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

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.

To establish a practical benchmark for minimum colonoscopy observation time to ensure reliable SRH detection in patients with CDB.

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.

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.

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.