title: Effects of carbon dioxide insufflation in balloon-assisted enteroscopy: A systematic review and meta-analysis.
abstract: OBJECTIVE
  The efficacy of CO2 insufflation during balloon-assisted enteroscopy remains controversial. This study aimed to perform a systematic review with meta-analysis of randomized controlled trials (RCTs) in which CO2 insufflation was compared with air insufflation in balloon-assisted enteroscopy.
  
  
  METHODS
  PubMed, the Cochrane library, and the Igaku-Chuo-Zasshi database were searched to identify RCTs eligible for inclusion in the systematic review. Data from the eligible studies were combined to calculate the pooled odds ratios (ORs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs).
  
  
  RESULTS
  Four RCTs (461 patients) were identified. Compared with air insufflation, CO2 insufflation significantly increased intubation depth of oral enteroscopy (WMD: 55.2, 95% CI: 10.77-99.65, p = 0.015). However, there was significant heterogeneity. The intubation depth of anal enteroscopy showed no significant difference between the CO2 group and the air group. CO2 insufflation significantly reduced abdominal pain compared with air insufflation (WMD: -2.463, 95% CI: -4.452 to -0.474, p = 0.015), without significant heterogeneity. The PaCO2 or end-tidal CO2 level showed no significant difference between the CO2 group and air group.
  
  
  CONCLUSIONS
  Compared with air insufflation, CO2 insufflation during balloon-assisted enteroscopy caused less post-procedural pain without CO2 retention.
authors.affiliation: Division of Research and Development for Minimally Invasive Treatment, Cancer Center, Keio University School of Medicine, Tokyo, Japan; Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nishizawa
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Division of Research and Development for Minimally Invasive Treatment, Cancer Center, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Fujimoto
authors.affiliation: Division of Research and Development for Minimally Invasive Treatment, Cancer Center, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Yasutoshi
authors.initials: Y
authors.lastname: Ochiai
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Kanai
authors.affiliation: Division of Research and Development for Minimally Invasive Treatment, Cancer Center, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Yahagi
authors.initials: Y
authors.lastname: Naohisa
keywords: Carbon dioxide; balloon-assisted enteroscopy; meta-analysis; systematic review