Abstract
Peritoneal dialysis is a therapy alternative to conventional hemodialysis for end-stage renal disease patients, which utilizes patients' peritoneal membrane for the treatment. Continuous Ambulatory Peritoneal Dialysis (CAPD) is based on the continuous presence of dialysate in the peritoneal cavity that enables to remove toxic substances with low mass transfer rates. Usually mass transfer rates in peritoneal dialysis were well-explained mathematically with a diffusion-limited model however, experiments in which mass transfer rates had been measured before and after the total evisceration revealed that the peritoneal blood flow rate should play a significant role for mass transfer. A new mass transfer model, which includes both diffusion-limited and blood-flow limited situations as extremes, was proposed and termed Comprehensive Blood flow-Diffusion Model. This model explained all the paradoxical data that had previously been experienced.
Convective mass transfer across the peritoneum is crucial right after the infusion of new dialysate solution. However, diffusion mass transfer should dominate over convective one through out one-whole exchange of the dialysate not to mention for small molecules but even for so-called middle/large molecules.
