Miguel Filipe Guia José Pedro Boléo-Tomé Pasquale Imitazione, et al. - In view of the necessity for developing tools to assess early CPAP failure in COVID-19, HACOR (heart rate, acidosis, consciousness, oxygenation, respiratory rate) score performance was evaluated in these patients as a predictor of CPAP failure. In this prospective observational multicentric study (three centers in different countries), adult patients with SARS-CoV-2 pneumonia, who presented with PaO₂/FiO₂ < 300 and PaCO₂ < 45 mmHg and received CPAP, were included. HACOR was calculated 1 hour after initiating CPAP. Among 128 enrolled patients (mean age 61,7 years), 35 (27,3%) presented CPAP failure: 29 underwent oro-tracheal intubation and 6 died due to COVID-19 (all having a do-not-intubate order). Accuracy for predicting CPAP failure was 82,03% for HACOR, while accuracy was 81,25% in correlation with PaO₂/FiO₂. Per these findings, HACOR score as well as PaO₂/FiO₂ exhibited a good diagnostic performance in predicting CPAP failure in COVID-19-related acute respiratory failure.