A quality-improvement project investigating the carbon offset, courtesy of a global pandemic

Anaesthetic gases are potent contributors to the enhanced greenhouse gas effect and ozone depletion Their use accounts for 5% of acute NHS hospitals' total carbon footprint [1] The NHS 'Long term plan' 2019 aims to reduce its carbon footprint by 51% by 2025, with 2% of this to be achieved by transforming anaesthetic practices Desflurane is the most environmentally noxious of the volatiles, with a tropospheric lifetime of 14 years and a global warming potential 19 5 times worse than sevoflurane Our aim was to investigate the carbon offset within our Trust that resulted from reduced elective surgery and volatile usage during the COVID-19 pandemic We plan to use this information to raise awareness of the environmental impact of anaesthetic gases to our peers and encourage the adoption of greener anaesthetic strategies Methods We reviewed the number of bottles of sevoflurane, isoflurane and desflurane consumed during the COVID-19 pandemic from 01/03/2020-30/05/2020 at Princess Royal University Hospital and King's College Hospital, then compared this to the amount consumed in the same time period in 2019 We translated these data into carbon emissions using experimentally derived data for each volatile agent [1] to evaluate the reduction in anaesthetic agent-related carbon emissions during the COVID-19 pandemic period We also calculated the financial savings Results Over the period analysed, we saw a 41% reduction in sevoflurane use, a 71% reduction in desflurane use and a 65% reduction in isoflurane use This was a financial saving of £33,030 and a carbon dioxide equivalent reduction of 229,082 kg, which approximates to the greenhouse gases emitted from a standard car driving 568,442 miles, nearly 23 times around the world Staggeringly, this amount of carbon would take 1 year for 299 acres of forest to sequester Discussion We hope to see a reduction in our anaesthetic gas-associated carbon footprint for the same time period next year by presenting our findings to our anaesthetic colleagues, and by highlighting greener anaesthetic strategies such as low-flow anaesthesia and the avoidance of desflurane and nitrous oxide