Carbon dioxide versus air insufflation enteroscopy: a systematic review and meta-analysis based on randomized controlled trials

OBJECTIVES: To compare the insufflation of CO (2) and ambient air in enteroscopy. SEARCH SOURCES: The investigators researched the electronic databases MedLine, Cochrane Library, Central, LILACS, BVS, Scopus and Cinahl. The grey search was conducted in the base of theses of the University of São Paulo, books of digestive endoscopy and references of selected articles and in previous systematic revisions. STUDY ELIGIBILITY CRITERIA: The evaluation of eligibility was performed independently, in a non-blind manner, by two reviewers, firstly by title and abstract, followed by complete text. Disagreements between the reviewers were resolved by consensus. DATA COLLECTION AND ANALYSIS METHOD: Through the spreadsheet of data extraction, where one author extracted the data and a second author checked the extraction. Disagreements were resolved by debate between the two reviewers. The quality analysis of the studies was performed using the Jadad score. The software RevMan 5 version 5.3 was used for the meta-analysis. RESULTS: Four randomized clinical trials were identified, totaling 473 patients submitted to enteroscopy and comparing insufflation of CO (2) and ambient air. There was no statistical difference in the intubation depth between the two groups. When CO (2) insufflation was reduced, there was a significant difference in pain levels 1 hour after the procedure (95 % IC, –2.49 [–4.72, –0.26], P : 0.03, I (2) : 20%) and 3 hours after the procedure (95% IC, –3.05 [–5.92, –0.18], P : 0.04, I (2) : 0 %). There was a usage of lower propofol dosage in the CO (2) insufflation group, with significant difference (95 % IC, –67.68 [–115.53, –19.84], P : 0.006, I (2) : 0 %). There was no significant difference between the groups in relation to the use of pethidine and to the oxygen saturation. LIMITATIONS: Restricted number of randomized clinical trials and nonuniformity of data were limitations to the analysis of the outcomes. CONCLUSION: The use of CO (2) as insufflation gas in enteroscopy reduces the pain levels 1 hour and 3 hours after the procedure, in addition to the reduction of the sedation (propofol) dosage used.