Conservative oxygen therapy did not increase survival with a favorable functional outcome at 180 days compared to liberal oxygen therapy (38.2% vs 39.7%; RR 0.97; 95% CI 0.87-1.09; P=0.65).
RCT (n=1,840)
Randomized
Yes
Relative Risk: 0.97 (95% CI 0.87–1.09)
Absolute Event Rate: 38.2% vs 39.7%
p-value: p=0.65
Background In patients who are unresponsive after resuscitation from cardiac arrest, limiting oxygen exposure to that necessary to achieve acceptable oxygenation may increase the likelihood of survival with a favorable functional outcome. Methods We randomly assigned unresponsive adults receiving mechanical ventilation in the intensive care unit (ICU) after cardiac arrest to conservative or liberal oxygen therapy. In the two groups, the default lower limit of arterial oxygen saturation as measured by pulse oximetry (Sp o 2 ) was 90%. In the conservative-oxygen group, the alarm for the upper limit of the Sp o 2 was set at 95%, and the fraction of inspired oxygen (F io 2 ) was decreased to 0.21 provided that the Sp o 2 was above the lower limit. In the liberal-oxygen group, there were no measures limiting the upper Sp o 2 , but the minimum F io 2 permitted during mechanical ventilation was 0.3. The primary outcome was survival with a favorable functional outcome at 180 days, assessed with the Extended Glasgow Outcome Scale (GOS-E). Levels on the GOS-E range from 1 (death) to 8 (“upper good recovery”). We defined survival with a favorable functional outcome as a GOS-E level of 5 (“lower moderate disability”) or higher. Research Summary Conservative Oxygen for Unresponsive Patients after Cardiac Arrest Results A total of 1840 patients were recruited from 53 ICUs in Australia, New Zealand, and Ireland, with 882 assigned to conservative oxygen therapy and 958 assigned to liberal oxygen therapy. A favorable functional outcome at 180 days was observed for 313 of 819 patients (38.2%) in the conservative-oxygen group and 353 of 890 patients (39.7%) in the liberal-oxygen group (relative risk, 0.97; 95% confidence interval, 0.87 to 1.09; P=0.65). No adverse events were reported. Conclusions Among unresponsive adults undergoing mechanical ventilation in the ICU after a cardiac arrest, the percentage who survived with a favorable functional outcome was not higher with conservative oxygen therapy than with liberal oxygen therapy. (Funded by the Health Research Council of New Zealand and others; LOGICAL Australian New Zealand Clinical Trials Registry number, ACTRN12621000518864 .)
“Conservative oxygen therapy does not improve patients' outcomes regardless of the timing of initiation.”
The LOGICAL trial, published in a top-tier journal, addresses a common and debated topic in critical care cardiology. The finding that conservative oxygen therapy did not improve outcomes compared to a liberal approach provides important clarity for post-cardiac arrest care protocols.
The LOGICAL Investigators and the Australian and New Zealand Intensive Care Society Clinical Trials Group (2026) conducted an RCT in Cardiac arrest (n=1,840). Conservative oxygen therapy vs. Liberal oxygen therapy was evaluated on Survival with a favorable functional outcome at 180 days (RR 0.97, 95% CI 0.87-1.09, p=0.65). Conservative oxygen therapy did not increase survival with a favorable functional outcome at 180 days compared to liberal oxygen therapy (38.2% vs 39.7%; RR 0.97; 95% CI 0.87-1.09; P=0.65).