Introduction Entonox may be used to improve patient experience during colonoscopy. Nitrous oxide is rapidly eliminated which minimises after effects and inconvenience to patients. Despite its advantages, Entonox is used in only a minority of procedures in the UK. We sought to understand the reasons for its low utilisation.

Methods Colonoscopists within the English Bowel Cancer Screening Programme (BCSP) were invited to participate in a web-based survey, assessing the availability, current practices and perceptions of Entonox during colonoscopy. Respondents were able to select pre-defined answers or offer written responses. Free text responses were assessed using thematic analysis. Categorical data was compared using the χ2 test.

Results The survey was completed by 208/298 (70%) of the English BCSP colonoscopists. Entonox was available to 152/208 (73%) respondents but this varied between NHS deaneries. Nearly half (47%) of the respondents stated that Entonox was used in < 20% of examinations. Colonoscopists who administered Entonox frequently (>20% of examinations) rated its efficacy (49% vs. 76%, OR: 3.3, p = 0.001) and usefulness (69% vs. 95%, OR: 8.4, p < 0.0001) more favourably. But there were no differences in how they rated its safety (90% vs. 97%, OR: 4.2, p = 0.085), frequency of side effects (92% vs. 96%, OR: 2.3, p = 0.31) or influence on discharge time (70.4 vs. 79.5%, OR: 1.63, p = 0.26). Most respondents for whom nitrous oxide was available stated that they would use it if they were to have a colonoscopy themselves (74%). Most respondents reported their patients were advised to use Entonox ‘as required’ (92%) rather than continuously (8%) and from the start of colonoscopy rather than as rescue medication when other medications are inadequate. Some respondents never combined Entonox with other sedatives. Many respondents indicated that Entonox was used for the patients and the procedures which are expected to have least discomfort. Most of the colonoscopists for whom Entonox wasn’t available had considered introducing it (94%). Practical difficulties (37%) and satisfaction with current analgesics and sedation (28%) were the most common reasons it was not available. The introduction of the English flexible sigmoidoscopy screening programme was cited as the reason for its introduction by several respondents.

Conclusion Entonox is used in a minority of colonoscopy examination. It is generally perceived to be safe, effective and most colonoscopists would use it if they required a colonoscopy. Entonox is often chosen when patients wish to avoid the inconvenience caused by intravenous sedation and analgesics. Its use is likely to increase with the introduction of the English screening programme.

Disclosure of Interest None Declared.