REPLACEMENT OF AMINO-ACID AND PROTEIN LOSSES WITH 1.1-PERCENT AMINO-ACID PERITONEAL-DIALYSIS SOLUTION

Objective: Losses of nutrients into dialysate may contribute to malnut rition. Peritoneal dialysis (PD) patients are reported to lose 3 - 4 g /day of amino acids (AAs) and 4 - 15 g/day of proteins. The extent to which one exchange with a 1.1% AA dialysis solution (Nutrineal, Baxter , Deerfield, IL, U.S.A.) offsets these losses was investigated in a 3- day inpatient study in 20 PD patients. Design: Simple, open-label, cro ss-over study on consecutive days in a clinical research unit. On day 1 all patients were given a peritoneal equilibration test (PET). On da y 2 they received 1.5% dextrose Dianeal (Baxter) as the first exchange of the day and their usual regimen thereafter. On day 3, the first ex change of the day was the 1.1% AA solution in place of 1.5% Dianeal an d the usual PD regimen thereafter. On days 2 and 3 all dialysate efflu ent was collected and analyzed for AAs and proteins. Patients were mai ntained on a constant diet. Results: Losses of AAs and total proteins on day 2 were 3.4 +/- 0.9 g and 5.8 +/- 2.4 g, respectively, totaling 9.2 +/- 2.7 g. The net uptake of AAs on day 3 was 17.6 +/- 2.6 g (80 /- 12% of the 22 g infused). Mean gains of AAs on day 3 exceeded losse s of proteins and AAs on day 2, p < 0.001. Losses of total proteins, b ut not losses of AAs, and the net absorption of AAs from the dialysis solution were correlated directly with peritoneal membrane transport c haracteristics, obtained from the PET. Conclusion: Daily losses of AAs and proteins into dialysate are more than offset by gains of AAs abso rbed from one exchange with 1.1% AA-based dialysis solution. Net gains of AAs exceeded losses of proteins and AAs in all patients studied. T he difference was relatively constant across a wide range of membrane transport types. Net AA gains were approximately two times the total A A and protein losses.