Oxygen Targets in Comatose Survivors of Cardiac Arrest

N Engl J Med. 2022 Oct 20;387(16):1467-1476. doi: 10.1056/NEJMoa2208686. Epub 2022 Aug 27.


Background: The appropriate oxygenation target for mechanical ventilation in comatose survivors of out-of-hospital cardiac arrest is unknown.

Methods: In this randomized trial with a 2-by-2 factorial design, we randomly assigned comatose adults with out-of-hospital cardiac arrest in a 1:1 ratio to either a restrictive oxygen target of a partial pressure of arterial oxygen (Pao2) of 9 to 10 kPa (68 to 75 mm Hg) or a liberal oxygen target of a Pao2 of 13 to 14 kPa (98 to 105 mm Hg); patients were also assigned to one of two blood-pressure targets (reported separately). The primary outcome was a composite of death from any cause or hospital discharge with severe disability or coma (Cerebral Performance Category [CPC] of 3 or 4; categories range from 1 to 5, with higher values indicating more severe disability), whichever occurred first within 90 days after randomization. Secondary outcomes were neuron-specific enolase levels at 48 hours, death from any cause, the score on the Montreal Cognitive Assessment (ranging from 0 to 30, with higher scores indicating better cognitive ability), the score on the modified Rankin scale (ranging from 0 to 6, with higher scores indicating greater disability), and the CPC at 90 days.

Results: A total of 789 patients underwent randomization. A primary-outcome event occurred in 126 of 394 patients (32.0%) in the restrictive-target group and in 134 of 395 patients (33.9%) in the liberal-target group (hazard ratio, 0.95; 95% confidence interval, 0.75 to 1.21; P = 0.69). At 90 days, death had occurred in 113 patients (28.7%) in the restrictive-target group and in 123 (31.1%) in the liberal-target group. On the CPC, the median category was 1 in the two groups; on the modified Rankin scale, the median score was 2 in the restrictive-target group and 1 in the liberal-target group; and on the Montreal Cognitive Assessment, the median score was 27 in the two groups. At 48 hours, the median neuron-specific enolase level was 17 μg per liter in the restrictive-target group and 18 μg per liter in the liberal-target group. The incidence of adverse events was similar in the two groups.

Conclusions: Targeting of a restrictive or liberal oxygenation strategy in comatose patients after resuscitation for cardiac arrest resulted in a similar incidence of death or severe disability or coma. (Funded by the Novo Nordisk Foundation; BOX ClinicalTrials.gov number, NCT03141099.).

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biomarkers / analysis
  • Coma* / etiology
  • Coma* / mortality
  • Coma* / therapy
  • Humans
  • Out-of-Hospital Cardiac Arrest* / complications
  • Out-of-Hospital Cardiac Arrest* / therapy
  • Oxygen* / administration & dosage
  • Phosphopyruvate Hydratase / analysis
  • Respiration, Artificial* / methods
  • Respiratory Insufficiency* / etiology
  • Respiratory Insufficiency* / therapy
  • Survivors


  • Oxygen
  • Phosphopyruvate Hydratase
  • Biomarkers

Associated data

  • ClinicalTrials.gov/NCT03141099