Dialyzer-dependent changes in solute and water permeability with bleach reprocessing

The effects of bleach reprocessing on the performance of high-flux dialyzers have not been comprehensively characterized. We compared the effects of automated bleach/formaldehyde reprocessing on solute and hydraulic permeability for cellulose triacetate (CT190) and polysulfone (F80B) dialyzers using an in vitro model. Dialyzers were studied after initial blood exposure (R0) and after 1 (R1), 5 (R5), 10 (R10), and 15 (R15) reuse cycles. Ultrafiltration coefficient (K(uf)), serial clearances, and/or sieving coefficients (SCs) of urea, creatinine, vancomycin, inulin, myoglobin, and albumin were determined. Urea, creatinine, and vancomycin clearances and SCs did not significantly differ from R0 to R15 with either dialyzer. Inulin clearances and SC also did not significantly change from R0 to R15 for the CT190. However, these same values for the F80B significantly increased (P < 0.05). The inulin clearance and SC values for the CT190 dialyzer were significantly higher than those for the F80B at all stages except R15. Myoglobin clearances significantly increased over 15 reuses for both dialyzers (P < 0.01). However, CT190 myoglobin clearances were significantly higher at all stages (R0 = 37.7 +/- 9.7; R15 = 52.5 +/- 8.8 mL/min) than the F80B (R0 = negligible; R15 = 41.3 +/- 16.5 mL/min; P < 0.01). Albumin pre- and postdialysis SCs significantly increased for both dialyzers (P < 0.01). K(uf) for R0 and R15 were 52.3 +/- 3.3 and 52.6 +/- 7.6 mL/h/mm Hg for CT190 (P = not significant) and 48.8 +/- 4.4 and 87.3 +/- 7.0 mL/h/mm Hg for F80B (P < 0.0001). We conclude that bleach reprocessing significantly increases larger solute and hydraulic permeability of high-flux cellulosic and polysulfone dialyzers. This effect is more pronounced for the polysulfone membrane. Until 10 reuses or greater, the removal of solutes greater than 1,500 d is significantly compromised with the polysulfone dialyzer used in this study.