Dipeptides have been reported to be more efficiently absorbed from the gastrointestinal tract than free amino acids. The objective of this study was to compare prospectively a peptide enteral formula (PEF) with a standard enteral formula (SEF) for tolerance and nutritional outcome in acutely injured, hypoalbuminemic (less than 3.0 g/dL) patients who require enteral nutrition support. The prevalence of diarrhea and elevated gastric residuals was assessed daily. Prealbumin, transferrin, colloid oncotic pressure, Prognostic Nutritional Index, and nitrogen balance were measured on days 0, 5, and 10 of enteral nutrition support. Forty-one patients received 345 days of enteral nutrition support. Prevalences of diarrhea and elevated gastric residuals were similar between groups. Prealbumin increased and the Prognostic Nutritional Index decreased significantly from baseline at day 10 in both groups. Transferrin increased in both groups, but not significantly. Colloid oncotic pressure increased significantly from baseline at days 5 and 10 in the SEF group and day 10 in the PEF group. Nitrogen balance increased significantly from baseline at days 5 and 10 in each group. The only significant difference between groups was for nitrogen balance at day 10, which was higher in the SEF group. We conclude based upon our selected measurements of tolerance and nutritional outcome PEF seems to offer no advantage over SEF in acutely injured, hypoalbuminemic patients.

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Minimal information is available defining urinary nitrogen constituents in preterm neonates receiving parenteral nutrition (PN). The study objective was to evaluate 24-hour urine collections for total urinary nitrogen (TUN), urinary urea nitrogen (UUN), and the nitrogen content in creatinine, ammonia, free amino acids, protein, hippuric acid, and uric acid at baseline (days 1 to 2 of PN and days 1 to 3 after surgery) and 7 days later in eight preterm, postsurgical neonates. Calculation of undetermined nitrogen was also completed. Comparisons with historic, normal data were made for each urinary nitrogen constituent. At baseline, PN provided 59 +/- 10 nonprotein kcal/kg.day-1 and 430 +/- 54 mg/kg.day-1. At day 7, PN provided 106 +/- 23 nonprotein kcal/kg.day-1 and 432 +/- 30 mg/kg.day-1. TUN, UUN, and protein nitrogen decreased significantly from baseline at day 7 (p < .05). The percentages of TUN as amino acids, creatinine, and uric acid nitrogen were calculated. Percent amino acid nitrogen (6.0 +/- 2.3% vs 8.4 +/- 1.5%, p < .05), percent creatinine nitrogen (1.6 +/- 0.5% vs 2.9 +/- 0.8%, p < .001) and percent uric acid nitrogen (1.7 +/- 0.9% vs 3.6 +/- 2.1%, p < .05) increased significantly at day 7. The observed urinary free amino acid nitrogen fraction represented a higher percentage of TUN both at baseline and at day 7 when compared with term neonatal reference data, whereas creatinine nitrogen, uric acid nitrogen, and protein nitrogen represented a lower percentage of TUN. However, amino acid and creatinine nitrogen as a percentage of TUN were similar to levels in milk formula-fed preterm infants.(ABSTRACT TRUNCATED AT 250 WORDS)