Evaluation of an experimental rat model for peritoneal dialysis: fluid and solute transport characteristics

The aim of this study was to develop a reference model of fluid and solute transport during experimental peritoneal dialysis in rats, which would simulate the conditions of clinical dialysis in CAPD patients as much as possible. For this purpose a 4-h dialysis study was performed in 13 normal Sprague-Dawley rats with conventional glucose solutions (Dianeal 1.36% solution, n = 6 and Dianeal 3.86% solution, n = 7) and a protocol and methods like those used in clinical dwell studies. The dilution of a marker, radioactive human serum albumin (RISA), was used to determine the intraperitoneal dialysate volume with corrections for the elimination of RISA from the peritoneal cavity and sample volumes. The isovolumetric method was employed to calculate the diffusive mass transport coefficients. To compare our data with reference values in CAPD patients, the data were scaled by a factor calculated as a ratio of the dialysate volume in CAPD to the dialysate volume in the rats. In a separate series of experiments the intraperitoneal hydrostatic pressure was monitored with increasing infusion volumes. The fluid transport characteristics, described as the percentage changes of the initial intraperitoneal volume, were essentially comparable to those in CAPD patients. However, the intraperitoneal volume curves were shifted more to the left than were the reported values in CAPD patients. The scaled diffusive mass transport coefficient for urea was similar to that in CAPD patients. However, the transport of other solutes, in particular glucose, was faster in the rats than in CAPD patients.(ABSTRACT TRUNCATED AT 250 WORDS)