Nutritional Aspects of CAPD and the Potential Use of Amino Acid Containing Dialysis Solutions

As a result of a combination of a decreased appetite with increased nutrient losses in the dialysate, a number of CAPO patients may develop malnutrition. A decrease in appetite is also observed in normal animals undergoing CAPO which suggests that some factors related to CAPO influence appetite so that these animals eat less.

In addition to protein losses, CAPO patients are losing approximately two grams of amino acids a day, and they have plasma amino acid abnormalities similar to those produced by malnutrition and uremia.

An amino acid-containing dialysis solution (2%) is an effective solution with respect to ultrafiltration and solute removal.

Amino acids can be absorbed by the peritoneal route and produce an increase in plasma amino acids to levels similar to those observed after a protein meal. These observations indicate that administration of amino acids via the peritoneal route may prevent or correct malnutrition developed in patients on CAPO.

Use of Amino Acid Containing Solution in CAPD Patients

A number of CAPD patients may develop malnutrition due to multiple causes. Average daily amino acid loss during CAPD was 2 gm per day. Serum concentrations of almost all essential and non essential amino acids were significantly lower than controls. Amino acid containing solution is an effective osmotic agent and at the same time is suitable for nutritional supplementation. Use of this solution up to 4 weeks did not lead to any abnormal accumulation of amino acids and patient appeared to tolerate it well.

A number of CAPD patients may develop malnutrition which appears to be brought about by a combination of decreased appetite, and increased nutrient loss in the dialysate. In a group of 13 patients whose daily protein and caloric intakes at the beginning of CAPD were 1.5 9 per kg, and 35 Kcal/kg respectively, intakes decreased spontaneously after one year on CAPD even though they were being advised during their clinic visits to maintain initial protein and caloric intakes (1). Reduced intakes appear to result from decreased appetite and a feeling of fullness, although these factors are difficult to evaluate quantitatively. To gain information as to the etiology of appetite suppression during CAPD, we performed CAPD in nonuremic rabbits.

Plasma Amino Acid Profiles and Amino Acid Losses in Patients Undergoing CAPD

Fasting plasma amino acid levels and 24hour amino acid losses in the dialysate were measured in six nondiabetic female and six diabetic male patients on CAPD. Comparison of their plasma amino acid values with sex matched controls showed that CAPD did not restore the plasma amino acid levels of these patients to normal, and that the abnormalities in the non-diabetics were more marked than in the diabetics. The daily total amino acid losses in the dialysate were small relative to protein intake, averaged 2.25 9 per day and were similar for the non-diabetic and diabetics. The concentrations of most amino acids in the dialysate were proportional to their plasma concentrations. Loss of amino acids in the dialysate does not account for the abnormal plasma patterns of CAPD patients.