title: Performance of polysulfone membrane dialyzers and dialysate flow pattern.
abstract: BACKGROUND
  It is important to observe the flow pattern of dialysate when evaluating dialyzer function and developing the most appropriate design. We investigated dialysate flow through two polysulfone membrane dialyzers (TS-UL [Toray Medical] and APS-S [Asahi Medical]) by computed tomography (CT), with barium sulfate as the contrast medium. We also performed a clinical comparison of these two dialyzers.
  
  
  METHODS
  For the in vitro experiment, after confirming the steady-state flow of mock blood (xanthan gum solution; 200 ml/min) and dialysate (500 ml/min), fresh dialysate, containing 5% (w/v) barium sulfate was perfused, and longitudinal CT scans of the dialyzer were obtained. Then the concentration of barium sulfate was measured (in Hounsfield units) in three fixed regions of interest. For the in vivo experiment, 12 patients on stable hemodialysis who had been using the APS-S for more than 1 month were switched to the TS-UL for 1 month and changes in various parameters were assessed.
  
  
  RESULTS
  The distribution of dialysate was homogeneous on CT scans of the TS-UL, but not on scans of the APS-S. The dialysate concentration curves for the three regions of interest were similar with the TS-UL, but not with the APS-S. Clearance of urea nitrogen and albumin loss were both significantly higher with the TS-UL than with the APS-S. The decrease in alpha 1-microglobulin was larger with the TS-UL than with the APS-S, but not significantly.
  
  
  CONCLUSIONS
  Clearance of substances over a wide range of molecular weights was higher with the TS-UL than with the APS-S, and differences in the design of the dialysate compartment may have been involved in this feature.
authors.affiliation: Department of Molecular and Internal Medicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, and Department of Internal Medicine, Sanyo Hospital, Fukuyama, Japan.
authors.forename: Ayumu
authors.initials: A
authors.lastname: Nakashima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogata
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Doi
authors.forename: Michihiro
authors.initials: M
authors.lastname: Yamahira
authors.forename: Satoe
authors.initials: S
authors.lastname: Naraki
authors.forename: Norihisa
authors.initials: N
authors.lastname: Takasugi
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Ohmoto
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ito
authors.forename: Takao
authors.initials: T
authors.lastname: Masaki
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yorioka
mesh_terms: D000328:Adult; D001466:Barium Sulfate / Q000493:pharmacokinetics; D001672:Biocompatible Materials / Q000627:therapeutic use*; D003287:Contrast Media / Q000493:pharmacokinetics; D015314:Dialysis Solutions / Q000008:administration & dosage*; D004867:Equipment Design / Q000295:instrumentation; D006801:Humans; D008567:Membranes, Artificial; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011108:Polymers / Q000627:therapeutic use*; D011135:Polysaccharides, Bacterial; D006435:Renal Dialysis / Q000295:instrumentation* / Q000379:methods; D013450:Sulfones / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed
chemical_list: D001672:Biocompatible Materials; D003287:Contrast Media; D015314:Dialysis Solutions; D008567:Membranes, Artificial; D011108:Polymers; D011135:Polysaccharides, Bacterial; D013450:Sulfones; C017662:polysulfone P 1700; D001466:Barium Sulfate; C002563:xanthan gum