Figure 2

Examples of partial and full expiratory flow-volume curves before (a) and after (b) inhalation of methacholine in a young woman. Partial curves were performed from end-tidal inspiration; upon reaching residual volume level, subjects inspired to total lung capacity level and performed the full curve. In this example MEF₄₀ was greater than PEF₄₀ before methacholine inhalation, and the difference became much more after inhalation of 0.5 mg/ml of methacholine, indicating stronger bronchodilator effect of deep inspiration (DI) on methacholine-induced bronchoconstriction.