Positively Green

Nitrous oxide has been used in hospitals for more than 250 years, but the way we use and supply it is changing. Many people know it as “laughing gas”, but what’s less well known is that it has a much higher environmental impact than other medical gases. Because of this, the NHS is working nationally to modernise how nitrous oxide is provided and to reduce any unnecessary waste.

For many years, nitrous oxide was supplied through large piped systems installed at a time when the gas was used far more frequently than it is today. As clinical practice has evolved, demand has reduced, and the NHS now recognises that these older systems are often larger than modern services require. National work, including a major project led by NHS Lothian, has shown that most avoidable nitrous oxide loss tends to occur around older storage manifolds and pipework rather than during patient care. The national nitrous oxide waste‑reduction toolkit reflects this learning and encourages hospitals to review their systems and consider moving to portable cylinders where appropriate.

At University Hospitals Plymouth (UHP), we have already made strong progress. Most of our theatres and the Emergency Department have now had their piped nitrous oxide supply capped off. These areas are using portable cylinders instead, which provide gas only when needed and avoid the inefficiencies associated with older infrastructure. This approach is fully supported by national guidance, which highlights portable cylinders as a simple and effective way to reduce waste and improve monitoring.

Only a small number of areas at UHP still use piped nitrous oxide: maternity theatres, MRI and paediatrics. These areas continue to use nitrous oxide for specific clinical reasons, and they are being reviewed carefully to understand when and how they might transition to portable cylinders in the future. Any changes will be made only when clinically appropriate and operationally safe, with oversight from the Trust’s anaesthetic sustainability lead.

This work is also helping us plan sensibly for the future. NHS England advises that new piped nitrous oxide systems should only be installed where there is a clear clinical need. For UHP, this means early conversations between estates, sustainability teams and clinical leads during new build and refurbishment projects, ensuring we avoid installing systems that are no longer required.

By modernising how nitrous oxide is supplied, UHP is reducing one of the most carbon‑intensive parts of the clinical estate and contributing to a more sustainable future for healthcare.