title: Patient- and treatment-related determinants of convective volume in post-dilution haemodiafiltration in clinical practice.
abstract: BACKGROUND
  Large convective volumes are recommended for online haemodiafiltration (HDF) to maximize solute removal. There has been little systematic evaluation of factors that determine convective volumes in routine clinical practice.
  
  
  METHODS
  In the present study, potential patient- and treatment-related determinants of convective volume were analysed in 235 consecutive patients on post-dilution HDF using multivariable linear regression models. All patients (age 64 +/- 14 years; 61% male) participated in the ongoing CONvective TRAnsport STudy (CONTRAST). Additionally, differences in convective volumes between dialysers were evaluated.
  
  
  RESULTS
  The mean convective volume was 19.4 +/- 4.0 L (+/-SD) per treatment, with a large variation between the participating centres (centre means ranging from 13.4 +/- 0.9 L to 24.5 +/- 0.12 L, +/- SE). The mean filtration fraction of the blood flow was 25.9 +/- 3.6. In the multivariable analysis, factors that were significantly related to convective volume were haematocrit [inversely, regression coefficient (B) = -1.4 +/- 0.4 L per 10%], serum albumin (positively, B = 1.0 +/- 0.4 L per 10 g/L), blood flow rate (positively, B = 0.4 +/- 0.04 L per 10 mL/min) and treatment time (positively, B = 5.1 +/- 0.4 L/h). In addition, significant differences between dialysers were observed, likely explained by different operational conditions.
  
  
  CONCLUSIONS
  Apart from increasing the treatment time and blood flow rate, convective volumes could be optimized by increasing the filtration fraction in each individual, provided that transmembrane pressures are well within safe limits. The precise role of dialyser characteristics on maximal achievable convective volumes in clinical practice is a topic for further research.
authors.affiliation: Department of Nephrology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: E Lars
authors.initials: EL
authors.lastname: Penne
authors.forename: Neelke C
authors.initials: NC
authors.lastname: van der Weerd
authors.forename: Michiel L
authors.initials: ML
authors.lastname: Bots
authors.forename: Marinus A
authors.initials: MA
authors.lastname: van den Dorpel
authors.forename: Muriel P C
authors.initials: MP
authors.lastname: Grooteman
authors.forename: Renée
authors.initials: R
authors.lastname: Lévesque
authors.forename: Menso J
authors.initials: MJ
authors.lastname: Nubé
authors.forename: Piet M
authors.initials: PM
authors.lastname: Ter Wee
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Blankestijn
mesh_terms: D000328:Adult; D000368:Aged; D018481:Convection; D005260:Female; D005374:Filtration; D006400:Hematocrit; D017583:Hemodiafiltration; D006801:Humans; D008297:Male; D008875:Middle Aged; D012709:Serum Albumin / Q000032:analysis
chemical_list: D012709:Serum Albumin