title: Efficacy and safety of carbon dioxide insufflation versus air insufflation for endoscopic retrograde cholangiopancreatography: A meta-analysis update.
abstract: OBJECTIVE
  Endoscopic retrograde cholangiopancreatography (ERCP) is essential for visualising the biliary tree and pancreatic ducts, and carbon dioxide (CO2) insufflation during ERCP is considered an alternative technique to air insufflation for relieving post-procedural abdominal discomfort (abdominal pain and distension). The aim of the present study was to evaluate the effect of CO2insufflation on the remission of abdominal discomfort and the potential side effects by conducting a meta-analysis.
  
  
  METHODS
  The method recommended by the Cochrane Collaboration was employed to conduct a meta-analysis of randomised controlled trials (RCTs) of CO2insufflation versus air insufflation during ERCP. The PubMed, EMBASE, Cochrane Library, ISI Web of Science and China Biology Medicine disc (CBMdisc) databases were comprehensively searched.
  
  
  RESULTS
  Nine high-quality RCTs were reviewed. The updated meta-analysis showed that the CO2groups achieved a lower abdominal pain score [1-hour (SMD: -1.44, 95% CI: -2.76, -0.15), 3-hour (SMD: -1.17, 95% CI: -2.18, -0.16) and 6-hour (SMD: -1.39, 95% CI: -2.68, -0.10)], a lower abdominal distension score [1-hour (SMD: -1.05, 95% CI: -1.73, -0.38), 3-hour (SMD: -0.63, 95% CI: -1.10, -0.16) and 6-hour (SMD: -0.54, 95% CI: -0.99, -0.08)] and a lower overall rate of complications (OR: 0.59; 95% CI: 0.37, 0.93). There was no significant difference between the groups regarding abdominal discomfort immediately after recovery or 24-hour post-procedure. There was no evidence to indicate higher pressure of CO2(pCO2) values in the CO2groups during the procedure when the patients were under sedation anaesthesia.
  
  
  CONCLUSIONS
  Compared to air insufflation, CO2insufflation is currently the preferred method for ERCP and decreases post-procedural abdominal pain and distension without significant side effects.
authors.affiliation: Departments of Gastroenterology and Hepatology, First Affiliated Hospital of Wenzhou Medical University, Shangcai Street, Nanbaixiang Town, Ouhai District, 325000 Wenzhou, China; School of First Clinical Medical, Wenzhou Medical University, Chashan Advanced Education Park, 325000 Wenzhou, China.
authors.forename: Wen You
authors.initials: WY
authors.lastname: Zhang
authors.affiliation: Departments of Gastroenterology and Hepatology, First Affiliated Hospital of Wenzhou Medical University, Shangcai Street, Nanbaixiang Town, Ouhai District, 325000 Wenzhou, China; School of First Clinical Medical, Wenzhou Medical University, Chashan Advanced Education Park, 325000 Wenzhou, China.
authors.forename: Xue Pei
authors.initials: XP
authors.lastname: Jiang
authors.affiliation: Departments of Gastroenterology and Hepatology, First Affiliated Hospital of Wenzhou Medical University, Shangcai Street, Nanbaixiang Town, Ouhai District, 325000 Wenzhou, China; School of First Clinical Medical, Wenzhou Medical University, Chashan Advanced Education Park, 325000 Wenzhou, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Miao
authors.affiliation: Departments of Gastroenterology and Hepatology, First Affiliated Hospital of Wenzhou Medical University, Shangcai Street, Nanbaixiang Town, Ouhai District, 325000 Wenzhou, China; School of First Clinical Medical, Wenzhou Medical University, Chashan Advanced Education Park, 325000 Wenzhou, China.
authors.forename: Fei Chi
authors.initials: FC
authors.lastname: Chen
authors.affiliation: Departments of Gastroenterology and Hepatology, First Affiliated Hospital of Wenzhou Medical University, Shangcai Street, Nanbaixiang Town, Ouhai District, 325000 Wenzhou, China. Electronic address: zwywzmc@163.com.
authors.forename: Zhi Ming
authors.initials: ZM
authors.lastname: Huang
authors.affiliation: School Renji Clinical Medical, Wenzhou Medical University, Advanced Education Park, Wenzhou, China.
authors.forename: Xie Lin
authors.initials: XL
authors.lastname: Huang
mesh_terms: D015746:Abdominal Pain / Q000209:etiology / Q000517:prevention & control*; D000368:Aged; D000369:Aged, 80 and over; D000388:Air; D002245:Carbon Dioxide; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000009:adverse effects / Q000379:methods; D006801:Humans; D007327:Insufflation / Q000379:methods*; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic
chemical_list: D002245:Carbon Dioxide