Purpose of review: Full nutritional support during the acute phase of critical illness has traditionally been recommended to reduce catabolism and prevent malnutrition. Approaches to achieve full nutrition include early initiation of nutritional support, targeting full nutritional requirement as soon as possible and initiation of supplemental parenteral nutrition when enteral nutrition does not reach the target.
Recent findings: Existing evidence supports early enteral nutrition over delayed enteral nutrition or early parenteral nutrition. Recent randomized controlled trials have demonstrated that permissive underfeeding or trophic feeding is associated with similar outcomes compared with full feeding in the acute phase of critical illness. In patients with refeeding syndrome, patients with high nutritional risk and patients with shock, early enteral nutrition targeting full nutritional targets may be associated with worse outcomes compared with less aggressive enteral nutrition strategy.
Summary: A two-phase approach for nutritional support may more appropriately account for the physiologic changes during critical illness than one-phase approach. Further evidence is awaited for the optimal protein amount during critical illness and for feeding patients at high nutritional risk or with acute gastrointestinal injury.