Fig. 1

Patterns of conductive pressure–time waveform (Pcond) during volume-controlled ventilation. In pattern A1, the apparent DP matches the actual DP as Pcond = Pres. In pattern B1, respiratory pattern with AC where Pcond may unveil DP overestimation because Pcond > Pres. AC can be unveiled by a low-flow inflation pressure–time curve with a flow of 5 L/min. In pattern B2, respiratory pattern with intrinsic positive end-expiratory pressure (i.e. PEEPi) where Pcond may unveil DP overestimation because Pcond > Pres. PEEPi can be detected by an end-expiratory hold maneuver. In panel C, patient undergoing venous-arterial ECMO for cardiac arrest and severe respiratory failure with the presence of both phenomena leading to DP overestimation (i.e., AC and PEEPi) that can be visually detected by the presence of Pcond as first (on the left), and that can be subsequently quantitatively estimated by a low-flow inflation (in the middle) and by an end-expiratory hold maneuver (on the right). AOP, airway opening pressure with the visible “Uncorking effect”; DP, driving pressure; Paw, airway pressure; Pcond, conductive pressure; PEEPi, intrinsic PEEP; PEEPe, extrinsic PEEP; PEEPtot, total PEEP; Ppeak, peak pressure; Pplat, plateau pressure; Pres, resistive airway pressure; Vt, tidal volume