Figure 3

PaO ₂ /FiO ₂ ratios of patients in the two randomization groups. (a) Group A: PaO₂/FiO₂ ratio of patients at baseline in supine position, after 1 and 2 h of prone position (PP 1 h and PP 2 h), and after 1, 2, and 6 h of prone position with additional upright position (PP + UP 1 h, PP + UP 2 h, and PP + UP 6 h). *Statistically significant increase. (b) Group B: PaO₂/FiO₂ ratio of patients at baseline in supine position, after 1 and 2 h of prone position with additional upright position (PP + UP 1 h and PP + UP 2 h), and after 1, 2, and 6 h of prone position (PP 1 h, PP 2 h, and PP 6 h). *Statistically significant increase; §statistically significant decrease. PP, prone position; UP, upright position.