Microbiological purity of dialysate for on‐line substitution fluid preparation

Abstract

Dialysate purity has become a major concern in recent years since it was shown that low levels of endotoxin in dialysate were able to induce the production of proinflammatory cytokines, which were putatively implicated in the development of dialysis-related pathology. On-line haemodiafiltration (HDF; or haemofiltration) using the dialysate as the source of substitution fluid magnifies this risk and reinforces the critical role of the dialysate quality to be used. In order to virtually abolish the risk related to dialysate contaminants, it is mandatory to ensure the highest purity of the dialysate used in order that the substitution fluid produced satisfies the quality demands of a sterile and pyrogen-free infusion solution. Ultrapure dialysate production is therefore a common need for all on-line systems where substitution fluid is prepared continuously by sterilizing filtration of the dialysate. However, since dialysate purity plays a role in the complex haemocompatibility interaction which occurs during the haemodialysis session, the use of ultrapure dialysate must be considered as a suitable option for all haemodialysis modalities. To achieve this goal, one must keep in mind that ultrapure dialysate and infusate result from a complex chain of production where ultrapurity and/or sterility of the final solution relies on the weakest or worst component of the chain. Reliable production of ultrapure dialysate and infusate relies on several prerequisites: use of ultrapure water, use of clean electrolytic concentrates, implementation of ultrafilters on specifically designed HDF machines, microbiological monitoring of the chain with adequate and sensitive methods, and hygienic handling of the chain including frequent disinfection to reduce the level of contamination and to prevent biofilm formation. When properly done, the safety and reliability of on-line systems have been confirmed in large clinical studies. It is now time to validate the on-line process in large controlled clinical trials.

A New Procedure Allowing the Complete Removal and Prevention of Hemodialysis Biofilms

“…The idea of biomass detachment is a very new approach and represents an existing and viable solution to the problem of biofi lm persistence. The use of this procedure in combination with other preventive methods against biofi lm development, such as systems producing highly purifi ed water and dialysate ultrafi ltration, could provide the highest microbiological security for patients on dialysis [20,21] .…”

Emerging Clinical Evidence on Online Hemodiafiltration: Does Volume of Ultrafiltration Matter?

“…The cold sterilization filtration process of dialysis fluids (dialysate and infusate) enabled by online sterilizing filters offers a safe and affordable way of producing large amounts of substitution fluid for HDF modalities [2,3]. OL-HDF machines have the advantages of being certified by European-notified bodies and recognized by EBPG [4,5,6].…”

Advances in Hemodialysis Techniques

“…The performance, success and benefits of online HDF (figure 2), however, depends on availability of special requirements. These include (1) experienced nephrologists and nursing staff, (2) high quality water treatment plant that can provide ultrapure water (bacterial growth < 0.1 colony factor unit/ml and endotoxin level < 0.03 endotoxin unit/ml) with frequent assessment of water quality [152][153][154], (3) dialysis machine specially designed and approved for online fluid preparation, (4) high-flux dialyzers and (5) good functioning vascular access with adequate blood flow. These essential requirements for ensuring successful online HDF therapy may incur extra costs and may limit its widespread implementation.…”