Fondazione IRCCS LogoThe existing proposal reveals that patients with acute respiratory distress syndrome should be positioned lying face down while receiving mechanical ventilation. However, the latest findings of the study indicate that this positioning may not considerably reduce the risk of death in contrast to similar patients positioned lying face up during ventilation.

Acute respiratory distress syndrome (ARDS) is known to be a serious lung condition with a high mortality rate. More so, it could possibly be associated with severe hypoxemia. Hypoxemia appears to be abnormally low levels of oxygen in the blood leading to shortness of breath.

Presently, prone positioning seems to be suggested for patients with ARDS, for whom a variety of factors make mechanical ventilation likely injurious. Moreover, prone positioning has been advocated as a rescue scheme for severe hypoxemia, owing to its positive effects on oxygenation.

Oxygenation is known to have been frequently documented since its first description in 1976. However, no randomized clinical trial seems to have established a considerable reduction in mortality rate associated with prone positioning.

Paolo Taccone, M.D., of Fondazione IRCCS-‘Ospedale Maggiore Policlinico, Mangiagalli, Regina Elena’ di Milano, Milan, Italy, along with his colleagues conducted a trial to identify the possible survival benefit of prone positioning in patients with moderate and severe hypoxemia who are affected by ARDS.

The randomized controlled trial was observed to have been conducted in 23 centers in Italy and 2 in Spain. Also, the study included 342 adult patients with ARDS receiving mechanical ventilation, enrolled from February 2004 through June 2008. Further, the patients seem to have been stratified into subgroups with moderate i.e. n = 192 and severe n = 150 hypoxemia. Patients were randomized to undergo supine i.e. lying face up; n = 174 or prone 20 hours per day; n = 168 positioning during ventilation.

“Outcomes were also similar for patients with moderate hypoxemia in the prone and supine groups at 28 days (25.5 percent vs. 22.5 percent) and at 6 months (42.6 percent vs. 43.9 percent). The 28-day mortality of patients with severe hypoxemia was 37.8 percent in the prone and 46.1 percent in the supine group, while their 6-month mortality was 52.7 percent and 63.2 percent, respectively,” explains Taccone.

“Do the findings of this trial, together with those of previous studies, represent the end of the prone position technique? 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, considering the strong pathophysiological background, the post hoc result of our previous study, the most recent meta-analysis, and the favorable trend observed prospectively in this study,” concludes Taccone.

The findings of the study revealed that prone and supine patients from the entire study population seem to have similar 28-day despite significantly higher complication rates in the prone group i.e. 31.0 percent against 32.8 percent and 6-month i.e. 47.0 percent vs. 52.3 percent mortality rates. The authors further found that median Sequential Organ Failure Assessment (SOFA) scores, ventilator-free days, and intensive care unit length of stay appear to have also been similar between the different groups of patients.

The findings of the study have been published in the Journal of the American Medical Association.