Characterization of intraluminal impedance patterns associated with gas reflux in healthy volunteers

Mean nocturnal baseline impedance and endoscopic mucosal impedance measurements in patients with eosinophilic esophagitis: a new tool for follow up and management?

Eosinophilic esophagitis (EoE) is the second most common cause of chronic esophageal inflammation after GERD, with increasing incidence and prevalence across all age groups. Since current diagnosis and follow up of EoE require endoscopy with biopsies, there is an increased interest in non or less invasive tests for its diagnosis and follow up. Baseline mucosal impedance measurement allows evaluation of mucosal barrier properties and is widely accepted as an adjunct method in GERD diagnosis. As EoE is associated with increased mucosal permeability, the use of baseline impedance to evaluate mucosal integrity has been investigated in several studies. It was found that baseline mucosal impedance, measured either during 24 h reflux monitoring or during endoscopy, was significantly lower in all parts of the esophagus in EoE patients. Impedance measurement correlated with eosinophil counts on biopsies, offering a tool to monitor treatment response. Additionally, baseline impedance patterns differed between those responding to proton pump inhibitor (PPI) treatment and those resistant to PPI, potentially allowing to tailor future treatment to the individual patient. In summary, baseline impedance measurement offers a potential tool for diagnosis and follow up in EoE. Its exact place in EoE treatment is yet to be determined and requires further future studies.

The inability to belch syndrome: A study using concurrent high-resolution manometry and impedance monitoring

INTRODUCTION

Although inability to belch has previously been linked to dysfunction of the upper esophageal sphincter (UES), its underlying pathogenesis remains unclear. Our aim was to study mechanisms underlying inability to belch and the effect of UES botulinum toxin (botox) injections in these patients.

METHODS

We prospectively enrolled consecutive patients with symptoms of inability to belch. Patients underwent stationary high-resolution impedance manometry (HRIM) with belch provocation and ambulatory 24-h pH-impedance monitoring before and 3 months after UES botox injection.

RESULTS

Eight patients (four males, age 18-37 years) were included. Complete and normal UES relaxation occurred in response to deglutition in all patients. A median number of 33(15-64) gastroesophageal gas reflux episodes were observed. Despite the subsequent increase in esophageal pressure (from -4.0 [-7.7-4.2] to 8 [3.3-16.1] mmHg; p < 0.012), none of the gastroesophageal gas reflux events resulted in UES relaxation. Periods of continuous high impedance levels, indicating air entrapment (median air presence time 10.5% [0-43]), were observed during 24-h impedance monitoring. UES botox reduced UES basal pressure (from 95.7[41.2-154.0] to 29.2 [16.7-45.6] mmHg; p < 0.02) and restored belching capacity in all patients. As a result, esophageal air presence time decreased from 10.5% (0-43.4) to 0.7% (0.1-18.6; p < 0.02) and esophageal symptoms improved in all patients (VAS 6.0 [1.0-7.9] to 1.0 [0.0-2.5]; p < 0.012).

CONCLUSION

The results of this study underpin the existence of a syndrome characterized by an inability to belch and support the hypothesis that ineffective UES relaxation, with subsequent esophageal air entrapment, may lead to esophageal symptoms.

Mucosal impedance for esophageal disease: evaluating the evidence

Impedance has traditionally been employed in esophageal disease as a means to assess bolus flow and reflux episodes. Recent and ongoing research has provided new and novel applications for this technology. Measurement of esophageal mucosal impedance, via either multichannel intraluminal impedance catheters or specially designed endoscopically deployed impedance catheters, provides a marker of mucosal integrity. Mucosal impedance has been shown to segregate gastroesophageal reflux disease (GERD) and eosinophilic esophagitis from non-GERD controls and may play a role in predicting response to reflux intervention. More data are needed with regard to other esophageal subgroups, outcome studies, and functional disease. Our paper reviews the history of impedance in esophageal disease, the means of assessing baseline and mucosal impedance, data with regard to the newly developed mucosal impedance probes, the clinical utility of mucosal impedance in specific clinical conditions, and limitations in our existing knowledge, along with suggestions for future studies.

Combined multichannel intraluminal impedance-pH monitoring should be used to diagnose reflux-related otitis media with effusion in children

AIM

This study investigated the diagnostic usefulness of combined multichannel intraluminal impedance-pH monitoring (MII-pH) in children with suspected reflux-related otitis media with effusion (OME) as existing data were scarce.

METHODS

This was a prospective study that included children up to seven years of age who underwent MII-pH due to OME lasting more than three months. The study was conducted in the Children's Hospital Zagreb, Croatia, from January 2014 to August 2016.

