Respirology : official journal of the Asian Pacific Society of Respirology
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It is difficult for clinicians to identify changes in breath sounds caused by bronchoconstriction when wheezing is not audible. A breath sound analyser can identify changes in the frequency of breath sounds caused by bronchoconstriction. The present study aimed to identify the changes in the frequency of breath sounds during bronchoconstriction and bronchodilatation using a breath sound analyser. ⋯ Methacholine-induced bronchoconstriction significantly increased HFI, and the increase in HFI was correlated with bronchial reactivity.
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Eosinophilic bronchitis (EB) shares many pathological features with asthma. However, patients with EB do not develop the characteristic physiological abnormalities of asthma: variable airflow obstruction and bronchial hyperresponsiveness (BHR) to a direct bronchial challenge with methacholine. Indirect bronchial challenges with AMP and mannitol are dependent on the presence of airway inflammation, and positive in 10% of asthmatic subjects who have a negative response to methacholine. We have therefore investigated whether subjects with EB are responsive to indirect airway challenge with AMP and mannitol. ⋯ The airways of patients with EB are not responsive to either direct or indirect bronchial challenge. This supports the view that it is the presence of functionally abnormal airway smooth muscle that is the key determinant of BHR in asthma, and that while this may be aggravated by the presence of mucosal airway inflammation, it is not caused by it.