Following colonoscopy abdominal pain can often occur, due to bowel distension by insufflated gas.
Insufflation of the bowel using CO2 rather than air can avoid such bloating and abdominal pain because CO2, unlike air, can be rapidly cleared from the colon by passive absorption.
A new commercially available CO2 delivery system has recently become available and this has been used by researchers from McMaster University Medical Center, in Hamilton, Ontario, Canada, to compare the effects of CO2 and air insufflation on residual bowel gas and post-procedure pain.
A total of 100 patients undergoing colonoscopy were randomized to receive insufflation of air (n = 51) or CO2 (n = 49) by means of a regulator.
Patients with active gastrointestinal bleeding, inflammatory bowel disease, or previous colectomy were excluded from the study group, with 97 of those originally recruited completing the study.
Pain scores, as measured on an ordinal scale (0 = no pain, to 5 = extreme pain) were recorded immediately following colonoscopy, and again at 1, 6, and 24 hours.
Residual colonic gas was evaluated on abdominal radiographs at 1 hour.
| Pain at 1 hour: 45% with air vs. 7% with CO2.
| Gastrointestinal Endoscopy |
Both post-procedural pain and residual colonic gas at 1 and 6 hours were found to be significantly less in the CO2 group.
In addition, 71% of patients insufflated with room air had colonic distension in excess of 6 cm compared to only 4% of those in the CO2 group.
Minimal colonic gas was evident in only 2% of patients insufflated with air versus 94% in whom CO2 was used.
Of patients insufflated with air, 45% and 31% had pain at, respectively, 1 hour and 6 hours, versus 7% and 9%, respectively, for those insufflated with CO2.
No complications resulted from use of the CO2 delivery system.
Concluding on behalf of her fellow authors Dr Katica Sumanac commented, "Insufflation of CO2 rather than air significantly reduces abdominal pain and bowel distension after colonoscopy."
She added, "CO2 may be insufflated safely and effectively with the new CO2 delivery system."