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Abstract: PO1128

Filter Operation Mode Affects the In Vivo Performance of a Synthetic Plasma Fractionation Membrane

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Krieter, Detlef H., University Hospital Würzburg, Div. of Nephrology, Würzburg, Bayern, Germany
  • Kiefer, Niclas Leonard, University Hospital Würzburg, Div. of Nephrology, Würzburg, Bayern, Germany
  • Rueth, Marieke, eXcorLab GmbH, Obernburg, Germany
  • Lemke, Horst-Dieter, eXcorLab GmbH, Obernburg, Germany
  • Wanner, Christoph, University Hospital Würzburg, Div. of Nephrology, Würzburg, Bayern, Germany

The mode a dialyzer or fractionator is operated may affect the fouling processes of the filter membrane and, hence, may determine its patency and performance. Purpose of the present study was to assess such effects in vivo. To avoid the often varying treatment conditions in humans, a large animal model was used.


In a prospective, randomized, controlled, crossover trial, four sheep were subjected to double filtration plasmapheresis with a polyethersulfone plasma fractionation membrane intended for lipid apheresis (FractioPES® 200; 3M, Germany). Five different operation modes were tested in each animal: Low (30 mL/min), medium (36 mL/min) and high (42 mL/min) plasma flow rates as well as high flow rate at increased plasma temperature (38.5 °C; thermofiltration) and reversed plasma filtration flow direction (outside-in), respectively. The totally treated plasma volume was 1500 mL. Reduction ratios (RR) and sieving coefficients (SK) at 300, 600, 900 and 1200 ml of treated plasma were determined for LDL cholesterol (2.500-3.000 kDa), HDL cholesterol (175-360 kDa), fibrinogen (305-385 kDa), immunoglobulin IgG (150 kDA) and albumin (67 kDa).


Compared to the other modes (medium flow rate, 0.05±0.02 to, high flow rate, 0.08±0.01), SK for LDL were significantly higher (P<0.001) in outside-in filtration at 300 mL (0.21±0.03). SK for LDL were also significantly higher (P<0.001) in both outside-in (0.19±0.07) and at high flow (0.17±0.02) conditions at 600 mL. For IgG at 900 mL, SK for low flow (0.57±0.32) was lower (P=0.049) compared to the high flow rate (1.05±0.07). For fibrinogen, SK at 600 mL (0.23±0.03) was higher (P=0.001) in outside-in filtration compared to the other modes. At 900 mL, the SK for fibrinogen determined in outside-in (0.37±0.12) was superior to the low and high plasma flow modes (0.08±0.08 and 0.13±0.01, resp.). Several significant differences in SK were identified at different plasma volumes within the same operation mode. No significant differences in RR were determined between operation modes.


Compared to the other operation modes, outside-in filtration and, less pronounced, also high plasma flow rates increase the permeability of a synthetic fractionation membrane for larger proteins. The differences in SK did not translate into different reduction ratios.


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