Mechanisms of Albumin Loss during Peritoneal Dialysis in Man

Albumin loss in the dialysate was evaluated during a total of 5 peritoneal dialyses carried out on 3 uraemic patients. The measurements were made by two different methods, the first based on the evaluation in the dialysate of intravenously injected radioiodinated albumin, the second one based on a radioimmunoassay of the protein in the dialysate. The results obtained showed three main mechanisms of protein loss during peritoneal dialysis: 1) albumin shift from extravascular sites adjacent to the peritoneum, 2) direct passage of albumin from blood stream to peritoneal cavity, and 3) tendency of the inter‐dialysis peritoneal fluid to equilibrate with plasma proteins. Furthermore, the observations made on a patient with evident peritonitis proved the importance of the intrinsic biological properties of the peritoneum in determining the amplitude of protein wasting by the dialysate.