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

NCT ID: NCT00404677

Last Updated: 2008-01-23

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 18 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2006-06-30
• Study Completion Date: 2007-02-28

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.

Conditions

Asthma

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

Standard

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

Group Type: PLACEBO_COMPARATOR

deep inhalation

Intervention Type: OTHER

deep inhalation is comprised of an inhalation manoeuver from FRC to TLC

Modified

Five deep inhalation maneouvers are incorporated into the standardized methacholine challenge

Group Type: ACTIVE_COMPARATOR

deep inhalation

Intervention Type: OTHER

deep inhalation is comprised of an inhalation manoeuver from FRC to TLC

Interventions

deep inhalation

deep inhalation is comprised of an inhalation manoeuver from FRC to TLC

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• diagnosis of asthma

Exclusion Criteria

• other lung disease(s)
• smoking

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Saskatchewan

OTHER

Sponsor Role: lead

Responsible Party

University of Saskatchewan

Principal Investigators

Donald Cockcroft, MD, FRCP(C)

Role: PRINCIPAL_INVESTIGATOR

Department of Medicine, Division of Respirology, Critical Care and Sleep Medicine, University of Saskatchewan

Other Identifiers

BIO-REB 06-92

Identifier Type: -

Identifier Source: secondary_id

BIO-REB 06-92

Identifier Type: -

Identifier Source: org_study_id