What triggers a double-trigger dyssynchrony and how can it be addressed?

• A. The ventilator fails to deliver a breath during inspiration
• B. The tidal volume is too low
• C. The patient triggers again just after a delivered breath
• D. The patient stops breathing during a breath

Answer: (C)

Double-trigger dyssynchrony happens when the patient makes another inspiratory effort while the current breath is still being delivered, so the ventilator starts a second breath immediately after the first. This breath stacking often makes the tidal volume larger than intended and shows a mismatch between patient demand and machine delivery. It’s driven by continued neural drive and a relatively short inspiratory phase, so the patient effectively “triggers again” at the end of the first breath. To address it, adjust the settings to better align with the patient’s effort: lengthen the inspiratory time (adjust I time or I:E ratio), modify trigger sensitivity to prevent a second trigger during the same effort, and/or reduce the patient’s ventilatory drive with analgesia/sedation or switch to a mode less prone to breath stacking.