RESULTS

The study comprised 63 children (63% male) with a mean age of 4.7 years. Gastroesophageal reflux (GER) disease was detected by impedance in 22 (35%) of the children and by pH-metry in nine (14%). In children with OME, MII-pH found a median number of 24 proximal GER episodes, of which a median of nine was acidic and a median of 11 was weakly acidic. There was a significant positive correlation between the number of GER episodes and the presence of eosinophils in nasal swabs.

CONCLUSION

Both acidic and weakly acidic refluxes seemed to play a significant role in the pathogenesis of OME. Localised nasal eosinophilia may serve as a marker of extraoesophageal reflux in children with suspected reflux-related OME.

Esophageal mucosal integrity improves after laparoscopic antireflux surgery in children with gastroesophageal reflux disease

Background

Esophageal intraluminal baseline impedance reflects the conductivity of the esophageal mucosa and may be an instrument for in vivo evaluation of mucosal integrity in children with gastroesophageal reflux disease (GERD). Laparoscopic antireflux surgery (LARS) is a well-established treatment option for children with proton pump inhibitory (PPI) therapy resistant GERD. The effect of LARS in children on baseline impedance has not been studied in detail. The aim of this study was to evaluate the effect of LARS on baseline impedance in children with GERD.

Methods

This is a prospective, multicenter, nationwide cohort study (Dutch national trial registry: NTR2934) including 25 patients [12 males, median age 6 (range 2–18) years] with PPI-resistant GERD scheduled to undergo LARS. Twenty-four hour multichannel intraluminal impedance pH monitoring (MII-pH monitoring) was performed before and 3 months after LARS. Baseline impedance was evaluated during consecutive 2-h intervals in the 24-h tracings.

Results

LARS reduced acid exposure time from 8.5 % (6.0–16.2 %) to 0.8 % (0.2–2.8 %), p < 0.001. Distal baseline impedance increased after LARS from 2445 Ω (1147–3277 Ω) to 3792 Ω (3087–4700 Ω), p < 0.001. Preoperative baseline impedance strongly correlated with acid exposure time (r −0.76, p < 0.001); however, no association between symptomatic outcome and baseline impedance was identified.

Conclusions

LARS significantly increased baseline impedance likely reflecting recovery of mucosal integrity. As the change in baseline impedance was not associated with the clinical outcome of LARS, other factors besides mucosal integrity may contribute to symptom perception in children with GERD.

Expanding Instrumental Options for Dysphagia Diagnosis and Research: Ultrasound and Manometry

Diagnostic assessment of swallowing in routine clinical practice relies heavily on the long-standing techniques of videofluoroscopic swallowing study (VFSS) and videoendoscopic evaluation of swallowing (VEES). These complementary and sophisticated techniques provide a real-time visualization of biomechanical movements of the structures involved in swallowing and consequent effects on bolus flow. Despite the sophistication of this instrumentation, interpretation relies heavily on subjective clinical judgement and temporal resolution is limited, limitations that may influence patient management. Adjunctive diagnostic assessments may be utilized to compensate for the limitations posed by VFSS and VEES. Ultrasound and pharyngeal manometry do not represent the latest in technological advances, with both emerging in swallowing research over 20 years ago. However, both have resisted integration into routine clinical practice, despite the fact that they offer quantitative metrics of swallowing that are not available using standard techniques. The aim of this review is to present recent research on these two less frequently used modalities in clinical swallowing assessment, discuss potential applications in clinical practice and review supportive data on test-retest reliability, rater reliability and validity. The paper will conclude with a case report that exemplifies the unique contribution of these modalities in executing and revising therapeutic approaches for a patient with neurogenic dysphagia.

Evaluation of gastroesophageal function and mechanisms underlying gastroesophageal reflux in infants and adults born with esophageal atresia

PURPOSE

To evaluate the mechanisms underlying gastroesophageal reflux (GER) following esophageal atresia (EA) repair and gastroesophageal function in infants and adults born with EA.

METHODS

Ten consecutive infants born with EA as well as 10 randomly selected adult EA patients were studied during their first postoperative follow-up visit and a purposely planned visit, respectively. A (13)C-octanoate breath test and esophageal pH-impedance-manometry study were performed. Mechanisms underlying GER and esophageal function were evaluated.

RESULTS

Transient lower esophageal sphincter relaxation (TLESR) was the most common mechanism underlying GER in infants and adults (66% and 62%, respectively). In 66% of all GER episodes, no clearing mechanism was initiated. On EFT, normal motility patterns were seen in six patients (four infants, two adults). One of these adults had normal motility overall (>80% of swallows). Most swallows (78.8%) were accompanied by abnormal motility patterns. Despite this observation, impedance showed normal bolus transit in 40.9% of swallows. Gastric emptying was delayed in 57.1% of infants and 22.2% of adults.

