Short Daily Hemodialysis vs. Short Daily Hemofiltration (Search for Optimal Prescription)

Abstract

It has been shown that daily hemodialysis as well as convective transfer by hemofilitration improve the quality of extra renal treatment. Two following phases of treatment of three weeks each were tested in 2 patients: daily hemodialysis 2.5 h 6 times/week (HD*6) and daily hemofiltration 2.75 h 6 times/week (HF*6) performed according to the following modalities. Phase I, blood flow rates (QB): 300 mL/min, hemofilter 1.4 m2AN 69 dialysate flow 500 mL/min. Phase II, QB: 150 mL/min, hemofilter 1m2AN 69, exchange volume of 10 L/session; 5 L predilution and 5 L postdilution (conditions were limited by the device). We measured, during the third week of treatment of each phase, the weekly mass transfers and the predialysis plasma levels of urea (U), creatinine (C), phosphate (P), and B2 microglobulin (B2M). In the 2 phases, HD*6 and HF*6, respectively, the weekly urea Kt was: 120 vs. 60 L; std Kt/V: 3.30 vs. 2.0; npcr: 1.26 vs. 1.42 g kg–1 day–1. Mass transfer/week Predialytic levels/L HD*6 HF*6 HD*6 HF*6 U (mmol) 2366 2204 23.2 38.5 C (µmol) 67240 51096 769.5 934.8 P (mmol) 127 111.5 1.91 2.34 B2M (mg) 311 763.5 34.2 30.16 In HF*6, predialysis solute concentration increased and weekly small molecule mass transfer was insufficient. B2M mass transfer was significantly increased and predialytic plasma concentration decreased, showing a higher clearance of middle molecules with convective transfer. The clinical tolerance was excellent during the two phases of treatment. This study allows to determine the optimal conditions for adequate daily HF: higher QB and exchange volume. Further studies with QB of at least 300 mL/min and with exchange volume of 15 L/session seem to be necessary.