SELECTED ARTICLES FROM THE RECENT LITERATURE 2005
9/15/05
Mucociliary clearance in chronic asthma
Summary
Background – Chronic asthma is characterized by airway inflammation, mucus hypersecretion and impaired mucociliary clearance (MCC). Does inhaled beta agonist correct this impaired MCC?
Findings – Daviskas et al of the Royal Prince Alfred Hospital in Sydney, Australia evaluated the acute effects of inhaled terbutaline, a beta agonist, on MCC and spirometric measures in 16 asthmatics (mean age – 52 years) on long-term treatment with inhaled salmeterol (Sal) along with inhaled corticosteroids (ICS).
They found that MCC was impaired in such asthmatics (compared to age-matched normals) despite the long-term treatment with Sal/ICS. Three inhalations of terbutaline (1 mg each) over an 80 minutes period led to a modest increase in MCC in some asthmatics who tended to have higher baseline FEV-1 and FEF (25-75%) than did asthmatics without a terbutaline-induced increase in MCC.
Reference
Respirology 2005;10:426-35
Editor's Comments
It has been postulated that continued anti-inflammatory therapy with ICS would reduce the airway inflammation and associated abnormalities such as decreased MCC in chronic asthma. However, in this relatively small study, the MCC was significantly decreased despite such ICS therapy. Although inhalation of terbutaline, a beta agonist, caused the expected bronchodilatation, there was little, if any, improvement in the previously abnormal MCC. Perhaps the older age of this asthmatic population (mean age - 52 years) indicated long-standing chronic asthma in which significant irreversible airway abnormalities had occurred.
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