The effects of reprocessing high-flux polysulfone dialyzers with peroxyacetic acid on beta 2-microglobulin removal in hemodiafiltration

Effect of Peracetic Acid Reprocessing on the Transport Characteristics of Polysulfone Hemodialyzers

Peracetic acid is used extensively for reprocessing hemodialyzers, despite several indications that reprocessing alters the dialyzer transport characteristics. The objective of this study was to obtain quantitative data for the effects of peracetic acid reprocessing on the clearance and sieving coefficients of urea, vitamin B12, and polydisperse dextrans using Fresenius F80A polysulfone dialyzers. Reprocessing restored the urea and vitamin B12 clearance to close to their original values. However, the reprocessed dialyzers had substantially lower clearance of the larger molecular weight dextrans, which was attributed to reductions in the effective pore size caused by residual plasma proteins within the membrane. Storage in peracetic acid provided some additional removal of residual proteins, although the clearance and sieving coefficients of the larger dextrans remained well below their original values. Peracetic acid caused no degradation of the membrane polymer, in sharp contrast to results obtained with bleach reprocessing.

In vitro performance of hemodialysis membranes after repeated processing

BACKGROUND

Dialyzers reprocessed with chlorine-based solutions have been associated with increases in ultrafiltration coefficient and middle-molecule removal. Increased pore size has been hypothesized as the mechanism for the latter phenomenon. Dialyzers exposed to Amukin-D (Amuchina Int Inc, Gaithersburg, MD), a chlorine-based reprocessing agent, were evaluated for changes in molecular weight (MW) cutoff and ultrafiltration properties.

METHODS

In vitro MW cutoff studies were performed on Fresenius F-80A (Fresenius, Lexington, MA) and Gambro Polyflux 17 (Gambro, Lakewood, CO) hemodialyzers that were reprocessed 20 times using Amukin-D. Permeability (Uf-A), defined as the area from the ultrafiltered compartment (Uf) compared with the area from the equivalent arterial compartment (A), for dextran across the hemodialyzer membrane was determined after the initial use and after reuses 1, 5, 10, 15, and 20 by using size-exclusion chromatography.

RESULTS

Uf-A for dextran increased approximately 10-fold between hemodialyzer reuses 1 and 5. Thereafter, additional reprocessing did not increase the Uf-A ratio further. MW cutoff increased during these 5 washes and did not change thereafter.

CONCLUSION

Reprocessing with Amukin-D increased the MW cutoff and permeability of both hemodialyzers between reuses 1 and 5, resulting in a greater ultrafiltration rate and greater middle-molecule removal. After reuse 5, there were no further increases in MW cutoff with additional reprocessing in either hemodialyzer. This suggests that reprocessing and storage of each hemodialyzer with Amukin-D affects the permeability of dextran in a nonlinear fashion and to a finite level, such that subsequent reprocessing has no further effect on the MW cutoff of the membrane.

Effect of hemodialysis membranes on beta 2-microglobulin amyloidosis

Early after the identification of beta(2)-microglobulin amyloidosis (A beta(2)M) as the cause of carpal tunnel syndrome, it was thought that hemodialysis was a major cause in the development of the disease. It was subsequently shown that hemodialysis was not necessary for the development of dialysis-related amyloidosis; however, it was believed that the different dialysis membranes did modulate the progression of the disease. Current data demonstrate that hemodialysis fails to prevent or reverse the disease, but there is substantial evidence that high-flux, high-efficiency dialyzers slow its progression. Many factors related to hemodialysis have been evaluated in relation to A beta(2)M, including the effect of the bioincompatibility of the membrane, the capacity of the different membranes to remove beta(2)M, and the effect of reuse on beta(2)M levels. Moreover, there have been intensive efforts to evaluate, explore, and improve the different mechanisms in beta(2)M removal, with adsorption as a promising prospect. With the available evidence, it seems that the removal of beta(2)M by the membrane plays the most important role in modulating the disease outcome and rate of progression, although a large, long-term, multicentered and randomized study is still lacking to prove this relationship. However, it is possible that with the continuing advances in optimizing the beta(2)M removal efficiency of the different membranes, the frequency and severity of the disease can be substantially decreased.

The effects of peracetic acid-hydrogen peroxide reprocessing on dialyzer solute and water permeability

We characterized the effects of peracetic acid-hydrogen peroxide (PAHP) reprocessing on hemodialyzer permeability to water and solutes of various molecular weights and compared these effects within and between dialyzers. An aqueous-based solution containing urea, creatinine, vancomycin, inulin, myoglobin, and albumin was dialyzed for 60 minutes with a hemodialyzer after undergoing 0, 1 , 5, 10, and 15 reuse cycles. Solute clearance, sieving coefficient (SC), and ultrafiltration coefficient were determined. We found that PAHP reprocessing significantly decreased water and solute removal (urea, creatinine, vancomycin, inulin) by cellulose triacetate dialyzers (CT190) over 15 reuses (p<0.05) but did not affect the permeability of polysulfone dialyzers (F80A). Inulin removal was significantly lower for F80A than for CT190 (p<0.0001 and p<0.001 for clearance and SC values, respectively). Myoglobin and albumin removal by CT190 significantly decreased over 15 reuses (p<0.05), but no protein was detected in dialysate or ultrafiltrate at any reuse number for F80A. Reprocessing with PAHP alters dialyzer permeability; the effect is more pronounced for the CT190 dialyzer, but removal of solutes with molecular weight above 1500 Da is significantly lower with F80A dialyzers than with CT190. These changes in dialyzer permeability should be considered when determining optimal reuse procedures.

