Interobserver Agreement of Lung Ultrasound Findings of COVID-19

Background

Lung ultrasound (LUS) may be used in the diagnostic evaluation of patients with COVID-19. An abnormal LUS is associated with increased risk for ICU admission in COVID-19. Previously described LUS manifestations for COVID-19 include B-lines, consolidations, and pleural thickening. The interrater reliability (IRR) of these findings for COVID-19 is unknown.

Research Question

What is the interrater reliability of lung ultrasound findings in patients with RT-PCR confirmed COVID-19?

Study Design and Methods

This study was conducted at conducted at two academic medical centers between 03/2020-06/2020. Nine physicians (hospitalists: n=4; emergency medicine: n=5) independently evaluated n=20 LUS scans (n=180 independent observations) collected from RTPCR confirmed COVID-19 patients. These studies were randomly selected from an image database consisting of COVID-19 patients evaluated in the emergency department with portable ultrasound devices. Physicians were blinded to any patient information or previous LUS interpretation. Kappa values (κ) were used to calculate IRR.

Results

There was substantial IRR on the following items: normal LUS scan (κ=0.79 [95% CI: 0.72-0.87]), presence of B-lines (κ=0.79 [95% CI: 0.72-0.87]), >=3 B-lines observed (κ=0.72 [95% CI: 0.64-0.79]). Moderate IRR was observed for the presence of any consolidation (κ=0.57 [95% CI: 0.50-0.64]), subpleural consolidation (κ=0.49 [95% CI: 0.42-0.56]), and presence of effusion (κ=0.49 [95% CI: 0.41-0.56]). Fair IRR was observed for pleural thickening (κ=0.23 [95% CI: 0.15-0.30]).

Interpretation

Many LUS manifestations for COVID-19 appear to have moderate to substantial IRR across providers from multiple specialties utilizing differing portable devices. The most reliable LUS findings with COVID-19 may include the presence/count of B-lines or determining if a scan is normal. Clinical protocols for LUS with COVID-19 may require additional observers for the confirmation of less reliable findings such as consolidations.

<ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://Clinicaltrials.gov">Clinicaltrials.gov</ext-link> Registration: <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="clintrialgov" xlink:href="NCT04384055">NCT04384055</ext-link>

Disclosures

Andre Kumar, MD, MEd is a paid consultant for Vave Health, which manufactures one of the ultrasound devices used in this study. His consultant duties include providing feedback on product development. The other authors do not have any items to disclose.