To the Editor:
The European Community Respiratory Health Survey (ECRHS) II is a multicentre study that includes assessment of bronchial responsiveness using the MefarTM dosimeter (MefarTM, Brescia, Italy). Ward et al. 1 report that in some centres taking part in ECRHS II, there is potential for systematic variation in MefarTM dosimeter driving pressure, which constitutes possible …