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PTU-016 Entonox vs Sedation in Colonoscopy: a Prospective Cohort Study
  1. A Mcculloch1,
  2. S Muthlagappan1,
  3. E Harrison1,
  4. J Mannath1,
  5. C Nwokolo1,
  6. R Arasaradnam1
  1. 1Gastroenterology, University Hospital Coventry and Warwickshire, Coventry, UK


Introduction Intravenous sedation for colonoscopy is associated with cardiorespiratory risk and delayed recovery. There is also the perception that patients tolerate the procedure better with sedation. Moreover some studies suggest that colonoscopy performance is compromised if patients do not tolerate the procedure well. This study aimed to compare inhaled nitrous oxide (entonox) with intravenous sedation during colonoscopy in terms of completions rates, patient comfort and changes in physiological status.

Abstract PTU-016 Table

Methods 288 patients undergoing elective colonoscopy were included performed by a single endoscopist. Carbon dioxide was used for insufflation. Patients were offered a choice to have intravenous sedation or entonox. Vital signs were recorded before, during and after the procedure. Following the colonoscopy, patients completed a satisfaction survey questionnaire charting symptoms of pain and bloating (modified 10 mm Visual analogue score tool) and the endoscopist scored patient comfort.

Results Out of the 288 participants, 143 (48 women and 95 men) chose entonox and 145 (66 women and 79 men) opted for sedation. Of those who received entonox intially, 25 were converted to sedation during their procedure (results not reported). For those who had sedation, the mean dose of Midazolam was 2.4 mg (SD 0.6) and Pethidine was 28.5 mg (SD 9.0). The most common indications for colonoscopy in both groups were altered bowel habit, chronic diarrhoea and inflammatory bowel disease surveillance.


  1. Entonox is as effective as intravenous sedation in relieving pain and bloating during colonoscopy without compromising performance.

  2. Entonox had less effect on systolic blood pressure suggesting it may be more appropriate in the elderly or those with cardio-pulmonary compromise.

Disclosure of Interest None Declared

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