Near-normal glycemia for critically ill patients receiving nutrition support: Fact or folly

Purpose of review: In critically ill patients, nutrition support may be a life-saving intervention, but is not without risk. Adverse metabolic changes, including hypertriglyceridemia and hyperglycemia, are common. Hyperglycemia is associated with adverse outcomes, in particular, infection. Four major studies have addressed whether near-normal glycemia (80-110 mg/dl) in this clinical setting improves outcomes compared with blood sugars of approximately 150 mg/dl. The purpose of this review is to determine whether tight glycemic control is superior to moderate glycemic control (150 mg/dl) in critically ill patients receiving nutrition support. Recent findings: Initial data collected in postsurgical patients suggested that near-normal glycemia dramatically improved outcomes compared with moderate glycemic control. However, three recent studies were unable to duplicate these results and suggest that the benefits of tight glycemic control may be limited to postsurgical patients. Controlling hyperlipidemia and preventing overfeeding may improve outcomes more than tight control of blood sugars. Furthermore, near-normal glycemic control caused frequent hypoglycemia and, in some cases, worsened outcomes. Summary: Glycemic control to approximately 150 mg/dl is not inferior to near-normal glycemia in critically ill patients requiring nutrition support and is clearly safer. Lipid changes caused by insulin infusion may improve outcomes more than glycemic control itself, and prevention of hypertriglyceridemia should be a major focus of clinical care.