The Anesthesia Green Revolution: Study finds how Choice Architecture is Reducing Emissions?

Up to 5% of greenhouse gas emissions from hospitals are linked to volatile anesthetics, highlighting the need for sustainability initiatives in anesthesiology. A behavioral economics approach known as choice architecture was employed to reduce fresh gas flow (FGF) during anesthesia maintenance, where flow rates below 2 L/min are considered safe. In a recently published article, default FGF settings on GE Datex-Ohmeda Carestation anesthesia machines were altered from a frequently chosen 2 L/min to a new default of 1 L/min at a tertiary teaching hospital,. Additionally, educational efforts, including journal clubs, were provided to all anesthesia providers, including attending anesthesiologists, certified registered nurse anesthetists, and residents.

Evaluation of Outcomes

Outcomes were evaluated by comparing data from July 2022 (baseline) and November 2022 (post-intervention). Key metrics included mean FGF reduction, the percentage of cases with mean FGF < 2 L/min and < 1.5 L/min, and reductions in mean FGF by provider type. Data were sourced from the Multicenter Perioperative Outcomes Group and ASPIRE Sustainability metrics, focusing on general anesthetic cases that adhered to specific MPOG standards, with valid intraoperative data and patient demographics.

Analysis of Case Data

The analysis encompassed 1,275 cases from July and 1,660 from November 2022. Following the three-month intervention, a 15% (0.32 L/min) reduction in mean FGF was recorded. The change in default settings resulted in a substantial 22% increase in cases with mean FGF < 2 L/min and a 21% increase for mean FGF < 1.5 L/min. These findings demonstrated effectiveness comparable to a previous study where compliance rates increased by 29% with similar interventions.

Provider Cohort Variability

Provider cohort analysis revealed variability in mean FGF reductions. The largest reduction (27%) occurred in multidisciplinary cases (anesthesiologist, certified anesthetist, resident), while the single attending anesthesiologist cohort showed the smallest reduction (3%). Histograms illustrated shifts in median FGF usage towards lower values and a significant decrease in interquartile ranges across most provider groups post-intervention. Limitations included the brevity of the intervention period and potential biases such as the Hawthorne effect. Suggestion for future research included multiple Plan-Do-Study-Act cycles to explore long-term effects and the feasibility of sustaining reductions in FGF use through continuous choice architecture adjustments. Overall, the intervention provided insights into the effectiveness of nudge strategies within anesthesiology for reducing ecological impact.

Key Points

- -Environmental Impact of Anesthesia-: Up to 5% of hospital greenhouse gas emissions are attributed to volatile anesthetics, underscoring the critical need for sustainability initiatives in the field of anesthesiology.

- -Choice Architecture Application-: An intervention utilizing behavioral economics principles, particularly choice architecture, was implemented by altering the default fresh gas flow (FGF) setting on anesthesia machines from 2 L/min to 1 L/min, deemed a safe level during continuous anesthesia maintenance. - -Outcomes Evaluation Metrics-: The outcomes were assessed by comparing baseline and post-intervention data from July 2022 to November 2022, focusing on metrics that included mean FGF reductions, percentages of cases maintaining FGF below 2 L/min and below 1.5 L/min, and mean FGF variations among different provider types.

- -Data Analysis Results-: Analysis of 2,935 cases (1,275 in July and 1,660 in November) showed a significant mean FGF reduction of 15% (0.32 L/min) post-intervention, alongside a 22% increase in cases with FGF < 2 L/min and a 21% increase for FGF < 1.5 L/min, reflective of effectiveness in comparison with similar studies.

- -Provider Cohort Variability-: The effectiveness of the intervention was not uniform across provider cohorts; a notable 27% mean FGF reduction was observed in multidisciplinary cases, while single attending anesthesiologists exhibited only a 3% reduction. Histograms demonstrated a notable shift in median FGF usage and a tightening of interquartile ranges post-intervention.

- -Future Research Directions-: Limitations such as the short duration of the study and potential biases (e.g., the Hawthorne effect) were acknowledged. Future recommendations include the implementation of multiple Plan-Do-Study-Act cycles to investigate long-term sustainability of FGF reductions and the enduring applicability of choice architecture in reducing environmental impact in anesthesiology.

Reference –

Lu-Boettcher, Y.E., Muldowney, B.L., Roth, M.A. et al. Effects of a choice architecture intervention for improvement of sustainability practices in anesthesiology. Can J Anesth/J Can Anesth 72, 514–516 (2025). https://doi.org/10.1007/s12630-025-02934-2