Sensory-Mechanical Responses to Eucapneic Voluntary Hyperventilation and Mannitol
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Methacholine (MCh) Challenge Testing, Eucapneic Voluntary Hyperventilation (EVH), Mannitol Inhalation Kit.
- Who it may be relevant to
- Registry conditions: Asthma, Cough, Cough Variant Asthma. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Canada
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Sensory-Mechanical Responses to Eucapneic Voluntary Hyperventilation and Mannitol in Individuals With Cough Variant Asthma and Chronic Cough
Overview
The objectives of this study are to determine the sensory-mechanical responses to Eucapneic Voluntary Hyperventilation (EVH) and Mannitol in individuals with cough variant asthma (CVA) and methacholine-induced cough with normal airway sensitivity (COUGH) and compare these responses to a control group of healthy individuals without asthma or chronic cough. We hypothesize: 1. EVH and Mannitol cause dyspnea, cough, small airway obstruction with resultant dynamic hyperinflation, gas trapping and autoPEEP in individuals with CVA and COUGH, but not healthy controls. 2. The sensory-mechanical responses to both hyperosmolar challenges (EVH and Mannitol) are comparable within groups (CVA, COUGH and healthy controls).
Detailed description
Asthma is a chronic respiratory condition characterized by eosinophilic airway inflammation. Individuals with classic asthma experience paroxysmal symptoms including cough, wheeze, shortness of breath and chest tightness. Cough variant asthma (CVA) is asthma in which chronic cough (cough lasting eight weeks or more) is the sole or predominant symptom of asthma. The pathophysiologic mechanisms which differentiate asthma, CVA, and eosinophilic bronchitis without asthma are not fully understood. We have recently identified individuals with chronic cough who cough during methacholine but have normal airway sensitivity (ie. do not have asthma or CVA) (COUGH) and may or may not have eosinophilic bronchitis. The purpose of this research is to further explore the pathophysiologic basis for cough in these conditions using two 'indirect' inhalation challenge tests: eucapneic voluntary hyperventilation (EVH) and Mannitol), which induce osmotic and/or temperature changes in airway. Specifically, this study will collect preliminary data on the sensory-mechanical responses of individuals with CVA, COUGH and healthy controls to EVH and Mannitol Challenges.
Interventions
- Drug Methacholine (MCh) Challenge Testing
Visit 1: Informed consent, Baseline screening and pulmonary function tests and Low-dose methacholine challenge testing using partial and full flow-volume loops. - Diagnostic test Eucapneic Voluntary Hyperventilation (EVH)
Visit 2 or 3: Will be conducted in random order and subjects will perform one of the two challenge tests at either visit. - Drug Mannitol Inhalation Kit
Visit 2 or 3: Will be conducted in random order and subjects will perform one of the two challenge tests at either visit.
Primary outcome measures
- Mid expiratory flows [Time frame: Time frame of the methacholine challenge varies between individuals. At provocative dose/ventilation causing a 20% decline in FEV1 (PD20 and PC20 respectively). On average, these occur about 15-25 minutes into the challenge test]
Secondary outcome measures (5)
- Respiratory System Reactance (X5) [Time frame: After dose administration; will occur 2-5 minutes after dose]
- Peripheral Resistance (R5-R20) [Time frame: After dose administration; will occur 2-5 minutes after dose]
- Central Airway Resistance [Time frame: After dose administration; will occur 2-5 minutes after dose]
- Forced Vital Capacity (FVC) [Time frame: After dose administration; will occur 2-5 minutes after dose]
- FEV1/FVC [Time frame: After dose administration; will occur 2-5 minutes after dose]
Eligibility criteria
Inclusion criteria
- Individuals aged 18-65 years of age with CVA and individuals with methacholine-induced cough but normal airway sensitivity. The following definitions will be used:
- CVA: chronic cough (≥8 weeks) is the sole or predominant symptom and positive methacholine challenge (PC20 ≤ 16 mg/mL) and history of cough responding to specific asthma treatment (such as inhaled steroid or 1 week trial of bronchodilator);
- Methacholine-induced cough but normal airway sensitivity: chronic cough (≥8 weeks) is the sole or predominant symptom and negative methacholine challenges (PC20 > 16 mg/mL).
- Individuals aged 18-65 years of age with no history of asthma or chronic cough.
Exclusion criteria
- an exacerbation necessitating a change in medication, emergency department visit or hospitalizations within the previous 4 weeks
- inability to perform acceptable spirometry
- medical contraindications to methacholine challenge testing
- smoking history in excess of 10 pack years Note: Previous treatment with inhaled or systemic corticosteroids is not an exclusion criterion; medication use will be recorded and examined in the analysis.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Randomized
- Model
- Crossover
- Masking
- Open label
- Primary purpose
- Basic science
Study locations
Canada · 1 center
- Kingston Health Sciences Centre — Kingston
Identifiers
NCT: NCT03105843 · 2023-17