Continuously available ratio of SpO2/FiO2serves as a noninvasive prognostic marker for intensive care patients with COVID-19

Abstract

Rationale: Oxygen saturation to fraction of inspired oxygen ratio (SpO2/FiO2) has been described as potential predictor of poor outcome for COVID-19, without considering its time-varying behavior though. Methods: Prognostic value of SpO2/FiO2 was evaluated by jointly modeling the longitudinal responses of SpO2/FiO2 and time-to-event data retrieved from 280 severe and critically ill (intensive care) patients with COVID-19. Results: A sharply decrease of SpO2/FiO2 from the first to second measurement for non-survivors was observed, and a strong association between square root SpO2/FiO2 and mortality risk was demonstrated, with a unit decrease in the marker corresponding to 1.82-fold increase in mortality risk (95% CI: 1.56-2.13). Conclusions: The current study suggested that SpO2/FiO2 could serve as a non-invasive prognostic marker to facilitate early adjustment for treatment, thus improving overall survival.