Nutrient support of the healing wound.

Wound healing is a series of complex physicochemical interactions that require various micronutrients at every step. In the critically ill or severely injured patient, wound healing is impaired by the protein-catabolic, hypermetabolic response to stress. The hypothalamus responds to cytokine stimulation by increasing the thermoregulatory set-point and by augmenting elaboration of stress hormones (catecholamines, cortisol, and glucagon). In turn, the stress hormones induce thermogenic futile substrate cycling, lipolysis, and proteolysis. Increased glucose production results at the expense of skeletal muscle degradation, producing amino acid substrate for hepatic gluconeogenesis. Nutritional support of the hypermetabolic state is an essential part of ensuring efficient wound healing in these patients. Protein catabolism cannot be reversed by increased amino acid availability alone, due partly to a defect in amino acid transport. This defect can be reversed by anabolic agents, such as growth hormone and insulin-like growth factor-1. Growth hormone treatment dramatically improves wound healing in severely burned children. Supplementation with protein and vitamins, specifically arginine and vitamins A, B, and C, provides optimum nutrient support of the healing wound.