Study Design Summary: Randomized trial of 1,000 patients of patients with less than 2 hours of invasive or noninvasive mechanical ventilation. Separated into 2 groups of conservative vs usual oxygen therapy groups. Primary outcome was ventilator free days, secondary outcomes included death at 90 and 180 days as well as others.
Notes: There were many patients excluded from this trial, some for reasons that seem like the investigators were quite selective, including 254 patients excluded for “severe morbidity.” Overall the intervention and control groups were not the most balanced but were balanced enough.
Both the intervention and control group used SpO2 of 90% as the lower acceptable limit. The control group of “usual oxygen therapy” had no other specific requirements but FiO2 of less than 0.3 was discouraged. The intervention group of “conservative oxygen therapy” targeted a SpO2 of less than 97%. Alarms were set on both groups to alert staff if the SpO2 was out of goal range. Clinicians could deviate from protocol if they felt it was necessary.
There was no difference in between the intervention and control group in terms of both the primary outcome of ventilator free days (15.5 vs 16.0) as well as secondary outcomes including death at 90 days, 180 days, vasopressor free days and number of patients required renal replacement therapy.
There were no real difference in adverse outcomes between the two groups listed, but it is mentioned in the paper. Previous studies have shown improved mortality and ventilator free days with conservative oxygen therapy. This study notes that previous papers with that conclusion have had very liberal oxygen strategies for the control groups and as opposed to the “usual oxygen therapy” in this group, meaning previous papers’ control groups had higher hyperoxia than the control group in this study.
Study Conclusion: The use of conservative oxygen therapy as opposed to usual care did not increase the number of ventilator free days.
Fusion Beat Bottom Line Impression: This study supports the conclusion that conservative oxygen therapy does not increase the number of ventilator free days, but given previous papers showing harm from hyperoxia, and the low adverse outcomes demonstrated with conservative oxygen therapy in this study, overall targeting normoxia is likely best.
A Fusion Beat 