The effect of burn wound excision on measured energy expenditure and urinary nitrogen excretion

The effect of wound closure on the metabolic response to burn injury is uncertain. Energy expenditures were measured in 20 patients by indirect calorimetry (MEE) and estimated initially by the Curreri formula (CEE) and susequently by a modification of the Curreri formula (MCEE), adjusted for changes in open wound size and body weight. Urinary urea nitrogen (UUN) excretions were measured over 24 hours. Second-and third-degree burns, initially involving 31% to 74% of the body surface areas, were reduced in size to less than 15% by excisions and grafting procedures. The correlations among percentage open wounds, MEE’s, CEE’s, and MCEE’s were low. UUN excretions were not correlated with percentage open wounds or with MEE’s. Estimates of energy expenditures using the Curreri formula appear to be of limited usefulness in prescribing caloric intakes in burned patients. Serial UUN’s are useful in determining protein requirements, but were not correlated with MEE’s or with the extent of open wounds.