In cases where a patient exerts minimal inspiratory effort, the flow-time scalar usually displays an exponential decay, while the pressure remains constant throughout the inspiratory phase in pressure support mode. A similar appearance can also be observed during false triggering when the patient is in a passive state.  In the second breath, the waveform exhibits typical characteristics of pressure support waveforms, indicating the possibility of either a patient-triggered br

A notch on the pressure waveform (1) accompanied by a sudden rise in inspiratory flow (2) signifies a neural diaphragmatic contraction induced by passive mechanical inflation, a phenomenon termed reverse triggering. Since mechanical inflation precedes neural inspiration, it is also referred to as early triggering.

The following waveform illustrates three consecutive breaths, each with distinct morphologies. On this ventilator (Maquet, Getinge), patient-triggered breaths are marked in pink at the initial rise in pressure and flow, corresponding to pressure or flow triggering. In this case, flow triggering was used. The breaths appear to be patient-triggered, as suggested by a small negative deflection in airway pressure preceding inspiration and the pink marking on the flow–time scalar.

These breaths are initiated by the ventilator (time-triggered). An observable change in the pressure-time curve occurs during late inspiration, where the pressure waveform returns towards the baseline without maintaining a plateau. This suggests that neural inspiration begins after passive mechanical inflation, a phenomenon known as reverse triggering. Neural inspiration extends into the expiratory phase, causing an upward distortion of the expiratory flow-time curve (where i