Background: More than 600,000 adults in the United States experience an out-of-hospital or in-hospital cardiac arrest each year. Following resuscitation from cardiac arrest, most patients receive mechanical ventilation. The oxygenation target that optimizes neurologic outcomes following cardiac arrest is uncertain.

Research question: Following cardiac arrest, does a lower oxygen saturation (Spo2) target improve neurologic outcomes compared with a higher Spo2 target?

Study design and methods: This study was a secondary analysis of patients who experienced a cardiac arrest prior to enrollment in the Pragmatic Investigation of Optimal Oxygen Targets (PILOT) trial. The PILOT trial assigned critically ill adults receiving mechanical ventilation to a lower (88%-92%), intermediate (92%-96%), or higher (96%-100%) Spo2 target. This subgroup analysis compared patients randomized to a lower or intermediate Spo2 target (88-96%) vs a higher Spo2 target (96%-100%) regarding the primary outcome of survival with a favorable neurologic outcome at hospital discharge (Cerebral Performance Category 1 or 2).

Results: Of 2,987 patients in the PILOT trial, 339 (11.3%) experienced a cardiac arrest prior to enrollment: 221 were assigned to a lower or intermediate Spo2 target, and 118 were assigned to a higher Spo2 target. Overall, the median age was 60 years, 43.5% were female, 58.7% experienced an in-hospital cardiac arrest, and 10.2% had an initial shockable rhythm. Survival with a favorable neurologic outcome occurred in 50 patients (22.6%) assigned to a lower or intermediate Spo2 target and 15 (12.7%) patients assigned to a higher Spo2 target (absolute risk difference, 9.9 percentage points; 95% CI, 1.8-18.1; P = .03).

Interpretation: Among patients receiving mechanical ventilation following a cardiac arrest, use of a lower or intermediate Spo2 target was associated with a higher incidence of a favorable neurologic outcome compared with a higher target. A randomized trial comparing these targets in the cardiac arrest population is needed to confirm these findings.