Oxygen Therapy in the ICU

To the Editor: Mackle et al. (March 12 issue) 1 report that ICU-ROX (Intensive Care Unit Randomized Trial Comparing Two Approaches to Oxygen Therapy) showed that in patients undergoing mechanical ventilation, there was no significant difference in ventilator-free days between those who received conservative oxygen supplementation to avoid systemic hyperoxemia and those who received usual oxygen therapy. Although patients who had received invasive mechanical ventilation or noninvasive ventilation for 2 hours or more before enrollment were excluded, there was no mention or documentation of the fraction of inspired oxygen (F i o 2 ) received before the trial interventions. This may be a considerable omission . . .