Diagnostic Value of the Maximal Expiratory Flow–Volume Curve for Central Airway Obstruction

This study showed that MEFV curves with expiratory phase plateau-like changes were not specific to patients with CAO; they could also be seen in patients without CAO, and they were highly indicative of CAO when combined with a significant decrease in PEF, FEF25, and their actual/predicted values. In subjects without CAO, the MEFV curve can form an expiratory phase plateau when the driving pressure is high enough and the equal pressure point and/or the choke point remains in the large airway.