NORCCAP (Norwegian colorectal cancer prevention): a randomised trial to assess the safety and efficacy of carbon dioxide versus air insufflation in colonoscopy

Abstract

Background: To eliminate the risk of combustion during electrosurgical procedures and to reduce patient discomfort, carbon dioxide (CO₂) insufflation has been recommended during colonoscopy. However, air insufflation is still the standard method, perhaps due to the lack of suitable equipment and shortage of randomised studies.

Aims: This randomised controlled trial was conducted to assess patient tolerance and safety when using CO₂ insufflation during colonoscopy.

Patients: Over an eight month period a successive series of patients referred for a baseline colonoscopy due to findings in a flexible sigmoidoscopy screening trial were randomly assigned to the use of either air or CO₂ insufflation during colonoscopy.

Methods: End tidal CO₂ (ETCO₂), a non-invasive parameter of arterial pCO₂, was registered before and repeatedly during and after the examination. The patient's experience of pain during and after the examination was registered using a visual analogue scale (VAS). Sedation was not used routinely.

Results: CO₂ insufflation was used in 121 patients (51%) and air in 119 patients (49%). The groups were similar in age, sex, and caecal intubation rate. No rise in ETCO₂ was registered. There were statistically significant differences in VAS scores between the groups with less pain reported when using CO₂.

Conclusions: This randomised study of unsedated patients shows that CO₂ insufflation is safe during colonoscopy with no rise in ETCO₂ level. CO₂ was found to be superior to air in terms of pain experienced after the examination.