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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
- For more on assessment of respiratory effort, see this post
- Understanding trigger, limit, and cycle
Ready to tackle more dyssynchronies? Check out my posts on and Multiple Triggering and Cycle Dyssynchronies.
References
- 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: https://doi.org/10.4187/respcare.09316
PEER Reviewed by
Komal Parikh
PEER Reviewed by
Terren Trott
PEER Reviewed by
Steve Haywood