Excessive dynamic airway collapse: A condition behind the veil

Figure 2 Schematic representation of expiratory flow limitation based on equal pressure point and wave speed theories, with dynamic airway collapse during normal expiration and with excessive dynamic airway collapse secondary to various causes. A: Dynamic airway collapses during normal expiration; B: Excessive dynamic airway collapses secondary to various causes. COPD: Chronic obstructive pulmonary disease; DAC: Dynamic airway collapse; EDAC: Excessive dynamic airway collapse; EPP: Equal pressure point; GERD: Gastroesophageal reflux disease; Palv: Alveolar pressure (Palv = Ppl + Pel); Patm: Atmospheric pressure; Pel: Total elastic recoil pressure; Pl: Intraluminal pressure; Ppl: Pleural pressure.