CONCLUSIONS

TLESR is the main mechanism underlying GER events in patients with EA. Most infants and adults have impaired motility, delayed bolus clearance, and delayed gastric emptying. However, normal motility patterns were seen in a minority of patients.

Mechanisms of gastric and supragastric belching: a study using concurrent high-resolution manometry and impedance monitoring

BACKGROUND

Esophageal impedance monitoring has made it possible to distinguish two types of belches, designated gastric and supragastric. We aimed to compare the esophageal pressure characteristics during supragastric belches and gastric belches using combined high-resolution manometry and impedance monitoring.

METHODS

We included 10 patients with severe and frequent belching. Combined high-resolution manometry and impedance monitoring was performed.

KEY RESULTS

Whereas gastric belching was relatively rare in all patients (median incidence 2 per 90-min period), nine of the 10 patients exhibited excessive supragastric belching (36 in 90 min). Supragastric belches were characterized by: (i) movement of the diaphragm in aboral direction and increased esophagogastric junction (EGJ) pressure, (ii) decrease in esophageal pressure, (iii) upper esophageal sphincter (UES) relaxation, (iv) antegrade airflow into the esophagus, and (v) increase in esophageal and gastric pressure leading to expulsion of air out of the esophagus in retrograde direction. In contrast, gastric belches were characterized by: (i) decreased or unchanged EGJ pressure, which was significantly lower than during supragastric belches, (ii) absence of decreased esophageal pressure preceding entrance of air into the esophagus (iii) retrograde airflow into the esophagus, (iv) common cavity phenomenon, and (v) upper esophageal sphincter relaxation after the onset of the retrograde airflow.

CONCLUSIONS & INFERENCES

In gastric belching UES relaxation is a late event, allowing efflux of air that entered the esophagus from the stomach. In most patients with supragastric belching air is brought into the esophagus by movement of the diaphragm in aboral direction, creation of negative esophageal pressure, and UES relaxation.

Inter- and intraobserver agreement in 24-hour combined multiple intraluminal impedance and pH measurement in children

OBJECTIVES

Assessment of intra- and interobserver agreement in multiple intraluminal impedance (MII) measurement between investigators from different institutions.

METHODS

Twenty-four 18- to 24-hour MII tracings were randomly chosen from 4 different institutions (6 per center). Software-aided automatic analysis was performed. Each result was validated by 2 independent investigators from the 4 different centers (4 investigator combinations). For intraobserver agreement, 6 measurements were analyzed twice by the same investigator. Agreement between investigators was calculated using the Cohen kappa coefficient.

RESULTS

Interobserver agreement: 13 measurements showed a perfect agreement (kappa > 0.8); 9 had a substantial (kappa 0.61-0.8), 1 a moderate (kappa coefficient 0.41 to 0.6), and 1 a fair agreement (kappa coefficient 0.11-0.4). Median kappa value was 0.83. Intraobserver agreement: 5 tracings showed perfect and 1 showed a substantial agreement. The median kappa value was 0.88.

CONCLUSIONS

Most measurements showed substantial to perfect intra- and interobserver agreement. Still, we found a few outliers presumably caused by poorer signal quality in some tracings rather than being observer dependent. An improvement of analysis results may be achieved by using a standard analysis protocol, a standardized method for judging tracing quality, better training options for method users, and more interaction between investigators from different institutions.

Small volumes of feed can trigger transient lower esophageal sphincter relaxation and gastroesophageal reflux in the right lateral position in infants

OBJECTIVE

To investigate the threshold amount of constantly infused feed needed to trigger lower esophageal sphincter relaxation (TLESR) in the right lateral position (RLP) and left lateral position (LLP).

STUDY DESIGN

Eight healthy infants (3 male; gestational age: 32.9 +/- 2.4 weeks; corrected age: 36.1 +/- 1.3 weeks) were studied using an esophageal impedance-manometry catheter incorporating an intragastric infusion port. After tube placement, infants were randomly positioned in RLP or LLP. They were then tube-fed their normal feed (62.5 [40 to 75] mL) at an infusion rate of 160 mL/h. Recordings were made during the feed and 15 minutes thereafter. The study was repeated with the infant in the opposite position.

RESULTS

More TLESRs were triggered in the RLP compared with LLP (4.0 [3.0 to 6.0] vs 2.5 [1.0 to 3.0], P = .027). First TLESR occurred at a significantly lower infused volume in RLP compared with LLP (10.6 +/- 9.4 vs 21.0 +/- 4.9 mL, P = .006). The percentage of feed infused at time of first TLESR was significantly lower in RLP compared with LLP (17.6% +/- 15.5% vs 35.4% +/- 8.02%, P = .005).

CONCLUSIONS

In the RLP, TLESRs and gastroesophageal reflux are triggered at volumes unlikely to induce gastric distension.