Characteristics of protein and energy metabolism in neonates with necrotizing enterocolitis - A pilot study

Background/Purpose: It is assumed that neonates with necrotizing enterocoli tis (NEC) are hypermetabolic. However, the dynamics of protein and energy m etabolism in neonates with NEC have not been characterized. The purpose of this study was to test the hypothesis that protein turnover and energy expe nditure are increased during the acute stage of NEC and later return to nor mal values. Methods: A pilot study was performed on six neonates with proven NEC (Bell' s stage II or III). Patients were studied in two phases: (1) in the acute s tage of their disease and (2) when their clinical condition had stabilized. Whole-body protein turnover was calculated using an intravenous infusion o f [1-C-13] leucine and by measuring the isotopic enrichment of plasma [C-13 ]alpha-ketoisocaproic acid and (CO2)-C-13. Respiratory gas exchange was mea sured simultaneously by computerized indirect calorimetry. Results: Median gestational age was 36 weeks (range, 28 to 40) with a media n postnatal age of 21 days (range, 6 to 47). All patients recovered from th e acute episode, although three patients died after recovering from the acu te disease from other conditions. The patients studied showed marked variab ility in protein metabolism kinetics. However, there was no difference in w hole-body protein flux between the acute phase (7.6 g/kg/d; range, 5.6 to 1 8.2) and the recovery phase (7.0 g/kg/d; range, 6.9 to 12.2; P = .89). Furt hermore, there was no difference in any of the component parts of whole-bod y protein turnover. Resting energy expenditure did not change between the a cute phase (42.8 kcal/kg/d; range, 34.4 to 52.5) and the recovery phase (51 .0 kcal/kg/d; range, 34.9 to 55.3; P = .18). Conclusions: This pilot study shows that the rates of protein and energy me tabolism in neonates with NEC are comparable with reported values in stable neonates. There was no difference in protein or energy dynamics between st udy phases. The authors speculate that neonates with NEC may divert the pro ducts of protein synthesis from growth to tissue repair. J Pediatr Surg 34: 5-12. Copyright (C) 1999 by W.B. Saunders Company.