Fig. 2

A Pressure/Time and Flow/Time curves = generated by the ARDSnet method to set and adjust the Volume Assist-Control mode. Key features include an inspiratory: expiratory ratio of 1:3 where the peak/plateau inspiratory pressure is brief. A set positive end-expiratory pressure (Set-PEEP) and FiO₂ are adjusted using oxygenation as the trigger for change [20]. B Pressure/Time and Flow/Time curves for the Time Controlled Adaptive Ventilation (TCAV) method to set and adjust the Airway Pressure Release Ventilation (APRV) mode. Key features include an inspiratory: expiratory ratio of ~ 12:1, where. the continuous positive airway pressure (CPAP) Phase is ~ 90% of each breath. A tidal volume (V_T), which is measured as the volume of gas released during the Release Phase (brown arrow), is not set but is influenced by changes in (i) respiratory system compliance (C_RS), (ii) the CPAP Phase pressure, and (iii) the duration of the Release Phase. The Release Phase is determined by the Slope of the Expiratory Flow Curve (red arrowhead), which is a breath-to-breath measure of C_RS. The lower the C_RS, the faster the lung recoil, the steeper the slope, and the shorter the Release Phase, further reducing V_T. Thus, the V_T will be low in a non-compliant, injured lung and will increase in size only when the lung recruits and C_RS increases. Since a change in C_RS directs the Release Phase duration, which in turn adjusts the V_T and the time-controlled PEEP (TC-PEEP) the TCAV method is both personalized and adaptive as the patient’s lung gets better or worse [104]. Reproduced from Reference [104], under terms of the Creative Commons Attribution 4.0 International License