Patient-specific insulin-resistanceguided infusion improves glycemic control in cardiac surgery

Background: Maintenance of appropriate capillary blood glucose in cardiovascular surgery patients has been associated with improved outcomes, including lower mortality. Interpatient variability in insulin resistance can make management difficult, leading to unexpected episodes of hypoglycemia and hyperglycemia. To improve postoperative glucose control at our institution, a patient-specific insulin-resistanceguided (IRG) protocol was developed. Methods: Prospective data were gathered on 100 consecutive cardiovascular surgery patients managed with our standard insulin infusion protocol and 100 patients managed using the IRG protocol. Clinical characteristics and glycemic indices were analyzed for the two groups. Primary endpoints included (1) percentage of time spent in the target range, (2) number of hypoglycemic and hyperglycemic episodes, (3) time to achievement of target blood glucose, and (4) the total daily dose of insulin required. Results: The IRG protocol resulted in significant improvements, including increased percentage of time spent in the normoglycemic range (82.5% versus 65.8%, p < 0.001), reduced rate of hypoglycemic episodes (0.12 versus 0.99, p < 0.01), reduced rate of hyperglycemic episodes (capillary blood glucose >126 mg/dL: 4.8 versus 8.2, p < 0.01), and a reduced time to the first measurement in the target range. Total daily dose of insulin was mildly increased, but failed to reach statistical significance (92.48 versus 82.64 units, p = 0.32). Conclusions: Use of the IRG protocol led to improved glycemic indices while reducing episodes of hypoglycemia in both diabetic and nondiabetic patients. The ability to adjust a patient's insulin dosing based upon factors related to their insulin resistance results in improved blood glucose control and safety in cardiovascular surgery patients.