Relationship Between Cerebral Oximetry and Outcomes in Post-Cardiac Arrest Patients: A Systematic Review and...

Poor neurologic outcomes are common in post-cardiac arrest patients. Reduced cerebral perfusion and inadequate oxygen delivery may persist even following return of spontaneous circulation (ROSC), which may exacerbate hypoxic-ischemic brain injury. Cerebral oximetry is a noninvasive method of assessing brain oxygenation. We performed a systematic review to assess whether post-arrest regional oxygen saturation (rSO2) during the initial 48 hours post-ROSC is associated with death or severe disability.

MEDLINE, Embase, Cochrane Central Register of Controlled Trials, World Health Organization Global Health Library.

We included studies reporting outcomes in adult post-arrest patients who underwent continuous cerebral oximetry immediately following ROSC for at least 6 hours.

rSO2 over the 48 hours post-arrest was compared between patients with favorable vs. unfavorable outcomes, as dichotomized within individual studies.

Random effects models were used to pool studies. 10,876 records were identified, of which 16, with a total of 864 patients, met inclusion criteria. Twelve studies provided neurologic outcomes, and four reported only survival. rSO2 was similar at baseline, but higher at 24 hours (3.3%, 0.9-5.7%, p = 0.009) and 48 hours (2.1%, 0.3-3.9%, p = 0.02) post-arrest among patients with favorable outcomes. There was significant heterogeneity between studies. rSO2 averaged over time was significantly higher between 24 and 48 hours in patients with favorable outcomes (5.2%, 1.6-8.8%; p = 0.005). rSO2 was lower in studies where cardiac arrest duration was relatively longer (modeled difference -7.1%, -3.1% to -11.1%, p = 0.0005). Although very low rSO2 had high specificity for unfavorable outcome in two studies, no consistent threshold could be identified for use in neuroprognostication.

Current evidence suggests that rSO2 during the initial 48 hours following ROSC is slightly lower in post-cardiac arrest patients with unfavorable neurologic outcomes (low certainty of evidence). Prospective research is needed to determine whether treatment of reduced rSO2 can improve outcomes.