The lung ultrasound "Rule of 7" in the prognosis of COVID-19 patients: Results from a prospective multicentric study.

Purpose: There is growing evidence regarding the imaging findings of coronavirus disease 2019 (COVID-19) in lung ultrasound (LUS), however the use of a combined prognostic and triage tool has yet to be explored.To determine the impact of the LUS in the prediction of the mortality of patients with highly suspected or confirmed COVID-19.The secondary outcome was to calculate a score with LUS findings with other variables to predict hospital admission and emergency department (ED) discharge. Material and methods: Prospective study performed in the ED of three academic hospitals. Patients with highly suspected or confirmed COVID-19 underwent a LUS examination and laboratory tests. Results: A total of 228 patients were enrolled between March and September 2020. The mean age was 61.9 years (Standard Deviation - SD 21.1). The most common findings in LUS was a right posteroinferior isolated irregular pleural line (53.9%, 123 patients). A logistic regression model was calculated, including age over 70 years, C-reactive protein (CRP) over 70 mg/L and a lung score over 7 to predict mortality, hospital admission and discharge from the ED. We obtained a predictive model with a sensitivity of 56.8% and a specificity of 87.6%, with an AUC of 0.813 [ Conclusions: The combination of LUS, clinical and laboratory findings in this easy to apply "rule of 7" showed excellent performance to predict hospital admission and mortality.