Greenhouse gas emissions associated with anaesthetic gases in Australia, 2002–2022: a retrospective descriptive analysis

Objectives
To assess changes in greenhouse gas emission rates associated with the use of anaesthetic gases (desflurane, sevoflurane, and isoflurane) in Australian health care during 2002–2022, overall and by state or territory and hospital type.

Study design
Retrospective descriptive analysis of IQVIA anaesthetic gases purchasing data.

Setting
All Australian public and private hospitals, 1 January 2002 – 31 December 2022.

Main outcome measures
Absolute carbon dioxide equivalent (CO2e) emissions and CO2e emissions rate per 100 000 population by gas and year, overall and by state/territory and hospital type (public or private).

Results
The overall emissions rate increased from 74 t CO2e per 100 000 population in 2002 to 328 t CO2e per 100 000 population in 2012, most rapidly during 2002–2004 (annual percentage change [APC], 51%; 95% confidence interval [CI], 38–62%). The rate then declined to 83 t CO2e per 100 000 population in 2022, most rapidly during 2017–2022 (APC, –21%; 95% CI, –23% to –20%). Patterns of emissions rate change were similar for all states and territories. More units of sevoflurane than of desflurane or isoflurane were purchased each year throughout 2002–2022, but desflurane provided the largest proportion of total emissions from anaesthetic gases during 2002–2022: 33% in 2002, 88% in 2013, and 68% in 2022. Mean emission rates per 100 000 population during 2002–2022 were highest for South Australia/Northern Territory (276 t CO2e per year) and lowest for Victoria/Tasmania (196 t CO2e per year). The desflurane emissions rate was consistently higher for private than public hospitals; it declined for public hospitals during 2009–2018 (APC, –8%; 95% CI, –10% to –5%) and 2018–2022 (APC, –43%; 95% CI, –48% to –37%), but for private hospitals only during 2017–2022 (APC, –20%; 95% CI, –24% to –17%).

Conclusions
In Australia, the CO2e emissions rate for anaesthetic gases increased during 2002–2008 but declined during 2017–2022, at first primarily in public hospitals. Continuing to reduce the use of anaesthetic gases, particularly desflurane, will advance the decarbonisation of clinical practice in Australian health care.