<b>Background and study aims</b> Single-balloon enteroscopy (SBE) is a valuable but difficult modality for the diagnosis and treatment of small-bowel diseases. The water exchange (WE) method has the advantage of facilitating intubation during colonoscopy. Here, we evaluated the effects of WE on procedure-related variables related to SBE.
<b>Patients and methods</b> This randomized controlled trial was conducted in a tertiary-care referral center in China. Patients with attempt at total enteroscopy (ATE) were randomly allocated to undergo WE-assisted (WE group) or carbon dioxide-insufflated enteroscopy (CO<sub>2</sub> group). All patients were planned to undergo both antegrade and retrograde procedures. The primary outcome was the total enteroscopy rate (TER). Secondary outcomes included maximal insertion depth, positive findings, procedural time and adverse events.
<b>Results</b> In total, 110 patients were enrolled, with 55 in each group. Baseline characteristics between the two groups were comparable. TER was achieved in 58.2% (32/55) of the WE group and 36.4% (20/55) of the control group (p=0.022). The estimated intubation depth was 521.2±101.4 cm in the WE group and 481.6±95.2 cm in the CO<sub>2</sub> group (p=0.037). The insertion time was prolonged in the WE group compared with CO<sub>2</sub> group (178.9±45.1 min vs. 154.2±27.6 min, p<0.001). Endoscopic findings and adverse events were comparable between the two groups.
<b>Conclusions</b> The WE method improved TER and increased intubation depth during SBE. The use of WE did not increase complications of enteroscopy. Clinical trial registation: https://clinicaltrials.gov/， NCT01942863.
Carbon dioxide insufflation during endoscopic retrograde cholangiopancreatography reduces bowel gas volume but does not affect visual analogue scale scores of suffering: a prospective, double-blind, randomized, controlled trial
