Figure 3.

Graphical representation of ΔPl and ΔPes waveform swings after 2 hours of NIV for (A and C) a patient who had failure in the noninvasive mechanical ventilation trial at 24 hours and for (B and D) a patient who had success. The beginning of the inspiratory phase was identified at the time of Pes initial decay, whereas the end of inspiration was considered at the point of Pes that elapsed 25% of time from its maximum deflection to return to baseline. ΔPes = tidal change in esophageal pressure; ΔPl = tidal change in dynamic transpulmonary pressure.