Kinetic analysis of daily hemofiltration

Abstract

Daily hemofiltration (D-HF) is a new treatment modality that shows unique solute removal characteristics and possibly provides a high quality of life for patients with end-stage renal disease. We evaluated solute removal characteristics of D-HF for five patients by kinetic modeling analysis. Five patients treated with normal 3 x 4 hr/week hemodialysis (HD) were switched to D-HF (6 x 2 hr/week). Ultrafiltration rates (Q(F)) or small-solute clearances ranged from 63 to 106 mL/min. All the necessary kinetic parameters were determined from patients' physical data and HD portion of the clinical measurements. The two-compartment kinetic model predicted the concentration changes after switching from normal HD to D-HF. Concentrations of small solutes such as urea nitrogen (UN) increased, whereas that of beta(2)-microglobulin (beta(2)-MG) decreased after switching from normal HD to D-HF in all five patients. Predicted solute concentrations and clinical measurements for UN and beta(2)-MG were in good agreement with mean error less than 10%. The model predicted that Q(F) = 155 mL/min may be necessary for time-averaged concentration (TAC) of UN to be unchanged. The model also predicted that the 7 times/week D-HF should not increase the pretreatment concentration of UN, expecting even much lower beta(2)-MG concentration after switching from normal HD to D-HF. D-HF is superior to normal HD for removing larger solutes but may increase the TAC of small solutes. Seven-day (7 times/week) D-HF may improve the solute removal capacity of small solutes.