Appropriate time for selective biliary cannulation by trainees during ERCP - a randomized trial.

Background and study aim: The allocation of sufficient time for trainees to attempt cannulation is necessary for learning and to ensure success with endoscopic retrograde cholangiopancreatography (ERCP) training. However, it is important to balance the benefit to trainee practice against the potential risks to patients. The appropriate time for attempted cannulation by trainees remains unclear. Patients and methods: Three different time limits (5, 10, 15 minutes) were set for cannulation attempts made by four trainees in patients with native papilla undergoing ERCP. Patients were randomly assigned to the 5-, 10-, or 15-minute groups in a 1: 1: 1 ratio. Rectal indomethacin was used in high-risk patients. The primary outcome was successful cannulation within the allocated time. Secondary outcomes included performance scores, overall success rate, and post-ERCP pancreatitis (PEP). Results: A total of 256 patients were randomly assigned to the 5-minute (n=84), 10-minute (n=86), or 15-minute (n=86) groups. Patients' base-line characteristics were comparable. Success rates for selective bile duct cannulation by trainees were 43.8 %, 75.0 %, and 71.8% in the 5-, 10-, and 15-minute groups, respectively (P<0.001). Trainees' self-reported performance scores and video assessment by an independent reviewer were comparable between the 10- and 15-minute groups, which were higher than the 5-minute group (both P < 0.001). Trainers took over the cannulation procedure when trainees did not succeed within the allocated time. There was no significant difference in the overall success rates in cannulation between the three groups. No differences were noted in the use of rectal indomethacin and overall complication rates. Four patients in each group developed PEP (P=0.996). Conclusion: A time of 10 minutes was considered to be appropriate for trainees to attempt cannulation, with acceptable cannulation success rates and complications.