Performance of oxygenation indices and risk scores to predict invasive mechanical ventilation and mortality in COVID-19

Abstract

Background Information on the performance of oxygenation indices (IO) and risk scores in patients requiring invasive mechanical ventilation (IMV) is limited. We determine the performance of the IOs and risk scores in hospitalized patients with COVID-19 to predict the requirement of IMV and death at 7, 14 and 28 days after admission. Methods Retrospective cohort study in patients admitted to the emergency department, hospitalization, and intensive care unit diagnosed with COVID-19 and in whom oxygenation indices were measured within the first 6 hours of admission, between 6 and 12 hours, 12 to 24 hours and greater than 24 hours. The receiver operating characteristic curve (ROC-curve) were built with the OIs and risk scores to predict IMV and mortality. Results A total of 1402 subjects entered the final analysis, of whom 19.5% (274/1402) received IMV and 23.0% (323/1402) died at 28 days. In the general population, the mean age was 59.9 years (SD 16.19), the male sex represented 63.3% (888/1402) and the duration from the onset of symptoms was 7.3 days (SD: 13.26). Analysis with the De Long test showed that at 7, 14 and 28 days the ROC-curves with the best performance for IMV were PaO2/FiO2, 4C score, SOFA score and SaO2/FiO2, the ROC curves of the rest of the OI evaluated were lower (p < 0.001). At 28 days, the ROC-curve with the best behavior for death was 4C compared to the ROC-curves of the rest of the OI and risk scores evaluated (p < 0.001). Conclusion PaO2/FiO2 ≤ 300, 4C score ≥ 8, SOFA score ≥ 4 y SaO2/FiO2 ≤ 300 were weak predictors of the IMV requirement from admission, and 4C score ≥ 8 was weak predictors of the mortality from admission in patients with pulmonary involvement by COVID-19.