Anaesthetic gases contribute about 2% of the NHS’s carbon footprint. Nitrous oxide, commonly used in childbirth, makes up 75% of this. Desflurane, another anaesthetic gas, has a much higher environmental impact: its global warming potential is 2,540 times greater than carbon dioxide. Reducing these emissions helps tackle climate change, lowers air pollution and supports NHS net zero goals.

Work being undertaken

At King’s College Hospital (KCH), a project team from various departments worked together to reduce nitrous oxide waste. An audit revealed that only 8% of nitrous oxide gas purchased was used, with the rest being wasted. By switching from large manifolds to local cylinders, the hospital reduced nitrous oxide emissions by 55% each month, saving costs and reducing staff exposure to the gas.

In 2023, this project was shortlisted for the HSJ Award: Towards Net Zero. NHS Scotland also recognised the work in their guidelines on Entonox® System Loss Mitigation.

Laura Stephenson, KCH Associate Chief Pharmacist and Medicines Sustainability Lead, led the project and published an article about it in the Pharmaceutical Journal.

Both Lewisham and Greenwich NHS Trust (LGT) and KCH have made significant progress in reducing the use of desflurane. LGT no longer uses it, and KCH reduced its desflurane use to just 4% of all volatile anaesthetics by April 2021. Guy’s and St Thomas’ NHS Foundation Trust has also made progress, announcing in January 2023 that desflurane will be decommissioned, with limited use starting in April 2024.