Influence of Glucose-Insulin-Potassium on Left Ventricular Function During Coronary Artery Bypass Grafting

To evaluate the hemodynamic effect of glucose-insulin-potassium administered during cardiopulmonary bypass grafting (CABG), i.v. infusion of glucose 0.5 g, insulin 1.35 IU and potassium 0.25 mmol/kg b.w/hour was begun after induction of anesthesia and continued until aortic cross-clamping in seven patients. Seven controls underwent CABG without such infusion. The left ventricular ejection fraction was measured after i.v. injection of Tc-99m-HSA before and at termination of cardiopulmonary bypass (CPB), in conjunction with invasive measurements to obtain left ventricular pressure-volume indices at end-systole and end-diastole. Three-step transfusion from the oxygenator was given before and after CPB in order to assess left ventricular contractility during volume-load, using the end-systolic pressure-volume index. Left ventricular contractility remained unchanged after CPB in the patients given glucose-insulin-potassium but decreased significantly in the controls. The left ventricular passive diastolic properties were unchanged after the ischemic period in both groups. The arterial glucose concentration rose markedly in the infused group (7.3-18.5 mmol/l) and moderately (6.4-8.2) in the controls. Glucose-insulin-potassium infusion thus favorably influenced left ventricular function during CABG by preventing decrease in contractility after CPB.