title: Evaluation of high-flux hemodiafiltration efficiency using an on-line urea monitor.
abstract: On-line urea monitoring of the effluent dialysate offers a real-time assessment of dialysis efficiency and metabolic/nutritional characteristics of hemodialysis patients. Quantitative parameters were evaluated by dialysate urea kinetic modeling (DUKM) with an on-line urea sensor in 23 patients treated by high-flux hemodiafiltration (HDF) (215 sessions of 210 to 240 minutes with a mean blood flow rate of 367 +/- 44 mL/min). Overall, the mean effective Kt/V was 1.52 +/- 0.29, the urea mass removed (22.8 +/- 5.5 g/session or 814 +/- 198 mmol/session), the solute removal index (SRI) 73% +/- 6.1%, and the mean normalized protein catabolic rate (nPCR), 1.15 +/- 0.31 g/kg/day. Blood urea kinetic modeling (BUKM), based on pre- and postsession urea concentrations, using equations from Daugirdas and Garred to calculate equilibrated Kt/V and nPCR, respectively, were in good agreement with DUKM, the differences observed appearing not clinically relevant. The variability of evaluated parameters was verified over consecutive sessions for a mean period of 3 weeks in the entire group. Mean variation in Kt/V was 8%; in urea mass removal, 18%; and in nPCR, 18%. When assessed over 1 week in a subgroup of 13 patients, Kt/V and PCR remained relatively stable, and urea mass removal per- and postsession declined from 23.5 +/- 8.0 g (840 +/- 285 mmol) to 18.7 +/- 6.3 g (667 +/- 225 mmol) from the first to the third session of the week, most likely as a consequence of interdialytic intervals. Predialysis urea concentrations followed the same trend. In the current study, DUKM with on-line urea sensor has confirmed that HDF is a highly efficient renal replacement modality; the variability observed in quantitative parameters supports a need for frequent adequacy monitoring. On-line urea monitoring of effluent dialysate is a simple device that provides the opportunity to tailor treatment to patient needs.
authors.affiliation: Lapeyronie Hospital, University of Montpellier, France. b.canaud@sc.univ-montpl.fr
authors.forename: B
authors.initials: B
authors.lastname: Canaud
authors.forename: J Y
authors.initials: JY
authors.lastname: Bosc
authors.forename: M
authors.initials: M
authors.lastname: Leblanc
authors.forename: L J
authors.initials: LJ
authors.lastname: Garred
authors.forename: T
authors.initials: T
authors.lastname: Vo
authors.forename: C
authors.initials: C
authors.lastname: Mion
mesh_terms: D001806:Blood Urea Nitrogen; D005069:Evaluation Studies as Topic; D005260:Female; D017583:Hemodiafiltration; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009862:Online Systems; D014508:Urea / Q000032:analysis* / Q000097:blood
chemical_list: D014508:Urea