Prone Positioning Not Relevant to Survival Rate in Patients with ARDS

Prone positioning during mechanical ventilation may not improve survival duration in patients with acute respiratory distress syndrome (ARDS), according to a new study.

Researchers at the Ospedale Maggiore Policlinico di Milano (Italy) conducted the multicenter randomized Prone-Supine II trial to evaluate possible outcome benefits of prone positioning in patients with ARDS and moderate or severe hypoxemia. A total of 342 adults with ARDS receiving mechanical ventilation at 23 centers in Italy, and two in Spain, were enrolled in the study, and were prospectively stratified into subgroups with moderate and severe hypoxemia. The participants were randomly selected to supine positioning (174 patients) or prone positioning for 20 hours per day (168 patients) during ventilation. The main endpoint of the study was 28-day all-cause mortality, and secondary endpoints were 6-month mortality and mortality at intensive care unit discharge, organ dysfunction, and complication rate associated with prone positioning.

The researchers found that for the overall entire study population evaluated between February 2004 and June 2008, prone and supine positioning were associated with similar mortality rates at 28 days and six months; however, the prone group had a significantly higher complication rate. For patients with moderate hypoxemia, outcomes were also similar in the prone and supine groups at 28 days and at 6 months. For patients with severe hypoxemia, 28-day mortality rate was 37.8% in the prone group and 46.1% in the supine group, and six-month mortality rate was 52.7% and 63.2%, respectively. Positioning was not associated with any apparent differences in median sequential organ failure assessment (SOFA) scores, ventilator-free days, or intensive care unit length of stay. The study was published in the November 11, 2009, issue of the Journal of the American Medical Association (JAMA).

"Do the findings of this trial, together with those of previous studies, represent the end of the prone position technique?” inquired lead author Paolo Taccone, M.D., and colleagues of the department of anesthesia. "Undoubtedly, the data of the present trial together with previous results clearly indicate that prolonged prone positioning, in the unselected ARDS population, is not indicated as a treatment. However, its potential role in patients with the most severe hypoxemia, for whom the possible benefit could outweigh the risk of complications, must be further investigated.”

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Ospedale Maggiore Policlinico di Milano