Efficacy of Heat Disinfection With the Aksys Personal Hemodialysis System.

The first objective of this study was to validate the use of water at 85°C ± 5°C to achieve high-level disinfection of a clean-in-place extracorporeal dialysis circuit. The second objective was to demonstrate that applying this hot water method to the entire fluid pathways of a newly designed dialysis instrument, including an integral reverse-osmosis membrane, routinely allowed the production of back-filtered dialysate meeting the U.S. Pharmacopeia (USP) standard for the water for injection (WFI). In a first study, six dialyzers were inoculated with P. aeruginosa, incubated, and subjected to 75°C water for 30 minutes. No organisms could be recovered from the experimental dialyzers nor from three negative controls, but they were recovered from three positive controls. In a second study, the carbon tanks in the water inlet line and the dialysate tank were both inoculated with massive amounts of dialysis water-adapted Gram-negative organisms, followed by seven dialysis treatments using bovine blood, where the fifth and sixth procedures were separated by 2 idle days and the sixth and seventh procedures were separated by 3 idle days. In addition, the bovine blood used in each treatment was highly contaminated. In every case, the back-filtered dialysate met the WFI standard. From the above results we conclude that a hot water disinfection process is efficacious in reducing even grossly exaggerated contamination in the Aksys personal hemodialysis system to the point where it can produce water and dialysate that greatly exceed the Association for the Advancement of Medical Instrumentation (AAMI) standards and priming and rinse-back solution (back-filtered dialysate) that meets the USP standard for WFI.