B-LINES IN COVID-19: “UNSPECIFICITY” IS NOT “MEANINGLESS”

Luigi Vetrugno^1,2 MD, Prof, Tiziana Bove^1,2 MD, Prof, Daniele Orso¹ MD, Federico Barbariol² MD, Flavio Bassi² MD, Enrico Boero³ MD, Giovanni Ferrari⁴ MD, Robert Kong⁵MD, FRCA, EDIC,

¹Department of Medicine, University of Udine, Italy

Anesthesia and Intensive Care Clinic

Via Colugna n° 50, 33100 Udine, Italy

²University-Hospital of Udine, Italy

Department of Anesthesia and Intensive Care

P.le S. Maria della. Misericordia n° 15, 33100 Udine, Italy

³Anesthesia and Intensive Care, San Giovanni Bosco Hospital, Torino, Italy

⁴SC Pneumologia ad Indirizzo Semi Intensivo, Azienda Ospedaliera Ordine Mauriziano. Largo Turati 62 – Torino, Italy

⁵ Cardiac Anaesthesia & Intensive Care, Brighton & Sussex University Hospital, Brighton BN2 5BE United Kingdom

Short title: lung ultrasound and B-lines

*Corresponding author:

Prof. Luigi Vetrugno, MD

Department of Medicine, University of Udine, Italy

Anesthesia and Intensive Care Clinic

Via Colugna n° 50, 33100 Udine, Italy

Phone: +39 0432 559509

Fax: +39 0432 559502

Financial Support and Sponsorship: None.

Conflict of Interest: Luigi Vetrugno received travel support for Congress Lecture by Cook Medical.

The other authors declare no conflict of interest.

Key works: Lung Ultrasound; interstitial syndrome, COVID-19, B-lines.

Authors’ contributions LV and DO concept, design and drafting the manuscript. TB, FB, EB, FB, GF critical revision of the manuscript for important intellectual content. RK critical review and editing the manuscript. All authors read and approved the final manuscript.

We thank Prof. Trovato and Dr Sperandeo for commenting on our article.¹ We agree with them that lung ultrasound (LU) imaging is useful and our aim was to provide readers with a succinct overview of how LU was used in the care of COVID-19 patients at two centres in Italy.² The frequent finding in COVID-19 patients of lung consolidation at the inferior and basal regions means that one of the limitations of LU, which is to perform a complete assessment of the periphery of the lungs, is mitigated, as affected regions are not obscured by the scapula. Other authors have shown that in COVID-19 patients, LU provided results similar to those of computed tomography (CT) of the lung and superior to those of standard chest x-rays.^3-5 Therefore, LU provides clinicians with another mode of lung imaging that can be performed non-invasively and without the logistic challenges of obtaining CT lung scan in these patients, as is well-known to centers who have been faced with a large caseload.⁶ As stated in our article, we have not identified an LU finding that is pathognomonic of COVID-19.^1-7 However, the presence of B lines in several different clinical situations does not decrease their significance. In medicine, many signs are frequent in various diseases, like fever, but this is not a good reason to underestimate or not consider them at all. Furthermore, emerging ultrasound image analysis based on artificial intelligence and deep learning has the potential to further enhance the utility of LU.^8-9 Although caution is needed in terms of exaggerating the power of LU, we hope it will continue to be used widely after the pandemic.

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