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

University of Saskatchewan

Status: Completed

Conditions: Asthma

Treatments: Other: deep inhalation

Study type: Interventional

Funder types: Other

Identifiers

NCT00404677

BIO-REB 06-92

Details and patient eligibility

About

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.

Enrollment: 18 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• diagnosis of asthma

Exclusion criteria

• other lung disease(s)
• smoking

Trial design

Primary purpose: Diagnostic

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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18 participants in 2 patient groups, including a placebo group

Standard

Placebo Comparator group

Description:

Methacholine challenges are performed using the standardized two minute tidal breathing method

Treatment:

Other: deep inhalation

Modified

Active Comparator group

Description:

Five deep inhalation maneouvers are incorporated into the standardized methacholine challenge

Treatment:

Other: deep inhalation