What is optimal nutritional support?

Nutritional support of the seriously ill patient has evolved with time and reflects new developments in the field of critical care. Current information suggests that optimal nutritional support can be provided by supplying at least 80% of energy requirements with at least 70% of the energy given as carbohydrate and the remaining 30% or less administered as fat (with > or = 3% of energy requirements as essential fatty acids). The caloric load may be reduced to 50% of requirements if growth factors (e.g., growth hormone) are utilized and the patient has adequate fat stores. Protein should be given as 1.5 g/kg/day; more catabolic patients, such as patients with burn injury, should receive 2 g/kg/day. All protein or amino acid feeding should include glutamine. There is an increased need for vitamins (especially A, C, and E) and minerals (zinc, selenium, and magnesium). The preferred route of feeding should be enteral, followed by enteral plus supplemental parenteral nutrition. If the gastrointestinal tract cannot be used, parenteral nutrition should be given. Nutrients should be administered early in the catabolic course, especially glucose, sodium, potassium, vitamins, and minerals. Over time (approximately 7 days) amino acids should be added and approximately 50% of caloric support should be provided. Finally, full nutritional support should be provided (by 7 to 10 days) if the catabolic course is expected to continue.