Fig. 2
Impedance waveform, tidal images (TID), center of ventilation (COV), change of end-expiratory lung impedance against reference (dEELI), and global inhomogeneity index (GI) before, during, and after prone positioning. In TID, the white area indicates being maximally ventilated. In dEELI, orange or blue color indicates the decrease or increase of impedance value compared to the reference (supine, plateau pressure of 21 cmH2O), respectively. Ventral shift of ventilation was unexpectedly observed during prone positioning