Fig. 2.

Schematic illustration of the effect of locally increasing external pressure on the monitored airway pressure waveform by ‘belly push’ or by sternal weighting during passive volume targeted ventilation with constant flow. When steady pressure is applied (downward block arrow) the plateau pressure falls from 40 to 28 cmH₂O. These changes are reversed when the external pressure is relieved (upward block arrow). Note that as indicated by the double arrows, the peak pressure may not change as much as the plateau pressure if airway resistance is increased by compression during loading