Full Nutrition or Not?

Enteral nutrition (EN) is widely used in intensive care units around the world, but the optimal dosing strategy during the first week of critical illness is still controversial. Numerous studies in the past decade have provided conflicting recommendations regarding the roles of trophic and permissive/intentional underfeeding strategies. Further complicating effective medical decision making is the widespread, yet unintentional and persistent underdelivery of prescribed energy and protein, in addition to the trend for recommending ever-higher amounts of protein delivery. We postulate that the key to appropriate enteral strategy lies within an accurate and patient-specific assessment. Patients with a baseline high nutrition risk and those with increased nutrition demands, such as those with wounds, surgery, or burns, likely require full nutrition support, in contrast with medical patients, such as those with acute respiratory distress syndrome, who may selectively be appropriate for trophic strategies. In this analysis, we review several key trials for and against full EN in the first week of critical illness, as well as key issues such as the role of autophagy and immunonutrition in enteral dose selection.