Feasibility of a forty-minute post-colonoscopy observation period for diverticular bleeding: Assessing the five per cent plateau model

Abstract

This letter appraises the 5% plateau time model proposed by Ichita et al for colonoscopy in colonic diverticular bleeding. By quantifying stigmata of recent hemorrhage detection in 5-minute intervals, the authors identify an overall 40 minutes observation plateau and computed tomography-stratified targets of 30 minutes, 35 minutes and 40 minutes. We highlight how this approach operationalizes a “time-to-yield” concept and argue that the 40-minute period should be interpreted as a flexible observation floor rather than a rigid rule. We discuss clinical feasibility in the context of patient tolerance, operator factors and guideline-based management of acute lower gastrointestinal bleeding, and propose practical strategies for implementation, including computed tomography-stratified guidance, a 20-25 minutes quality checkpoint, individualized shortening of observation in high-risk patients, and systematic documentation of observation time. Finally, we outline priorities for future validation, such as multi-center outcome studies, analyses of operator learning curves and integration of artificial intelligence-assisted stigmata of recent hemorrhage detection.

Key Words: Diverticular bleeding; Colonoscopy; Stigmata of recent hemorrhage; Observation time; 5% plateau model

Core Tip: This article interprets the 5% plateau time model for colonoscopy in colonic diverticular bleeding and emphasizes that a 40-minute observation period should be treated as a flexible minimum floor rather than a rigid rule. By framing observation time as a “time-to-yield” curve, we propose practical strategies for computed tomography-stratified targets, a 20-25 minutes quality checkpoint, individualized shortening in high-risk patients and structured documentation. These suggestions aim to improve time efficiency and operational quality in the management of acute lower gastrointestinal bleeding.

TO THE EDITOR

We commend Ichita et al[1] for incorporating a pragmatic “5% plateau time”, primarily designed to reduce diminishing returns in the detection of stigmata of recent hemorrhage (SRH) during colonoscopy for colonic diverticular bleeding. In addition to the therapeutic duration, the observation period commenced upon colonoscope insertion and involved evaluating the incremental yields at 5-minute intervals. Based on these parameters, the authors identified the concept of a 40-minute observation plateau and stratified participants using computed tomography (CT) (40 minutes, 35 minutes, and 30 minutes for no, right-sided, and left-sided extravasation, respectively). More specifically, the SRH detection rate was calculated at 5-minute intervals, representing the proportion of procedures in which SRH was first identified within each interval. In this context, the plateau was defined as the earliest time after which each subsequent 5-minute interval contributed less than 5% additional detections[1]. We highly value this work, as it not only presents transparent methodologies but also establishes reproducible benchmark standards and mitigates operator-related variability in colonoscopy.

METHODOLOGICAL STRENGTHS

This study effectively demonstrates the concept of “time-to-yield” in practice by measuring the speed at which SRH is initially detected over 5-minute intervals[1]. By defining a 5% plateau, the authors transform an experience-based procedure into a measurable observation threshold that could be easily adapted. Thus, the credibility of this plateau as a minimum observation threshold was enhanced through CT-guided stratification and the use of 3% and 10% thresholds in sensitivity analyses[1], aligning with the contemporary guidelines that prioritize risk stratification and imaging-assisted diagnosis for ongoing significant bleeding. Therefore, this plateau should be applied flexibly within CT-stratification and adjusted for patient tolerance and operational conditions of colonoscopy, rather than being applied as a fixed period[2,3].

CLINICAL FEASIBILITY

Rooted in patient tolerance variability and operator factors, the 40-minute plateau should serve as the observation threshold rather than a definitive marker for diagnosis. Although Ichita et al[1] reported inter-endoscopist variability in detection rates and median observation times, all participants in their study demonstrated an approximate 40-minute plateau[1]. More importantly, because time is a surrogate marker of quality rather than a definitive indicator, it is preferable to incorporate a 40-minute observation time into priority criteria, such as professional endoscopist training in SRH detection, vision optimization (e.g., lavage, cap assistance for cleaning), and thorough evaluation, as well as documentation of net observation time (excluding the therapeutic period and separating insertion from observation). As the above findings demonstrate, this approach aligns closely with guideline-oriented care, particularly in supporting the notion that early colonoscopy (e.g., less than 24 hours) has substantial potential to ameliorate the early diagnostic evidence for acute lower gastrointestinal bleeding. Furthermore, this plateau highlights that both faster and prolonged observation are not necessarily associated with improved patient prognosis. In summary, the considerations above support the clinical feasibility of the 40-minute threshold in clinical practice[2-4].

CLINICAL UTILIZATION

To facilitate the implementation of the 40-minute plateau model in clinical practice, we propose several key considerations: (1) Apply CT-stratified guidance. For cases involving the left side, right side, and situations without extravasation or when uncertainty exists, the observation times should be set at 30 minutes, 35 minutes, and 40 minutes, respectively[1]; (2) Establish a formal quality checkpoint at 20-25 minutes. Specifically, visual quality (cleanliness, stability, field control) should be formally evaluated at approximately 20-25 minutes. This evaluation can assist endoscopists in assessing image quality and mucosal coverage, thereby justifying the extension of observation time[1]; (3) Monitor high-risk patients and allow early termination when risks outweigh incremental benefits. In patients with high sedation risks (e.g., elderly individuals, those with impaired cardiopulmonary function, or long-term use of antithrombotic medications), the procedure may be terminated early if the incremental benefits are unlikely to outweigh the risks. This approach aligns with the guidelines' recommendations for individualized management[2,3]. Therefore, for such patients, the 40-minute observation time remains a flexible threshold that can be shortened when the incremental benefits are marginal; and (4) Record insertion, net observation and therapeutic time separately. Operators should record the times for various phases of the colonoscopy, including insertion, observation and therapy. Additionally, reasons for distractions from the target area and detailed examination findings should be noted. Such documentation is essential for ensuring operational quality and accuracy.

PROSPECTIVE FUTURE RESEARCH

In the future, further studies are necessary to verify the transition of this simple benchmark to a universally recognized standard. For instance, in line with several recent studies, we could: (1) Conduct multi-center studies to compare the prognosis of 40-minute plateau-guided treatment with conventional treatments, analyzing key indicators (e.g., rebleeding, blood transfusion, intensive care unit utilization rates, duration of hospitalization, and other adverse events)[2-4]; (2) Examine the learning curves of operators and how anatomical differences (e.g., diverticular distribution and colonic redundancy) affect the efficacy of observation time; and (3) Incorporate artificial intelligence-assisted screening for SRH detection to maintain sensitivity while safely shortening observation time in high-risk patients[1].

CONCLUSION

Ichita et al[1] have pioneered a clinically feasible framework for standardizing the observation time for SRH. In conjunction with CT-guidance, priority criteria, and quality measurements, we also recommend a 40-minute observation period, based on a 5% threshold, as a flexible minimum. However, it is essential to conduct a multi-center validation to facilitate the broader application of this approach in colonoscopy detection[1-4].