Cough Reflex Sensitivity and Bronchial Hyper-responsiveness

Mayo Clinic24 enrolled

Overview

The aim of this study is to provide pilot data on the possible gastrointestinal predictors of respiratory hyper-responsiveness and how these relate to the clinical sub-types of gastroesophageal reflux disease (GERD) and visceral acid hypersensitivity.

This study recruited participants into three groups: reflux patients with non-erosive disease (NERD) with abnormal levels of acid reflux, NERD patients with normal levels of reflux and healthy volunteers. Participants were assessed for cough reflex sensitivity (CRS) to citric acid and bronchial-hyperresponsiveness (BHR) to methacholine challenge, both before (baseline) and after esophageal acid infusion (HCl, 0.15M) or normal saline control (8ml/min). The order of CRS and BHR was randomized, as was the order of the acid/saline infusions.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Gastroesophageal Reflux Disease Chronic Cough Broncho-hyperreactivity

Interventions

Cough Reflex SensitivityPROCEDURE

Subjects inhaled increasing concentrations of citric acid, which induces coughing in a dose-dependent, reproducible matter. Following each inhalation, the number of coughs in the subsequent 15 seconds was counted and recorded. The challenge was terminated once the citric acid induced 5 or more coughs and the logarithmic (base 10) concentration provoking 5 coughs was recorded.

Methacholine ChallengePROCEDURE

A baseline spirometry was used to assess how well the participant's lungs work by measuring how much air was inhale, how much was exhale and how quickly the participant exhaled. If this was normal, the subject inhaled slowly and deeply the methacholine test solution from a nebulizer and was told to hold their breath for 5 seconds. This was repeated until 5 inhalations were performed in no more than two minutes.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * symptomatic reflux (i.e., one symptom at least one day a week, with at least 'moderate' severity) * no evidence of esophagitis * non-smokers Exclusion Criteria: * previous gastrointestinal surgery (excluding minor surgeries, such as cholecystectomy, appendectomy * active peptic ulcer disease * Zollinger Ellison Syndrome * Barrett's esophagus * eosinophilic esophagitis * cardiac disease * diabetes or neurological deficit * use of tricyclics * selective serotonin reuptake inhibitors * narcotics or benzodiazepines * current use of medications that may affect symptoms of perception,lower esophageal sphincter basal pressure, acid clearance time or acid suppression * antibiotics within 60 days * Nursing mothers will be excluded * allergies to citrus * asthma * chronic lung disease * heart attack or stroke within the last three months * hypersensitivity to methacholine products * know aortic aneurysm * uncontrolled hypertension (defined as systolic pressure greater than 200 or diastolic greater than 100) * reduced pulmonary function test (forced expiratory volume in one second (FEV1) or the FEV1 to forced vital capacity (FVC) ratio (FEV1/FVC) of less that 70% of predicted value) * None of the controls will have any GERD symptoms or ever used antireflux treatment.

Locations (1)

Mayo Clinic Florida

Jacksonville, Florida, United States

Outcomes

Primary Outcomes

Change in cough reflex sensitivity (CRS)

Time frame: baseline, approximately 4 weeks

Data from ClinicalTrials.gov

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