Comparison between Carbon Dioxide and Air Insufflation in Colonoscopy: A Systematic Review and Meta-Analysis Based On Randomized Control Trials

Objectives: The colorectal cancer is a common and lethal neoplasia.Colonoscopy detects diseases in the initial stages decreasing the mortality.Pain and abdominal discomfort are usual complaints associated mainly with the use of air insufflation.Carbon dioxide (CO2) is increasingly utilized to augment tolerance and disposition to repeat the examination.Compare which insufflation method is related to less unpleasant symptoms, safer examination and best performance are objectives of the study.Methods: Electronic databases were accessed selecting only randomized controlled trials comparing insufflation with CO2 and ambient air in colonoscopy.The evaluated outcomes were pain, abdominal distension and flatulence, cecal intubation rate, cecal intubation and total procedure time, volume of gas, CO2 measurement, and need of sedation or analgesia, and polyp detection rate.Results: Thirty randomized controlled trials were selected (4854 patients).Meta-analysis showed reduction in pain risk in the CO2 group immediately after the colonoscopy (Risk difference-RD 0.11[0.03,0.19]), 1h (RD 0.29 [0.24, 0.34]), 3h (RD 0.22[0.11,0.34]) and 6h (RD 0.21 [0.17, 0.26]) after colonoscopy.The reduction of flatulence risk 1h and 6h after the procedure was greater in CO2 group (RD 0.54 [0.43, 0.66] and RD 0.65[0.38,0.92],respectively).There were no significant differences between the two groups regarding pain during the procedure, pain and flatulence 24h after colonoscopy, abdominal bloating, request for medication, safety, gas volume, polyp detection rate, cecal intubation rate, time to cecum and total procedure time.Conclusions: CO2 insufflation improves tolerance to colonoscopy, reducing pain and flatulence out to 6 hours following the procedure.