Nutrition therapy in the intensive care unit

Nutrition therapy is challenging in critically ill patients. Critical illness is associated with a state of catabolic stress, in which stress hormones and inflammatory mediators are activated, resulting in proteolysis. The aim of nutrition therapy in critically ill patients is to preserve lean body mass, to preserve immune function, and to avoid metabolic complications. Enteral nutrition is preferred over parenteral nutrition. Enteral nutrition should be initiated within 24 to48 hours of intensive care unit admission. However, enteral nutrition should be withheld until the patient is fully resuscitated. If enteral nutrition is not feasible within several days, supplementary parenteral nutrition is necessary. In the acute phase, energy requirements should not be over 20 to 25 kcal/kg/d, and protein should be supplemented in the range of 1.2 to 2.0g/kg/day. Monitoring tolerance is very important in critically ill patients with artificial nutrition to avoid complications. Immunonutrition such as glutamine and omega-3 fatty acid is helpful to modulate effects on the immune system in critically ill patients. Implementation of a feeding protocol and the involvement of a nutrition support team can systemize nutrition therapy. Together, these steps will hopefully enable the integration of evidence-based guidelines into practice, leading to improvements in nutrition performance so that patients' chances of a good outcome are optimized.