Continuously available ratio of SpO2/FiO2 serves as a noninvasive prognostic marker for intensive care patients with COVID-19
Xiaofan Lu, Liyun Jiang, Taige Chen, Yang Wang, Bing Zhang, Yizhou Hong, Jun Wang, Fangrong Yan
Abstract
Abstract Rationale Oxygen saturation to fraction of inspired oxygen ratio (SpO 2 /FiO 2 ) has been described as potential predictor of poor outcome for COVID-19, without considering its time-varying behavior though. Methods Prognostic value of SpO 2 /FiO 2 was evaluated by jointly modeling the longitudinal responses of SpO 2 /FiO 2 and time-to-event data retrieved from 280 severe and critically ill (intensive care) patients with COVID-19. Results A sharply decrease of SpO 2 /FiO 2 from the first to second measurement for non-survivors was observed, and a strong association between square root SpO 2 /FiO 2 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 SpO 2 /FiO 2 could serve as a non-invasive prognostic marker to facilitate early adjustment for treatment, thus improving overall survival.