Urea Kinetics with Dialyzer Reuse – A Prospective Study

Abstract

We performed a prospective study to examine the impact of dialyzer reuse on KT/V under rigidly standardized conditions on 3 membrane types. Heparin dosage was standardized with ACT during an eight week run-in period and remained unchanged through the study. Post dialysis BUN and weight were obtained at five minutes after exactly 80 ± 0.5 l of blood were processed through the dialyzer. Dialyzers were reused after automated glutaraldehyde processing and after ensuring >80% open fiber bundles. Each membrane type was utilized 3 times on a set of 3 patients; each individual dialyzer was reused 8 times. KT/V was done on the 1st, 2nd, 4th and 8th uses of each dialyzer (36 measurements) starting mid week; BUN measurements were grouped. The KT/V (mean ± SD) for the 1st, 2nd, 4th, and 8th uses of the cellulose acetate dialyzer were 1.3 ± 0.2, 1.3 ± 0.3, 1.3 ± 0.2, 1.3 ± 0.2 respectively; the corresponding values of the cuprophane dialyzer were 1.4 ± 0.3, 1.4 ± 0.3, 1.3 ± 0.4, 1.3 ± 0.3 respectively; and those of the polysulfone dialyzer 1.7 ± 0.3, 1.6 ± 0.2, 1.6 ± 0.2 respectively. By a 3 way ANOVA there were no significant differences between the 1st and subsequent uses of any of the dialyzers tested. Conclusions: Reuse of dialyzers up to 8 times does not result in a loss of urea clearance. We believe this model is useful for further studies on reuse and quality assurance.

Improving Hollow Fiber Dialyzer Efficiency with a Recirculating Dialysate System I: Theory and Applicability

“…We wish to describe the clearance of solutes with mass-transport across membrane controlled by diffusion, null membrane adsorption rate, and diffusive permeability essentially independent of the protein deposition fouling, as occurs with low MW uremic toxins such as urea and creatinine in HD. That renal replacement therapy is characterized by the small weight of the filtration term, 18,23,33 what supports that this study will be restricted to diffusive clearance.…”

Improving Hollow Fiber Dialyzer Efficiency with a Recirculating Dialysate System II: Comparison Against Two-Chamber Dialysis Systems

“…This study confirms again the good agreement between the in vitro behavior of dialyzers and the unidimensional theory, when the ultrafiltration flow rate is kept at zero. Although the accuracy of these mathematical models decreases for in vivo conditions, our findings could be extrapolated for solutes whose diffusive mass-transport coefficients are essentially independent of the protein deposition fouling, as occurs with many low and medium-MW uremic toxins, 22,25,35 ifR t is increased to consider the higher overall blood-phase mass-transfer resistance. In addition, the force that governs the diffusive mass-transport in the blood side is now the blood water solute concentration.…”

Effects of reuse on dialyzer function

“…Several groups have investigated the effect of dialyzer reprocessing methods on dialyzer function. Urea clearance for both polysulfone and cellulosic membranes, has generally been found to be unaffected by various specific methods of reprocessing (9–13).…”