‘To prone or not to prone’ in severe ARDS: questions answered, but others remain

Expanded abstractCitationsGuérin C, Reignier J, Richard JC, Beuret P, Gacouin A, Boulain T, Mercier E, Badet M, Mercat A, Baudin O, Clavel M, Chatellier D, Jaber S, Rosselli S, Mancebo J, Sirodot M, Hilbert G, Bengler C, Richecoeur J, Gainnier M, Bayle F, Bourdin G, Leray V, Girard R, Baboi L, Ayzac L, PROSEVA Study Group: Prone positioning in severe acute respiratory distress syndrome. N Engl J Med 2013, 368: 2159.BackgroundPrevious trials involving patients with the acute respiratory distress syndrome (ARDS) have failed to show a beneficial effect of prone positioning during mechanical ventilator support on outcomes. We evaluated the effect of early application of prone positioning on outcomes in patients with severe ARDS.MethodsObjective: The objective was to evaluate the effect of early application of prone position on mortality in patients with severe ARDS.Design: The PROSEVA group conducted a multicenter, prospective, randomized controlled trial.Setting: Patients with ARDS were recruited from 26 ICUs in France and one ICU in Spain.Subjects: The subjects were critically ill patients admitted to the ICU with respiratory failure requiring mechanical ventilation for severe ARDS. Severe ARDS criteria - an arterial partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2) ratio of less than 150 mm Hg, an FiO2 of at least 0.6, a positive end-expiratory pressure of at least 5 cm of water, and a tidal volume of about 6 mL per kilogram of predicted body weight - were confirmed after 12 to 24 hours of mechanical ventilation in the participating ICUs. Subjects were eligible after 12 to 24 hours of stabilization and were randomly assigned to either the prone group or the supine group.Intervention: Four hundred sixty-six patients with severe ARDS underwent prone position ventilation of at least 16 hours or ventilation in the supine position. Patients assigned to the prone group were manually turned in standard ICU beds to the prone position within the first hour of random assignment and were placed prone for at least 16 consecutive hours. Standard ventilator protocols and weaning protocols were implemented for study participants.Outcomes: The primary outcome was the proportion of patients who died from any cause within 28 days after random assignment.ResultsIn total, 237 patients were assigned to the prone group and 229 patients were assigned to the supine group. The 28-day mortality rates were 16% in the prone group and 32.8% in the supine group (P <0.001). The hazard ratio for death with prone ventilation was 0.39 (95% CI 0.25 to 0.63). Unadjusted 90-day mortality rates were 23.6% in the prone group and 41% in the supine group (P <0.001), with a hazard ratio of 0.44 (95% CI 0.29 to 0.67). The incidence of complications did not differ significantly between the groups, except for the incidence of cardiac arrests, which was higher in the supine group.ConclusionsIn patients with severe ARDS, early application of prolonged prone-positioning sessions significantly decreased 28-day and 90-day mortality.