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Technical Review: PillSense ®, a Novel Swallowable Capsule to Detect Upper Gastrointestinal Bleeding

Klaus Mönkemüller, MD, PhD, FASGE, FJGES
Professor of Medicine, Virginia Tech Carilion School of Medicine, Virginia, USA, Universidad de la República, Montevideo, Uruguay, University of Belgrade, Serbia, UEES, Guayaquil, Ecuador
Upper gastrointestinal bleeding (UGIB) is a common medical condition worldwide. Patients present with frank, visible bleeding such as hematemesis, melena or hematochezia with hemodynamic compromise of frank shock or with subjective or “suspected bleeding”. The decision to perform urgent or emergent endoscopy depends on the clinical presentation and the visibility of blood. Although there are mathematical predictors available such as the Glasgow-Blatchford or Rockall scores to estimate the severity of bleeding, they are impractical and rarely used. Indeed, in my experience working in continental Europe, USA and South America, I have rarely seen these scores being used. Although in the past nasogastric tubes were used to find out whether the patient with reported UGIB had blood in the upper GI tract, this practice is not routine anymore, especially after a landmark study in the 1990s showed its futility (1). The development of innovative, non-invasive triage tools would facilitate the effective risk-stratification of patients with suspected UGIB, minimizing unnecessary hospital admissions and/or urgent endoscopies (2). Another frustrating aspect of dealing with “suspected” UGIB is the often-negative findings on EGD.

A novel device to detect UGIB (PillSense® was just approved by the FDA (Food and Drug Administration, USA) (Figure 1). The PillSense system is a noninvasive, easy-to-use system designed for the real-time detection of GI bleeding as liquid blood and/or hematin (3). The system consists of 2 components, a single-use, swallowable capsule containing an optical sensor that detects blood as it is propelled through the UGI tract (panels A, B, C), and a wireless bedside receiver (size of a small tablet) (panels C, D). The capsule is pill shaped, 11×27 mm in size, and battery-powered (3) (panels A, B,C). The external casing is a biocompatible polycarbonate, which ensures the capsule’s smooth and safe passage through the GI tract, while protecting the capsule from the GI tract environment. The capsule begins to gather data as soon as it is immersed in liquid. In brief, the visible light emitted by the capsule passes through the surrounding liquid, and the wavelengths detected by the sensor are analyzed. The resulting sensor output indicates the presence or absence of blood, and the wireless receiver automatically reports either “blood detected” or “no blood detected” (3) (panel E).
In a recent landmark comparative clinical trial, Akiki and colleagues evaluated the safety and efficacy of the PillSense System (4). The authors enrolled 126 adults (mean age, 62.4 years; 59.5% men) with suspected UGIB at Mayo Clinic in Rochester. Participants underwent esophagogastroduodenoscopy (EGD) within 4 hours of capsule administration and were monitored up to 21 days to confirm capsule passage.The capsule correctly detected the presence of blood in 26 out of 28 cases and the absence of blood in 87 out of 96 cases compared with EGD, demonstrating a sensitivity and specificity of 92.9% (95% CI, 76.5-99.1) and 90.6% (95% CI, 82.9-95.6), respectively, as well as positive and negative predictive values of 74.3% and 97.8%. The positive and negative likelihood ratios were 9.9 and 0.08. The mean PillSense recording time was 6.71 minutes (4).
This study demonstrated that a novel blood-sensing swallowed,easily to deploy capsule device provided highly accurate and rapid detection of UGIB. Other advantages were the simpliocity to deploy and easy to interpretation, which was visible within a mean time of 6 minutes. In contrast to the traditional wireless caspule endosocope (WCE), which requires formal reading and interpretaion of images, and has senstivity adnspeificity of 88% and 64%, repsectively, the Pillsense capsule does not require any pads or cables attached to patient and. can be deployed and interpreted by nursing and paramedical staff, and has much higher sensitivy and specificity.
Aspects that require further study are costs and use outside the hospital, for example during initial evaluation of patients at home. Hence, an accurate, rapid, easy to-interpret, and non-invasive tool could assist in both diagnosing and offering guidance for clinical decision-making in scenarios of suspected UGIB (4). The existence of this blood-sensing, swallowing capsule opens new horizons to work on improving outcomes of patients with UGIB, and may also alter the diagnostic and treatment algorithm for patients with a suspected UGIB.
References:
1. Cuellar RE, Gavaler JS, Alexander JA, et al. Gastrointestinal tract hemorrhage: the value of a nasogastric aspirate. Arch Intern Med 1990;150:1381-4.
2. Meltzer AC, Ward MJ, Gralnek IM, et al. The cost-effectiveness analysis of video capsule endoscopy compared to other strategies to manage acute upper gastrointestinal hemorrhage in the ED. Am J Emerg Med. 2014;32:823–832.B, Albers D, Hoffmeister A, Feisthammel J, Walter B, Meining A, Wedi E, Zachäus M, Pickartz T, Küllmer A, Schmidt A, Caca K. Over-the-scope-clips versus standard treatment in high-risk patients with acute non-variceal upper gastrointestinal bleeding: a randomised controlled trial (STING-2). Gut. 2022 Jul;71(7):1251-1258. doi: 10.1136/gutjnl-2021-325300. Epub 2022 Mar 23. PMID: 35321938.
3. Bajer L, Ryou M, C Thompson C, Drastich P. Novel upper gastrointestinal bleeding sensor capsule: a first human feasibility and safety trial. Clin Endosc. 2024 Mar;57(2):203-208. doi: 10.5946/ce.2023.111. Epub 2024 Jan 17. PMID: 38229441; PMCID: PMC10984735.
4. 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 May;99(5):712-720. doi: 10.1016/j.gie.2023.11.051. Epub 2023 Dec 6. PMID: 38065512.
5. Meltzer AC, Ali MA, Kresiberg RB, et al. Video capsule endoscopy in the emergency department: a prospective study of acute upper gastrointestinal hemorrhage. Ann Emerg Med 2013;61:438-43.e1.
Images from EndoCollab. See endocollab.com for more information, including videos, quick tips and lectures on these and many other practical endoscopy tricks and techniques.
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