Abstract Body: Introduction:
Hypoxic-ischemic brain injury after cardiac arrest (CA) results from both the primary insult of cerebral hypoperfusion and secondary injury mechanisms post–return of spontaneous circulation (ROSC), such as microvascular dysfunction, cerebral edema, and impaired autoregulation. Despite improved resuscitation protocols, neurological outcomes remain poor. Interventions like targeted temperature management and MAP optimization have yielded inconsistent results, prompting a shift toward phenotyping cardiac arrest patients using clinical examination, biomarkers, and imaging. This study aimed to identify comorbidities and biomarkers associated with mortality and motor outcomes to aid in future phenotypic classification.
Method:
A retrospective cohort study was conducted at an urban academic center, analyzing health records of patients treated for in-hospital and out-of-hospital CA between 2015-2025. Patients were divided into deceased and survivor groups. Data abstraction from the EMR was completed for variables including comorbidities, post-arrest biomarkers (pH, lactate, and MAP), and neurologic status (GCS). In a subgroup analysis, motor outcomes were compared between those with good (GCS M4–6) and poor (GCS M1–3) function.
Results:
Among 1,086 CA patients, compared to survivors, mortality was significantly associated with acute kidney injury (79.4% vs. 61.2%), cirrhosis (39.4% vs. 16.4%), malignancy (35.0% vs. 21.8%), arrhythmia (45.5% vs. 38.8%), myocardial infarction (43.8% vs. 36.0%), and atrial fibrillation (41.8% vs. 30.6%) (all p<0.05). A history of drug use was more common in survivors (25.2% vs. 18.6%, p=0.011). Non-survivors had higher lactate (4.01 vs. 3.44 mmol/L, p=0.025), lower arterial pH (7.29 vs. 7.32, p=0.049), and consistently lower MAP at 24, 48, and 72 hours post-ROSC. In the motor outcome subset, patients with better function (GCS M4–6) had lower rates of AKI and cirrhosis, lower lactate (3.21 vs. 4.69 mmol/L), higher pH (7.32 vs. 7.28), and higher post-ROSC GCS scores (12.5 vs. 10.24, p<0.0001).
Conclusion:
Comorbidities such as AKI, cirrhosis, malignancy, arrhythmias, prior MI, and AF are associated with mortality and should be considered in phenotyping post-ROSC patients. Drug use may define a distinct subgroup with a different risk profile. Biomarkers, including pH, lactate, and MAP, reflecting early brain injury severity and hemodynamic status, are strongly associated with both survival and motor outcomes.