Fig. 1

Dynamic profile of SpO₂/FiO₂ marker and dynamic survival probabilities of five intensive care patients with COVID-19 during follow-up. The first time line chart illustrates the distribution (mean ± standard error) of square root SpO₂/FiO₂ in 280 patients (112 non-survivors and 168 survivors) at each measurement time point, and no record of day 28 for non-survivors because the death event occurred earlier then 28 days. The following conditional survival curves for five patients showing how survival probability varied with the marker. The solid survival curves represent the median estimator and the corresponding longitudinal trajectories are depicted in the dotted boxes at the bottom left with four measurements because these patients discharged or died before the 28-day since admission to intensive care wards