Intermittent prone positioning improves oxygenation but has no influence on outcome in the treatment of post-traumatic lung injury: a prospective, randomized, controlled study

In a randomized trial the effect of a predefined strategy of prone positioning on the duration of mechanical ventilation was evaluated in multiple trauma patients with acute lung injury or acute respiratory distress syndrome. Patients in the prone group (n = 21) were continuously kept prone for at least 8 hours and a maximum of 24 hours per day. Prone positioning was continued until a PaO₂:FiO₂ ratio of more than 300 was present in the prone as well as the supine position over a period of 48 hours. Patients in the supine group (n = 19) were positioned according to standard care guidelines. The duration of ventilatory support did not differ significantly between the two groups (20 ± 17 days in the prone group and 33 ± 23 days in the supine group). The mean duration of ventilatory support in prone position was 11 ± 5 hours a day. A mean of 7 ± 4 posture changes was applied per patient. One patient in the prone group and three patients in the supine group died due to multiorgan failure (P = 0.33). The PaO₂:FiO₂ ratio increased significantly more in the prone group than in the supine group in the first 4 days (P = 0.03). Thereafter no significant difference in the PaO₂:FiO₂ ratio was evident between the two groups. The number of adverse effects was not different between the groups. Therefore, despite an improvement of gas exchange, no clinical outcome benefit was detected.