Lung ultrasound findings in patients with novel SARS-CoV-2

Background Over 2 million people worldwide have been infected with Severe Acute Respiratory Distress Syndrome Corona Virus 2 (SARS CoV-2). Lung ultrasound has been proposed to diagnose and monitor it, despite the fact that little is known about the ultrasound appearance due to the novelty of the illness. The aim of this manuscript is to characterise the lung ultrasonographic appearance of critically ill patients with SARS CoV-2 pneumonia with particular emphasis on its relationship with the time course of the illness and clinical parameters.

Methods On the Intensive Care Unit of two academic hospitals, adult patients who tested positive for SARS-CoV-2 were included. Images were analysed using internationally recognised techniques which included assessment of the pleural line, number of B-lines, pathology in the PLAPS (Postero Lateral Alveolar and Pleural Syndrome) point, BLUE-profiles (Bedside Lung Ultrasound in Emergency), and the lung ultrasound score (LUS). The primary outcomes were frequencies, percentages and differences in lung ultrasound findings overall and between short (≤14 days) and long (>14 days) duration of symptoms and their correlation with clinical parameters.

Results In this pilot observational study, 61 patients were included with 76 examinations for analysis. 26% of patients had no anterior lung abnormalities, while the most prevalent pathological ultrasound findings present but subtle lung sliding (35%), thickening of the pleura (42%), ≥B-lines per view (38%) and present PLAPS (74%). Patients with “long” duration of symptoms presented more frequently with a thickened and irregular pleura (21% (32) versus 9% (11)), C-profile (47% (18) versus 25% (8)) and pleural effusion (19% (14) versus 5% (3)), compared to patients with short duration of symptoms. Lung ultrasound findings did not correlate with P/F ratio, fluid balance or dynamic compliance.

Conclusion SARS CoV-2 results in significant, but not specific, ultrasound changes, with decreased lung sliding, thickening of the pleura and a B-profile being the most observed. With time, a thickened and irregular pleura, C-profile and pleural effusion become more common findings. When screening patients, a comprehensive ultrasound protocol might be necessary.