Usefulness of lung ultrasound in the early identification of severe COVID-19: results from a prospective study

Aim: There is growing evidence regarding the imaging findings of coronavirus disease 2019 (COVID-19) in lung ultrasound (LUS); however, its role in predicting the prognosis has yet to be explored. The aim of the study was to assess the relationship between lung ultrasound findings with the degree of respiratory failure measured by the PaO2/FiO2 ratio (PaFi) and the prognosis of these patients: need for non-invasive mechanical ventilation (NIMV), admission to the Intensive Care Unit (ICU) and mortality. Material and method: Prospective, longitudinal and observational study performed in patients with confirmed COVID-19 underwent a LUS examination and laboratory tests. Results: A total of 107 patients were enrolled: 93.4% with bilateral involvement and 73.83% presented at least one consolidation. A good inverse correlation (Rho Spearman coefficient -0.897) between the ultrasound score and PaFi was obtained. The AUC for identification of patients with more severe respiratory failure, a moderate and severe ARDS, was 0.97 (CI 95%: 0.95-1) and a cut-off score of 34.5 showed a sensitivity of 0.94 and a specificity of 0.91. The Kappa index showed a high concordance (0.83) of the classification by ultrasound lung involvement and ARDS. Conclusions: The combination of the ultrasound score and the presence of respiratory failure can easily identify patients with a higher risk to present complications.