Nitrous oxide and the environment: the time to change is now

A Pearman, G Rai, M Children

Blackpool Teaching Hospitals NHS Foundation Trust Blackpool, UK

Introduction 

• Climate change is no longer a construct for the future but a devastating issue we are facing in the present.

• Anaesthetic gases represent 5% of the carbon footprint for acute NHS trusts.

• In 2019/2020, nitrous oxide accounted for 80% of the gas footprint in anaesthetics and a bigger contributor to carbon dioxide emissions than desflurane.

• The NHS has committed to achieving net zero omissions by 2040.

• We investigated the use of nitrous oxide at a district general hospital and whether the clinical benefits outweigh the benefits of decommissioning the central manifolds to reduce our carbon footprint.

Methods

We collected data from logbook records of nitrous oxide usage at the central manifolds over a three-year period.

• These results were compared with anaesthetic machine usage in main theatres over a seven-day period.

• Results from anaesthetic machine data were extrapolated to attain an annual figure.

Discussion 

• An estimated 100,000 litres of nitrous oxide used in clinical practice at Blackpool Victoria Hospital in 2022.

• Large disparity between manifold turnover and clinical usage.

• In 2021, clinical usage only made up 10% of manifold turnover.

• It is postulated that most of the nitrous oxide was going to waste through leakage.

• This finding is consistent with The Nitrous Oxide Project conducted by NHS Lothian.

• Using this data, the manifolds at the trust have been decommissioned.

• Anaesthetic machines have been fitted with nitrous oxide cylinders. 

Conclusion

Nitrous oxide is a contributor to climate change.

• Majority of nitrous oxide was deemed to be wasted through manifold leaks.

• Plans to decommission the central manifold bank based on the results of this audit have been implemented successfully.