J. Hansen describes an interesting method for assessing small airways dysfunction, namely via the bronchodilator effects on forced expiratory volume in three seconds (FEV3) and FEV6, as compared with the effects on FEV1. As they are derived from flow–volume manoeuvres, these parameters are indeed simple to obtain, low-cost, show acceptable repeatability 1, 2 and may reflect relevant changes in small airways obstruction. We therefore retrospectively analysed the FEV3 and FEV6 values and compared …