Impact of water exchange colonoscopy on endoscopy room efficiency: a systematic review and meta-analysis

Gastrointest Endosc. 2019 Jan;89(1):159-167.e13. doi: 10.1016/j.gie.2018.07.020. Epub 2018 Jul 23.


Background and aims: Separate randomized controlled trials (RCTs) showed water exchange (WE) colonoscopy outperformed other techniques in minimizing insertion pain and optimizing adenoma detection rate. Longer insertion time required for removal of infused water, residual air, and feces might have hampered its wider adoption. We evaluate the impact of WE compared with air or carbon dioxide insufflation (GAS) on room turnaround efficiency measured by cecal intubation, withdrawal, and total procedure times.

Methods: With a systematic search in PubMed, Embase, and Cochrane Library, we identified RCTs (published before March 18, 2018) that compared WE with GAS. We focused on parameters of turnaround efficiency and patient-centered outcomes.

Results: We analyzed 8371 subjects from 17 studies. Demographics and indications were comparable. Mean cecal intubation time (± standard deviation) was WE 12.5 ± 6.1 minutes versus GAS 11.1 ± 7.0 minutes, with a mean difference of 1.4 ± 3.4 minutes. Six studies showed significant differences in insertion time, with mean cecal intubation times of 11.6 ± 5.1 minutes for WE versus 7.7 ± 5.2 minutes for GAS, with a mean difference of 3.9 ± 1.1 minutes. Mean withdrawal time was similar. Mean total procedure time was WE 26.0 ± 9.7 versus GAS 24.2 ± 9.6, with a mean difference of 1.8 ± 6.2 minutes. All mean procedure times were significantly different. Patient-centered outcomes revealed that patients examined with WE had significantly lower real-time insertion pain score, less need for sedation, and higher willingness to repeat the procedure.

Conclusions: Based on parameters of procedural time, the impact of WE colonoscopy on endoscopy room turnaround yields an increase in total procedure time of about 2 minutes and is associated with significant improvement in specific patient-centered outcomes.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Adenoma / diagnosis*
  • Air
  • Carbon Dioxide
  • Colonoscopy / methods*
  • Colorectal Neoplasms / diagnosis*
  • Efficiency*
  • Humans
  • Insufflation
  • Operative Time*
  • Pain, Procedural
  • Time Factors
  • Water*


  • Water
  • Carbon Dioxide