Fig. 2

Distribution of regional ventilation during forced breathing and breathing at rest within four dorsal to ventral regions of equal size. a Abdominal surgical cohort. b Peripheral surgical cohort. Percentages of total impedance variation in electric impedance tomography represent the regional ventilation in the most dorsal (lines 1–8 of the 32 × 32 matrix), dorsal (lines 9–16), ventral (lines 17–24) and most ventral (lines 25–32) regions preoperatively, as well as during the first postoperative and third postoperative day