Estimate of specific energy expenditure of fat-free mass and fat mass in children receiving total parenteral nutrition.

OBJECTIVES: Simple methods for calculation of the energy expenditure may be useful for clinicians involved in the treatment of nutritional disorders in children. The aims of this study were to (1) estimate the specific energy expenditure (SEE) of fat mass (FM) and fat-free mass (FFM) and (2) determine a sensitive predictive indicator of resting energy expenditure (REE). METHODS: The REE of 26 children receiving longterm TPN, was measured by long-term indirect calorimetry. Body composition was estimated from the sum of four skinfold measurements. RESULTS: The following regression equations were derived: (1) REE (kcal/d) = 56.6 x FFM (kg) + 97.9 (r2 = 0.98, p < 0.001); (2) REE (kcal/d) = 45.6 x BW (kg) + 136 (r2 = 0.92, p < 0.001); (3) REE (kcal/d) = 68.9 x FFM (kg) + 3.3 x FM (kg) (r2 = 0.985, p < 0.001). The results obtained allowed the estimate of K1 and K2 with their respective SEE: K1 = 3.3 +/- 18.0 kcal/kg of FM, K2 = 68.9 +/- 3.1 kcal/kg of FFM. CONClUSIONS Anthropometrically measured FFM is an easily determined predictive factor of REE. The above equations may be used to estimate the REE in stable children receiving TPN.