Understanding glycemic control in the critically ill: 2011 update.

Intensive monitoring of blood glucose concentrations in critically ill patients has become a standard of care in intensive care units over the past 10 years, following the publication of a single-center randomized trial targeting euglycemia in postoperative patients. This article summarizes the literature describing the relationship between hyperglycemia and mortality in the critically ill, the main findings of the major interventional trials of intensive insulin therapy, the association between hypoglycemia and increased glycemic variability with adverse outcomes, and the impact of a preexisting diagnosis of diabetes. A framework for understanding dysglycemia in the critically ill, an approach that recognizes disturbances in the "3 domains" of glycemic control--hyperglycemia, hypoglycemia, and increased glycemic variability--is presented. Finally, practical considerations relating to the implementation of glycemic management protocols are discussed.