Nutrition in the head-injured patient

Head injury initiates a systemic response characterized by hypermetabolism, hypercatabolism, the acute-phase response, decreased immunologic function, hyperglycemia, increased counterregulatory hormone levels, increased ventricular fluid and serum cytokine levels and altered gastrointestinal function. Early and adequate nutrition, whether enteral or parenteral, is believed to be an essential component of patient care and has been shown to improve outcome. Recent studies indicate that enteral nutrition is more effective than parenteral nutrition in maintaining the integrity of gastrointestinal mucosa, reducing the incidence of septic morbidity and decreasing the risk of bacterial translocation. Thus, enteral administration of nutrients is the preferred route of nutrition. Because of the high incidence of gastroparesis, enteral nutrition support may be difficult. However, many benefits of early enteral nutrition can be achieved even if the patient receives only 1/3 of needs. Supplemental parenteral nutrition may be used until enteral nutrition becomes adequate. Modulation of injury response by provision of specific nutrients such as arginine appears to improve the immune response in critically ill patients, but has not been specifically evaluated in patients following head injury. Future researches should be aimed at defining optimal nutritional support utilizing specific nutrients and nutritional regimens to improve the outcome of patients with head injury.