Figure 3.

Physiological effects of awake prone positioning

Means are indicated by points, with standard deviation indicated by the shaded area. (A) Ratio of peripheral arterial oxygen saturation to the fraction of inspired oxygen (SpO₂:FiO₂). (B) Respiratory rate in breaths per minute. (C) The ROX index is equal to SpO₂:FiO₂ divided by the respiratory rate. Lower values indicate more severe respiratory compromise. Values were recorded 1 h to immediately before the first awake prone positioning session, during the session 30 min to 1 h after the patient was placed into prone position and 30 min to 1 h after the patient had returned into the supine position.