Background More than 600,000 adults in the United States experience a cardiac arrest each year. After resuscitation from cardiac arrest, most patients receive mechanical ventilation. The oxygenation target that optimizes neurologic outcomes after cardiac arrest is uncertain.

Research Question After cardiac arrest, does a lower oxygen saturation (SpO2) target improve neurologic outcomes compared to a higher SpO2 target?

Study Design and Methods We conducted a secondary analysis of patients who experienced a cardiac arrest before 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%) versus a higher SpO2 target (96-100%) with regard to the primary outcome of survival with a favorable neurologic outcome at hospital discharge (Cerebral Performance Category 1 or 2). The secondary outcome was in-hospital death.

Results Of 2,987 patients in the PILOT trial, 339 (11.3%) experienced a cardiac arrest before 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 (P=0.03). In-hospital death occurred in 146 patients (66.1%) assigned to a lower-or-intermediate SpO2 target and 89 (75.4%) assigned to a higher target (P=0.08).

Interpretation Among patients receiving mechanical ventilation after 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.

The authors have declared no competing interest.

Grant Support: This work was supported in part by grants from the National Institutes of Health. J.D.C. was supported in part by the NIH (K23HL153584). S.C.D was supported in part by the NIH (5T32GM108554). K.P.S. was supported in part by the NIH (5T32HL087738). M.W.S. was supported in part by the NIH (K23HL143053). T.W.R. was supported in part by the NIH (UL1TR002243). W.H.S. was supported in part by the NIH (UL1TR002243). N.J.J. receives funding from NIH, CDC, and American Heart Association (AHA) and serves on guidelines committees for the AHA and International Liaison Committee on Resuscitation.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The PILOT trial was approved by the institutional review board at Vanderbilt University Medical Center.

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All data produced in the present study are available upon reasonable request to the authors. Note this manuscript is currently under peer review at CHEST.