Compared with performing each procedure individually, performing two combined procedures such
as colonoscopy consecutive Esophagogastroduodenoscopy (EGD) cause more bowel gases, abdominal
distension and post-procedure pain because of longer procedure time related to more bowel
insufflated gas than one procedure. To the best of the investigators knowledge, there has
been no randomized controlled trial of CO2 versus air for insufflations during combined two
procedures, colonoscopy with consecutive EGD. And there are a few well randomized trials
concerned CO2 insufflation in patients receiving sedation during colonoscopy.
The aim of the present study was to evaluate the efficacy of CO2 in reducing post-procedural
abdominal pain and distension during colonoscopy consecutive EGD and to confirm the safety of
CO2 insufflation when it is used during procedure in sedated outpatients.