Fig. 1

Ventilation and perfusion measured by EIT in a representative patient. A Electrical impedance tomography signals during the infusion of saline bolus. The white arrow indicates the duration of the end-inspiratory hold during which the saline bolus is administered. Note that changes in impedance due to tidal ventilation are interrupted; the drop in impedance due to the bolus pass is indicated by the red arrow. b Representative image of the perfusion (red-colour map) and ventilation (blue-colour map) distribution. Note the gray circle indicating the cardiac region that has been removed from the analysis. c Top: representative map with the percentage perfusion (red numbers) and ventilation (blue numbers) in the three lung regions. Bottom: representative map obtained by integrating ventilation and perfusion maps: the grey area indicates matched units which are both ventilated and perfused, while red area indicated only perfused units and blue area only ventilated units