Carbon dioxide vs air insufflation for elective colonoscopy: a meta-analysis and systematic review of randomized controlled trials

Carbon dioxide vs air insufflation for elective colonoscopy: a meta-analysis and systematic review of randomized controlled trials

Aims and objective: The aim was to conduct a meta-analysis and systematic review of RCTs comparing two methods of colonic insufflation for elective colonoscopy i.e. carbon dioxide or air and to evaluate their efficiency, safety and side effects.

Material and Methods: Prospective RCTs comparing carbon dioxide versus air insufflation for colonic distension during colonoscopy were selected by searching PubMed, Medline, Embase, Science Citation Index, Current Contents, and the Cochrane Central Register of Controlled Trials published between January 1980 and October 2014.The outcome variables analyzed included procedural and immediate post-procedural pain (during, end or within 15 min after procedure), early post-procedural pain (between 30-120 min), intermediate post-procedural pain (360 min) and late post-procedural pain (720-1140 min), cecal/ileal intubation rate, cecal/ileal intubation time, and total colonoscopy examination time. These outcomes were unanimously decided to be important since they influence the practical approach towards patient management within and outside of hospital. Random effects model was used to calculate the effect size of both binary and continuous data. Heterogeneity amongst the outcome variables of these trials was determined by the Cochran Q statistic and I2 index. The meta-analysis was prepared in accordance with PRISMA guidelines.

Results: Twenty four RCTs totaling 3996 patients (CO2=2017, Air=1979) were analyzed. Statistically significant differences for the pooled effect size were observed for procedural and immediate post-procedural pain (WMD 0.49, 95% CI 0.32, 0.73, p= 0.0005), early post-procedural pain between 30 and 120 minutes (WMD 0.25, 95% CI 0.12, 0.49, p=<0.0001), intermediate post-procedural pain i.e. 360 minutes post completion (WMD 0.35, 95% CI 0.23, 0.52, p=<0.0001) and late post-procedural pain, between 720 and 1440 minutes (WMD 0.53, 95% CI 0.34, 0.84, p=0.0061). Comparable effects were noted for cecal/ileal intubation rate (WMD 0.86, 95% CI 0.61, 1.22, p=0.3975), cecal/ileal intubation time (WMD -0.64, 95% CI -1.38, 0.09, p=0.0860) and total examination time (WMD -0.20, 95% CI -0.96, 0.57, p=0.6133).

Conclusions: On the basis of our meta-analysis and systematic review, we conclude that carbon dioxide insufflation significantly reduces abdominal pain during and following the procedure lasting up to 24 hours. There is no difference in the cecal/ileal intubation rate and time and total examination time between the two methods. Carbon dioxide retention with CO2 insufflation during and after the colonoscopy shows inconsequential variation compared to air insufflation and has no adverse effect on patients. Carbon dioxide instead of air should be routinely utilized for colonoscopy.

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