Effects of Protein/Nonprotein caloric intake on parenteral nutrition-associated cholestasis in premature infants weighing 600-1000 grams

Background: Parenteral nutrition-associated cholestasis (PNAC) has historically been a significant cause of morbidity and mortality in neonates undergoing parenteral feeding. Studies examining the causes of cholestasis in the PN-dependent neonate have produced a wide range of data, with some conflicting results. Increased protein/ nonprotein calorie ratios, increased glucose concentrations, and increased lipid concentrations have all been implicated as possible causes of PNAC. However, these studies were done in the pre-TrophAmine (neonatal-specific amino acid parenteral nutrition [PN] formulation) era. With the introduction of TrophAmine, infants are now receiving higher concentrations of protein, often being advanced rapidly even when nonprotein calories may not be sufficiently advanced to meet the infants' caloric needs. To the best of our knowledge, no studies have been conducted to evaluate the protein/ nonprotein calorie ratio as a cause of PNAC in the TrophAmine era. Methods: A retrospective chart review of 25 cholestatic and 25 noncholestatic PN-dependent premature neonates was conducted. All neonates weighed between 600 and 1000 g. Cholestasis was defined as a serum total bilirubin (TB) >= 2.0 mg/dL, with a serum direct bilirubin (DB) >= 20% of the TB. Neonates with major congenital anomalies or who underwent major surgery were excluded. PN macronutrient compositions were analyzed to examine if the different amounts of protein concentrations and protein/nonprotein calorie ratios played a role in the development of PNAC. Statistical analysis was performed using Student's t-tests. p Values <.05 were considered statistically significant. Results: All measured nutrition parameters did not differ significantly between the cholestatic and noncholestatic groups. Protein intake, the protein/nonprotein calorie ratio, and renal function as evaluated by blood urea nitrogen (BUN) and creatinine did not differ between the 2 study groups. The only parameters that differed significantly between the groups were the duration of PN therapy and length of hospital stay. Conclusions: Protein to nonprotein calorie ratio was not an etiology in the development of cholestasis in infants (600-1000 g) receiving PN. Renal function elicited not to have an impact, on cholestasis status of these infants. Therefore, providing adequate protein calories should not be limited in this patient population, as suggested by previous studies in the pre-TrophAmine era. We found that increased duration of PN therapy and increased length of hospital stay were associated with PNAC.