Patient ventilator asynchrony in critically ill adults: Frequency and types

Karen G. Mellott, Mary Jo Grap, Cindy L. Munro, Curtis N. Sessler, Paul A. Wetzel, Jon O. Nilsestuen, Jessica M. Ketchum

    Research output: Contribution to journalArticle

    20 Scopus citations


    Background: Patient ventilator asynchrony (PVA) occurs frequently, but little is known about the types and frequency of PVA. Asynchrony is associated with significant patient discomfort, distress and poor clinical outcomes (duration of mechanical ventilation, intensive care unit and hospital stay). Methods: Pressure-time and flow-time waveform data were collected on 27 ICU patients using the Noninvasive Cardiac Output monitor for up to 90min per subject and blinded waveform analysis was performed. Results: PVA occurred during all phases of ventilated breaths and all modes of ventilation. The most common type of PVA was Ineffective Trigger. Ineffective trigger occurs when the patient's own breath effort will not trigger a ventilator breath. The overall frequency of asynchronous breaths in the sample was 23%, however 93% of the sample experienced at least one incident of PVA during their observation period. Seventy-seven percent of subjects experienced multiple types of PVA. Conclusions: PVA occurs frequently in a variety of types although the majority of PVA is ineffective trigger. The study uncovered previously unidentified waveforms that may indicate that there is a greater range of PVAs than previously reported. Newly described PVA, in particular, PVA combined in one breath, may signify substantial patient distress or poor physiological circumstance that clinicians should investigate.

    Original languageEnglish (US)
    Pages (from-to)231-243
    Number of pages13
    JournalHeart and Lung: Journal of Acute and Critical Care
    Issue number3
    StatePublished - May 2014


    • Artificial
    • Mechanical
    • Patient ventilator asynchrony
    • Patient ventilator dyssynchrony
    • Patient ventilator interaction
    • Respiration
    • Ventilators

    ASJC Scopus subject areas

    • Pulmonary and Respiratory Medicine
    • Critical Care and Intensive Care Medicine
    • Cardiology and Cardiovascular Medicine

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    Mellott, K. G., Grap, M. J., Munro, C. L., Sessler, C. N., Wetzel, P. A., Nilsestuen, J. O., & Ketchum, J. M. (2014). Patient ventilator asynchrony in critically ill adults: Frequency and types. Heart and Lung: Journal of Acute and Critical Care, 43(3), 231-243.