Effect of Dexmedetomidine Preconditioning on Myocardial Ischemia-reperfusion Injury in Patients Undergoing Open Heart Surgery With Cardiopulmonary Bypass

About 200000 cardiac operations are performed in China every year. Cardiopulmonary bypass is the basic strategy of open-heart surgery, which may lead to myocardial ischemia-reperfusion injury and low cardiac output syndrome. It will inevitably affect the patient's postoperative recovery. A number of studies have shown that dexmedetomidine, as an auxiliary sedative, has the effects of inhibiting stress response, antiarrhythmia and cardiac protection.Dexmedetomidine has been widely used in anesthesia in cardiac surgery. However, at present, few clinical studies pay attention to its mechanism. In this study, dexmedetomidine will be used in cardiac surgery with cardiopulmonary bypass to explore the mechanism of cardiac ischemia-reperfusion injury and the protective effect of dexmedetomidine.

Inclusion Criteria:Aged 18-70 yearsAmerican Society of Anesthesiologists(ASA) physical status of I-ⅣBMI: 18.5-28 kg/m2Type of operation: elective open-heart surgery with cardiopulmonary bypassThe patient and/or family members have signed the informed consent.Exclusion Criteria:Preoperative diagnosis of heart failure 、gradeⅡ-Ⅲ heart block and diabetesLEVF<40%Severe coagulation dysfunctionSevere heart, lung, liver and kidney insufficiencyUsed to have immunosuppressive therapies such as radiotherapy, chemotherapy and glucocorticoid, or have immune system diseasesPerioperative allogeneic blood transfusion