Solute transport characteristics in hemodiafiltration

A simple one-dimensional model was employed to develop a set of general equations for predicting the solute transport characteristics in hemodiafiltration (HDF). The enhancement in solute clearance from blood under HDF operation may be predicted from the data and parameters obtained in conventional hemodialysis (HD)and hemofiltration (HF)operation alone. For middle-molecular metabolites of molecular weight greater than 1000 daltons, the efficacy of hemodiafiltration over conventional HD operation as predicted in a typical case (sieving coefficient ? 1)is over 40 percent higher. This enhancement in clearance for HDF is generally greater as the molecular weight of solute to be removed becomes larger. A similar analysis can be extended to other merebrane separation systems in which convective mass transport is utilized to enhance the separation efficiency over that with diffusive mass transport alone.