FIGURE 2.

Reverse trigger phenotypes. The figure shows 5 Reverse trigger phenotypes during assist/control ventilation. The vertical solid line indicates an initiation of a mandatory breath, the vertical dashed line indicates an initiation of a patient effort which is express as the negative fluctuation of esophageal pressure, the arrow indicates maximal Inspiratory effort or maximal delta esophageal pressure (Peso). If an initiation of a patient effort precede a mandatory breath, we define it is an assist breath [e.g., the first breath in (E)]. If a patient effort emerge after an initiation of a mandatory breath, we define it is a breath with Reverse trigger [e.g., (A–D)]. Depending on the time phase of initiation of a patient effort and maximal delta Peso, a Reverse trigger was defined as different phenotypes according to Kassis E B’s classification (Kassis et al., 2020). (A) Early RT with Early Relaxation (No.4 patient): patient effort initiation and the max Peso are among inspiratory phase, and termination of patient effort are among early period of expiratory phase; (B) Early RT with Delayed Relaxation (No.2 patient): patient effort initiation and the max Peso are among inspiratory phase, and termination of patient effort are among late period of expiratory phase; (C) Mid Cycle RT (No.4 patient): patient effort initiate in inspiratory phase and the max Peso emerge in expiratory phase; (D) Late RT (No.3 patient): patient effort emerge in expiratory phase; (E) RT with breath stacking (No.3 patient): during any phenotype of above reverse trigger, patient effort is sufficient to trigger another assist mechanical breath. Ttot_mech is the duration of the mechanical cycle. Ti is the inspiratory phase of the mechanical cycle.