Protein losses in patients receiving continuous ambulatory peritoneal dialysis

Total protein and 12 specific proteins were measured in dialysates from 8 patients on continuous ambulatory peritoneal dialysis during training. Mean daily loss of total protein was 10.5 g and this included 5.2 g albumin, 805 mg of the immunoglobulins G, A and M, 323 mg transferrin and 530 mg of the remaining 7 proteins measured. The plasma to dialysate ratio of protein concentrations correlated with the natural logarithm of molecular weight, suggesting that proteins in dialysate are an ultrafiltrate of plasma. A greater loss of proteins overnight was due to longer dwell time as the mean rate of loss was similar for all exchanges. Losses were similar with 1.36% and 3.86% dextrose fluids, suggesting that the initial effects of hypertonicity are diminished or reversed by dilution and absorption of dextrose. Daily outflow volumes for 4 patients correlated inversely with the quantities of several proteins removed, probably due to effects of osmolality. It is concluded that protein losses are related to plasma concentration, molecular weight and osmolality of the dialysis solution and to the physiology of the patient.