Kinetics and dose of daily hemofiltration.

Daily hemofiltration (D-HF) is a new treatment modality that shows unique solute removal characteristics and possibly provides high quality of life for patients with end-stage renal disease. We evaluated solute removal characteristics of D-HF for 5 patients by kinetic modeling analysis. Five patients treated with normal 4-hour x 3 times/week hemodialysis (HD) were switched to D-HF (2-hour x 6 times/week). Ultrafiltration rates (Q(F)) or small solute clearances ranged from 63 to 106 ml/min. All the pertinent kinetic parameters were determined from patients' physical data and the HD portion of the clinical measurements. The two-compartment kinetic model predicted the concentration changes after switching from normal HD to D-HF. In all 5 patients, 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. Predicted solute concentrations and clinical measurements for UN and beta(2)-MG were in good agreement with average error less than 10%. The model predicted that Q(F) = 155 ml/min may be necessary for the 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. A 7-day treatment (7 times/week) D-HF may improve the solute removal capacity of small solutes. Copyright (c) 2004 S. Karger AG, Basel.