Effects of two different doses of amino acid supplementation on growth and blood amino acid levels in premature neonates admitted to the neonatal intensive care unit: a randomized, controlled trial

Abstract

Objectives: The goal was to measure the effects of 2 distinct strategies for parenteral nutrition on neonatal growth and blood amino acid profiles.

Methods: In a multicenter trial (n = 11 sites), we randomly allocated premature (23-29 weeks and 6 days of gestation) neonates to 1 of 2 approaches to intravenous amino acid administration. In one group, amino acid supplementation was started at 1.0 g/kg per day and advanced by 0.5 g/kg per day to a maximum of 2.5 g/kg per day (2.5 g/kg per day group). The other group received amino acids starting at 1.5 g/kg per day and advancing by 1.0 g/kg per day to a maximum of 3.5 g/kg per day (3.5 g/kg per day group). Filter paper blood spots were obtained from each infant on the day of random assignment and on days 7 and 28 of age, to monitor blood amino acid levels.

Results: We enrolled 122 neonates (64 in the 3.5 g/kg per day group and 58 in the 2.5 g/kg per day group). There were no differences in demographic or baseline characteristics between the 2 treatment groups. There was no significant difference in growth by day 28 after birth (median weight gain: 12.9 and 11.4 g/kg per day for the 3.5 and 2.5 g/kg per day groups, respectively), and the incidences of secondary morbidities were similar in the 2 groups. On day 7, blood levels of several amino acids and the serum urea nitrogen level were higher in the 3.5 g/kg per day group, compared with the 2.5 g/kg per day group; none of the amino acid levels were lower.

Conclusions: Higher doses of amino acid supplementation did not improve neonatal growth and were associated with increased blood amino acid and urea nitrogen levels.

Trial registration: ClinicalTrials.gov NCT00120926.