- For ICU patients undergoing mechanical ventilation, minimizing exposure to high oxygen saturation (SpO2) does not lead to more ventilator-free days.
- Editorial discusses challenges to measuring oxygen saturation, heterogeneity of organ perfusion; concludes “avoiding excess oxygen seems sensible,” suggests setting lower SpO2 target bound at 90%.
Why this matters
- Hyperoxemia has been tied to mortality in observational studies, suggesting potential benefit to a more conservative approach.
- Conservative vs liberal group:
- Median ventilator-free days: 21.3 vs 22.1 (P=.80).
- Time in ICU with fraction of inspired oxygen (FIO2) of 0.21: 29 vs 1 hour.
- Time with SpO2 ≥97%: 27 vs 49 hours.
- 180-day mortality: 35.7% vs 34.5%;
- aOR, 1.05 (95% CI, 0.81-1.37).
- No differences in later employment status, cognitive function.
- Possible benefit to conservative oxygen in subgroup with acute hypoxic encephalopathy.
- Multicenter parallel-group randomized clinical ICU-ROX trial (n=965).
- Participants intubated, mechanically ventilated in ICU were randomly assigned to:
- Conservative oxygenation, in which FIO2 was decreased to 0.21 if SpO2 hit 97%.
- Usual oxygenation, with no FIO2 limit or SpO2 upper limit.
- Outcome: ventilator-free days through day 28.
- Funding: Health Research Council of New Zealand.
- Clinicians allowed to increase oxygen under some circumstances, potentially reducing outcome differences.
- Appearing in same issue: LOCO2 trial of conservative oxygen in acute respiratory distress syndrome.
- Editorial discussed both.