As set out in our introductory sustainability blog earlier in the year, Shelford Group members are committed to achieving net zero ambitions for the benefit of our people, our NHS, and our planet. In this blog, Policy Fellow Emily Hughes sets out how members are reducing nitrous oxide usage and wastage – a medical gas with significant global warming potential.
Addressing anaesthetic emissions
Climate change poses a major threat to our health and wellbeing, with direct and immediate consequences that threaten to undermine years of health gains. The NHS accounts for 4% of the UK’s total carbon emissions; in recognition of the role it therefore needs to play to tackle climate change, on 1 July 2022, the NHS became the first health system in the world to embed net zero carbon into legislation, committing to doing so by 2045.
Anaesthetic and analgesic practices account for 2% of the NHS carbon footprint, making it crucial for the NHS to address the emissions associated with this specialty. Significant work is underway in this regard; NHS England, with the support of the Royal College of Anaesthetists and the Association of Anaesthetists, have committed to cease purchasing desflurane – a volatile anaesthetic used for surgery – from January 2024, with clinicians across the country opting to use clinically appropriate alternatives, with a significantly lower global warming potential.
Much work remains to be done, however, to achieve these ambitious net zero targets. Nitrous oxide – used to assist sedation in medical procedures, and in a diluted form to provide pain relief – accounts for more than 80% of the total anaesthetic gas footprint, and is almost 300 times more potent as a greenhouse gas than carbon dioxide. Nitrous oxide can readily escape into the atmosphere, either directly from patients exhaling, or from the piped networks providing the gas.
A data sharing process across Shelford members identified a large gap between volumes of nitrous oxide purchased and volumes used for clinical care, suggesting significant (often 90%+) wastage due to expired stock, overprovision, and leaks. Recognising the need to drive impact in this area, colleagues across Shelford agreed to come together to commit to collectively going further, faster.
Achieving the ambitious targets as described above will require all NHS employees to play their part in delivering a net zero NHS. Bringing together an interdisciplinary group of leaders across Shelford, as well as members of the Greener NHS team, we set out to:
- share learning, data, and best practice case studies around reducing nitrous oxide usage and wastage;
- engage colleagues across professional groups;
- challenge members to accelerate the current 7% year on year rate of reduction.
Case study: decommissioning nitrous oxide manifolds
In a major step to reducing their anaesthetic emissions, Imperial College Healthcare have been working in recent months to decommission the nitrous oxide manifold at the Charing Cross Hospital. Manifolds are the typical method of storage for nitrous oxide, however the wastage associated with manifolds is often high, due to leaks and loss of gas from the supply. Imperial’s analysis suggests that around 97.5% of nitrous oxide usage at Charing Cross Hospital is lost through leaky pipes.
Decommissioning the manifold and ensuring an alternative source for a small number of specific clinical uses will reduce Imperial’s annual environmental impact by at least 460 tonnes of CO2e – around 1% of the Trust’s directly controllable emissions – and will generate recurrent savings of over £3,500 from eliminating nitrous oxide wastage.
Case study: using innovative technology to provide climate-friendly pain relief
Entonox (or ‘gas and air’) is a popular choice for short acting pain relief in maternity, made up of a mixture of nitrous oxide and oxygen, and presents significant global warming potential – 4 hours of moderate-to-heavy pain relief with Entonox produces the equivalent of 870 miles’ worth of CO2e in an average car. Driving forward its ambitions to be net zero for direct emissions by 2031, in May this year, University College London Hospitals installed six new mobile Entonox destruction units (MDUs) across its birthing centre and labour wards.
Pioneered in the UK by Shelford member Newcastle upon Tyne Hospitals, MDUs are an innovative technology that collect and break up exhaled Entonox emissions into harmless gases, reducing emissions by up to 80% in the rooms they are used. As well as providing huge benefit for the environment, this also benefits staff by reducing the amount of nitrous oxide they are exposed to while at work, which can be harmful where legal workplace levels are exceeded.
Working together to drive positive change
The case studies presented at the interdisciplinary session share many common themes and enablers to success; the importance of clinical leadership and building shared motivation across different teams, the need for dedicated funding of sustainable solutions, and the driving force of green improvement resource. Patient and staff safety are paramount to success, and in many ways can be a positive force for change.
The success of desflurane reduction over the last five years should be a source for optimism in our net zero ambitions – anaesthetists in over 40 trusts across England have now stopped using it altogether, with use across the NHS falling from 20% of all anaesthetic gases used to just 3% over the last 4-5 years. Reducing usage and wastage of nitrous oxide presents a different and more complex challenge, however excellent work is underway on both a national and individual trust level.
By September 2023, at least 23 manifolds are due to have been decommissioned across the Shelford Group – this will account for approximately 5,760 tonnes of CO2e saved. In working together and facilitating opportunities for real-time peer to peer learning, our member trusts are committed to going further, faster, on nitrous oxide usage and wastage, and will continue to monitor progress over the next year.