Amino acid patterns of infants of very low birth weight. I. Characterization and clinical significance of change over time.

: Plasma amino acid levels were determined in 40 premature, very low birth weight infants. All blood samples were drawn prior to parenteral nutrition and blood transfusions. Levels were taken from 0 to 90 hours after birth at approximately 12-hour intervals. Dextrose 5% or 10% in water was given intravenously, beginning shortly after birth, as the only caloric source. A total of 69 plasma amino acid determinations were used for statistical analysis of 25 amino acids versus time. Plasma amino acid profiles were separated into several time intervals. An analysis of covariance of the means of these intervals demonstrated a statistical difference (p less than or equal to 0.01 or better) for taurine, lysine, alanine, threonine, valine, tryptophan, cystine and free cysteine/cystine. Thus, plasma amino acid levels should be reviewed in relation to the hours after birth of sampling. By 12 hours after birth, a relatively stable pattern was observed for all amino acids except taurine. Taurine levels continued to decline throughout the observation period. No statistically significant correlations were observed between the plasma amino acid levels and gestational age.