Thread by @dan___kim

The largest study of ultrasound for #COVID19 to date (that I'm aware of) - retrospective, 30 pts with COVID confirmed via PCR, who underwent both lung US and CT

Lung US was compared to CT which was used as the reference standard

#POCUSforCOVID

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All US scans were performed at the bedside by a single physician
-6 region scan per hemithorax (anterior, lateral, posterior divided into upper and lower regions)
-scanning in BOTH longitudinal and transverse
-used BOTH convex and linear probes
-5-8 min per scan

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Yet *another* scoring system:
0 pt: normal pleural line, A lines, <3 B lines
1 pt: >3 B lines
2 pt: coalescent B lines
3 pt: consolidation

Total score summed up (0-36 pt):
-none: 0 pt
-mild: 1-7 pt
-moderate: 8-18 pt
-severe: 19+ pt

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CT was scored via a different mechanism, where the two lungs were divided into 20 equal segments (each segment 5% of the total):
-none: 0%
-mild: 5-30%
-moderate: 31-50%
-severe: 51+%

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Clinically, 50% had moderate illness, 37% had severe illness, 13% had critical illness, but this is never defined

Unfortunately, the authors never analyze the relationship between imaging findings and clinical severity

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-3 of 30 pts had no findings on lung US
-27 of 30 pts had lung US findings: all had B-lines
-6 had consolidation
-3 had pleural thickening
-only 1 had a small pleural effusion
-22 with bilateral involvement
-lower lobes and posterior regions more commonly involved

6/

Diagnostic accuracy of lung US compared to reference standard of CT:
-Normal: 93%
-Mild: 77%
-Moderate: 77%
-Severe: 93%

9 cases had POOR correlation between US and CT

Common problem with US was poor imaging of apices of lungs, especially upper posterior (due to scapula)

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It's great to have more evidence on #POCUSforCOVID

Unfortunately, this isn't a true diagnostic test assessment of US for COVID, as all included pts were known to have COVID based on PCR testing

We still don't know what the "definition" of a positive lung US for COVID is

8/

Take homes:
-There is moderate agreement between lung US and chest CT findings - one of the issues with US was visualizing apical abnormalities
-10% of pts had normal lung US
-All pts with lung US findings had B lines, most abnormalities were found posteriorly and inferiorly

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Things we still need to learn about #POCUSforCOVID
-Best scanning protocol
-Learning curve and generalizability
-Actual test characteristics for COVID
-Definition of positive US
-Clinical significance of findings (severity, prognosis)

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