The Correlation Between Airway Inflammation and Loss of Deep Inhalation Bronchoprotection in Asthmatics

Not Applicable

Completed

• Conditions: Asthma
• Interventions: Other: deep inhalation

• Registration Number: NCT00404677
• Lead Sponsor: University of Saskatchewan

Brief Summary

The loss of deep inhalation bronchoprotection in asthmatic individuals has been shown to be related to the degree of airway hyperresponsiveness, a hallmark of asthma. In several studies, asthmatic individuals with mild airway hyperresponsiveness (AHR) (methacholine PC20 \> 2 mg/mL) had a difference in methacholine PC20 with and without deep inhalations that averaged 1.8 doubling methacholine concentrations (p=0.0003). Conversely, asthmatic individuals with moderate to severe AHR (methacholine PC20 ≤ 2 mg/mL) had a non-significant difference in methacholine PC20 with and without deep inhalations (p=0.09). This loss of deep inhalation bronchoprotection is also now believed to play an important role in the pathogenesis of asthma. Airway inflammation is another of the key features of asthma and information on airway inflammation is increasingly being used in the diagnosis and treatment of asthma. The level of airway inflammation (as measured by fraction of exhaled nitric oxide and sputum eosinophilia) has also been shown to be correlated to the level of airway hyperresponsiveness (as measured by methacholine PC20). In addition, glucocorticoids have been shown to decrease airway hyperresponsiveness, further suggesting that these two phenomena, airway inflammation and airway hyperresponsiveness, are related. We therefore suggest that the degree of airway inflammation is related to the loss of deep inhalation bronchoprotection and expect there to be a negative correlation between the degree of deep inhalation bronchoprotection and airway inflammation.

Detailed Description

Not available

Study Timeline

• Study Start: 2006-06
• Study First Submitted: 2006-11-27
• Study First Submitted QC: 2006-11-27
• Study First Posted: 2006-11-29
• Primary Completion: 2007-02
• Study Completion: 2007-02
• Status Verified: 2008-01
• Last Update Submitted: 2008-01-18
• Last Update Posted: 2008-01-23

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 18

Inclusion Criteria

• diagnosis of asthma

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Exclusion Criteria

• other lung disease(s)
• smoking

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Standard	deep inhalation	Methacholine challenges are performed using the standardized two minute tidal breathing method
Modified	deep inhalation	Five deep inhalation maneouvers are incorporated into the standardized methacholine challenge

Primary Outcome Measures

Name	Time	Method
fraction of exhaled nitric oxide, sputum eosinophils and methacholine PC20	freaction of exhaled nitric oxide data collected prior to methacholine challenges; sputum collected after the first methacholine challenge