Traditional vs wireless intragastric pH monitoring: are the two techniques comparable?

Gastroesophageal Reflux Disease-Functional Dyspepsia Overlap: Do Birds of a Feather Flock Together?

INTRODUCTION

Gastroesophageal reflux disease (GERD) and functional dyspepsia (FD) are 2 of the most prevalent upper gastrointestinal (GI) disorders in the Western world. Previous Rome definitions excluded patients with predominant heartburn from the definition of FD because they were considered to have GERD. However, more recent studies showed that heartburn and acid regurgitation are also common symptoms in patients with FD. The aim of this study is to provide an overview of the prevalence of overlap between GERD and FD, the underlying pathophysiology and implications for treatment.

METHODS

A review of the literature was performed using the PubMed database, and a meta-analysis with random effects model was completed.

RESULTS

This review showed considerable overlap between GERD and FD. A meta-analysis on the data included in this review showed 7.41% (confidence interval [CI]: 4.55%-11.84%) GERD/FD overlap in the general population, 41.15% (CI: 29.46%-53.93%) GERD with FD symptoms, and 31.32% (CI: 19.43%-46.29%) FD with GERD symptoms. Although numerous committees and consensus groups attempted to develop uniform definitions for the diagnosis of GERD and FD, various diagnostic criteria are used across studies and clinical trials (frequency, severity, and location of symptoms). Several studies showed that the overlap between GERD and FD can be explained by a shared pathophysiology, including delayed gastric emptying and disturbed gastric accommodation.

DISCUSSION

For diagnoses of GERD and FD, uniform definitions that are easy to implement in population studies, easy to interpret for physicians, and that need to be well explained to patients to avoid overestimation or underestimation of true prevalence are needed. Both GERD and FD coexist more frequently than expected, based on coincidence, suggesting a potential pathophysiological link. More research is needed to explore the common GERD/FD overlap population to identify the underlying pathophysiological mechanisms, which may lead to a more effective therapeutic approach.

Fluorescence lifetime imaging of upper gastrointestinal pH in vivo with a lanthanide based near-infrared τ probe

Lanthanide complex was successfully applied in the design of pH-responsive NIR τ probe for quantitative in vivo imaging.

Time-resolved fluorescence lifetime imaging (FLIM) in the near-infrared region of 900–1700 nm not only allows a deep tissue penetration depth but also offers the unique benefit of the quantitative visualization of molecular events in vivo and is independent of local luminescence intensity and fluorophore concentration. Herein, we report the design of a wide-range pH sensitive molecular probe based on Yb³⁺ porphyrinate. The Yb³⁺ probe shows increasing NIR emission and lifetime with pK_a values of ca. 6.6 from pH 9.0 and 5.0 and also displays an elongated lifetime from ca. 135 to 170 μs at lower pH values (5.0–1.0) due to aggregation and reduced exposure to water at low pH values. Importantly, the probe is able to monitor a wide range of in vivo gastrointestinal pH values in mice models and the potential applications in imaging-guided gastrointestinal diagnostics and therapeutics were revealed. This study shows that lifetime contrast is important for preclinical imaging; lanthanide complexes could be successfully used in the design of stimuli-responsive NIR τ probes for advanced in vivo imaging.

Large Buffering Effect of the Duodenal Bulb in Duodenal Switch: a Wireless pH-Metric Study

Introduction

Bariatric procedures result in massive weight loss, however, not without side effects. Gastric acid is known to cause marginal ulcers, situated in the small bowel just distal to the upper anastomosis. We have used the wireless BRAVO™ system to study the buffering effect of the duodenal bulb in duodenal switch (DS), a procedure in which the gastric sleeve produces a substantial amount of acid.

Methods

We placed a pre- and a postpyloric pH capsule in 15 DS-patients (seven men, 44 years, BMI 33) under endoscopic guidance and verified the correct location by fluoroscopy. Patients were asked to eat and drink at their leisure, and to register their meals for the next 24 h.

Results

All capsules but one could be successfully placed, without complications. Total registration time was 17.2 (1.3–24) hours prepyloric and 23.1 (1.2–24) hours postpyloric, with a corresponding pH of 2.66 (1.74–5.81) and 5.79 (4.75–7.58), p < 0.01. The difference in pH between the two locations was reduced from 3.55 before meals to 1.82 during meals, p < 0.01. Percentage of time with pH < 4 was 70.0 (19.9–92.0) and 13.0 (0.0–34.6) pre and postpylorically, demonstrating a large buffering effect.

Conclusion

By this wireless pH-metric technique, we could demonstrate that the duodenal bulb had a large buffering effect, thus counteracting the large amount of gastric acid passing into the small bowel after duodenal switch. This physiologic effect could explain the low incidence of stomal ulcers.

Gastric perforation following endoscopic removal of a Bravo pH capsule in a cat

A 7-year-old domestic shorthair cat was evaluated for hyporexia and weight loss following endoscopic placement of an intragastric pH monitoring device. Physical examination of the cat was unremarkable, and its blood work was notable for a mild hypoalbuminemia. The cat's acute hyporexia and weight loss was attributed to discomfort associated with the intragastric pH monitoring device, as has been reported in humans. Endoscopic removal of the intragastric pH monitoring device resulted in gastric perforation. The cat underwent exploratory laparotomy for surgical resection and repair of the perforated area. To our knowledge, this is the first report of gastric perforation secondary to removal of a Bravo pH capsule. Caution may be advised when considering intragastric pH capsule removal in cats.