Greenhouse gas emissions from surgical care: a retrospective cohort study of scope 1 and scope 2 emissions across specialties and operative approaches

Objectives To quantify Scope 1 and Scope 2 greenhouse gas (GHG) emissions associated with surgical care and identify key modifiable drivers at the institutional level, including operative duration and operating room (OR) type.Design Retrospective cohort study.Setting A tertiary university hospital with 17 ORs in Japan.Participants All 6996 elective surgeries were performed under general anaesthesia between 1 January and 31 December 2022.Primary and secondary outcome measures The primary outcome was per-case total Scope 1 and Scope 2 carbon dioxide equivalent emissions (CO ₂e) emissions. Secondary analyses evaluated emission differences across specialties, surgical approaches (open, endoscopic, and robotic), and temporal electricity consumption patterns. Multivariable linear regression was performed to assess the associations between per-case scope 2 emissions, operative time, and OR type.Results Total emissions were 1943.4 t CO ₂e, of which Scope 1 accounted for 71.0%, predominantly driven by desflurane (69.2% of total emissions). Although scope 2 accounted for 29.0% of total institutional emissions, scope 1 emissions dominated the carbon footprint of most individual procedures because of volatile anaesthetic use. Weekday daytime electricity consumption accounted for only 47.7% of total weekly use, with more than half occurring during nighttime and weekend periods, largely due to continuous heating, ventilation and air conditioning (HVAC) operation. Regression analysis demonstrated that operative time had a limited independent effect on per-case scope 2 emissions, whereas OR type—including hybrid and bio-clean rooms—was strongly associated with higher emissions.Conclusions Anaesthetic choice and infrastructure-related energy demand are the principal determinants of surgical GHG emissions. Within direct and energy-related emissions, reducing volatile anaesthetic use and optimising OR energy consumption—particularly during non-operative periods—represent the most effective strategies for emission reduction.