Ultrasonography: An unchartered modality in the current pandemic – A study among patients admitted in the COVID-19 intensive care unit

Abstract

Background: The objectives were to perform an analysis of lung ultrasonography (LUS) findings in severely ill patients with novel coronavirus disease-2019 (COVID-19) and to compare the accuracy with high-resolution computed tomography (HRCT) of the thorax. Methods: Sixty-two intensive care unit (ICU) patients with COVID-19 were evaluated during their hospital stay. LUS was performed with convex and linear transducers using a designated ultrasonography machine placed in the COVID-19 ICU. The thorax was scanned in 12 areas. Initial LUS was performed on admission and follow-up LUS was done in 7 (mean) days. At the time of the initial LUS, HRCT was performed in 28/62 patients and a chest radiography in 19/62 patients. Results: On admission, LUS detected pleural line thickening (>6 lung areas) in 49/62, confluent B-lines in 38/62, and separate B-lines in 34/62, consolidation in 12/62, C prime profile in 19/62, and pleural and cardiac effusions in 4/62 and 1/62, respectively. The single beam “torchlight” artifact was seen in 16/62, which may possibly be a variation of the B-line which has not been described earlier. Follow-up LUS detected significantly lower rates ( P < 0.05) of abnormalities. Conclusion: Ultrasound demonstrated B-lines, variable consolidations, and pleural line irregularities. This study also sheds light on the appearance of the C prime pattern and “torchlight” B-lines which were not described in COVID-19 earlier. LUS findings were significantly reduced by the time of the follow-up scan, insinuating at a rather slow but consistent reduction in some COVID-19 lung lesions. However, the lung ultrasound poorly correlated with HRCT as a diagnostic modality in COVID-19 patients.

Point-of-care ultrasound use in COVID-19: a narrative review

“…In early stages of COVID-19 pneumonia, there are focal B-lines, progressing to confluent and multifocal B-lines with subpleural consolidations as the infection advances ( 20 ). Confluent B-lines have been described as “shining white lung” ( 26 ), “torchlight” sign ( 27 ) and “waterfall” sign ( 28 ).…”

“…It is, however, ubiquitous even in lower resource healthcare settings and the skills can be readily acquired by physicians ( 43 ). Previous studies have shown that interobserver variability in ultrasound findings and LUS scoring among physicians experienced in POCUS have substantial and good agreement ( 27 , 33 , 44 - 46 ).…”

“…Ultrasound protocols described in the literature since the emergence of COVID-19 vary among institutions. Common protocols for lung POCUS include scanning 6-, 8-, 12- or 14-zone on the chest ( 27 , 52 - 56 ), with the 12-zone protocol being the most frequently used. Bedside Lung Ultrasound in Emergency (BLUE) protocol was first described in 2008 by Lichtenstein et al as a quick method to diagnose the aetiology for acute respiratory failure ( 57 ).…”

The Role of POCUS to Face COVID-19: A Narrative Review

“…Furthermore, in another cohort study, it was observed that monitoring of lung involvement was possible only with US instead of CT scan [32]. Conversely, different results were found in another prospective follow-up study: a lower rate of abnormalities were detected by LUS with respect to CT [26]. Furthermore, in a prospective observational study, only 67% of subjects did not present US abnormalities after 3 months from COVID-19 infection, even if the PaO 2 /FiO 2 ratio returned to normal values (>400 mmHg), concluding that even if, during follow-up, LUS kept detecting lung abnormalities, it did not correlate with clinical state.…”

“…In two prospective observational studies, the prevalence of LUS findings in COVID-19-affected patients was studied. In the first, thickening of the pleural line (>6 lung areas) were found in 49/62, confluent B lines (B2) in 38/62, separated B lines (B1) in 34/62, and consolidations (C) in 19/62 [26]. In the second, only patterns B2 and C were reported, which were found in 19.3% and 58.9% of cases, respectively [25].…”