Capsaicin evoked cough responses
Participants inhaled four breaths of doubling concentrations of
capsaicin (0.97-1,000µM: Stockport Pharmaceuticals Ltd, Stockport, UK)
at 30 second intervals using a dosimeter (KoKo dosimeter; DeVilbiss
Healthcare Inc., Somerset, PA). Only the coughs evoked in the first 15
seconds post each inhalation were counted. The challenge continued until
the maximum tolerated dose or the final concentration was inhaled. The
maximum number of coughs evoked at any concentration (Emax) and the
concentration evoking 50% of the maximal response (ED50) were
calculated.