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

Abstract

Objectives: 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. Design: A retrospective observational study was conducted. Setting: The study included two major tertiary intensive care units in Melbourne from January 2017 to December 2024. Participants: We analysed 70,000 h of treatment data stored on CRRT machines, captured from 2464 patients. Interventions: Quantities of all major consumables were obtained. A chemical composition analysis was performed, and life cycle analysis was done for each component. Main outcome measures: Carbon dioxide—equivalent values and financial cost estimates were calcu lated using local, commercial pricing. Results: 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. Conclusion: Extended circuit lifespan, autoeffluent, and moderated effluent doses translate to the most sustainable delivery of CRRT with associated cost savings.