Figure 4
From: Chest wall mechanics during pressure support ventilation
Pressure-volume dynamic relationship of the total and compartment chest wall. (a) Change in oesophageal pressure (ΔPes) versus chest wall volume changes (ΔVcw). (b) Upper panel: changes in oesophageal pressure (ΔPes) versus pulmonary rib cage volume changes (ΔVrc, p); averaged loops. Middle panel: changes in transdiaphragmatic pressure (ΔPdi) versus abdominal volume changes (ΔVab); averaged loops. Lower panel: changes in gastric pressure (ΔPga) versus abdominal volume changes (ΔVab); Each point represents the mean ± standard error of the mean (i.e. the average of all patients at the different times [see definition in Figure 1]): The loops refer to the different levels of pressure support: 5 cmH2O (solid thick line), 10 cmH2O (dased thick line), 15 cmH2O (solid thin line) and 25 cmH2O (dashed thin line). The arrows indicate the direction of the loops. The symbols in (b) are t0 (closed circles), t1 (open squares), t2 (open triangles) and t3 (open circles).