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 (SF_25% and SF_50%) from standard spirometric parameters.

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