Amino acids in parenteral nutrition of preterm infants. Comparison of oral and parenteral supply.

Parenteral feeding of preterm infants has been accepted as an alternative form of nutrition in those infants unable to accept oral feeding. The amount of amino acid nitrogen and the composition of the amino acid solution to be used, however, have not yet been defined. The amino acid intake and the plasma amino acid concentration of three groups of preterm infants were compared. Twenty-three infants were fed parenterally. Of these, 16 were studied during the first week of life (group I) and 7 during the second week (group II). A control group of 9 infants fed with oral formula was also studied in the second week (group III). In general, plasma amino acid concentrations in the parenterally fed groups were higher than in the orally fed group, in spite of a lower intake. Comparison of the amino acid intake of groups I and II relative to group III, with the plasma amino acid concentrations of groups I and II relative to group III, revealed a rather constant ratio with the exception of tyrosine and aspartic acid, where higher values were found. It is concluded that further increase in the amino acid nitrogen in parenteral feeding of preterm infants requires a more adapted preparation.