The association between post-cardiac arrest cerebral oxygenation and survival with favorable neurological outcomes: A multicenter study

Objective: Cerebral oximetry is a non-invasive system that uses near infrared spectroscopy to measure regional cerebral oxygenation (rSO₂) in the frontal lobe of the brain. Post-cardiac arrest rSO₂ may be associated with survival and neurological outcomes in out-of-hospital cardiac arrest patients; however, no studies have examined relationships between rSO₂ and neurological outcomes following in-hospital cardiac arrest (IHCA). We tested the hypothesis that rSO₂ following IHCA is associated with survival and favorable neurological outcomes. Design: Prospective study from nine acute care hospital in the United States and United Kingdom. Patients: Convenience sample of IHCA patients admitted to the intensive care unit with post-cardiac arrest syndrome. Interventions: Cerebral oximetry monitoring (Equanox 7600, Nonin Medical, MN, USA) during the first 48 h after IHCA. Measurements and Main Results: Subject's rSO₂ was calculated as the mean of collected data at different time intervals: hourly between 1−6 h, 6−12 h, 12−18 h, 18−24 h and 24−48 h. Demographic data pertaining to possible confounding variables for rSO₂ and primary outcome were collected. The primary outcome was survival with favorable neurological outcomes (cerebral performance scale [CPC] 1−2) vs severe neurological injury or death (CPC 3−5) at hospital discharge. Univariate and multivariate statistical analyses were performed to correlate cerebral oximetry values and other variables with the primary outcome. Among 87 studied patients, 26 (29.9%) achieved CPC 1−2. A significant difference in mean rSO₂ was observed during hours 1−2 after IHCA in CPC 1−2 vs CPC 3−5 (73.08 vs. 66.59, p = 0.031) but not at other time intervals. There were no differences in age, Charlson comorbidity index, APACHE II scores, CPR duration, mean arterial pressure, PaO₂, PaCO₂, and hemoglobin levels between two groups. Conclusions: There may be a significant physiological difference in rSO₂ in the first two hours after ROSC in IHCA patients who achieve favorable neurological outcomes, however, this difference may not be clinically significant.