The effects of hemodialyzer reprocessing on the removal of varying molecular weight solutes during high-permeability hemodialysis

This project assessed the effect of automated bleach/formaldehyde and peracetic acid-hydrogen peroxide (PAHP) reprocessing on solute and hydraulic permeability of cellulose triacetate (CT190) and polysulfone (F80A and F80B) dialyzers after 15 reuses. During in vitro simulated hemodialysis (HD), a 6L buffer solution containing urea (60 Da), creatinine (113 Da), vancomycin (1448 Da), inulin (5200 Da) and albumin (66 kDa) was dialyzed at 400 mL/min for 60 minutes. To account for secondary membrane effects, dialyzers were exposed to bovine blood before first use while each simulated reuse cycle consisted of blood exposure for 40 minutes followed by reprocessing. HD was performed on dialyzers after first use, and after undergoing one, five, ten and fifteen reuse cycles. Solute clearance, sieving coefficient (SC) and ultrafiltration coefficient $\rm (K\sb{uf})$ were determined for each experimental HD. Bleach reprocessing, up to 15 reuses, did not significantly alter CT190 solute permeability of urea, creatinine, vancomycin and inulin. While the SC of albumin significantly increased $\rm (p \u3c 0.0001)$ and the $\rm K\sb{uf}$ significantly decreased $\rm (p \u3c 0.05),$ these changes were probably not clinically significant. Permeability characteristics of the F80B to urea, creatinine and vancomycin were not significantly altered by increasing bleach reuses. Inulin removal (clearance and SC) significantly increased $\rm (p \u3c 0.05),$ suggesting bleach appears to influence the removal of solutes with $\rm MW \u3e 1500$ Da. However, this inulin removal by the F80B was significantly lower than that of the CT190 $\rm (p \u3c 0.01)$ until ${\ge}10$ bleach reuses. A significant increase in F80B permeability was also demonstrated for albumin $\rm (p \u3c 0.0001)$ and $\rm K\sb{uf}\ (p \u3c 0.01).$ PAHP reprocessing of the F80A did not significantly influence solute or water permeability. CT190 diffusive removal of urea, creatinine, vancomycin and inulin was significantly decreased by PAHP reprocessing. Initial inulin clearance and SC were significantly higher for the CT190 compared to the corresponding F80A values $\rm (p \u3c 0.001).$ Although the albumin SC and $\rm K\sb{uf}$ also significantly decreased for the CT190 $\rm (p \u3c 0.0001$ and $\rm p \u3c 0.01,$ respectively), these changes were probably not clinically significant. These data demonstrate reprocessing significantly alters dialyzer permeability to water and solutes. The specific effect is determined by the individual membrane-reprocessing system combination. These resultant effects should be considered when determining optimal reuse procedures for enhancing patient care