RESPIRATORY SYSTEM: Edited by Ewan C. Goligher and Eddy FanMonitoring diaphragm function in the ICUDres, Martina,b; Demoule, Alexandrea,bAuthor Information aSorbonne Université, INSERM, UMRS1158 Neurophysiologie respiratoire expérimentale et clinique bAP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie, Médecine intensive – Réanimation (Département ‘R3S’), F-75013, Paris, France Correspondence to Martin Dres, Service de Pneumologie, Médecine intensive – Réanimation, Groupe Hospitalier Pitié-Salpêtrière, 47-83 boulevard de l’Hôpital, 75651 Paris Cedex 13, France. Tel: +33 1 42 16 77 61; fax: +33 1 70 24 72 82; e-mail: [email protected] Current Opinion in Critical Care: February 2020 - Volume 26 - Issue 1 - p 18-25 doi: 10.1097/MCC.0000000000000682 Buy Metrics Abstract Purpose of review To review the clinical problem of diaphragm function in critically ill patients and describes recent advances in bedside monitoring of diaphragm function. Recent findings Diaphragm weakness, a consequence of diaphragm dysfunction and atrophy, is common in the ICU and associated with serious clinical consequences. The use of ultrasound to assess diaphragm structure (thickness, thickening) and mobility (caudal displacement) appears to be feasible and reproducible, but no large-scale ‘real-life’ study is available. Diaphragm ultrasound can also be used to evaluate diaphragm muscle stiffness by means of shear-wave elastography and strain by means of speckle tracking, both of which are correlated with diaphragm function in healthy. Electrical activity of the diaphragm is correlated with diaphragm function during brief airway occlusion, but the repeatability of these measurements exhibits high within-subject variability. Summary Mechanical ventilation is involved in the pathogenesis of diaphragm dysfunction, which is associated with severe adverse events. Although ultrasound and diaphragm electrical activity could facilitate monitoring of diaphragm function to deliver diaphragm-protective ventilation, no guidelines concerning the use of these modalities have yet been published. The weaning process, assessment of patient–ventilator synchrony and evaluation of diaphragm function may be the most clinically relevant indications for these techniques. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.