Improving efficiency in nitrous oxide hospital supply systems to aim towards a carbon neutral NHS Wales

N20 reduction for greener surgery

Abstract

Background: Nitrous oxide (N20) is a greenhouse gas with a global warming potential of 280 times that of carbon dioxide. This project aims to identify potential nitrous leak and reduce the waste of N20 in Glangwili Hospital, a small district general hospital in South Wales. 

Methods: British Oxygen Company (BOC) supplied us with data on how much N20 was supplied to, and returned from, the hospital between 2021-2022. Data was collected from the anaesthetic machines over a period of three months, looking at the consumption of N20. A leak test of the piped nitrous system was performed during which no nitrous was used. Lastly, anaesthetists were surveyed on their practice with regards to N20. 

Results: On average, Glangwili purchased 54,000L of N20 per month and consumed 2109L, a usage of 3.9%.  The leak test identified a leak of 1.3L/min. From the survey of local anaesthetists, 80% of respondents state they use N20 only four times a year or less.  

Conclusion: This project has identified that 96% of the N20 purchased does not reach the patient. These findings are consistent with results from Cardiff and Vale University Health board, where a similar project was performed, and other audits across the United Kingdom. These results should encourage other health boards, including smaller hospitals, to investigate the efficiency of their N20 supply, as significant gains could be made in our steps towards carbon neutrality.