Early introduction of parenteral nutrition in premature infants and its effect on calcium and phosphate homeostasis.

Calcium and phosphate homeostasis was evaluated in two matched groups of sick premature neonates. Parenteral nutrition in the form of an amino acid solution was administered to 10 infants (group A), and a dextrose-electrolyte-calcium solution was administered to 11 infants (group B). The infants did not demonstrate the immediate phosphaturia previously described following infusion of amino acids and/or glucose. In both groups, phosphate excretion was directly related to phosphate intake (r = 0,45; P less than 0,001). In group A infants infusion of the amino acid solution was associated with a significantly greater fall in serum calcium levels on the 2nd day of life (P = 0,02 v. group B), despite similar intake and excretion of calcium in the two groups. We suggest that the phosphate content of the amino acid solution may aggravate the neonate's tendency to hypocalcaemia, although frank hyperphosphataemia was not observed.