PillSense: A capsule to detect an upper GI bleed

Review by Prof. Eamonn Quigley (USA)

Study Summary 

This clinical scenario will be familiar to every practicing gastroenterologist – you are called to the emergency department/room to provide advice on a young man who has come in with a somewhat vague history of vomiting blood/altered blood but is otherwise well, vital signs are stable, and hematocrit and hemoglobin have not dropped significantly. Has he had or is he having a significant upper GI bleed? Scoring systems may help to identify high risk individuals but are not infallible, and nasogastric tube insertion and lavage have been abandoned because of poor sensitivity and specificity. So, is an upper gastrointestinal endoscopy (esophago-gastro-duodenoscopy, EGD) your only option in attempting to triage this situation and other upper GI bleed scenarios?

This new capsule-based device offers an alternative. The device, called PillSense, is a capsule that incorporates an optical sensor linked to an external sensor that detects blood and provides a very simple dichotomous result: either Blood Detected or Blood not Detected. In this study, 126 individuals presenting with a suspected upper GI bleed swallowed the capsule and all had an EGD within 4 hours. The sensitivity and specificity of the capsule for detecting blood (in comparison to the EGD) were 93% and 91%, respectively, with excellent positive and negative likelihood ratios of 9.9 and 0.8, respectively. There were no AEs related to the device.

Commentary 

This is the latest in a growing number of capsule-based technologies being applied to the evaluation of the GI tract. The PillSense approach is relatively non-invasive, can be performed without preparation, and is simple to interpret. The average recording time was only about 7 minutes, so its diagnostic range is strictly limited to the upper GI tract. Two patients had false negative results – at EGD, one was found to have a gastric ulcer and the other gastric antral vascular ectasia (GAVE) with mild oozing in both cases. I can see the attraction of this device to the ER/ED physician coping with a large volume of patients and needing to make quick decisions on GI bleeds – are they real, do they need an EGD? As usual, its use will be determined by a cost-benefit analysis. The performance of this analysis will be aided by comparisons to available risk scoring systems and studies of long-term outcome. This system will not replace clinical assessment and scoring systems but may serve as a very valuable adjunct.

Citation

Akiki K, Mahmoud T, Alqaisieh MH, Sayegh LN, Lescalleet KE, Abu Dayyeh BK, Wong Kee Song LM, Larson MV, Bruining DH, Coelho-Prabhu N, Buttar NS, Sedlack RE, Chandrasekhara V, Leggett CL, Law RJ, Rajan E, Gleeson FC, Alexander JA, Storm AC. A novel blood-sensing capsule for rapid detection of upper GI bleeding: a prospective clinical trial. Gastrointest Endosc. 2024;99:712-720. 

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