Comparison of two neonatal intravenous amino acid formulations in preterm infants: a multicenter study

Two neonatal intravenous amino acid solutions (Aminosyn-PF and Troph-Amine) were compared in 44 preterm infants. The rate of weight gain, nitrogen balance, and changes in plasma aminograms were determined over 7 days to ascertain whether different outcomes could be identified for the two solutions. At study entry, the infants received a minimum infusion of 2 g amino acid/kg/d with 50 or more nonprotein kcal/kg/d. Group mean amino acid intake over the study period was approximately 2.6 g/kg/d for both groups; nonprotein caloric intake approximated 90 kcal/kg/d. Results showed no significant differences between solutions for the rate of weight gain, nitrogen balance, and nitrogen retention, which approximated intrauterine rates. The rate of weight gain averaged nearly 15 g/kg/d for both solutions. Differences between day 0 and day 7 plasma aminograms showed significant changes between solutions for histidine, lysine, methionine, phenylalanine, threonine, and glutamic acid. However, day 7 plasma aminograms for both solutions compared favorably with those from enterally fed preterm infants reported in the literature. Failure to identify significant differences for the rate of weight gain, nitrogen balance, or nitrogen retention between the two groups suggests that differences in plasma aminograms resulting from use of one solution or the other had no short-term clinical consequences in the premature infants studied.