Hyperglycemia in the critically ill.

Hyperglycemia is frequently seen in acutely ill patients and has historically been viewed as a normal response to stress. Treatment is often not initiated unless blood glucose exceeds 200 to 250 mg/dL. Recent evidence suggests that hyperglycemia is associated with worse outcomes within the population of medical and surgical intensive care units. Hyperglycemia in this population of patients develops from increased gluconeogenesis and insulin resistance. Although the specific mechanisms by which hyperglycemia contributes to poor outcomes are as yet unknown, disruption of normal mitochondrial respiration, direct glucose toxicity, accumulation of asymmetric dimethylarginine, and impairment of immune cell function are among the possibilities implicated. Studies demonstrate that intensive insulin therapy to achieve euglycemia reduces mortality and morbidity in critically ill patients. In addition to recognizing and treating hyperglycemia, it is as important to identify other frequently overlooked factors that contribute to hyperglycemia, such as medications, intravenous fluids, and enteral and parenteral nutrition.