Figure 3.

An adult mechanically ventilated patient examined by electrical impedance tomography (EIT) (Enlight, Timpel, Sao Paulo, Brazil; with a finite element method (FEM)-based Newton Raphson image reconstruction algorithm) during a decremental positive end-expiratory pressure (PEEP) trial. The patient suffered from severe acute respiratory distress syndrome as detected in the CT scan (top left) obtained at the same chest plane where the EIT electrode belt was located during the EIT examination. The panels 1–10 show regional lung hyperdistension and collapse at each PEEP step in white and blue colours, respectively. The percentages of collapse and overdistension are provided at the right side of each panel and in the diagram (bottom left). With decreasing PEEP, hyperdistension fell (green curve) and collapse rose (blue curve). The crossover point between the curves is highlighted by the red arrow. The corresponding PEEP step preceding the crossover shows the value of 17 cm H₂O in red in panel 4.