Obscure gastrointestinal bleeding and iron-deficiency anemia—Where does capsule endoscopy fit?

Endoscope Capsules: The Present Situation and Future Outlooks

This paper presents new perspectives on photonic technologies for capsule endoscopy. It first presents a review of conventional endoscopy (upper endoscopy and colonoscopy), followed by capsule endoscopy (CE), as well as their techniques, advantages, and drawbacks. The technologies for CEs presented in this paper include integration with the existing endoscopic systems that are commercially available. Such technologies include narrow-band imaging (NBI), photodynamic therapy (PDT), confocal laser endomicroscopy (CLE), optical coherence tomography (OCT), and spectroscopy in order to improve the performance of the gastrointestinal (GI) tract examination. In the context of NBI, two optical filters were designed and fabricated for integration into endoscopic capsules, allowing for the visualization of light centered at the 415 nm and 540 nm wavelengths. These optical filters are based on the principle of Fabry-Perot and were made of thin films of titanium dioxide (TiO2) and silicon dioxide (SiO2). Moreover, strategies and solutions for the adaptation of ECs for PDT are also discussed.

Ingestible Sensors and Sensing Systems for Minimally Invasive Diagnosis and Monitoring: The Next Frontier in Minimally Invasive Screening

Ingestible electronic systems that are capable of embedded sensing, particularly within the gastrointestinal (GI) tract and its accessory organs, have the potential to screen for diseases that are difficult if not impossible to detect at an early stage using other means. Furthermore, these devices have the potential to (1) reduce labor and facility costs for a variety of procedures, (2) promote research for discovering new biomarker targets for associated pathologies, (3) promote the development of autonomous or semiautonomous diagnostic aids for consumers, and (4) provide a foundation for epithelially targeted therapeutic interventions. These technological advances have the potential to make disease surveillance and treatment far more effective for a variety of conditions, allowing patients to lead longer and more productive lives. This review will examine the conventional techniques, as well as ingestible sensors and sensing systems that are currently under development for use in disease screening and diagnosis for GI disorders. Design considerations, fabrication, and applications will be discussed.

Clinical outcomes of negative small-bowel capsule endoscopy for small-bowel bleeding: a systematic review and meta-analysis

BACKGROUND AND AIMS

Small-bowel bleeding is the primary indication for capsule endoscopy (CE). Many experts advocate a "watch-and-wait" policy in negative CE. This meta-analysis examines the odds of rebleeding after negative index CE and the impact on long-term follow-up.

METHODS

A comprehensive literature search identified articles examining the rebleeding rate after negative CE. Demographic and clinical information with emphasis on outcomes was retrieved, pooled, and analyzed. Heterogeneity among studies was assessed using the I² statistic. A random effects model was used as the pooling method because of high heterogeneity. Risk of bias was assessed using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool. The primary outcome evaluated was the pooled odds ratios (ORs) for rebleeding after a negative CE for obscure GI bleeding (OGIB).

RESULTS

Twenty-six studies with 3657 patients were included. The pooled rate of rebleeding after negative CE was .19 (95% CI, .14-.25; P < .0001). The pooled OR of rebleeding was .59 (95% CI, .37-.95; P < .001). The effect was more pronounced in studies with a short follow-up (OR, .47; 95% CI, .24-.94; P < .001). There was no statistically significant difference in rebleeding after CE for occult and overt OGIB. Prospective studies showed a lower OR of rebleeding of .24 (95% CI, .08-.73; P = .01). Most studies were high quality.

CONCLUSIONS

Our analysis shows that negative CE provides adequate evidence of a subsequently low risk of rebleeding. Such patients can therefore be safely managed with watchful waiting. However, patients who rebleed after 2 years may need to be investigated for a new source of blood loss.

A Therapeutic Wireless Capsule for Treatment of Gastrointestinal Haemorrhage by Balloon Tamponade Effect

OBJECTIVE

Wireless capsule endoscope (WCE) is a revolutionary approach to diagnose small bowel pathologies. Currently available WCEs are mostly passive devices with image capturing function only, while on-going efforts have been placed on robotizing WCEs or to enhance them with therapeutic functions. In this paper, the authors present a novel inflatable WCE for haemostasis in the gastrointestinal (GI) tracts by balloon tamponade effect.

METHODS

The proposed wireless capsule consists of a balloon that can be inflated using the endothermic reaction of acid and base. When the balloon reached a precalculated pressure level, it is able to stop at a bleeding site in the bowel, and achieve haemostasis by tamponade effect. The prototype is 14 mm in diameter, with three sections of 13, 35, and 12 mm in length, respectively. The three sections are linked together with flexible joints and enclosed in a silicone balloon. The prototypes were tested in ex vivo porcine intestine models.

RESULTS

In the ten ex vivo trials conducted, the inflatable wireless capsule achieved average balloon pressure of 46.0 mmHg and withstood average maximum longitudinal pulling force at 1.46 N. An in vivo study was carried out as a proof-of-concept for treating bleeding in a porcine model. The proposed inflatable WCE succeeded in the animal test by controlling haemostasis within 5 min. No rebleeding was observed in the next 20 min.

CONCLUSION

The results suggested that the inflatable capsule with a real-time bleeding detection algorithm can be implemented. Moreover, the proposed inflatable WCE prototype can achieve haemorrhage control in the lower GI.

SIGNIFICANCE

To our best knowledge, this is the first study that demonstrated the potential to treat GI haemorrhage by an inflatable WCE. The proposed capsule enables the development of a closed-loop system based on a body sensor network to provide early treatment of GI bleeding for p-medicine.