NEJM: No Benefit to Higher or Lower Blood Pressure and Oxygen Targets in Comatose Patients After Cardiac Arrest

Patricia Kritek, MD, reviewing Schmidt H et al. N Engl J Med 2022 Aug 27 Kjaergaard J et al. N Engl J Med 2022 Aug 27

Oxygen delivery to the brain is essential after cardiac arrest. Inadequate perfusion worsens ischemic injury; however, animal models suggest that hyperoxia also can be harmful. Evidence is limited for blood pressure and oxygenation goals for patients who are comatose after cardiac arrest; two recent large trials showed no benefit for conservative oxygenation (NEJM JW Gen Med Mar 1 2021 and N Engl J Med 2021; 384:1301; NEJM JW Dec 15 2019 and N Engl J Med 2020; 382:989).

Danish investigators randomized nearly 800 comatose survivors of out-of-hospital cardiac arrest to a mean arterial pressure (MAP) target of 63 mm Hg or 77 mm Hg during their intensive care unit stay and also, in a 2×2 factorial design, to a restrictive or liberal oxygenation target (partial pressure of oxygen [PaO₂], 68–75 mm Hg or 98–105 mm Hg, respectively). Most patients had shockable rhythms and witnessed arrests with bystander resuscitation. All patients had targeted temperature management to 36°C for 24 hours. Volume resuscitation, vasopressor administration, and oxygen titration were protocolized.

The protocol achieved good between-group separation in mean MAP (difference, 11 mm Hg), mean PaO₂, and mean fraction of inspired oxygen. Similar numbers of patients in all groups (32%–34%) were discharged from the hospital with poor neurological outcome or died at 90 days. No interaction between interventions was noted.