Prone positioning improves oxygenation in post-traumatic lung injury--a prospective randomized trial.

BACKGROUND: In a prospective randomized trial the effect of prone positioning on the duration of mechanical ventilation was evaluated in multiple trauma patients and was compared with patients ventilated in supine position.

METHOD: Multiple trauma patients of the intensive care units of two university hospitals were considered eligible if they met the criteria for acute lung injury or the acute respiratory distress syndrome. Patients in the prone group (N = 21) were kept prone for at least eight hours and a maximum of 23 hours per day. Prone positioning was continued until a PaO2:FiO2 ratio of more than 300 was present in prone as well as supine position over a period of 48 hours. Patients in the supine group (N = 19) were positioned according to standard care guidelines.

RESULTS: The duration of ventilatory support did not differ significantly (30 +/- 17 days in the prone group and 33 +/- 23 days in the supine group). Worst case analysis (death and deterioration of gas exchange) displayed ventilatory support for 41 +/- 29 days in the prone group and 61 +/- 35 days in the supine group (p = 0.06). The PaO2:FiO2 ratio increased significantly more in the prone group in the first four days (p = 0.03). The prevalence of Acute Respiratory Distress Syndrome (ARDS) following acute lung injury (p = 0.03) and the prevalence of pneumonia (p = 0.048) were reduced also. One patient in the prone and three patients in the supine group died due to multi organ failure (p = 0.27).

CONCLUSIONS: Intermittent prone positioning was not able to reduce the duration of mechanical ventilation in this limited number of patients. However the oxygenation improved significantly over the first four days of treatment, and the prevalence of ARDS and pneumonia were reduced.