Fig. 4.

Measured airway pressure (Paw, bold line) and its estimation (gray line) by the volume-dependent single-compartment model in the same patient depicted in Fig. 3. A single breath is presented at three different levels of positive end-expiratory pressure (PEEP): 2 (a), 5 (b), and 10 cmH₂O (c). Note that the negative value of the volume-dependent term related to the total respiratory system elastance (%E₂) suggests a minimal tidal recruitment. Additionally, Ers and driving pressure (peak airway pressure – PEEP) decrease with PEEP also suggesting PEEP-induced lung recruitment