2)CK-MB in group C at the time of T3 was apparently higher than group D(P<0.05).(3)The myocardial tissue results showed that there was a lower apoptosis rate in experimental group at the time of T2(P<0.05).Conclusion Desflurane post-conditioning has a myocardial protec-tive effect during cardiac surgery under cardiopulmonary bypass.