The use of a crystalline amino acid mixture for parenteral nutrition in low-birth-weight infants.

Thirty-six preterm, sick, low-birth-weight neonates were given either total or partial parenteral nutrition. The patients were divided into three groups according to their birth weights: group A -less than 1,000 gm, 12 patients: group B--between 1,000 and 1,500 gm, 15 patients: group C--more than 1,500 gm, 9 patients. The solution for total parenteral nutrition contained 20% glucose and 2.6% crystalline amino acids plus appropriate amounts of vitamins and minerals. The volume of infusate given was usually 125 ml/kg/day, but varied depending on the clinical condition of the patient; occasionally it was as high as 150 to 175 ml/kg/day. Infusate of one-half strength was administered initially; its concentrations of glucose and amino acids were increased to three quarters and full strength gradually, if tolerated. The solution for total parenteral nutrition was infused into the superior vena cava via a central venous catheter; that for partial parenteral nutrition was given into a peripheral vein to supplement inadequate oral feedings. The period of parenteral nutrition lasted from 5 to 49 days, with an average of 13.2 days. The intake of 500 mg of nitrogen as crystalline amino acids and 100 kcal as glucose was capable of achieving body weight gain. Positive nitrogen balance of various degrees was also observed. Hyperglycemia of a slight to moderate degree was observed in nine patients; only three required insulin therapy. Two patients had thrombotic occlusion of the central venous catheter. The conclusion was reached that total parenteral nutrition or partial parenteral nutrition, when properly managed, is a safe procedure in small, premature infants. The amino acid solution given as a nitrogen source along with adequate calories was effective in promoting weight gain and nitrogen balance; it was apparently well tolerated by low-birth-weight neonates.