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Asthma | Bronchodilating and Bronchoprotective Effects of Deep Inspirations

Asthma research study

What is the primary objective of this study?

The objectives of this research are to compare (i) the bronchodilating and (ii) the bronchoprotective effects of deep inspirations (DIs) in individuals with: (a) asthma, (b) CVA, (c) methacholine-induced cough but normal airway sensitivity and . (d) in healthy individuals (without asthma, chronic cough or asymptomatic airway hyperresponsiveness). Hypotheses: i. The bronchodilating effect of a DI will be: (a) absent or impaired in individuals with classic asthma; (b) impaired in individuals with CVA; (c) preserved in individuals with methacholine-induced cough but normal airway sensitivity; and (d) preserved in healthy individuals (without asthma, chronic cough or asymptomatic airway hyperresponsiveness). ii. The bronchoprotective effect of a DI will be: (a) absent in individuals with classic asthma; (b) impaired in individuals with CVA; (c) preserved in those with methacholine-induced cough but normal airway sensitivity; and (d) preserved in healthy individuals (without asthma, chronic cough or asymptomatic airway hyperresponsiveness). iii. Healthy individuals without asthma, chronic cough, or asymptomatic airway hyperresponsiveness, will not cough, or develop significant dyspnea, small airways obstruction or dynamic hyperinflation during high-dose methacholine bronchoprovocation.

Who is eligible to participate?

Inclusion Criteria: - Individuals aged 18-65 years of age with asthma, CVA and individuals with methacholine-induced cough but normal airway sensitivity. The following definitions will be used: 1. asthma: episodic respiratory symptoms occurring in association with variable airflow obstruction (Canadian Asthma Consensus Report definition); 2. 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); 3. 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 1. Severe airflow limitation (FEV1 <50% predicted or <1.0 L); 2. Heart attack or stroke in last 3 months; 3. Uncontrolled hypertension, systolic BP > 200 or diastolic BP > 100; 4. Known aortic aneurysm; 5. Moderate airflow limitation <60% predicted or 1.5) is a relative contraindication; 6. Inability to perform acceptable quality spirometry; 7. Current use of cholinesterase inhibitor medication (for myasthenia gravis); and 8. Pregnant or nursing mothers. - 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.

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?

Asthma

Cough

Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.

Other:Methacholine(MCh) Challenge TestingVisit 1: High-dose methacholine challenge test Visit 2 or 3: Will be conducted in random order and subjects will perform one of two modified single-dose methacholine challenge tests at either visit. During these modified challenges, subjects will (a) perform five DIs from functional residual capacity (FRC) to total lung capacity (TLC) back to FRC, or (b) refrain from taking DIs prior to inhaling the previously measured single PC20 dose of methacholine.

Other:Methacholine(MCh) Challenge TestingVisit 1: Baseline tests, and subjects will be randomized to complete either a high-dose methacholine using maximal expiratory flow-volume loop (MEFV), or a high-dose methacholine challenge with impulse oscillometry (IOS) and partial expiratory flow-volume loop (PEFV) and MEFV at each dose step. Visit 2: Subjects will perform the opposite protocol, based on their first visit:

Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

AsthmaIndividuals diagnosed with asthma.

Cough Variant AsthmaIndividuals diagnosed with cough variant asthma.

Mch-induced cough w/normal airway sensitivity

NormalIndividuals with no history of asthma or chronic cough

Study Status

Completed

Start Date: October 2012

Completed Date: August 2017

Phase: N/A

Type: Interventional

Design:

Primary Outcome: Mid expiratory flows

Secondary Outcome: percent fall in FEV1

Study sponsors, principal investigator, and references

Principal Investigator: M. Diane Lougheed, MD MSc

Lead Sponsor: Queen's University

Collaborator:

More information:https://clinicaltrials.gov/show/NCT01659476

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