Fig. 4
From: Time-Controlled Adaptive Ventilation (TCAV): a personalized strategy for lung protection
Adapted from Reference [104], under terms of the Creative Commons Attribution 4.0 International License
Expiratory Gas Flow/Time curve using the TCAV method to set TLow, the duration of the Release Phase (Fig. 2B, Release Phase). As lung injury increases from Normal Lung to Moderate and Severe ARDS, the respiratory system compliance (CRS) decreases, increasing the collapse recoil of the lung. The increased lung recoil causes faster gas flow during expiration resulting in a steeper slope of the expiratory flow curve (SlopeEF). a Using the SlopeEF to set the Release Phase duration (Fig. 2B, Release Phase), the Normal Lung has a release time of 0.5 s, Moderate ARDS 0.4 s, and Severe ARDS 0.3 s. Expiratory flow is terminated (red arrowhead) by the clinician by adjusting the TLow, following which the lung is rapidly reinflated to the CPAP Phase (Fig. 2B, CPAP Phase). Thus, using the TCAV method personalizes and adapts the Release Phase (TLow) according to the patient’s lung physiology. b Calculation of the termination point on the expiratory flow curve using the TCAV method. Termination of expiratory flow (TEF) is calculated as 75% of the peak expiratory flow (PEF) (PEF 50L/min × 0.75 = TEF 37.5L/min).