In vitro comparison of peracetic acid and bleach cleaning of polysulfone hemodialysis membranes

Dialyzer reuse has been employed throughout the history of hemodialysis, but the practice remains controversial. Many studies have found changes in the β₂-microglobulin clearance for reused dialyzers, but it is difficult to draw quantitative conclusions from the clinical data. The objective of this study was to quantitatively compare the effects of bleach and peracetic acid cleaning on the clearance and surface charge characteristics of Fresenius F80B polysulfone dialyzers (Fresenius Medical Care, Lexington, MA, USA). Clearance experiments were performed using urea, vitamin B₁₂, and polydisperse dextrans, with data obtained before and after exposure to human plasma in an in vitro dialysis circuit. Dialyzers cleaned with peracetic acid had significantly lower clearance of the larger dextrans due to the presence of residual protein on or within the membrane. Bleach was able to remove this protein deposit, restoring the clearance characteristics, but there was a significant increase in the net negative charge of the membrane due to chemical reaction with the bleach. In addition, longer time exposure to bleach altered the membrane transport characteristics, increasing the solute clearance. These results provide important insights into the effects of bleach and peracetic acid on the properties of the F80B dialyzers.