Figure 3.

Per-patient trajectory of PaO₂/FiO₂ at the three study timepoints, SP1, PP1, and SP2, for responders (A) and non-responders (B)

Each line is the trajectory of one patient, with datapoints showing the PaO₂/FiO₂ ratio at the three timepoints. Responders were defined as patients with an increased PaO₂/FiO₂ ratio between SP1 to SP2 for the main analysis. All other patients who were successfully put in the prone position were non-responders. PaO₂=partial pressure of oxygen. FiO₂=fractional concentration of oxygen in inspired air. SP1=baseline supine position. PP1=10 min after prone positioning. SP2=1 h after resuming supine position.