Modification of an amino acid solution for peritoneal dialysis to reduce risk of acidemia

Some patients develop a mild acidemia during treatment with amino acid-based peritoneal dialysis solutions due to hydrogen ion produced by metabolism of lysine, arginine, and methionine. In this study we modified the formulation of such a solution by reducing these amino acids and adding anionic amino acids so as to provide minimal net acid production.

A modified formula (MF) was compared to a conventional formula (CF) of the solution in a randomized cross-over study in 12 stable continuous ambulatory peritoneal dialysis patients. Patients were given each solution for 14 days without a wash-out period. Each patient replaced one or two dextrose dialysis exchanges with amino acid solution, depending upon oral protein intake and body weight. Total intake (oral protein plus amino acids absorbed) was equivalent to 1.1-1.3 g protein/kg body weight/day. Plasma bicarbonate and urea were assessed at the beginning and end of each 14-day period.

In the group as a whole, without regard to the order in which the solutions were given, patients had a decrease in serum bicarbonate with CF and an increase in bicarbonate when they received MF. Similar trends were observed regardless of the order in which the solutions were administered. Serum urea did not differ between the two solutions.

The results suggest that patients are less prone to develop acidemia when receiving MF as opposed to CF. Further studies will be necessary to determine the long-term effects and the relative nutritional benefits of the two solutions.