Greener colonoscopy: effect of judicious carbon dioxide use and adoption of a non-leak gas/water valve on gas emissions during colonoscopy

Abstract

Background

Healthcare is responsible for ~4.4% of global carbon dioxide (CO₂) emissions and endoscopy is the third largest contributor. This study aimed to quantify CO₂ use in colonoscopy and assess the impact of different valves and practices on emissions and costs.

Methods

CO₂ use was measured using a mass flow meter. The study compared CO₂ flow using the standard gas/water valves, which continuously release CO₂, with non-leak valves, which only release CO₂ when depressed. It also assessed the impact of judicious use of CO₂. An unpaired student t test was used to calculate statistical significance.

Results

Without a colonoscope attached, CO₂ flow averaged 3.24 L/min. With the standard valve, flow dropped to 2.55 L/min, and with the non-leak valve, it was negligible. CO₂ emissions were measured intraprocedurally during 351 colonoscopies. Using a non-leak valve and/or judicious CO₂ application significantly reduced emissions compared with standard practice using a standard valve. This approach could reduce local emissions by >87%. Nationally, it would lead to emissions reductions of 106.5 metric tons of CO₂ per annum with cost savings of >£260 000.

Conclusion

Judicious CO₂ application and use of a non-leak valve significantly reduced CO₂ emissions and costs in colonoscopy, contributing to the UK National Health Service goal of delivering a “net zero” service. We suggest turning off CO₂ when not needed, adopting non-leak valves, implementing this practice in other endoscopic procedures, and encouraging all endoscope manufacturers to develop similar valves.

Publication History

Received: 25 March 2025

Accepted after revision: 03 October 2025

Accepted Manuscript online:
03 October 2025

Article published online:
24 November 2025

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