Lung Ultrasound in the Emergency Department for Early Identification of COVID-19 Pneumonia

Background: Coronavirus disease 2019 (COVID-19) is a pandemic overwhelming the health care systems worldwide. Lung ultrasound (LUS) use has been proposed to identify suspected COVID-19 patients and direct them to the isolation area in the emergency department (ED) or to discharge them for outpatient treatment. Objective: Our aim was to retrospectively investigate the use of LUS in the ED to identify COVID-19 pneumonia (CP). Methods: We performed a retrospective single-center study including all patients accessing the ED who underwent LUS examination for suspicion of COVID-19 during the initial outbreak. Demographics, clinical parameters, laboratory values, imaging features, and outcome variables were collected. The receiver operating characteristic (ROC) curve was used to evaluate diagnostic accuracy. Results: A total of 41% patients were COVID-19-positive; 67% of them were diagnosed with CP. The ROC curve of the LUS score showed an area under the curve of 0.837 (95% CI 0.75-0.92) and with a cutoff value >= 3 identified 28 of 31 patients with CP and 11 of 15 without (sensitivity 90%, 95% CI 74-97%; specificity 75%, 95% CI 56-76%). LUS in combination with nasopharyngeal swab has a sensitivity of 100% (95% CI 74-97%) and a specificity of 61% (95% CI 44-67%). Conclusions: LUS is a promising technique for early identification of CP in patients who accessed the ED in an active epidemic time. The LUS score shows a sensitivity of 90% for CP, allowing to quickly direct patients with COVID-19 to the ED isolation area or to discharge them for outpatient treatment.