Oxygen After Cardiac Arrest: Conservative vs. Liberal Strategy

While a meta-analysis suggested that liberal oxygen therapy in hospitalized patients can be harmful, testing conservative oxygenation strategies seemed logical, especially after cardiac arrest, when the brain is most sensitive to oxidative stress. While subsequent randomized trials in critically ill patients did not demonstrate benefits to conservative oxygenation strategies, patients with cardiac arrest were underrepresented.

To address this gap, investigators identified more than 1800 unresponsive adults on mechanical ventilation after out-of-hospital or in-hospital cardiac arrest, with return of spontaneous circulation (ROSC) averaging 25 minutes after arrest. They were randomized to conservative oxygen therapy (target O₂ saturatio…