Expiratory flow-limitation in mechanically ventilated patients: A risk for ventilator-induced lung injury?

Figure 1 Flow-volume loops of negative expiratory pressure test breath and preceding control breath for two representative acute respiratory distress syndrome patients, one with expiratory flow limitation exceeding 35% of control tidal volume (left side) and the other without expiratory flow limitation (right side). Thin lines: Control breath; heavy lines: Negative expiratory pressure. In the expiratory flow limitation (EFL) patient, onset of EFL is heralded by an inflection point on the expiratory flow-volume curve (arrow). Reproduced with permission of the American Thoracic Society[34]. ZEEP: Zero end-expiratory pressure; PEEP: Positive end-expiratory pressure; V_T: Tidal volume.