Minimization of Hypoglycemia as an Adverse Event During Insulin Infusion: Further Refinement of the Yale Protocol

Background: The management of hyperglycemia in the intensive care unit has been a controversial topic for more than a decade, with target ranges varying from 80–110 mg/dL to <200 mg/dL. Multiple insulin infusion protocols exist, including several computerized protocols, which have attempted to achieve these targets. Importantly, compliance with these protocols has not been a focus of clinical studies. Methods: GlucoCare™, a Food and Drug Administration (FDA)-cleared insulin-dosing calculator, was originally designed based on the Yale Insulin Infusion Protocol to target 100–140 mg/dL and has undergone several modifications to reduce hypoglycemia. The original Yale protocol was modified from 100–140 mg/dL to a range of 120–140 mg/dL (GlucoCare 120–140) and then to 140 mg/dL (GlucoCare 140, not a range but a single blood glucose [BG] level target) in an iterative and evidence-based manner to eliminate hypoglycemia <70 mg/dL. The final modification [GlucoCare 140(B)] includes the addition of bolus insulin “midprotocol” during an insulin infusion to reduce peak insulin rates for insulin-resistant patients. This study examined the results of these protocol modifications and evaluated the role of compliance with the protocol in the incidence of hypoglycemia <70 mg/dL. Results: Protocol modifications resulted in mean BG levels of 133.4, 136.4, 143.8, and 146.4 mg/dL and hypoglycemic BG readings <70 mg/dL of 0.998%, 0.367%, 0.256%, and 0.04% for the 100–140, 120–140, 140, and 140(B) protocols, respectively (P < 0.001). Adherence to the glucose check interval significantly reduced the incidence of hypoglycemia (P < 0.001). Protocol modifications led to a reduction in peak insulin infusion rates (P < 0.001) and the need for dextrose-containing boluses (P < 0.001). Conclusion: This study demonstrates that refinements in protocol design can improve glucose control in critically ill patients and that the use of GlucoCare 140(B) can eliminate all significant hypoglycemia while achieving mean glucose levels between 140 and 150 mg/dL. In addition, attention to the timely performance of glucose levels can also reduce hypoglycemic events.