Fig. 2
From: The clinical relevance of the emphysema-hyperinflated phenotype in COPD
Dynamic hyperinflation. This is a real-life example of a 51 years-old woman with severe COPD (FEV1/FVC ratio 0.50, FEV1 1.31 L, 47 % predicted) who performed inspiratory capacity maneuvers during incremental cardiopulmonary exercise testing of cycle ergometer. Forced expiratory flow is shown in full black line, and resting tidal volume in short-dashed line. At peak exercise, VT expansion is produced at the expense of inspiratory reserve volume (long-dashed line), EELV increases and inspiratory capacity decreases. The difference in EELV between resting and exercise represents dynamic hyperinflation (DH). TLC = total lung capacity. EELV = end-expiratory lung volume. FEV1 = forced expiratory volume in 1 s. FVC = forced vital capacity. VT = tidal volume. IC = inspiratory capacity. DH = dynamic hyperinflation