Implementing a Green ICU Pathway Across a Large U.S. Health System: An Observational Study.

importanceICUs contribute substantial environmental impact within the healthcare industry, yet few practical solutions have been published to implement environmentally sustainable practices.

objectivesTo describe the implementation of a systemwide Green ICU initiative using a previously published sustainability pathway and to report early outcomes and lessons learned. DESIGN, SETTING, AND

participantsObservational implementation study within a large, multihospital U.S. healthcare system with adult ICUs. The initiative focused on operational and systems-level ICU processes rather than individual participant outcomes. MAIN OUTCOMES AND MEASURES: A coordinated sustainability infrastructure was established through partnerships among ICU clinicians, the Office of Sustainability, supply chain, and a multidisciplinary "Critical Care Sustainability Work Group." External engagement was expanded through the creation of a national "Green ICU Collaborative." Pilot projects were developed across the "reduce, rethink, recycle" framework. All emissions calculations were done using the Greenhouse Gas Protocol, the U.S. Environmental Protection Agency's U.S. Environmentally-Extended Input-Output modeling framework, and the Intergovernmental Panel on Climate Change accounting principles. The methodology uses large language models for classification to enable scalable, consistent categorization of procurement activities. Key outcomes included medication waste reduction, supply use optimization, and recycling.

resultsMedication waste transitioned to on-demand preparation which reduced IV medication waste from 4.8% to 1.4%. Reduction in unnecessary supplies entering ICU rooms diverted an estimated 3401 metric tons of carbon dioxide equivalent annually across 350 ICU beds. A saline flush recycling program collected more than 1600 lbs of recyclable material in its first year. Implementation revealed critical lessons, including the need for early verification of material composition, the incorporation of patients and families into sustainability workflows, and the development of adaptable metrics that align unit-level initiatives with systemwide emissions baselines. CONCLUSIONS AND RELEVANCE: Operationalizing a Green ICU pathway in a large health system is feasible and produces measurable environmental and financial benefits. Establishing strong partnerships, structured processes, and adaptable evaluation strategies is essential for scaling sustainability efforts. This work provides a detailed implementation roadmap to advance Green ICU initiatives and contributes the guidance needed to a growing yet underdeveloped field.