Patient-ventilator dyssynchrony is a sign of a disagreement between the patient's breathing and the ventilator's settings. Recognizing and fixing it is a critical skill to prevent lung injury and improve comfort. Ineffective triggering and double-trigger are two common types of dyssynchrony.
The patient tries to take a breath, but they are too weak to trigger the ventilator. This is the most common type of dyssynchrony. It causes increased work of breathing and discomfort.
Look for a small dip in the pressure waveform and a simultaneous scoop out of the expiratory flow waveform that is not followed by a delivered breath.
Troubleshooting options:
The patient's own breath outlasts the ventilator's set inspiratory time (Ti), causing one patient effort to trigger two stacked breaths. This results in delivery of large tidal volumes, risking lung injury (volutrauma).
Look for two consecutive breaths on the ventilator screen without a full exhalation in between.
Troubleshooting options:
Dyssynchrony means the ventilator settings do not match the patient's needs. Watch the waveforms to diagnose the mismatch, then either adjust the ventilator or treat the underlying problem.
Thille, A. W., Rodriguez, P., Cabello, B., Lellouche, F., & Brochard, L. (2006). Patient-ventilator asynchrony during assisted mechanical ventilation. Intensive care medicine, 32, 1515-1522.
Blanch, L., Villagra, A., Sales, B., Montanya, J., Lucangelo, U., Luján, M., ... & Kacmarek, R. M. (2015). Asynchronies during mechanical ventilation are associated with mortality. Intensive care medicine, 41, 633-641.
