Microbiologic purity of dialysate: rationale and technical aspects

Dialysate purity has become a major concern in hemodialysis since it has been shown that microbial-derived products were stimulating the production and the release of proinflammatory cytokines in hemodialysis patients. This chronic microinflammatory state induced by hemodialysis has been putatively implicated in the development of dialysis-related pathology. In order to prevent risk related to these offenders and to reduce patient/dialysis interaction, it appears highly desirable to use ultrapure dialysis fluid aiming at sterility and apyrogenicity on a regular basis. Ultrapure dialysate results from a complex chain of production where purity grade relies on the weaker link of this chain. Technical aspects and pitfalls in the production of ultrapure dialysate are summarized in this paper. Production of ultrapure dialysate may be achieved on a routine basis, provided adequate components are used, and hygienic handling is regularly ensured. It includes the use of ultrapure water, clean and or sterile electrolytic concentrates (liquid or powder), implementation of ultrafilters on hemodialysis machines, microbiologic monitoring and hygienic handling of the chain with frequent disinfection. Safety and reliability of ultrapure dialysate production relies on a continuous quality assurance process, where results are coupled to corrective action in a feedback loop process.