Increasing Peritoneal Contact Area During Dialysis Improves Mass Transfer

Abstract

Abstract. Previous studies in mice demonstrated that relatively large volumes in the peritoneal cavity made contact with only 40% of the anatomic peritoneum and that this contact area (Acontact) could be increased with use of a surfactant, dioctyl sodium sulfosuccinate (DSS). To investigate the hypothesis that mass transfer rates during peritoneal dialysis are dependent on the area of peritoneum in contact with the dialysis solution, rats were dialyzed for 2 h with a solution that contained14C-mannitol, with or without 0.02% DSS. The mass transfer-area coefficients (MTAC) were determined to be (mean ± SEM, ml/min): no DSS, 0.163 ± 0.008; with DSS, 0.247 ± 0.006 (P< 0.002). DSS also caused an increase in total protein loss over 2 h (mean ± SEM, mg): no DSS, 83.8 ± 15.8; DSS, 159.5 ± 6.3 (P< 0.001). In a separate set of animals, the ratio (R) of Acontactto anatomic area in each plane was measured as in the previous study Rmean(mean ± SEM) and equaled 0.466 ± 0.075, no DSS; 0.837 ± 0.074, with DSS. The ratio of MTAC (1.52) and protein loss (1.90) approximate the ratio of RmeanS(1.78). Because MTAC = mass transfer coefficient (MTC) × Acontact, small peritoneal transport chambers were used to determine MTC for14C-mannitol and fluorescein isothiocyanate-albumin. MTCmannitoldid not change significantly with the addition of DSS. MTCalnbumin(cm/min × 104, mean ± SEM) equaled 1.47 ± 0.45 without DSS and 1.78 ± 0.52 with DSS (P< 0.04). It was concluded that DSS increases the mass transfer rates of mannitol and protein by increasing Acontact, whereas protein transport is further augmented by an apparent increase in the barrier permeability to protein.