Greener Colonoscopy: CO2 emissions are reduced by 87% with judicious CO2 use and adoption of a non-leak gas/water valve

Introduction: Healthcare is responsible for ~4.4% of global CO2 emissions and endoscopy is the third largest contributor. This study aims 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 with the standard gas/water valves, which continuously release CO2, with non-leak valves, which only releases 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 3.24L/min. With the standard valve, flow dropped to 2.55L/min, and with the non-leak valve, it was negligible. CO2 emissions were measured intra-procedurally during 351 colonoscopies. Using a non-leak valve and/or judicious CO2 use significantly reduced emissions compared to standard practice with a standard valve. This practice could reduce local emissions by >87%. Nationally, it would lead to emissions reductions of 106.5 tonnes CO2 per annum with cost savings of >£260,000. Conclusion: Judicious CO2 use and adoption of a non-leak valve significantly reduces CO2 emissions and costs in colonoscopy, contributing to the NHS's 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.