Background: Cerebral ischemia/reperfusion injury in the post-resuscitation period contributes to morbidity and mortality following cardiac arrest (CA). Cerebral oximetry is a non-invasive system that uses near infrared spectroscopy to measure regional cerebral oxygenation level (rSO2) in the frontal lobe of the brain. Studies have shown that post-resuscitation rSO2 may be associated with survival and neurological outcomes in out-of-hospital cardiac arrest patients, however no studies have examined this in in-hospital cardiac arrest (IHCA) patients.
Hypothesis: rSO2 changes following return of spontaneous circulation (ROSC) after IHCA are associated with survival with favorable neurological outcomes.
Methods: A multi-site prospective study of consecutive day-time IHCA patients admitted to the ICU after ROSC at 7 sites. Continuous rSO2 monitoring (Equanox 7600, Nonin Medical, MN, USA) was applied for 48 hours after ROSC using a forehead sensor. Mean rSO2 was calculated hourly between 1-6 hrs. and at 6, 12, 18, 24, 48 hr. intervals. Demographic and data pertaining to possible confounding variables for rSO2 and survival with favorable neurological outcomes (cerebral performance scale [CPC] 1-2) vs death or severe neurological injury (CPC 3-5) at hospital discharge were collected.
Results: Among 87 studied patients, 26 (29.9%) achieved CPC1-2. There were no differences in age, Charlson comorbidity index, APACHE II scores, and resuscitation duration, however, CPC 1-2 was higher in men vs. women (36.5% vs. 12.5%, p = 0.036). A significant difference in mean rSO2 was observed during hours 1-2 after ROSC in CPC 1-2 vs CPC3-5 (73.08 vs. 66.59, p = 0.031) but not at other time points. There were no differences in mean arterial pressure, PaO2, PaCO2, and hemoglobin levels, however subjects with CPC 1-2 had lower glucose (154.4mg/dL vs. 202.8mg/dL, p = 0.0054), lactate level (4.11 mmol/dL vs. 6.39 mmol/dL, p = 0.030), and higher Glasgow coma scale (9.42 vs. 5.96, p = 0.0026) within the first 24 hours.
Conclusions: Changes in rSO2 as measured by cerebral oximetry in the first two hours after ROSC may predict survival with neurological outcomes after resuscitation following IHCA.