Effectiveness of combination of heat water disinfection, continuous water circulation, and minimalized dead space for dialysis piping in maintaining ultrapure dialysis fluid and preventing biofilm formation in a central dialysis fluid delivery system.

Various benefits have been attached to purifying the dialysis fluid used for hemodialysis therapy. The central dialysis fluid delivery system can treat approximately 50 dialysis patients simultaneously and is convenient to operate. In contrast, the dialysis fluid supply piping is complicated, and bacterial growth can cause biofilms. This study aimed to develop sustainable cleaning strategies to solve the complicated dialysis fluid piping, which is a weakness of the central dialysis fluid delivery system, and provide ultrapure dialysis fluid for a long term. Combination of heat water disinfection, continuous water circulation, and minimalized dead space in the dialysis piping were designed for a central dialysis fluid delivery system and used in a clinic for 6 years. As an index of water purification, endotoxin concentrations and microbial colony counts in reverse osmosis water and dialysis fluid were measured. In addition, we performed scanning electron microscopy of the silicon tube surface that had been used for 5 years to confirm the presence or absence of biofilm formation. For 6 years, endotoxin concentrations and microbial colonies were not detected in reverse osmosis water and dialysis fluid using the multiple-patient dialysis fluid supply equipment. The purity of the dialysis fluid was maintained. No biofilm formation was observed by scanning electron microscopy. Combination of heat water disinfection, continuous water circulation, and minimalized dead space designs for dialysis piping can supply ultrapure dialysis fluid with minimal biofilm formation in the piping in the long term.