Airway resistance at maximum inhalation as a marker of asthma and airway hyperresponsiveness.

Background: Asthmatics exhibit reduced airway dilation at maximal inspiration, likely due to structural differences in airway walls and/or functional differences in airway smooth muscle, factors that may also increase airway responsiveness to bronchoconstricting stimuli. The goal of this study was to test the hypothesis that the minimal airway resistance achievable during a maximal inspiration (R(min)) is abnormally elevated in subjects with airway hyperresponsiveness.

Methods: The R(min) was measured in 34 nonasthmatic and 35 asthmatic subjects using forced oscillations at 8 Hz.