Minimum colonoscopy observation time for colonic diverticular bleeding: A new benchmark based on the 5% plateau time.

BACKGROUND: Colonic diverticular bleeding (CDB) is a leading cause of gastrointestinal bleeding-related hospitalizations in Japan and is increasingly recognized as a significant burden in the United States. Identifying the stigmata of a recent hemorrhage (SRH) during colonoscopy enables targeted hemostasis and reduces rebleeding. However, no benchmark exists for an appropriate observation duration, resulting in operator-dependent variation. Short observation periods may lead to missed SRH, whereas unnecessarily prolonged procedures, particularly in older patients, can increase patient burden and limit endoscopy unit availability. AIM: To establish a practical benchmark for minimum colonoscopy observation time to ensure reliable SRH detection in patients with CDB. METHODS: We retrospectively analyzed patients with acute hematochezia who underwent an initial colonoscopy between January 2017 and December 2024 at a Japanese tertiary hospital. The Observation time was measured from scope insertion to SRH detection (excluding therapeutic time) or withdrawal. The primary outcome, the "5% plateau time", was defined as the point when the proportion of patients newly identified with SRH in each 5-minute interval consistently dropped below 5%. Computed tomography (CT)-based stratified analyses were performed by endoscopists who conducted ≥ 10% of procedures. RESULTS: Of the 1039 patients who underwent colonoscopy, 845 (mean age 77 ± 11 years; 64.5% male) were included. Nine board-certified endoscopists performed the procedures. SRH was detected in 286 patients (33.8%), with a median detection time of 19 minutes (interquartile range, 12-28 minutes). The overall 5% plateau time was 40 minutes and varied according to the CT findings: 40, 35, and 30 minutes for no extravasation, right-sided extravasation, and left-sided extravasation, respectively. This time point corresponded to when 80%-90% of SRH cases were detected. Despite variations in SRH detection rates and observation durations among endoscopists, the 5% plateau time was consistently approximately 40 minutes. CONCLUSION: Although it varied according to the CT findings, the overall 5% plateau time was 40 minutes. This offers a practical benchmark for the minimum observation time without SRH detection.