Fig. 1

An ever-shrinking, baby lung, known as a VILI Vortex has been used to describe the evolution of ventilator-induced lung injury (VILI) [28]. Upper left: The ‘patient’ with mostly open lung tissue (pink) and a lesser amount of collapsed tissue (red) defined as Mild ARDS is placed on ARDSnet LV_T ventilation. The LV_T and low airway pressures strategy is designed to ‘rest’ the ‘baby lung’, however, this ventilation method allows the acutely injured tissue to continually collapse pushing it into the VILI Vortex. Lung pathogenesis moves from Mild to Moderate ARDS as normal tissue progressively shrinks (pink → red), Disease progression into Severe ARDS is inevitable if unchecked at which point rescue methods such as extracorporeal membrane oxygenation (ECMO) may be necessary. ARDS causes the lung to become time and pressure dependent. This means that it will take more time for the alveoli to open and less time for them to collapse at any given airway pressure. Thus, the alveolar opening can be accelerated by an extended inspiratory time, and alveolar collapse minimized by a short expiratory time. The brief time at inspiration is not adequate to open collapsed alveoli while the extended time at expiration will not prevent alveolar collapse using the ARDSnet approach (Upper left Protect the Lung, Ventilator Monitor blue Pressure/Time curve). The open lung approach to rapidly reopen the lung (seconds or minutes) using recruitment maneuvers and higher PEEP has not been successful at reducing ARDS-related mortality. Using inspiratory and expiratory duration in addition to pressure to open and stabilize alveoli has been shown very effective and lung protective by our group and others [19, 72, 75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91]. An extended inspiratory time will progressively recruit alveoli and a brief expiratory time will prevent re-collapse. A correctly set time-controlled ventilator method will stabilize alveoli (Center, Stabilize the Lung, Ventilator Monitor blue Pressure/Time curve) using a short expiratory time pulling the lung from the Vortex. Once progressive lung collapse is halted, collapsed tissue can be reopened slowly (Red lung tissue turning pink) over hours or days depending on the level of lung pathophysiology [19, 72, 75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91]. This figure depicts the ability of TCAV to be used after ARDS has developed or as a rescue mode but if applied early during mild ARDS movement of the lung into the Vortex could be prevented.