A re-evaluation of energy expenditure during parenteral nutrition.

Nutritional support regimens are currently based on estimates of energy expenditure, and these estimates are then increased substantially in patients with severe trauma or sepsis because of a presumed hypermetabolic state. Forty-four patients on parenteral nutrition were evaluated using indirect calorimetry to measure actual energy expenditure, and an attempt was made to correlate metabolic rate with clinical diagnosis. We found no statistical difference in metabolic rates between groups of patients classified as malnourished, stressed, or catabolic, If high levels of nonprotein energy substrates are to be administered to a catabolic or "hypermetabolic" patient group, the justification must be on a basis other than a significant increase in actual rate of energy expenditure.