Category Ranking
98%
Total Visits
921
Avg Visit Duration
2 minutes
Citations
20
Article Abstract
Background: One of the characteristic features of the hyperresponsive airway smooth muscle in asthma is the loss of deep-inhalation bronchoprotection and bronchodilation. The airway of individuals with asthma is also characterized by inflammation.
Objective: To evaluate whether the loss of deep-inhalation bronchoprotection is correlated with the degree of inflammation in the asthmatic airway.
Methods: Eighteen study participants performed 2 methacholine challenges (identical doses), 1 with deep inhalations and 1 without, separated by at least 24 hours. Airway inflammation was evaluated by measurement of fraction of exhaled nitric oxide (FE(NO)) and induced sputum eosinophils.
Results: A significant negative correlation was found between the degree of deep-inhalation bronchoprotection and airway inflammation when measured by FE(NO) (P = .02, r = .54, n = 18) and by percentage of eosinophils (P = .002, r = .76, n = 12). A significant positive correlation was also found between the FE(NO) and percentage of eosinophils (P = .009, r = .68, n = 12).
Conclusions: Deep-inhalation bronchoprotection was significantly impaired in individuals with greater airway inflammation. This finding suggests that therapy directed at decreasing airway inflammation may promote the recovery of normal deep-inhalation bronchoprotection.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/S1081-1206(10)60319-5 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Methacholine challenges: comparison of different tidal breathing challenge methods.
ERJ Open Res
October 2021
Medicines Evaluation Unit, Manchester, UK.
Tidal-breathing methacholine challenges are now recommended by guidelines, to avoid the bronchoprotective effects of deep inhalation. This study compared different tidal breathing methacholine challenge methods; assessed the agreement between tidal dosimetric and continuous output challenges; and assessed challenge repeatability with different methods. 15 asthma patients performed dosimetric challenges and a continuous-output breath-actuated challenge, all ≥3 days apart.
View Article and Find Full Text PDFComparison of methacholine and mannitol challenges: importance of method of methacholine inhalation.
Allergy Asthma Clin Immunol
February 2020
1Department of Medicine, University of Saskatchewan, Saskatoon, SK Canada.
Background: Direct inhalation challenges (e.g. methacholine) are stated to be more sensitive and less specific for a diagnosis of asthma than are indirect challenges (e.
View Article and Find Full Text PDFThe effect of deep inhalation on mannitol responsiveness.
Clin Exp Allergy
March 2020
Division of Respirology, Critical Care and Sleep Medicine, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Background: Mannitol inhalation testing is specific for asthmatics with eosinophilic airway inflammation, a factor that has been negatively correlated with the development of deep inhalation bronchoprotection.
Objective: To evaluate the effect of deep inhalations on responsiveness to inhaled mannitol in correlation with the degree of airway inflammation.
Methods: Twenty participants with stable asthma completed this randomized, crossover study.
Direct bronchoprovocation test methods: history 1945-2018.
Expert Rev Respir Med
March 2019
a Division of Respirology, Critical Care and Sleep Medicine, Department of Medicine , University of Saskatchewan.
Introduction: Bronchoprovocation inhalation challenge tests with direct acting stimuli (e.g. methacholine) are widely used clinically to aid in the diagnosis of asthma.
View Article and Find Full Text PDFLow levels of fractional exhaled nitric oxide and deep inhalation bronchoprotection are associated with mannitol non-responsiveness in asthma.
Respir Med
June 2014
University of Saskatchewan, Department of Medicine, Division of Respirology, Critical Care and Sleep Medicine, Saskatoon, Saskatchewan, Canada.
Background: Airway hyperresponsiveness (AHR) to indirect agents like mannitol is thought to be dependent on concurrent airway inflammation as these stimuli exert their effects via the release of bronchoconstricting mediators from inflammatory cells. Airway inflammation correlates negatively with deep inhalation bronchoprotection against direct stimuli like methacholine. We hypothesised that deep inhalation bronchoprotection to methacholine would be absent and airway inflammation would be present in individuals with AHR to inhaled mannitol.
View Article and Find Full Text PDF