Journal Article

Point-of-care lung ultrasonography for early identification of mild COVID-19: a prospective cohort of outpatients in a Swiss screening center

Hartley, Mary-Anne, Schaad, Siméon, Brahier, Thomas, Espejo, Tanguy, Meuwly, Jean-Yves, Pantet, Olivier, Carron, Pierre-Nicolas, Hugli, Olivier, Cordonnier, Jean-Baptiste, Boillat-Blanco, Noémie, Bosso, Luca

2022

Overview

ObjectivesEarly identification of SARS-CoV-2 infection is important to guide quarantine and reduce transmission. This study evaluates the diagnostic performance of lung ultrasound (LUS), an affordable, consumable-free point-of-care tool, for COVID-19 screening.Design, setting and participantsThis prospective observational cohort included adults presenting with cough and/or dyspnoea at a SARS-CoV-2 screening centre of Lausanne University Hospital between 31 March and 8 May 2020.InterventionsInvestigators recorded standardised LUS images and videos in 10 lung zones per patient. Two blinded independent experts reviewed LUS recording and classified abnormal findings according to prespecified criteria to investigate their predictive value to diagnose SARS-CoV-2 infection according to PCR on nasopharyngeal swabs (COVID-19 positive vs COVID-19 negative).Primary and secondary outcome measuresWe finally combined LUS and clinical findings to derive a multivariate logistic regression diagnostic score.ResultsOf 134 included patients, 23% (n=30/134) were COVID-19 positive and 77% (n=103/134) were COVID-19 negative; 85%, (n=114/134) cases were previously healthy healthcare workers presenting within 2–5 days of symptom onset (IQR). Abnormal LUS findings were significantly more frequent in COVID-19 positive compared with COVID-19 negative (45% vs 26%, p=0.045) and mostly consisted of focal pathologic B lines. Combining clinical findings in a multivariate logistic regression score had an area under the receiver operating curve of 80.3% to detect COVID-19, and slightly improved to 84.5% with the addition of LUS features.ConclusionsCOVID-19-positive patients are significantly more likely to have lung pathology by LUS. However, LUS has an insufficient sensitivity and is not an appropriate screening tool in outpatients. LUS only adds little value to clinical features alone.

• Publisher: British Medical Journal Publishing Group,BMJ Publishing Group LTD,BMJ Publishing Group
• Subject: Adult / COVID-19 / COVID-19 - diagnostic imaging / COVID-19 diagnostic tests / diagnostic radiology / Humans / Infectious Diseases / Lung - diagnostic imaging / Medical diagnosis / Medical screening / Outpatients / Point of care testing / Point-of-Care Systems / Prospective Studies / SARS-CoV-2 / Switzerland - epidemiology / Ultrasonic imaging / ultrasonography / Ultrasonography - methods