The North West School of Anaesthesia and Manchester University NHS Foundation Trust are leading the way in preventing pollution from waste volatile anaesthetic gases, having procured innovative capture and recycling technology from SageTech Medical, a UK government grant funded startup company based in Devon, UK. The NHS decision to restrict or completely stop the use of desflurane, a highly environmentally polluting anaesthetic gas, has created a national problem of leftover desflurane waste. Preventing the release and environmental pollution caused by this gas is an NHS priority under its Scope 1 carbon emissions reduction target.


In June 2023, SageTech received an order for its waste anaesthetic gas capture solution from Manchester University NHS Foundation Trust (MFT), funded by the North West School of Anaesthesia. Together, MFT and North West School of Anaesthesia are leading the NHS in its mission to prevent the unwanted release of environmentally harmful anaesthetic gases, focussing on the unused desflurane contained inside decommissioned anaesthetic vaporisers. Dr Cliff Shelton, Consultant Anaesthetist and lead for sustainable anaesthesia at Wythenshawe Hospital, has worked with SageTech Medical to address this significant problem by using an innovative, safe and sustainable waste volatile anaesthetic gas capture solution. This commitment to SageTech Medical’s Solution provides a replicable approach for all 42 Integrated Care Systems (ICS’s) in England to adopt a plug and play solution to solve the national problem of unused desflurane. Once desflurane vaporisers have been emptied, SageTech Medical’s innovative capture technology will be deployed in high use sevoflurane theatres at MFT to prevent the current release of this commonly-used volatile anaesthetic. Sevoflurane is the dominant anaesthetic gas in use globally and has an environmental impact in carbon equivalent emission of 130 times1 (GWP100) that of carbon dioxide.


In the UK, an estimated 100,000 tonnes of CO2 equivalent (CO2e) emissions are released every year from volatile anaesthetic gases2,3,4,5, which equates to over 2% of all NHS carbon emissions3. With the NHS committed to an 80% reduction in CO2e emissions by 2032, an innovative solution is needed6.

The manufacture of virgin anaesthetic agents and their release as potent greenhouse gases are highly damaging to the environment and contributes significantly to the carbon footprint of healthcare. During an operation, only 5% of anaesthetic agents are absorbed and metabolised by the patient’s body, meaning that 95% of this volatile anaesthetic is expelled as waste. Once exhaled into the atmosphere as gas, waste volatile anaesthetics stay around for a long time and have high tropospheric lifetimes and subsequently high global warming potentials. These gases cause climate change by trapping heat, and they also contribute to respiratory disease from smog and air pollution. Over a 100-year period (GWP100), volatile anaesthetic gases sevoflurane, isoflurane and desflurane have an impact of 130, 510 and 2,540 times that of carbon dioxide, respectively1.


Dr Cliff Shelton reached out to SageTech Medical in January 2023 to work together to find a solution to the unspent desflurane retained inside decommissioned anaesthetic vaporisers at MFT, which had been decommissioned in the summer of 2022. The NHS in England has announced plans to withdraw desflurane from routine clinical use from early 2024 because of its high global warming potential, and many NHS Trusts have already ceased using it. This has left the NHS holding a significant volume of unusable desflurane vaporisers with no environmentally-responsible way of managing the residual desflurane still contained inside. Following the successful development of a protocol for emptying these decommissioned vaporisers using the SageTech Medical capture machine, the Northwest School of Anaesthesia supported the Trust to fund the purchase of 4 SID-Dock capture machines and associated reusable filters to initiate the immediate recovery and safe storage of unused desflurane from across the area served by The North West School of Anaesthesia, as part of a regional sustainability training programme based on innovation, research and quality improvement.


Currently, there is an unmet, time critical need to reduce the impact of waste volatile anaesthetic agents on the atmosphere to protect our environment for future generations. By preventing these agents from polluting the atmosphere and reducing the raw material associated with their virgin manufacture, SageTech Medical are proud to be leading the way in sustainable anaesthesia and providing hospitals and clinics with a straightforward solution to enable them to make a real difference to their carbon footprint and our planet.


Dr Cliff Shelton said “The NHS has made absolutely the right decision to withdraw desflurane from routine use. However, we need to consider how to achieve this in the most environmentally-responsible way. First and foremost, Trusts should minimise their use of desflurane and approach decommissioning in a way that minimises waste. However, it is likely that all Trusts will end up with some retained desflurane, and the solution we have pioneered with SageTech offers a way to reduce the environmental impacts of removing this from vaporisers. The funding from the North West School of Anaesthesia will allow us to roll this out regionwide, offering our anaesthetists-in-training an excellent opportunity to participate in this important initiative.”

Iain Menneer, CEO of SageTech said “We are very pleased to have been able to help Manchester University NHS Foundation Trust in solving this problem caused by the decommissioning of the most potent polluting anaesthetic gas, desflurane. The SageTech Medical team is driven by the belief that our solution offers a real opportunity to hospitals across the UK to significantly reduce their emissions from volatile anaesthetic gases.”


SageTech Medical has developed a safe, sustainable and easy to use circular economy solution to tackle the problem of pollution from waste volatile anaesthetic gases sevoflurane, isoflurane and desflurane. Exhaled waste volatile anaesthetic agents are captured onto two reusable capture canisters (‘SID-Cans’) which are housed inside a capture machine (‘SID-Dock’) that integrates simply, seamlessly and universally into existing anaesthetic equipment. When full, the SID-Cans are collected from the hospital, emptied at regional SID-Hub facilities, and quality checked before being returned for reuse. Captured agents are recovered from the SID-Cans back into a liquid form using proprietary SID-Lab technology. The recovered mixed agent is then transported back to the purification and manufacturing facility in Devon. The mixed liquid waste is processed and purified via a distillation process. The recycled waste volatile agents can be repeatedly recycled and reused as an anaesthetic, therefore reducing the significant burden associated with virgin drug manufacture and completing our circular economy solution.



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1. Environ.Sci.Technol. / The Global Warming Potentials for Anesthetic Gas Sevoflurane Need Significant Corrections
2. The Lancet / Health care’s response to climate change: a carbon footprint assessment of the NHS in England
3. NHS England / Putting anaesthetic-generated emissions to bed
4. RCoA / Sustainability: Intravenous and local anaesthetic agents
5. NHS / Delivering a ‘Net Zero’ National Health Service
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