Question special
Attending

In the manuscript, the authors comment that there were differences in the use of prone positioning between the conservative and liberal oxygen treatment groups in the trial. In reviewing the supplement, it appears that 17% more patients received in the liberal oxygenation arm were treated with prone positioning. In the PROSEVA trial, use of prone positioning in severe ARDS, as it appears many of the patients in this trial had, prone positioning reduced 28-day mortality.