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.