Fig. 1.
Representative example of measurements of the main variables studied. The displayed breath is during pressure control ventilation. All variables were calculated on a breath-by-breath basis for each mode and averaged over a 5-min stable respiratory pattern. Vertical dotted lines represent neural and mechanical respiratory cycles. Arrows indicate the different parameters that are calculated from the waveforms. Tidal volume is calculated as the integral of inspiratory flow over time. Transpulmonary pressure versus time product (PTPtp) is calculated as the integral of transpulmonary pressure (Ptp) over time. PTPtp was calculated during the following phases of inspiration: (A) trigger delay; (B) synchronous overlap period between neural and mechanical inspiration; and (C) cycle-off error. PON − EAdiON = trigger delay and POFF − EAdiOFF = cycle-off error. EAdi = electrical activity of the diaphragm; Paw = airway pressure; Pes = esophageal pressure.