Nutritional management in acute respiratory failure.

Nutrition in the intensive care unit is receiving increased attention. Patients with acute respiratory failure from primary lung disease are often initially malnourished, or become malnourished secondary to increased metabolic demands or inadequate nutritional support. Adverse effects of malnutrition on lung function include decreased respiratory muscle function, decreased ventilatory drive, and altered lung defense mechanisms. Nutritional support should be strongly considered if the patient has evidence of malnutrition by nutritional assessment or has a high likelihood of becoming malnourished by virtue of severe, prolonged critical illness. General nutritional goals in the intensive care unit include maintenance of body weight and lean body mass. Proper nutritional therapy includes assessment of adequate caloric requirements and appropriate protein, carbohydrate, and fat composition of the nutritional support. Nutritional therapy should be closely monitored with body weight and nitrogen-balance measurements.