The use of carbon dioxide for insufflation during GI endoscopy: a systematic review

Background Insufflation of the lumen is required for visualization during GI endoscopy. Carbon dioxide (CO2 ) has been proposed as an alternative to room air for insufflation. Objectives To assess the safety and efficacy of CO2 insufflation for endoscopy. Design Systematic review that focuses on evidence from randomized controlled trials (RCT). Methods Two investigators independently searched MEDLINE from 1950 to February 13, 2008, to identify all articles that reported the use of CO2 in a GI endoscopy application. Bibliographies of relevant articles were also hand searched to identify other pertinent reports. Data from RCTs, as well as from nonrandomized studies, were extracted. Results Nine RCTs were identified that compared CO2 and air insufflation for GI endoscopy. Fifteen other nonrandomized studies or reports were also reviewed. In the 8 RCTs in which postprocedural pain was assessed, pain was lower in the CO2 insufflation group compared with the air group. Two RCTs found decreased flatus in the CO2 group compared with the air group, and 3 RCTs showed there was decreased bowel distention on abdominal radiography in the CO2 group compared with the air group. Also, in all 9 RCTs and 6 additional studies in which safety was assessed, there was no CO2 retention and no adverse pulmonary events related to CO2 insufflation. Limitations Because of study heterogeneity, meta-analytic techniques could not be used. Conclusions Consistent RCT evidence indicates that CO2 insufflation is associated with decreased postprocedural pain, flatus, and bowel distention. CO2 insufflation also appears to be safe in patients without severe underlying pulmonary disease.