Oxygenation Index as Evolutionary Markers of Acute Lung Injury by SARS-CoV-2

Abstract

Background: acute lung injury (APL) is a heterogeneous syndrome manifested by acute respiratory failure; SARS-CoV-2 is an emerging virus capable of causing APL. The oxigenation index (OI) are the numerical expression that reflect the capillary alveolus gas exchange, highlighting the alveolar-arterial oxygen gradient (G (Aa) O₂), the arterial pressure of oxygen / inspired oxygen fraction (PaO₂ / FiO₂) and the respiratory index (IR). Objective: to identify the clinical evolution of APL through OI. Material and methods: retrospective, longitudinal, descriptive, analytical study. Patients with a diagnosis of a suspected or confirmed case of SARS-CoV-2 or COVID-19 pneumonia were classified according to the supplemental oxygen device used at the time of admission to the ICU. Group 1: No invasive respiratory support. Group 2: With invasive respiratory support. The OIs were calculated at admission, at 24 hours and at 96 hours and the outcome of the patients was observed. Results: 175 patients were recruited, for group 1 the GA-aO₂ at 96hrs had AUC 0.965 (95% CI 0.914-1.000) p = 0.000 and for group 2 the PaO₂ / FiO₂ at 96hrs with AUC of 0.836 (CI 95% 0.766-0.905) and the IR with AUC of 0.832 (95% CI 0.761-0.902) p = 0.000. Conclusion: OIs are markers of the progression of APL by SARS-CoV-2, improving their diagnostic performance over time.