Methodological and Clinimetric Evaluation of Inspiratory Respiratory Muscle Ultrasound in the Critical Care Setting: A Systematic Review and Meta-Analysis

Dominic Truong, Shaza Abo, Georgina A. Whish-Wilson, Aruska N. D'Souza, Lisa J. Beach, Sunita Mathur, Kirby P. Mayer, George Ntoumenopoulos, Claire Baldwin, Doa El-Ansary, Michael T. Paris, Marina Mourtzakis, Peter E. Morris, Amy M. Pastva, Catherine L. Granger, Selina M. Parry, Aarti Sarwal

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


OBJECTIVE: Significant variations exist in the use of respiratory muscle ultrasound in intensive care with no society-level consensus on the optimal methodology. This systematic review aims to evaluate, synthesize, and compare the clinimetric properties of different image acquisition and analysis methodologies. DATA SOURCES: Systematic search of five databases up to November 24, 2021. STUDY SELECTION: Studies were included if they enrolled at least 50 adult ICU patients, reported respiratory muscle (diaphragm or intercostal) ultrasound measuring either echotexture, muscle thickness, thickening fraction, or excursion, and evaluated at least one clinimetric property. Two independent reviewers assessed titles, abstracts, and full text against eligibility. DATA EXTRACTION: Study demographics, ultrasound methodologies, and clinimetric data. DATA SYNTHESIS: Sixty studies, including 5,025 patients, were included with 39 studies contributing to meta-analyses. Most commonly measured was diaphragm thickness (DT) or diaphragm thickening fraction (DTF) using a linear transducer in B-mode, or diaphragm excursion (DE) using a curvilinear transducer in M-mode. There are significant variations in imaging methodology and acquisition across all studies. Inter- and intrarater measurement reliabilities were generally excellent, with the highest reliability reported for DT (ICC, 0.98; 95% CI, 0.94-0.99). Pooled data demonstrated acceptable to excellent accuracy for DT, DTF, and DE to predicting weaning outcome after 48 to 72 hours postextubation (DTF AUC, 0.79; 95% CI, 0.73-0.85). DT imaging was responsive to change over time. Only three eligible studies were available for intercostal muscles. Intercostal thickening fraction was shown to have excellent accuracy of predicting weaning outcome after 48-hour postextubation (AUC, 0.84; 95% CI, 0.78-0.91). CONCLUSIONS: Diaphragm muscle ultrasound is reliable, valid, and responsive in ICU patients, but significant variation exists in the imaging acquisition and analysis methodologies. Future work should focus on developing standardized protocols for ultrasound imaging and consider further research into the role of intercostal muscle imaging.

Original languageEnglish
Pages (from-to)E24-E36
JournalCritical Care Medicine
Issue number2
StatePublished - Feb 1 2023

Bibliographical note

Publisher Copyright:
© 2023 Lippincott Williams and Wilkins. All rights reserved.


  • intensive care
  • meta-analysis
  • respiratory muscles
  • systematic review
  • ultrasonography

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine


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