Targeting the small airways with dry powder adenosine: a challenging concept

European Clinical Respiratory Journal

Martijn P. Farenhorst¹  Nick H. T. ten Hacken²  Maarten van den Berge²  Erica van der Wiel²  Dirkje S. Postma²  Paul Hagedoorn³  Anne H. de Boer³  Henderik W. Frijlink³  Anne J. Lexmond³ 

[1] University Medical Center Groningen;University of Groningen, University Medical Center Groningen;University of Groningen;

关键词: asthma;    bronchial hyperresponsiveness;    small airways;    bronchoprovocation test;    adenosine;   

DOI  :  10.1080/20018525.2017.1369328

来源: DOAJ

【 摘 要 】

Background: Small-particle inhaled corticosteroids (ICS) provide a higher small airway deposition than large-particle ICS. However, we are still not able to identify asthma patients who will profit most from small-particle treatment. Objective: We aimed to identify these patients by selectively challenging the small and large airways. We hypothesized that the airways could be challenged selectively using small- and large-particle adenosine, both inhaled at a high and a low flow rate. Design: In this cross-over study 11 asthma subjects performed four dry powder adenosine tests, with either small (MMAD 2.7 µm) or large (MMAD 6.0 µm) particles, inhaled once with a low flow rate (30 l min–1) and once with a high flow rate (60 l min–1). Spirometry and impulse oscillometry were performed after every bronchoprovocation step. We assumed that FEV1 reflects the large airways, and FEF25–75%, R5-R20 and X5 reflect the small airways. Results: The four adenosine tests were not significantly different with respect to the threshold values of FEV1 (p = 0.12), FEF25–75% (p = 0.37), R5-R20 (p = 0.60) or X5 (p = 0.46). Both small- and large-particle adenosine induced a response in the small airways in the majority of the tests. Conclusions: In contrast to our hypothesis, all four adenosine tests provoked a response in the small airways and we could not identify different large- or small-airway responders. Interestingly, even the test with large particles and a high flow rate induced a small-airway response, suggesting that selective challenging of the small airways is not necessary. Future studies should investigate the relation between particle deposition and the site of an airway response.

【 授权许可】

Unknown