Diffusive (KBD, A0/δx(t)) transport parameters and sieving coefficients (S) for small solutes and free water fraction (FWF), that is, the fraction of total water flow that is transported through aquaporins, were assessed as functions of dwell time t for 35 continuous ambulatory peritoneal dialysis patients using glucose 3.86% dialysis fluid. The individual values of the unrestricted pore area over diffusion distance, A0/δx(t), were estimated using the mixed effects nonlinear regression and applied for evaluation of S(t) for sodium and FWF(t). FWF decreased on average from the initial 51% of the total transcapillary water flow to 36% at 120 min, whereas the small pore water fraction and sodium sieving coefficient increased. Our results were consistent with the three-pore model if the contribution of the transcellular pores (αTP) at the beginning of dwell study was doubled and later decreased to the standard value of 0.02. We conclude that transport characteristics of fluid and small solutes should be considered as time-dependent variables during the peritoneal dialysis.
- Continuous ambulatory peritoneal dialysis
- Diffusive surface area parameter
- Free water fraction
- Sodium sieving
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Biomedical Engineering