Fig. 2.

Linear regression between the changes in airway pressure (x axis) (absolute terms) and esophageal pressure (y axis); a Baydur occlusion test, y = 0.096 + (0.993 × x), r = 0.984; b positive pressure occlusion test, y = 0.818 + (0.982 × x), r = 0.909. In each graph, continuous line represents the regression line, dashed lines represent 95 % CI bounds, and dotted lines represent 95 % prediction interval bounds. Empty dots represent each single ∆Pes/∆Paw ratio obtained in all enrolled patients