Cardiopulmonary bypass (CPB) is a necessary technique to maintain the circulation during cardiac surgery. But CPB itself is associated with a series of problems of organs, such as hyperglycemia induced by neuroendocrine stress. The research showed that hyperglycemia induced by stress would cause a worsened hospital outcome for patients undergoing cardiac surgery. Intraoperative and postoperative glucose control is beneficial for patients.~It has been for more than 40 year since the first application of glucose - insulin - potassium (GIK) in cardiac surgery but the clinical application of GIK shows controversial results. The beginning time of application and the ratio of glucose and insulin may be the key reasons for the controversy. In our pilot trial of 40 valve replacement cases, we found that perioperative treatment of GIK with an insulin-glucose ratio of 1:3 showed beneficial effects during heart surgery. Therefore, the investigators are planning to continue to test this modified GIK regimen for more heart surgery patients and determine whether GIK may have cardioprotective effects on patients undergoing CPB surgery.~Myocardial biopsies for biological mechanism analysis will be performed prior to CPB, 15 min after aortic cross clamp application and 15 min after reperfusion only in a small cohort. Myocardial biopsies will be snap frozen or fixed.
The purpose of this study is to evaluate the effects of modified glucose - insulin - potassium (GIK) therapy in cardiac surgery patients undergoing cardiopulmonary bypass (CPB).