Perioperative tight glucose control with hyperinsulinemic-normoglycemic clamp technique in cardiac surgery

Abstract 

Objective

Previous attempts to achieve tight glucose control in surgical patients were associated with a significant incidence of hypoglycemia. The purpose of this study was to evaluate the efficacy of perioperative glucose and insulin administration while maintaining normoglycemia using a hyperinsulinemic-normoglycemic clamp technique.

Methods

We studied 70 non-diabetic and 40 diabetic patients undergoing cardiac procedures. Before induction of anesthesia, insulin was administered at 5 mU · kg⁻¹ · min⁻¹. Blood glucose (BG) concentrations were determined every 15–30min. Dextrose 20% was infused at a rate adjusted to maintain BG within 3.5–6.1mmol/L. At the end of surgery, insulin infusion was decreased to 1 mU · kg⁻¹ · min⁻¹ and continued for 24h. The mean ± standard deviation of BG and the percentage of BG values within the target range were calculated perioperatively. Episodes of severe hypoglycemia, i.e., BG <2.2mmol/L, were recorded.

Results

The mean BG remained within target at all times. Normoglycemia in non-diabetic patients was achieved in 92.8% of measurements during and in 83.2% after surgery. In diabetic patients 87.4% of values were within target intraoperatively and 76.7% after surgery. The rate of severe hypoglycemia was 2.7% (three patients). In non-diabetic patients the incidence of severe hypoglycemia was 0.2% of measurements during and 0.1% after surgery. Diabetic patients showed only one episode of severe hypoglycemia after surgery (0.1%).

Conclusion

Perioperative use of a hyperinsulinemic-normoglycemic clamp technique established and maintained normoglycemia in patients undergoing cardiac surgery with little risk of hypoglycemia.

Keywords: Intensive insulin therapy, Insulin, Hypoglycemia, Intensive care unit, Cardiopulmonary bypass