Auto-triggering is a condition in which the ventilator repeatedly triggers itself because the trigger threshold is set too sensitive.
Auto-triggering is caused by flow distortions:
- Water in the ventilator circuit.
- Circuit leaks.
- Chest tubes.
- Endo-tracheal tube cuff leaks.
- Cardiac oscillations (high cardiac output, or balloon pump).
The above image demonstrates auto-triggering caused by a leak, by evidence of the volume waveform (highlighted) never returning to baseline. When no leaks are present the volume waveform will return to baseline.
To determine if the auto-triggering is due to cardiac oscillations:
- Evaluate the ECG or SPO2 waveform, does the triggering match the waveforms?
- Evaluate the Airway Occlusion Pressure @ 0.1 second (P.01) if the P.01 is zero & the measured frequency is greater than the set frequency the ventilator is auto-triggering.
To prevent Auto-triggering
- Minimize leaks.
- Make the trigger threshold less sensitive.
