Background: This study determined the hemodynamic and metabolic effects of insulin cardioplegia, glucose-insulin-potassium (GIK) solution combined with insulin cardioplegia, and bloodonly cardioplegia on postoperative recovery in coronary artery bypass grafting (CABG).

Methods: One-hundred and twenty patients with normal ventricle function and no history of diabetes mellitus (DM) were randomly divided into three groups. During the operation, 10 IU/L of crystalized insulin-added blood cardioplegia was administered to the patients in group 1 (n=40) and group 2 (n=40), and standard blood cardioplegia was used in group-3 (n=40). In addition, GIK solution was started before the removal of cross-clamp (CC) period in group 2. The blood samples from arterial and coronary sinus were collected before CC application (T0), before CC removal (T1) and 0, 5^th, 10^th, and 15^th minutes (T2-T3-T4-T5) after CC removal. Hemodynamic parameters were measured at the 30th minute after anesthesia induction and 1^st and 24^th hours following surgery. During the peri- and postoperative course, the need for defibrillation, inotropic and intraaortic balloon pump support, the incidence of postoperative arrythmias, duration of intubation, intensive care unit stay and hospitalization were recorded.

Results: The levels of arterial and coronary sinus lactate were significantly lower in group 2 compared to group 3 in the 5th, 10th, and 15th minutes. The blood glucose levels of arterial and coronary sinus were significantly higher in group 3. In group 2, the incidence of postoperative arrythmias and requirement for inotropic support was less than that of group 1 and group 3 (p<0.05).

Conclusion: After CABG, in the reperfusion period, persistant release of lactate or higher lactate levels demonstarate that myocardial protection was unsatisfactory and the recovery of aerobic metabolism was diminished perioperatively. Glucose-insulinpotassium solution combined with insulin cardioplegia decreases the myocardial lactate level, incidence of arrythmias, and requirement for inotropic support and leads to better myocardial protection.

Keywords : Coronary artery bypass surgery; glucose; insulin; intraaortic balloon pumping; metabolism; myocardium; neurosecretory system; potassium