Figure 26-13 Partial expiratory flow-volume curves before (A) and after (B) bronchodilator treatment. Forced expiration is begun just above midpoint of vital capacity (VC). Flows are quantitated at 20% and 40% of VC above residual volume (RV). A reference maximum expiratory curve (C) is also inscribed by beginning exhalation from total lung capacity (TLC).


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