The Use of a Crystalline Amino Acid Mixture for Parenteral Nutrition in Low-Birth-Weight Infants

Abstract

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 1,00 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 froni 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.

N‐acetyl Tyrosyluria Caused by Parenteral or Enteral Administration of N‐acetyl‐L‐tyrosine: Differentiation From Hereditary and Acquired Tyrosinemias

“…Alternatively, more soluble derivatives of tyrosine have been used, including NAT and dipeptides such as glycyltyrosine and alanyl-tyrosine, which can be hydrolyzed to yield free tyrosine. It can be debated whether NAT is effective (9)(10)(11)(12) or ineffective (13)(14)(15) in maintaining normal aromatic amino acid homeostasis in patients on parenteral nutrition, but there is no question that a significant proportion of administered NAT is excreted unchanged in the urine (11)(12)(13)(14)(15)(16).…”

3. Amino Acids

“…This principle works more rapidly than weight gain or growth studies (12)(13)(14)(15). Most current amino acid solutions are developed in a similar fashion (16)(17)(18).…”

Amino Acids and Lipid in Total Parenteral Nutrition for the Newborn

“…However, cysteine hydrochloride is highly unstable, being rapidly oxidised to the insoluble cystine unless the pH of the solution is very low, and can therefore be added only as the solution is prepared for infusion. Trophamine (Kendall McGaw) contains these supplements , and LBWN given this solution have satisfactory plasma tyrosine and total cyst(e)ine levels but metabolise both supplements less well than term neonates (13). However, some LBWN develop a metabolic acido- e Trophamine is the only solution listed here that contains additional cysteine and tyrosine as cysteine hydrochloride and n-acetyl-L-tyrosine.…”

“…Trophamine was formulated using an optimisation technique (13). This uses computer modelling to define the parenteral intake of each of the amino acids required to maintain normal plasma amino acid concentrations.…”