Comparison of Methacholine Bronchial Provocation With Wright and Devilbiss646 Nebulizers

Study Overview
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Brief Summary
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The purpose of this study is to compare the diagnostic validity (sensitivity and specificity) and evaluate the safety of 2-min Tidal Breathing methacholine bronchial provocation tests with the Wright and Devilbiss646 nebulizers in asthmatic in Guangzhou.

Detailed Description
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After screening,each asthmatic patient will visit the investigators' center 4 times. During the first week, the patient will be randomised to undergo methacholine bronchial challenge with Wright or Devilbiss 646 nebulizer on two separate days, which are at least 24 hours but not more than 7 days apart.The above procedure will be repeated for each patient in one month. But the nebulizer will be selected in a reverse order.Provocative concentration induced a 20% decrease in forced expiratory volume in one second (PC20) will be calculated for each test. Record all the adverse events during the tests.

Official Title
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Comparison of 2-min Tidal Breathing Methacholine Bronchial Provocation With Wright and Devilbiss646 Nebulizers

Conditions
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Asthma

Intervention / Treatment
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* Other: methacholine
* Device: Wright Nebulizer
* Device: Devilbiss646 Nebulizer


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: clinical diagnosis of asthma; stable for more than 4 weeks with FEV1≥65%pred Exclusion Criteria: exacerbation within 3 months; upper airway infections within 4 weeks; concomitant of hypertension or heart diseases; pregnancy; under immunotherapy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: asthma<br>methacholine(0.031-16mg/ml) bronchial provocation tests. this is a crossover,normal-control study. nebulized with Wright nebulizer for 2 minutes with an output of 0.13ml/min. | Other: methacholine<br>* methacholine (0.03,0.06,0.125,0.5,1.0,2.0,4.0,8.0,16.0 mg/ml),Canada<br>Device: Wright Nebulizer<br>* nebulized for 2 minutes with an output of 0.13ml/min<br>Device: Devilbiss646 Nebulizer<br>* nebulized for 2 minutes with an output of 0.13ml/min<br>|
| Experimental: normal controls<br>methacholine(0.031-16mg/ml) bronchial provocation tests. this is a crossover,normal-control study. nebulized with Devilbiss646 nebulizer for 2 minutes with an output of 0.13ml/min | Other: methacholine<br>* methacholine (0.03,0.06,0.125,0.5,1.0,2.0,4.0,8.0,16.0 mg/ml),Canada<br>Device: Wright Nebulizer<br>* nebulized for 2 minutes with an output of 0.13ml/min<br>Device: Devilbiss646 Nebulizer<br>* nebulized for 2 minutes with an output of 0.13ml/min<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| percentage of the participants that tested positive to methacholine bronchial provocation with Wright or Devilbiss646 nebulizer |  | 5 minutes after each challenge | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence and severity of Adverse Events during the methacholine bronchial provocation tests with Wright nebulizer and Devilbiss646 nebulizer |  | during and until 5 minutes after each challenge |