Lung ultrasound in ruling out COVID-19 pneumonia in the ED: a multicentre prospective sensitivity study.

PURPOSE: Early diagnosis of COVID-19 has a crucial role in confining the spread among the population. Lung ultrasound (LUS) was included in the diagnostic pathway for its high sensitivity, low costs, non-invasiveness and safety. We aimed to test the sensitivity of LUS to rule out COVID-19 pneumonia (COVIDp) in a population of patients with suggestive symptoms. METHODS: Multicentre prospective observational study in three EDs in Northeastern Italy during the first COVID-19 outbreak. A convenience sample of 235 patients admitted to the ED for symptoms suggestive COVIDp (fever, cough or shortness of breath) from 17 March 2020 to 26 April 2020 was enrolled. All patients underwent a sequential assessment involving: clinical examination, LUS, CXR and arterial blood gas. The index test under investigation was a standardised protocol of LUS compared with a pragmatic composite reference standard constituted by: clinical gestalt, real-time PCR test, radiological and blood gas results. Of the 235 enrolled patients, 90 were diagnosed with COVIDp according to the reference standard. RESULTS: Among the patients with suspected COVIDp, the prevalence of SARS-CoV-2 was 38.3%. The sensitivity of LUS for diagnosing COVIDp was 85.6% (95% CI 76.6% to 92.1%); the specificity was 91.7% (95% CI 86.0% to 95.7%). The positive predictive value and the negative predictive value were 86.5% (95%CI 78.8% to 91.7%) and 91.1% (95% CI 86.1% to 94.4%) respectively. The diagnostic accuracy of LUS for COVIDp was 89.4% (95% CI 84.7% to 93.0%). The positive likelihood ratio was 10.3 (95% CI 6.0 to 17.9), and the negative likelihood ratio was 0.16 (95% CI 0.1 to 0.3). CONCLUSION: In a population with high SARS-CoV-2 prevalence, LUS has a high sensitivity (and negative predictive value) enough to rule out COVIDp in patients with suggestive symptoms. The role of LUS in diagnosing patients with COVIDp is perhaps even more promising. Nevertheless, further research with adequately powered studies is needed. TRIAL REGISTRATION NUMBER: NCT04370275.

First comes the A, then the B: what we learned from the COVID-19 outbreak.

The SARS-CoV-2 epidemic, which has spread to many countries around the world, has hit Europe particularly hard. From our point of view, in a rural emergency department (with an annual patient census of around 25,000) in northeastern Italy, it is necessary to preserve the hospital and prevent it from becoming an outbreak of infection. In our experience, we reevaluated the negative predictive value of lung ultrasound to rule out lung involvement. Since severe acute respiratory failure appears to be the leading cause of death for COVID-19 patients, it is essential to focus on this clinical feature. We currently believe that a patient suspected of COVID-19, if he has a normal ultrasound examination (a so-called "A-profile"), can be discharged home to continue isolation and be treated without being hospitalized.