Mastering the Vent: Cycle Dyssynchronies

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Matt Siuba
Matt Siuba
Zentensivist. ARDS, Mechanical Ventilation, RV, & Shock Enthusiast.

The Pre-brief

Understanding patient-ventilator interactions is made easier by breaking it down into the following parts:

  • Trigger, the beginning of inspiration
  • Inspiratory phase interactions (like “flow starvation”)
  • Cycle, the end of inspiration
  • Expiratory phase interactions

This gives a much more systematic framework for understanding vent waveforms, more like reading different segments of an EKG. Today, I’ll cover the most common trigger dyssynchronies in the following infographic:

The Debrief

  • Trigger refers to the initiation of inspiration 
  • When we name vent dyssynchrony issues as “early” or “late”, the patient is the reference. E.g. if the vent is late to trigger relative to the patient, it is late triggering.
  • For more info, see the post on Failed Triggering.


Further Reading

Ready to tackle more dyssynchronies? Check out my posts on and Multiple Triggering and Cycle Dyssynchronies.


  1. 1. Mireles-Cabodevila E, Siuba MT, Chatburn RL, A Taxonomy for Patient-Ventilator Interactions and a Method to Read Ventilator Waveforms Respiratory Care September 2021, respcare.09316; DOI:


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