Double-Trigger Asynchrony Assessment

Key Points

  • Double triggering appears as two breaths delivered very close together and may indicate near breath stacking.
  • A common mechanism is inspiratory-time mismatch when patient inspiratory effort continues after ventilator inspiratory phase ends.
  • Pressure drop reaching trigger sensitivity can immediately trigger a second breath.

Equipment

  • Ventilator waveform display with pressure tracing visibility
  • Current ventilator settings view including I-time and trigger sensitivity
  • Continuous monitoring for oxygenation, pressure trends, and patient distress
  • Team escalation pathway for ventilator synchronization adjustments

Procedure Steps

  1. Observe waveform patterns when asynchrony or patient discomfort is suspected.
  2. Identify closely spaced paired breaths suggestive of double triggering.
  3. Assess whether patient appears to exhale before expiratory valve opening (I-time may be too long for patient need).
  4. Review pressure waveform for drop after ventilator-set inspiratory phase.
  5. Determine whether the pressure drop likely crossed trigger sensitivity and initiated a second breath.
  6. Correlate pattern with signs of breath stacking risk and increased respiratory effort.
  7. Notify respiratory therapy/provider and support synchronization-focused setting reassessment.
  8. Reassess waveforms and clinical response after any ordered adjustment.
  9. Document findings, likely mechanism, and response trend.

Common Errors

  • Treating double triggering as random artifact missed asynchrony correction opportunity.
  • Ignoring pressure-drop trigger behavior repeated breath stacking risk.
  • Delayed escalation in persistent asynchrony increased patient distress and ventilation inefficiency.
  • Failing to reassess post-adjustment waveforms unresolved mismatch can continue.