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Press release
Thursday 21 April 2022

University Hospital Southampton offers gas 'blueprint' towards helping NHS reach carbon net zero target

Anaesthetists working at University Hospital Southampton have offered a ‘blueprint’ towards the NHS reducing its environmental impact by cutting the use of nitrous oxide, commonly known as laughing gas.

New research led by anaesthetist Dr Tom Pierce has shown that over the last 12 years UHS has dramatically cut its use of the anaesthetic which has a big carbon footprint.

The findings are being offered as an approach for other health trusts across the UK as part of the ambition for the NHS to become the first net zero national health service. They are revealed today as UHS publishes its Green Plan to coincide with World Earth Day (Friday 22 April).

The results, published in the journal Anaesthesia, show UHS cut its use of nitrous oxide between 2008 and 2020, resulting in a drop in carbon dioxide equivalent emissions from 2,125 to 448 tonnes annually.

This was made possible by the introduction of new equipment which enables anaesthetists to choose settings that use less nitrous oxide gas, and technology that can safely monitor and automatically adjust the amount given, therefore reducing waste.

A survey, conducted as part of the study, found 75% of the anaesthetists who responded used less nitrous oxide than they used to, mainly due to environmental concerns.

Nitrous oxide, also called laughing gas, has long been used as an anaesthetic. Although used less often for general anaesthesia it is still used premixed with oxygen as entonox in the maternity department, where it is often referred to as ‘gas and air’. It is the maternity use that is the focus for other researchers in the UK.

Nitrous oxide is a potent greenhouse gas, 265 times more powerful than carbon dioxide. This gives it a big environmental impact, accounting for about 5% of the carbon footprint of the NHS acute sector.

Dr Pierce, cardiac anaesthetist and environmental advisor to the Royal College of Anaesthetists, said: “This study shows it is possible for an NHS trust to reduce its use of nitrous oxide, with anaesthetists at UHS showing that they care about the environment and are doing what they can to protect it.

Our results form a useful blueprint for other trusts to help the NHS reach net zero.

“Further reductions in nitrous oxide use could be achieved with national strategies to develop and promote the use of alternatives and technologies to safely capture the exhaled gas.”

Continuing to invest in technology that reduces the impact UHS has on the environment is one of a number of initiatives contained in the UHS Green Plan published by the Trust to coincide with World Earth Day (Friday 22 April).

The plan outlines actions that the Trust is committing to, and how it will be supporting its workforce to adopt changes that collectively work to reduce the carbon emissions generated by the organisation and its people. Working with patients and partners, UHS aims to deliver a healthier future by becoming carbon net zero.