Usefulness of lung ultrasound imaging in COVID‐19 pneumonia: The persisting need of safety and evidences

1.

Dear Editor

The early view article by Vetrugno et al, first published April 1, 2020, ¹ raises several elements of concerns for health professionals working in the field of Viral pneumonia and lung US.

1. The title “Our Italian experience using lung ultrasound for identification, grading and serial follow‐up of severity of lung involvement for management of patients with COVID‐19” is, in our view, misleading. We must respectfully observe that the title is claiming something not supported by the article itself and by the facts. None of the topics promised in the title is developed in the text.

2. May we note that this letter is deemed as a review article but not presented in this form and content?

3. The authors claim their Italian experience in identification, grading, and monitoring of patients with COVID‐19, but it is not clear where it was developed.

The unsupported belief that by US artifacts (B lines) any health professional may specifically and easily diagnose many lung disease cannot be further disseminated. ² , ³ , ⁴ , ⁵ , ⁶ , ⁷ Nonetheless, we still find that lung US imaging procedures and US‐guided intervention are useful. In quite a large lung ultrasound (US) series, in our Institution (CSS Hospital, February‐April 2020), we have found that COVID‐19 patient lung consolidation may be detected early and concurrently with CT, but without specific characterization. Such consolidation is frequently located posteriorly, and in COVID‐19, this is seemingly more often found there than in other viral pneumonias, ² allowing US monitoring. However, detection may be limited in one third of case, or impossible, because parts of chest windows are US‐probe‐blind, not allowing full US visibility of the lungs.

Differently, the detection and “count” of B lines in the use of US probes as a stethoscope surrogate, as some would still postulate, are speculative and misleading. ¹ Indeed, these same US artifacts are seen in many different pulmonary diseases without any specificity. ³

We would venture that the use of US equipment for this unreliable purpose, such as detection of B lines and “comet‐tails,” diverts resources and time from more effective and specific intervention. ⁴ The description of reverberation artifacts, that is, “hyperechoic laser‐like artifacts that resemble a comet tail”, ¹ moving also with respiration, reminds us the electrical artifacts seen in electrocardiographic tracings in any type of dyspnea, in pulmonary edema, and in severe lung diseases. ⁵ , ⁶

Echocardiography's readers are aware that these artifacts are unrelated to the electrical activity of the heart and do not reflect cardiac potentials on the body surface. Actually, also echocardiography refers to a core methodology where any lack of precision and, more, artifacts, must be excluded. EKG artifacts are detrimental, merely distort the electrocardiogram, disappearing with improvement or death, exactly like B lines in chest US. ⁷ For these reasons, we suggest caution especially when reporting and disseminating information on lung US use in COVID‐19 patients. ⁸

Trovato GM, Sperandeo M. Usefulness of lung ultrasound imaging in COVID‐19 pneumonia: The persisting need of safety and evidences. Echocardiography. 2020;37:1138–1139. 10.1111/echo.14769