Filtration Fluid for Hemodialysis Treatment

Abstract

Bacterial contamination of dialysis fluid has long been recognized as a problem in hemodialyis. Cytokines released as a consequence of contaminated dialysis fluid are believed to be responsible for many acute and chronic side effects in patients undergoing renal replacement therapy. For several years now, attempts have been made to eliminate pyrogenic substances and ensure a sterile and endotoxin-free dialysis fluid. A recent dialysis fluid filter known as DIASAFE®, containing a membrane based on Polysulfone® (Fresenius), was tested for a period of 1,000 hours (approx. 14 weeks). Dialysis fluid samples were collected once weekly before and behind the filter and cultivated for detection of microorganisms and endotoxins. Additionally, starting after the fourth week of the study, serum samples were collected weekly and the ß2-microglobulin concentration was determined.

The filter reduced microorganisms at a rate of at least 10⁵ and in the majority of cases (86% of samples) by more than 10⁶. Under clinical conditions the stability and microbiological functionality of the filters could be demonstrated for more than 1,000 hours and 150 disinfecting cycles. In four cases of endotoxin burden (>0.5 IU/ml) in the dialysis fluid in front of the filter the concentration behind the filter was lower than 0.1 IU/ml, indicating effective reduction of endotoxins. A tendency to a reduction of ß2-microglobulin in serum from 32.5 ± 3.9 mg/L to 21.5± 5.3 mg/L was observed. These results indicate that the dialysis fluid filter used was effective, dramatically reducing the bacterial contaminants in dialysis fluid, thus protecting patients from the potentially harmful acute and long-term life-threatening consequences of contaminated dialysis fluid.