Efficacy of Dx-pH Probe in Diagnosing Extra-esophageal Reflux Disease (ADHERE)

The purpose of this study is to establish the clinical application of a new device that records pH changes in the hypopharynx. The investigators also aim to compare the consistency of distal esophageal pH with hypopharyngeal pH using both the "short" and the "long" catheters in patients.

Gastroesophageal reflux disease (GERD) has been linked to many disorders and can be diagnosed through a variety of modalities utilizing 24 hour ambulatory pH monitoring which can register the duration, pattern and symptom correlation of distal esophageal acid exposure. This can be accomplished via a catheter probe connected from outside the body and placed through a nostril, advanced past the hypopharynx and down into the distal esophagus. Or, a small pH detector temporarily implanted in the distal esophagus during endoscopy can record reflux events. However, despite available technologies, there has long been a deficiency in detecting extra-esophageal reflux in the upper esophagus/ hypopharynx. This is of interest for gastroenterologists, otolaryngologists, and pulmonologists in the evaluation of extra-esophageal reflux as a potential culprit for asthma, chronic cough, laryngitis, globus, and non-cardiac chest pain. Until now, there has not been a device sensitive enough for accurately detecting extra-esophageal reflux (EERD) and clinicians have relied upon subjective response to empiric treatment with acid reducing medications to determine whether acid reflux was at the root of the symptoms. There are currently no well designed published studies with this device to assess its role in this group of difficult to treat patients.

The three study groups underwent dual pH measurements of the oropharyngeal as well as esophageal acid exposure employing the regular length probe for the oropharynx and the custom-designed long probe for the distal esophagus. The reason for the custom-designed esophageal measurement was to ensure that events noted in the oropharynx originated distally and were of gastric source. Measurements for the two locations were time synchronized to ensure accuracy. Calculations were based on length of time spent in upright and supine positions, and a combination of the two positions.

The three study groups underwent dual pH measurements of the oropharyngeal as well as esophageal acid exposure employing the regular length probe for the oropharynx and the custom-designed long probe for the distal esophagus. The reason for the custom-designed esophageal measurement was to ensure that events noted in the oropharynx originated distally and were of gastric source. Measurements for the two locations were time synchronized to ensure accuracy. Calculations were based on length of time spent in upright and supine positions, and a combination of the two positions. Reflux event was calculated for a drop in pH from baseline to either <4, or <5, or <6 and each event had to last more than 5 seconds and could not be during the meals.

The three study groups underwent dual pH measurements of the oropharyngeal as well as esophageal acid exposure employing the regular length probe for the oropharynx and the custom-designed long probe for the distal esophagus. The reason for the custom-designed esophageal measurement was to ensure that events noted in the oropharynx originated distally and were of gastric source. Measurements for the two locations were time synchronized to ensure accuracy. Calculations were based on length of time spent in upright and supine positions, and a combination of the two positions. Reflux event was calculated for a drop in pH from baseline to either <4, or <5, or <6 and each event had to last more than 5 seconds and could not be during the meals.

Reflux event was calculated for a drop in pH from baseline to <6 and each event had to last more than 5 seconds and could not be during the meals.

Inclusion Criteria: Male and female volunteers aged 18 to 65 years old. Control group: No known history of GERD or EERD or prior PPI use. GERD group: Patients with known history of GERD based on prior response to either histamine inhibitors (H2 blockers) or proton pump inhibitors (PPIs) and/or endoscopic esophagitis identified at endoscopy. EERD group: Patients with chronic cough, asthma and laryngeal findings felt to be GERD related. Exclusion Criteria: Use of H2 blockers or PPIs within one week prior to and during the study for the GERD and EERD patients. No prior PPI use is allowed for the control population. Use of antacids (Rolaids, Tums, Pepto-Bismol, etc.) within one day prior to or during the study. Esophageal motility abnormalities (achalasia, esophageal spasm, severe dysphagia) Expected non-compliance. Positive history of ongoing alcohol or tobacco use and inability to refrain from using either during study duration (24 hours). Recent nasal surgery or nasal obstruction. Significant medical conditions that, in the investigator's judgment, would compromise the subject's health and safety (mental disability, psychiatric impairment, inability to read or comprehend the consent form) Pregnancy