Newly Published
Critical Care Medicine  |   March 2020
Diagnostic Accuracy of Diaphragm Ultrasound in Detecting and Characterizing Patient–Ventilator Asynchronies during Noninvasive Ventilation
Author Notes
  • From the Intensive Care Unit, Saint Joseph Saint Luc Hospital, Lyon, France (E.V.); University Paris Est Créteil (UPEC), Mondor Institute of Biomedical Research (IMRB), Clinical Research Group on Cardiovascular and Respiratory Manifestations of Acute Lung Injury and Sepsis (CARMAS), Créteil, France (E.V., A.F.H., A.M.D., G.C.); Greater Paris Public Hospitals (Assistance Publique-Hôpitaux de Paris), Henri Mondor University Hospital, Ageing Thorax-Vessels-Blood Department, Departments of Intensive Care, Créteil, France (A.F.H., A.M.D., G.C.); National Institute of Health and Research (Institut National de la Santé et de la Recherche Médicale; INSERM), Clinical Research Center 1430, Henri Mondor University Hospital, Créteil, France (P.LC.); National Institute of Health and Research (INSERM), Unit U955, Team 13, Créteil, France (A.M.D., G.C.).
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    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Part of this paper was presented at the French Intensive Care Society International Congress in Paris, France, on January 24-26, 2018.
    Part of this paper was presented at the French Intensive Care Society International Congress in Paris, France, on January 24-26, 2018.×
  • Submitted for publication April 9, 2019. Accepted for publication February 7, 2020.
    Submitted for publication April 9, 2019. Accepted for publication February 7, 2020.×
  • Correspondence: Address correspondence to Dr. Vivier: Service de Réanimation Polyvalente, Hôpital Saint Joseph Saint Luc, 20 Quai Claude Bernard, 69007 Lyon, France. evivier@ch-stjoseph-stluc-lyon.fr. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Critical Care Medicine / Airway Management / Critical Care / Radiological and Other Imaging / Respiratory System
Critical Care Medicine   |   March 2020
Diagnostic Accuracy of Diaphragm Ultrasound in Detecting and Characterizing Patient–Ventilator Asynchronies during Noninvasive Ventilation
Anesthesiology Newly Published on March 19, 2020. doi:https://doi.org/10.1097/ALN.0000000000003239
Anesthesiology Newly Published on March 19, 2020. doi:https://doi.org/10.1097/ALN.0000000000003239
Abstract

Background: Management of acute respiratory failure by noninvasive ventilation is often associated with asynchronies, like autotriggering or delayed cycling, incurred by leaks from the interface. These events are likely to impair patient’s tolerance and to compromise noninvasive ventilation. The development of methods for easy detection and monitoring of asynchronies is therefore necessary. The authors describe two new methods to detect patient–ventilator asynchronies, based on ultrasound analysis of diaphragm excursion or thickening combined with airway pressure. The authors tested these methods in a diagnostic accuracy study.

Methods: Fifteen healthy subjects were placed under noninvasive ventilation and subjected to artificially induced leaks in order to generate the main asynchronies (autotriggering or delayed cycling) at event-appropriate times of the respiratory cycle. Asynchronies were identified and characterized by conjoint assessment of ultrasound records and airway pressure waveforms; both were visualized on the ultrasound screen. The performance and accuracy of diaphragm excursion and thickening to detect each asynchrony were compared with a “control method” of flow/pressure tracings alone, and a “working standard method” combining flow, airway pressure, and diaphragm electromyography signals analyses.

Results: Ultrasound recordings were performed for the 15 volunteers, unlike electromyography recordings which could be collected in only 9 of 15 patients (60%). Autotriggering was correctly identified by continuous recording of electromyography, excursion, thickening, and flow/pressure tracings with sensitivity of 93% (95% CI, 89–97%), 94% (95% CI, 91–98%), 91% (95% CI, 87–96%), and 79% (95% CI, 75–84%), respectively. Delayed cycling was detected by electromyography, excursion, thickening, and flow/pressure tracings with sensitivity of 84% (95% CI, 77–90%), 86% (95% CI, 80–93%), 89% (95% CI, 83–94%), and 67% (95% CI, 61–73%), respectively.

Conclusions: Ultrasound is a simple, bedside adjustable, clinical tool to detect the majority of patient–ventilator asynchronies associated with noninvasive ventilation leaks, provided that it is possible to visualize the airway pressure curve on the ultrasound machine screen. Ultrasound detection of autotriggering and delayed cycling is more accurate than isolated observation of pressure and flow tracings, and more feasible than electromyogram.

Editor’s Perspective:

What We Already Know about This Topic:

  • Use of noninvasive ventilation in patients with acute respiratory failure is often associated with asynchronies like autotriggering or delayed cycling. These asynchronies are likely to impair efficacy of noninvasive patient ventilation.

  • Surface diaphragm electromyography is the current reference for detecting synchronies in noninvasive ventilation. However this detection technique is not always effective and cannot be used routinely at the bedside. Therefore there is a clinical need for other techniques for monitoring for asynchronies in noninvasive ventilation.

What This Article Tells Us That Is New:

  • In 15 healthy volunteers, ultrasound assessment of diaphragm excursion and thickening detected noninvasive ventilator asynchronies with high sensitivity and specificity when compared with assessment of respiratory flow/pressure tracings.

  • Surface diaphragm electromyography also had significantly higher sensitivity and specificity for detecting noninvasive ventilator asynchronies, but was only able to be successfully implemented in 60% of the study patients, suggesting that ultrasound assessment of diaphragm excursion and thickening is a more feasible technique for detecting ventilator asynchrony.