Maintaining blood compartment volume in dialyzers reprocessed with peracetic acid maintains Kt/V but not beta2-microglobulin removal

A dialyzer is reused if its blood compartment volume is 80% of its initial value, a condition believed to ensure that the urea clearance remains at 90% of its initial value. This criterion was developed for dialyzers containing low permeability cellulose membranes reprocessed with formaldehyde. We tested the hypothesis that the criterion is also valid for more permeable membranes when dialyzers are reprocessed with peracetic acid/hydrogen peroxide. Kt/V for urea and reduction in beta2-microglobulin concentration were measured for up to 15 uses in dialyzers containing polysulfone or cellulose membranes. Kt/V for urea did not change for either dialyzer provided blood compartment volumes remained 80% of their initial value. The reduction in plasma beta2-microglobulin concentration from predialysis to postdialysis was 30% for the first use of the dialyzer containing polysulfone membranes, but decreased significantly (P = 0.042) following reuse to 12% for the tenth use. For the dialyzers containing cellulose membranes, the reduction in plasma beta2-microglobulin concentration was 18% for the first use and decreased to 12% by the twelfth use; however, this change was not significant. We conclude that removal of urea is maintained during reuse with peracetic acid/hydrogen peroxide provided the blood compartment volume remains 80% of its initial value. However, removal of beta2-microglobulin may not be maintained, even though blood compartment volumes remain at 80% of their initial value.

Daily home hemodialysis: a hybrid of hemodialysis and peritoneal dialysis

Despite that routine home hemodialysis, performed with thrice weekly frequency, had provided the best clinical results of any dialysis modality, it has been losing competition to center hemodialysis and home peritoneal dialysis. The main reason for this paradox is a lack of suitable equipment for home hemodialysis. Contrary to peritoneal dialysis, which is easy to learn and perform without need for a helper, home hemodialysis is difficult because the kidney machines are not designed for home therapy. Daily hemodialysis provides even better results than routine home hemodialysis. Several studies showed excellent intradialytic and interdialytic tolerance. In spite of these results the method is used only in a few centers. There are two major reasons for this incongruity: time requirement for the patient and the cost for the provider. With more frequent dialysis, more time is spent on machine setup, tear down, and cleaning. If supplies are not reused, the cost of dialysis increases substantially with increased frequency of dialysis. Daily home hemodialysis may become practical with a new machine. Three components seem crucial for this device: a built-in water treatment system; a simple, small, positive pressure, single pass, batch dialysate system; and a reusable extracorporeal circuit, automatically cleaned and disinfected daily. Daily home hemodialysis performed with the new artificial kidney system may be considered as a hybrid of hemodialysis and peritoneal dialysis. High efficiency is taken from hemodialysis; simplicity is taken from peritoneal dialysis.

Dialyzer reuse: interaction between dialyzer membrane, disinfectant (formalin), and blood during dialyzer reprocessing

The growing practice of dialyzer reuse in recent years is mainly based on medical and economic considerations. However, adverse reactions such as immunohemolytic anemia due to anti-Nform antibody associated with dialyzer reuse have been reported. In this study, scanning electron microscopy and cytologic staining were used to evaluate the interaction between blood components and the reprocessed synthetic dialyzer membrane (polysulfone) after disinfectant (formaldehyde) treatment. The results showed that various blood components such as fibrin and blood cells still adhered to the dialyzer membrane after reprocessing. The study also demonstrated that the adhered denatured blood components could be detached by sonication and/or simulated hemodialysis and then gain access into the circulation. The re-entry of the denatured blood components to the patients exposed to reused dialyzers may result in an enhanced immunological response which may contribute to antibody formation (such as anti-Nform antibody) with a reused hemodialyzer.

Clinical evaluation of a new dialyzer, FLX-12 GW, with a polyester-polymer alloy membrane

The performance of a membrane in renal failure therapy is determined by its structure, its overall mass transfer properties, and its blood compatibility. In this regard, removal of beta 2-microglobulin (beta 2M) has become a major objective of dialysis therapy. In the present study, a newly developed high-flux membrane composed of a polyester-polymer alloy (PEPA) with the components of polyarylate and polyethersulfone (dialyzer FLX-12 GW; Nikkiso Co., Japan) has been evaluated with regard to both biocompatibility and elimination capacity for beta 2M during hemodialysis of 8 stable chronic uremic patients. The clearance values of low molecular weight solutes were in the same range as those reported for high-flux dialyzers of comparable surface area. There was no drop in leukocyte counts and only a minimal fall in platelet counts nearly in the same range as has been observed by other investigators using polyamide membrane. C3a Des Arg generation was low, and C5a Des Arg formation was not significantly influenced. There was a sharp drop in the serum beta 2M level (-35%) during dialysis with a clearance between 59.7 +/- 5.6 ml/min (QB 200 ml/min) and 70.1 +/- 9.7 ml/min (QB 300 ml/min), respectively. Accordingly, the sieving coefficient was calculated to be 0.2 at 30 min after start of dialysis and 0.6 1 h later. The membrane was able to remove 184.0 +/- 22.3 mg/4 h due to an apparent rate of adsorption during the first hour of treatment in combination with high transmembrane transfer in the following time.