Alterations in the peritoneal transport of water and solutes during peritonitis in continuous ambulatory peritoneal dialysis patients.

The in situ intraperitoneal volume and the mass transfer area coefficients (MTC) of urea, lactate, creatinine, glucose, kanamycin, inulin, beta 2-microglobulin, albumin and IgG were studied in eight continuous ambulatory peritoneal dialysis (CAPD) patients. All patients were studied during a 4-h dialysis dwell, first during peritonitis and subsequently after recovery from the infection. The maximal intraperitoneal volume was reached at 68 min during peritonitis and at 150 min in the study after recovery (P less than 0.01), suggesting increased water transport during the infection. For all investigated solutes MTCs were higher in the presence of peritonitis than after recovery. This increase was most marked for the proteins (greater than 100%). The power curve relationships between MTCs and molecular weight indicated that peritoneal transport of the low- and middle-molecular weight solutes was determined by free diffusion and that the infection-induced rise was due to an increase in effective surface area. For protein transport restricted diffusion was found. The increase of this transport during peritonitis was probably caused by both a larger effective surface area and a higher vascular permeability.