Fig. 3
Functional impedance images (f-EIT) of two respective exemplary patients. According to the study protocol, volume-controlled ventilation was started with a PEEP of 5 cmH2O. In the exemplary patient in the intervention group (a-c), the PEEP was then increased to 7 cmH2O as the intratidal compliance profile analysis indicated a merely increasing compliance profile. In the patient in the control group (d-f), the PEEP was maintained at 5 cmH2O. f-EIT images were generated by subtracting the frames corresponding to the start of inspiration from the frames corresponding to the end of inspiration. a f-EIT image of the exemplary patient of the intervention group initially ventilated with PEEP 5 cmH2O; b f-EIT image of the exemplary patient of the intervention group during the last EIT measurement after the surgical procedure was finished; c Illustration of gain (red) and loss (blue) for the patient in the intervention group; d f-EIT image of the exemplary patient of the control group during baseline measurements; e f-EIT image of the exemplary patient of the control group during the last EIT measurement after the surgical procedure was finished; f Illustration of gain (red pixels) and loss (blue pixels) for the patient in the control group. Gain represents the amount of pixels that exhibited an increase in ventilation in the end compared to the beginning and loss the decrease in ventilation accordingly