Lung ultrasound as a prognostic tool in emergency patients clinically suspected of COVID-19

INTRODUCTION: Tools to quickly triage and evaluate patients with suspected COVID-19 in an emergency department (ED) can improve patient care and reduce risk of overcrowding. The aim of this study was to evaluate if lung ultrasound (LUS) may provide valuable prognostic information in adult patients suspected of COVID-19.

METHODS: A prospective cohort study of adult patients in an ED was conducted. LUS was performed within one hour of the patients' arrival; COVID-19 was defined by a respiratory syndrome coronavirus 2 RNA positive test. The primary outcome was the proportion of patients suspected of COVID-19 and normal LUS with critical outcomes during follow-up, defined as one or more of the following: need of non-invasive ventilation (NIV), invasive mechanical ventilation, intensive care unit (ICU) stay or death. Follow-up was 14 days.

RESULTS: A total of 83 patients were included between 9 March and 12 April 2020. In all, 47 (57%; 95% confidence interval (CI): 45.3-67.5%) had a normal LUS, 46 (98%; 95% CI: 88.7-99.9%) of whom had no critical outcomes. A total of 36 (43%; 95% CI: 32.5-54.7%) had an abnormal LUS, eight of whom (22%; 95% CI: 10.1-39.2%) had critical outcomes. Nine (11%; 95%: CI 5.1-19.6%) had one or more critical outcomes: three on NIV, five in ICUs, four on invasive mechanical ventilation and two died. Among the 12 patients (14%; 95% CI: 7.7-23.9%) tested positive for COVID-19, 11 (92%; 95% CI: 61.5-99.8%) had an abnormal LUS.

CONCLUSIONS: Among adult ED patients suspected of COVID-19, a normal LUS is associated with a low risk of critical outcomes. LUS might be considered for routine use as a prognostic tool in patients suspected of COVID-19.

FUNDING: none.

TRIAL REGISTRATION: not relevant.