Fig. 3
Topographic distribution of lung units with different Ventilation-Perfusion (\({{\dot{V}} \mathord{\left/ {\vphantom {{\dot{V}} {\dot{Q}}}} \right. \kern-\nulldelimiterspace} {\dot{Q}}}\)) ratios in a representative study patient at PEEP 5 and 15 cmH2O. \({{\dot{V}} \mathord{\left/ {\vphantom {{\dot{V}} {\dot{Q}}}} \right. \kern-\nulldelimiterspace} {\dot{Q}}}\) ratio was calculated as the pixel-level ventilation divided by perfusion measured by electrical impedance tomography. \({{\dot{V}} \mathord{\left/ {\vphantom {{\dot{V}} {\dot{Q}}}} \right. \kern-\nulldelimiterspace} {\dot{Q}}}\) ratio ranges from < 0.1 (non-ventilated units, red) to 1 (normal units, white) to > 10 (non-perfused units, blue). The color scale is displayed on the right side of the figure. ND: non-dependent part of the lungs, M: middle part of the lungs, D: dependent part of the lungs