Comparison of Two Methods of Bronchial Methacholine Provocation

Study Overview
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Brief Summary
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This study is meant to compare two routine diagnostic approaches in patients with bronchial asthma. Patients are challenged with methacholine in order to measure their bronchial response. We compare the evaluation of the effects of incremental concentrations versus incremental dosages.

Detailed Description
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Bronchial methacholine challenge is well established in asthma diagnostic and research purposes. ATS guidelines provide a short five-breath dosimeter protocol using a five-step dilution schedule. The Viasys APS system enables a feasible and less time consuming provocation with incremental dosages. In 48 young adults with bronchial hyperreactivity (BHR) the ATS-protocol with a five-step protocol using a single dilution of 16 mg/ml methacholine should be compared.

Official Title
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Comparison of Two Methods of Bronchial Methacholine Provocation: PC 20 FEV1 Versus PD 20 FEV1

Conditions
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Bronchial Hyperreactivity, Bronchial Asthma

Intervention / Treatment
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* Procedure: Bronchial methacholine provocation
* Procedure: Bronchial methacholine provocation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Informed consent Age 12-45 years Known bronchial hyperreactivity Exclusion Criteria: Age < 12 > 45 years Clinical asthma requiring regular inhalation Vital capacity < 80% FEV1 < 75% Chronic disease conditions or infections Pregnancy Inhalative or systemic steroid use Substance abuse Incapability of understanding the study's purpose and performance

Ages Eligible for Study
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Minimum Age: 12 Years
Maximum Age: 45 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: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: A<br>Methacholine challenge, five-breath dosimeter protocol | Procedure: Bronchial methacholine provocation<br>* A short five-breath dosimeter protocol using a five-step dilution schedule according to ATS guidelines (0.0625, 0.25, 1, 4, 16 mg/ml methacholine)<br>* Other names: DeVilbiss nebulizer;|
| Active Comparator: B<br>Methacholine challenge five incremental dosages protocol | Procedure: Bronchial methacholine provocation<br>* A five-step protocol using a single dilution of 16 mg/ml methacholine (0.01, 0.1, 0.4, 0.8, 1.6 mg)<br>* Other names: Viasys APS nebulizer;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| correlation of the two parameters PC20 FEV1 and PD20 FEV1 |  | feb 2007 - dec 2007 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| kappa index of concordance: reliability of the two procedures as to a FEV1 decrease of 20% depending on methacholine concentration |  | see above | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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PC20 FEV1, PD20FEV1, bronchial hyperreactivity, bronchial asthma