An extended kinetic model-based correction factor equation to account hemodialysis post-treatment hemoconcentration

Abstract

The hemoconcentration effect for middle weight solutes in hemodialysis is corrected by oversimplified methods based on hematocrit changes or distribution volume variations. Here we implemented a variable volume dual pool kinetic model targeted at obtaining a precise correction factor equation for extracellularly distributed solutes based on relevant kinetic parameters such as the ultrafiltration to dry weight ratio UF/DW, the dialyzer clearance, K_d, the intercompartment mass-transfer coefficient, K_c, and the central compartment to extracellular volume ratio, α. More than 300,000 solutions of the model were computed, performing a sweep among physiological values of the proposed kinetic parameters, resulting in a linear regression denoted by the expression f_corr = 1.0707 − 5.2246 (UF/DW) − 0.0005 K_d − 0.0004 K_c − 0.0007 α, with an excellent coefficient of determination R² = 0.983. The presented f_corr provides a substantial extension of the currently implemented methods to estimate the hemoconcentration factor for middle and high molecular weight extracellular distributed solutes in hemodialysis.