Clarifying the role of lung ultrasound in COVID-19 respiratory disease [RE: Lung ultrasound findings in a 64-year-old woman with COVID-19]
References
(1). Clarifying the role of lung ultrasound in COVID-19 respiratory disease [RE: Lung ultrasound findings in a 64-year-old woman with COVID-19]. 2020;:-.
(2) Mojoli F, Bouhemad B, Mongodi S, Lichtenstein D. Lung ultrasound for critically ill patients. Am J Respir Crit Care Med 2019;199:701-714.
(3) Doerschug KC, Schmidt GA. Intensive Care Ultrasound: III. Lung and pleural ultrasound for the intensivist. Ann Am Thorac Soc 2013;10:708-712.
(4) Copetti R, Soldati G, Copetti P. Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome. Cardiovasc Ultrasound 2008:6:16.
(5) See KC, Ong V, Tan YL, Sahagun J, Taculod J. Chest radiography versus lung ultrasound for identification of acute respiratory distress syndrome: a retrospective observational study. Crit Care 2018;22:203.
Thomas et al(1) describe a patient with COVID-19 pneumonia, in whom lung ultrasound demonstrated "multifocal B-lines, pleural thickening and subpleural consolidation." On the basis of these findings, they propose "that lung ultrasonography may be useful in the workup of patients with suspected COVID-19, even though differentiating between different causes of viral pneumonia is not possible." These comments require further clarification.
First, the sonographic findings described here are highly nonspecific, being found not only in other viral pneumonias, but also in non-viral pneumonias, as well as a wide spectrum of noninfectious processes, including interstitial lung disease and ARDS.(2)
Secondly and consequently, the nature of this patient's sonographic findings must be further qualified, particularly her 'multifocal' B-lines. If by this term three or more B-lines per acoustic window is designated, an 'interstitial' (or 'alveolar-interstitial') pattern is identified (whereas occasional B-lines, especially dependently, can be normal).(3) However, if by this term a certain global distribution of interstitial pattern is designated, diagnostic implications follow: whereas a homogeneous interstitial pattern favours cardiogenic edema, a heterogeneous interstitial pattern, particularly combined with subpleural consolidation, pleural thickening, and reduced lung sliding, is consistent with pneumonia and/or ARDS.(4) Presuming a heterogeneous interstitial pattern, this patient's overall presentation suggests concomitant COVID-19 pneumonia and ARDS.
In sum, the findings on lung ultrasound of COVID-19 respiratory disease appear to be nonspecific, and likely on par with similar non-COVID respiratory diseases; the need for microbiological confirmation remains. In general, lung ultrasound in critical illness provides data that are probably best regarded as complementary to chest radiography; its unique benefit in the current context includes bedside feasibility, particularly when advanced chest imaging is unavailable or contraindicated for infection control.(5)