The Cumulative Partial Pressure of Arterial Oxygen Is Associated With Neurological Outcomes After Cardiac Arrest Treated With Targeted Temperature Management

Objective: Hyperoxia could lead to a worse outcome after cardiac arrest. The aim of this study was to investigate the relationship between the cumulative partial pressure of arterial oxygen (Pao(2)) and neurological outcomes after cardiac arrest treated with targeted temperature management. Design: Retrospective analysis of a prospective cohort. Setting: An academic tertiary care hospital. Patients: A total of 187 consecutive patients treated with targeted temperature management after cardiac arrest. Interventions: None. Measurements and Main Results: The area under the curve of Pao(2) for different cutoff values of hyperoxia (>= 100, >= 150, >= 200, >= 250, and >= 300 mm Hg) with different time intervals (0-24, 0-6, and 6-24 hr after return of spontaneous circulation) was calculated for each patient using the trapezoidal method. The primary outcome was the neurologic outcome, as defined by the cerebral performance category, at 6 months after cardiac arrest. Of 187 subjects, 77 (41%) had a good neurologic outcome at 6 months after cardiac arrest. The median age was 54 (43-69) years, and 128 (68%) were male. The area under the curve of Pao(2) with cutoff values of greater than or equal to 200, greater than or equal to 250, and greater than or equal to 300 was higher in the poor outcome group at 0-6 and 0-24 hours. The adjusted odds ratios of area under the curve of Pao(2) greater than or equal to 200 mm Hg were 1.659 (95% CI, 1.194-2.305) for 0-24 hours after return of spontaneous circulation and 1.548 (95% CI, 1.086-2.208) for 0-6 hours after return of spontaneous circulation. With a higher cumulative exposure to oxygen tension, we found significant increasing trends in the adjusted odds ratio for poor neurologic outcomes. Conclusion: In a new method for Pao(2) analysis, cumulative exposure to hyperoxia was associated with neurologic outcomes in a dose-dependent manner. Greater attention to oxygen supply during the first 6 hours appears to be important for outcome after cardiac arrest.