Meta-analysis: the use of carbon dioxide insufflation vs. room air insufflation for gastrointestinal endoscopy

Aliment Pharmacol Ther. 2012 May;35(10):1145-54. doi: 10.1111/j.1365-2036.2012.05078.x. Epub 2012 Mar 27.


Background: Carbon dioxide (CO(2)) insufflation has been proposed as an alternative to air insufflation to distend the lumen in gastrointestinal (GI) endoscopy.

Aim: To perform a systematic review with meta-analysis of randomised controlled trials (RCTs) in which CO(2) insufflation was compared with room air insufflation in GI endoscopy.

Methods: Electronic and manual searches were combined to search RCTs. After methodological quality assessment and data extraction, the efficacy and safety of CO(2) insufflation were systematically assessed.

Results: Twenty-one RCTs [13 on colonoscopy, four on endoscopic retrograde cholangiopancreatography (ERCP), two on double-balloon enteroscopy (DBE), one on oesophagogastroduodenoscopy, and one on flexible sigmoidoscopy] were identified. For colonoscopy, CO(2) insufflation resulted lower postprocedural pain intensity, and increased the proportion of patient without pain at 1 h (RR: 1.84, 95% CI: 1.37-2.47) and 6 h (RR: 1.28; 95% CI: 1.14-1.44) postprocedure. For ERCP, the pain-releasing effect of CO(2) insufflation was not obvious (SMD: -1.48, 95% CI: -3.56, 0.59). CO(2) insufflation revealed no consistent advantages in the RCTs of DBE, but was shown as safe as air insufflation in oesophagus/stomach endoscopic submucosal dissection in one study. pCO(2) level showed no significant variation during these procedures.

Conclusions: Compared with air insufflation, CO(2) insufflation during colonoscopy causes lower postprocedural pain and bowel distension without significant pCO(2) variation. More RCTs are needed to assess its advantages in other GI endoscopic procedures.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Air*
  • Carbon Dioxide / administration & dosage*
  • Endoscopy, Gastrointestinal / methods*
  • Humans
  • Insufflation / methods*
  • Pain Measurement
  • Pain, Postoperative / prevention & control*
  • Randomized Controlled Trials as Topic


  • Carbon Dioxide