Determining the Optimal Adenosine Provocation Test

Asthma is a frequently occurring inflammatory lung disease that affects the whole bronchial tree including the small airways (\<2mm). Since the introduction of the solution hydrofluoroalkane (HFA) technology it is possible to generate medication with small particles of approximately 1-2 μm, and therefore to reach the small airways. However, at this moment the investigators have no reliable instruments to identify the asthmatic subjects who particularly benefit from treatment with inhaled small particles. Recently the investigators research group investigated whether provocation with small and large particles AMP is able to identify responders and non-responders to treatment with small and large particles of inhaled corticosteroids. This provocation technique gave promising results but needs further optimization. The aim of this study is to determine the optimal particle size of dry powder adenosine to assess small airway involvement in asthma. Secondary, to provide insight in the associations between the standard test, executed with nebulized AMP, and the new test, executed with dry powder Adenosine.