False Trigger & Failed Trigger- Simplified

PIC 1:The pressure-time scalar exhibits pressure drops varying in amplitude beneath the baseline. Smaller pressure drops (0.5 cm H2O) and larger pressure drops (2 cm H2O) arise from cardiac pulsations and patient's inspiratory efforts, respectively.

PIC 2: False trigger (also known as auto trigger)

Opting for a pressure trigger sensitivity threshold of 0.5 cm H2O can lead to both cardiac oscillations and inspiratory efforts meeting this threshold, leading to a situation where extra breaths are delivered (exceeding the patient's neural respiratory rate). This phenomenon is referred to as "false trigger" or "auto trigger." To mitigate this issue, one should select a higher trigger sensitivity threshold so that non patient signals fail to reach trigger sensitivity threshold (in this example more than 0.5 cm H2O/ more negative value/ less sensitive trigger).

PIC 3: All breaths are patient triggered breaths

When the trigger sensitivity threshold is set at 2 cm H2O, only the patient's inspiratory efforts have the potential to reach this threshold. Consequently, the number of ventilator-assisted breaths will be equal to the patient's neural rate.

PIC 4: Failed trigger (also known as missed trigger/ ineffective trigger/ wasted effort)

When the trigger sensitivity threshold exceeds 2 cm H2O (for instance, set at 3 cm H2O), neither the patient's inspiratory efforts nor cardiac pulsations will attain the trigger sensitivity threshold. As a consequence, breaths will not be delivered until either the time trigger interval is reached (in control modes) or the backup mode is initiated (after reaching apnea period- in pressure support mode).