Nutritional and metabolic support in the adult intensive care unit: key controversies.

OBJECTIVE: To discuss certain important features of nutrition and metabolism in the intensive care unit. DATA SOURCE: Prospective clinical trials examining issues related to glucose control, immunonutrition, and comparison of enteral and parenteral nutrition.
CONCLUSIONS: It remains unclear which glycemic threshold should be used in many patients for insulin initiation, but surgical patients receiving adequate nutrition should probably be treated to true normoglycemia. Immunonutrition may be beneficial in some populations, but the evidence does not justify its use in the intensive care unit. Contrary to popular belief, appropriately administered parenteral nutrition may provide similar or more benefit than enteral and clearly needs more widespread acceptance in cases where initiation of enteral nutrition is slow to start or is contraindicated.