The determinants of protein catabolism in neonates on extracorporeal membrane oxygenation

Background/Purpose: Protein catabolism appears to be markedly elevated among neonates on extracorporeal membrane oxygenation (ECMO). The aim of this study was to determine the effect of dietary caloric intake on protein catabolism in neonates on ECMO to help construct therapies that may promote anabolism. Methods: Twelve total parenteral nutrition (TPN)-fed (88.1 +/- 5.0 [SE] kcal/kg/d; range, 60 to 113 kcal/kg/d; 2.3 +/- 0.2 g/kg/d protein) neonates were studied on ECMO at day of life 7.2 +/- 0.8 d. Protein kinetics were determined using infusions of (NaHCO3)-C-13 and 1-[C-13]leucine. Results: As expected, C-reactive protein levels were significantly elevated compared with normal controls (44.0 +/- 7.6 mg/L v 1.9 +/- 1.1 mg/L; P < .001). Negative protein balance (-2.3 +/- 0.6 g/kg/dt range, 1 to -6.4 g/kg/d) highly correlated (r = -0.88, P < .001) with total protein turnover. Increased dietary caloric intake correlated with increased amino acid oxidation (r = 0.85, P < .001), increased total protein turnover (r = 0.73, P < .01), continued negative protein balance (r = 0.72, P < .01), increased whole-body protein breakdown (r = 0.66, P < .05), and increased CO2 production rate (r = 0.73, P < .01). Conclusions: A surplus of dietary caloric intake does not improve protein catabolism and merely increases CO2 production in these highly stressed neonates. Thus, judicious caloric supplementation is warranted. J Pediatr Surg 34:1086-1090. Copyright (C) 1999 by W.B. Saunders Company.