Sustainable continuous renal replacement therapy: The influence of blood flow rates, effluent dose, autoeffluent, and citrate anticoagulation on carbon dioxide emissions

The aim of this study was to quantify the consumables waste for continuous renal replacement therapy (CRRT) in intensive care, determine the carbon dioxide equivalent (CO 2 e) per patient per day, and identify the impact of blood (Q b) and effluent flow rates, citrate anticoagulation, autoeffluent, and circuit lifespan on emissions and cost. A retrospective observational study was conducted. The study included two major tertiary intensive care units in Melbourne from January 2017 to December 2024. We analysed 70, 000 h of treatment data stored on CRRT machines, captured from 2464 patients. Quantities of all major consumables were obtained. A chemical composition analysis was performed, and life cycle analysis was done for each component. Carbon dioxide–equivalent values and financial cost estimates were calculated using local, commercial pricing. Combined impact of autoeffluent, lowest effluent rate (<30 mL/kg/hr), and doubling of filter life linked to Q b (130–150 mL/h) and citrate anticoagulation was associated with a 56. 8% 54. 4%–59. 1% decrease in CO 2 e. kg/day and 38. 1% 34. 8%–40. 9% cost reduction. Median CO 2 e. kg/day fell from 25. 3 21. 5–29. 7 in 2017 to 19. 3 16. 3 – 22. 8 in 2024, p <0. 0001. The total cost per day of consumables also fell from 995. 89 (820. 40 – 1210. 67) in 2017 to 829. 07 (689. 64 – 1069. 19) in 2024. Extended circuit lifespan, autoeffluent, and moderated effluent doses translate to the most sustainable delivery of CRRT with associated cost savings.