Metabolic response to postoperative parenteral nutrition in infants.

Thirty-five infants who had tracheoesophageal fistula, esophageal stenosis, anal atresia, or Hirschsprung's disease were managed with various types of parenteral solution after their radical operations. The infants were divided into 6 groups and given 1) the usual low calorie infusion consisting of 5% glucose, water, and electrolytes, 2) high calorie formula consisting of 21 g/kg/day glucose, and 4 g/kg/day synthesized crystalline L-amino acids, 3) solutions without phosphate, 4) solutions of Cal/N ratio 200 providing 4 g/kg/day amino acids, 5) solutions of Cal/N ratio 400 providing 2 g/kg/day amino acids, and 6) a regimen containing fat emulsion. Nitrogen (N) and phosphorus (P) balances, blood urea nitrogen (BUN), blood glucose, plasma phosphate, immunoreactive insulin (IRI), and non-esterified fatty acid (NEFA) values were investigated. Parenteral solutions, providing 100 Cal/kg/day of Cal/N ratio 200, yielded sufficient positive N balance (120 mg/kg/day average). High calorie solutions without phosphate caused marked hypophosphatemia (0.3 mEq/1) with undetectable P in 24-hr urine. P balance correlated with N balance. Solutions of Cal/N 400 induced a lower BUN level, although there was a cumulative negative N balance. Solutions of Cal/N 200 induced higher levels of IRI and lower glucose than those of Cal/N 400. Increased IRI response and remarkedly decreased NEFA levels were seen in the group administered solutions without fat. Solutions with fat emulsion suppressed IRI response and improved the level of plasma NEFA.