Concave Pattern of a Maximal Expiratory Flow-Volume Curve: A Sign of Airflow Limitation in Adult Bronchial Asthma
Figure 1
(a–c) Representative cases of various patterns of concave maximal expiratory flow-volume curves in the subjects analyzed in this study. Arrows indicate the concave region of the curve. (d) Calculation of angle β and shape factors (SF25% and SF50%) from standard spirometric parameters.