The Prone Position in the Treatment of Patients with ARDS: Problems and Real Utility

Prone positioning is a life-saving treatment used in ARDS patients in order to improve oxygenation and reduce lung injury due to mechanical ventilation. The beneficial effects of this procedure are the result of complex mechanisms that cooperate in improving gas exchange and in reducing global “stress” and “strain” of the lung. Prone positioning seems to be more effective in extrapulmonary form of ARDS, where the main feature of the disease is represented by compression atelectasis in dependent lung regions caused by the gain in lung weight due to pulmonary edema. To date, it is recommended in ARDS patients that maintain a PaO2/FiO2 ratio lower than 150 mmHg even after optimization of mechanical ventilation. However, only the patients who react to prone positioning with a decrease in PaCO2 show a real benefit in terms of survival rate. The relationship between improvement in gas exchange and patient outcome still remains unclear. This is not a maneuver free of complications, and it is important to balance risks and benefits associated with the procedure. An expert team is required to safely prone the patient and to reduce the incidence of adverse effects.