title: Carbon dioxide insufflation for endoscopic retrograde cholangiopancreatography: A meta-analysis and systematic review.
abstract: OBJECTIVE
  To assess the safety and efficacy of carbon dioxide (CO(2)) insufflation during endoscopic retrograde cholangiopancreatography (ERCP).
  
  
  METHODS
  The Cochrane Library, Medical Literature Analysis and Retrieval System Online, Excerpta Medica Database, Science Citation Index Expanded, Chinese Biomedical Literature Database, and references in relevant publications were searched up to December 2011 to identify randomized controlled trials (RCTs) comparing CO(2) insufflation with air insufflation during ERCP. The trials were included in the review irrespective of sample size, publication status, or language. Study selection and data extraction were performed by two independent authors. The meta-analysis was performed using Review Manager 5.1.6. A random-effects model was used to analyze various outcomes. Sensitivity and subgroup analyses were performed if necessary.
  
  
  RESULTS
  Seven double-blind RCTs involving a total of 818 patients were identified that compared CO(2) insufflation (n = 404) with air insufflation (n = 401) during ERCP. There were a total of 13 post-randomization dropouts in four RCTs. Six RCTs had a high risk of bias and one had a low risk of bias. None of the RCTs reported any severe gas-related adverse events in either group. A meta-analysis of 5 RCTs (n = 459) indicated that patients in the CO(2) insufflation group had less post-ERCP abdominal pain and distension for at least 1 h compared with patients in the air insufflation group. There were no significant differences in mild cardiopulmonary complications [risk ratio (RR) = 0.43, 95% CI: 0.07-2.66, P = 0.36], cardiopulmonary (e.g., blood CO(2) level) changes [standardized mean difference (SMD) = -0.97, 95% CI: -2.58-0.63, P = 0.23], cost analysis (mean difference = 3.14, 95% CI: -14.57-20.85, P = 0.73), and total procedure time (SMD = -0.05, 95% CI: -0.26-0.17, P = 0.67) between the two groups.
  
  
  CONCLUSIONS
  CO(2) insufflation during ERCP appears to be safe and reduces post-ERCP abdominal pain and discomfort.
authors.affiliation: Department of Bile Duct Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Cheng
authors.forename: Xian-Ze
authors.initials: XZ
authors.lastname: Xiong
authors.forename: Si-Jia
authors.initials: SJ
authors.lastname: Wu
authors.forename: Jiong
authors.initials: J
authors.lastname: Lu
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Lin
authors.forename: Nan-Sheng
authors.initials: NS
authors.lastname: Cheng
authors.forename: Tai-Xiang
authors.initials: TX
authors.lastname: Wu
mesh_terms: D015746:Abdominal Pain / Q000517:prevention & control; D002245:Carbon Dioxide; D002760:Cholangiopancreatography, Endoscopic Retrograde; D006801:Humans; D007327:Insufflation / Q000009:adverse effects / Q000191:economics; D010149:Postoperative Pain / Q000517:prevention & control
chemical_list: D002245:Carbon Dioxide
keywords: Abdominal pain; Carbon dioxide insufflation; Endoscopic retrograde cholangiopancreatography; Meta-analysis; Systematic review