The Effect of the Hyperinsulinemic Normoglycemic Clamp on Myocardial Function and Utilization of Glucose

Prior to anesthetic induction, a baseline blood glucose value will be obtained, followed by an insulin infusion of 5 mU.Kg-1.min-1. When blood glucose is \<110 mg/dL, a variable continuous infusion of glucose (dextrose 20%) supplemented with potassium (40 mEq/L) and phosphate (30 mmol/L) is administered to preserve normoglycemia (80-110 mg/dL). The glucose infusion is titrated to target glucose levels by checking blood glucose every 5 - 15 min with Accu-Check (Roche Diagnostics, Switzerland) glucose monitor. At sternal closure, insulin infusion is decreased to 1 mU/Kg/min. On admission to the ICU, insulin treatment follows the ICU protocol. The dextrose infusion is slowly weaned off over 2 - 4 hrs maintaining blood glucose \> 80 mg/dL. Arterial blood glucose is measured every 30 - 60 min for 2 hrs, then, as stated in ICU protocol.

Baseline arterial blood glucose will be obtained before anesthetic induction. Repeat measurements are performed every 30-90 min. Glucose \>150 on CPB will receive insulin according to intraoperative protocol. After surgery, insulin is given according to ICU protocol. Target glucose \< 180 mg/dL.