In Vivo Solute Elimination of Paired Filtration Dialysis

Abstract

Paired filtration dialysis (PFD) is a new dialysis strategy whereby a hemofilter and a hemodialyzer are coupled in series. It has been assumed that this approach allows a better solute elimination than conventional hemodialysis (HD), allowing a shortening of dialysis time. To evaluate this hypothesis, solute elimination with PFD either with 0.4 m² polysulphone (PS) and 1.36 m² cuprophan (CU) 3×3 h/wk, or with 0.4 m² PS and 1.06 m² CU 3×4 h/wk, was compared to HD with 1.36 m² CU, 3×4 hours weekly in the same patients. During PFD, 10L were ultrafiltered and substituted by saline. Overall extraction of UV absorbing solutes (MW < 10,000 Dalton), and extraction of individual solutes identified by high performance liquid chromatography (HPLC) were compared as well as urea kinetics. For PFD 3×3 h overall extraction of UV-absorbing compounds and of hippuric acid was significantly higher than for HD 3×4 h (p < 0.05). Overall extraction of UV-absorbing copounds and of all but one individual compound under study was markedly higher for PFD 3×4 h vs conventional HD 3×4 h (p < 0.01), in spite of a higher diffusive area with the latter technique. No differences in urea kinetics were observed for the 3 strategies. It is concluded that solute extraction during PFD is higher than during HD, if the treatment time is the same. Even if treatment is shortened to 3×3 h weekly, solute extraction with PFD is at least as efficient as with HD.