The Effects of Mechanical Ventilation on Oxygen Levels

The trial did not control oxygen administration prior to mechanical ventilation because patients were enrolled in the emergency department shortly after ICU admission. I think it's possible that the one of the subgrouping variables where there might be greater effect is patients who would be expected have more exposure to the interventions. And can you just, the peep levels across the groups seem to be very similar, but the patients were on very different oxygen strategies and healed oxygen concentrations. Do you have any comments on that?