#1813 Safety and Efficacy of Reducing Hemodialysis Fluid Flow Rate—contribution to Planetary Health

Abstract Background and Aims Historically, increasing dialysate flow rates (Qd) have been recommended to improve hemodialysis (HD) efficiency. For decades, Qd has routinely been set to a fixed rate of 500 ml/min. A standard HD treatment uses on average around 500 L of water [1], resulting in a consumption of 78 000 L per patient and year with an additional estimated 10 000 L for post-dilution hemodiafiltration. This corresponds to the annual water consumption of 1.5 persons in developed countries and considerably more in developing countries. We investigated the effect of reducing dialysate flow rates on HD safety and efficacy. Method This is a prospective single-center non-blinded observational study. We investigated the effect of a 1:1 adjustment of online Qd to blood flow rate by adjusting autoflow (AF) settings of the dialysis monitor to a calculation factor of 1.0 with a lower Qd limit of 350 ml/min (AF 1.0 mode). We examined the effect on dialysis efficacy, metabolic markers, and anemia in routine biochemical analyses, and calculated energy, water, and waste savings in 116 stable chronic HD patients. Data were compared with previous turnover in energy, waste, and water, as well as with clinical results prior to the mentioned modifications. Results After 12 months of HD treatment with AF 1.0 mode we observed reductions of 10% in electricity consumption, 19% in raw water consumption, and 24% in dialysate concentrate consumption. Conversely, we did not observe deteriorations in treatment quality or dialysis dose (Table 1), nor phosphate or hemoglobin. Conclusion Long-term HD treatment with reduced dialysate fluid flow rates led to substantially improved water and carbon footprints with potential effects on planetary health and economic savings, while dialysis quality remained unchanged.