Abstract
Backfiltration in HP dialyzers, which are used for removing a larger amount of beta-2-microglobulin, could cause an inflow of endotoxins from contaminated dialysate. Change of dialyzer specifications makes it possible to reduce Backfiltration rate or to prevent endotoxins from getting into blood stream. The authors propose a theoretical design method for HP dialyzers to reduce backfiltration. Under countercurrent operations, simulation results showed that the backfiltration could be prevented for dialyzers with FB-190UGA and PAN-12CX2 membranes of a length of 5cm and housing diameters of 7.7 and 8.8cm, respectively. Under cocurrent operations, however, dialyzers had the minimal backfiltration rates, which could be zero, at a given hollow fiber density. No backfiltration would occur under cocurrent operations in dialyzers with above two membranes of a length of 25cm and a fiber density of 0.52 and 0.62, respectively. Results can be generalized that enlarging housing diameters and shortening fiber length for countercurrent operations prevent backfiltration to occur and choosing an appropriate fiber density for cocurrent operations reduces backfiltration rate.
