[Studies of the utilization of parenterally administered amino acid solutions]

Clinical studies on a newly devised amino acid solution for neonates

In 97 neonates receiving total parenteral nutrition in the postoperative period, clinical assessment was made for a newly devised amino acid solution (PF-I-III) from the standpoint of plasma amino acid profile and nutritional effect. These amino acid solutions prepared are characterized by the high concentration of branched-chain amino acids up to 40%, increased arginine and decreased glycine, phenylalanine and methionine as compared with commercially available solutions. In the PF group, each amino acid was kept within the range of standard value. Correlation between plasma amino acid profiles and the dose of each amino acid administered was obtained, from which minimum, standard, and maximum doses for each amino acid was determined. Based on these values, we proposed new formula for neonates which elicits no abnormal plasma amino acid pattern even when amino acids are administered at the dosage level of 1.5-2.5 g/kg/day.

[Investigations on the utilization of parenterally administered amino acids in premature and small-for-dates neonates. IV. Control of the amino acid blood level during infusion of a pharmacokinetically balanced amino acid solution (author's transl)]

An amino acid solution composed according to pharmacokinetic criteria was infused in 12 premature and 4 full-term infants. Imbalances of amino acids were not observed when the upper limit of the fasting level was accepted as a measure for balance or imbalance. The net transfer of total amino acids increased by about 40% over that in former experiments (second communication (4)). A decrease of cystine, a semiessential amino acid, could be avoided. The results were compared with the literature. During infusion, the urinary excretion of amino acids was not increased showing nearly complete utilization of the infused amin acids.

[Investigations on the utilization of parenterally administered amino acids by premature and hypotrophic neonates (author's transl)]

The composition of an amino acid solution for intravenous use in newborns is discussed in the light of the metabolic kinetics of its constituents. Such a solution would be optimal when based on the transfer characteristics of the single amino acids used. Under these circumstances one would avoid imbalances in the respective blood levels. In particular, the average amount of such a solution needed, and the maximal turnover rates per hour of the specific amino acids during the first 4 weeks of life are discussed.