Impact of solute exchange between erythrocytes and plasma on hemodialyzer clearance

Publication date: Available online 26 April 2019Source: Biocybernetics and Biomedical EngineeringAuthor(s): J. Waniewski, J. Poleszczuk, M. Pietribiasi, M. Debowska, A. Wojcik-Zaluska, W. ZaluskaAbstractThe standard theory of mass transport in dialyzer for water solutions was extended for solutes distributed in both plasma (PW) and erythrocyte intracellular (EW) water. Blood flow was divided into two separate flows of PW and EW with the diffusive exchange of solutes across cellular membrane (CM). Diffusive permeability of CM for urea and creatinine were assumed according to literature data. Computer simulations based on partial differential equations demonstrated that urea diffuses fast across CM and can be approximately considered as distributed uniformly in both blood flow components. In contrast, creatinine can be considered as distributed only in PW flow during the passage along the dialyzer. Therefore, the traditional formula for dialyzer clearance can be applied for urea and creatinine with the adjustment of their effective “blood” flow, but not for solutes with intermediate molecular mass. In vivo clearances of urea and creatinine were, as expected, lower than the respective theoretical predictions based of the diffusive permeability, P, times membrane surface area, A, parameters, PA, for dialyzer membrane, estimated for water solutions, by 33.6 ± 10.9% for creatinine and 10.8 ± 9.4% for urea. The estimated in vivo PAs were for creatinine 65.4...
Source: Biocybernetics and Biomedical Engineering - Category: Biomedical Engineering Source Type: research