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Drive to reduce the environmental impact of medical gases

A team from Cambridge University Hospitals NHS Foundation Trust is leading efforts to reduce the environmental impact of gases used to give pain relief and anaesthesia to hospital patients.

CUH anaesthetist Louisa Swain administers anaesthetic gas to a patient
Nitrous oxide is used as an anaesthetic agent for surgery

Anaesthetists, midwives, maintenance specialists, engineers and service providers are working together to find ways to limit the direct emissions of nitrous oxide and desflurane.

Both are powerful greenhouse gases and minimising any wastage and introducing alternative practice is a key target in the NHS ‘Net Zero’ plan.

Up to 5% of the NHS carbon footprint comes from anaesthetic practices. Long term the NHS hopes to almost half this.

CUH is committed to tackling the climate emergency and reaching our target of becoming a net-zero organisation by 2045.

Richard Hales, energy and sustainability Manager at CUH

Nitrous Oxide

Nitrous oxide is sometimes used by medical professionals to assist sedation in medical procedures, and, in a diluted form (sometimes referred to as ‘gas and air’) for pain relief, particularly during labour.

However, it is almost 300 times more potent as a greenhouse gas than carbon dioxide, and can readily escape into the atmosphere directly from patients exhaling or from the piped networks providing them.

Hospital engineers max and craig with anaesthetist Dr Louisa Swain in hospital theatre
Dr Louisa Swain and hospital engineers Craig West and Max Rokoszak

The health of our patients, be they young or old, is inexorably linked to the environment we live in.

Dr Louisa Swain, anaesthetic consultant at CUH

The team has already reduced wastage by using innovative sound detection technology to locate and then fix leaks in the extensive piped supply network.

Ultimately, the objective is to move away from the piped distribution system to mobile cylinders.

Colleague holds handheld device used to carry out leak detectection work
The team is reducing wastage by detecting leaks.


Desflurane, is a volatile anaesthetic sometimes used during surgery.

The volumes are much smaller but the atmospheric impacts are even greater than nitrous oxide: one bottle of desflurane has the same climate heating impact as burning 440kg of coal.

CUH is on track to permanently cut desflurane use to less than 5% of its overall volatile anaesthetic gas consumption by switching to alternative options and practice.

This also brings long term cost savings, enabling further investment in education and equipment to extend the use of total intravenous anaesthesia (TIVA) – no gases involved.

Hospital Engineer carrying out work to piped gas distribution system
Hospital engineer Craig West

Dr Louisa Swain, anaesthetic consultant at CUH said:

"So far, our department, which has many like-minded and enthusiastic team-members, has been working to reduce our volatile anaesthetic gas use, promote better waste management and recycling, and to positively engage our NHS colleagues in helping this cause.

"We also have plans to reduce our energy usage and reduce our single use plastics."

Members of CUH estates team pictured with gas cylinders
Hospital engineers Craig West, Max Rokoszak and Arunas Paulauskas

Richard Hales, energy and sustainability manager said:

"The reduction in the use of desflurane and nitrous oxide gases is one of many examples of how we are working together across departments to reframe our decision making and drive down our carbon emissions."

In April 2022 CUH launched its Action 50 Green Plan, setting out how the Trust will save more than two thousand tonnes from direct carbon emissions over the next three years and become a net-zero organisation by 2045.

The full range of actions includes upgrades to buildings and infrastructure, extending and developing active and low carbon travel options, establishing the all-important ‘circular’ link between purchasing, use and sustainable waste management, and helping all staff, patients and visitors to actively contribute.

The plan builds on the significant progress already made in addressing the climate emergency, and responds to the ‘Net Zero NHS’ plan published in 2020.