Abstract Body (Do not enter title and authors here): Introduction:
Patients with return of circulation after an out of hospital cardiac arrest (OHCA) remain at high risk for in-hospital morbidity and mortality from multiorgan dysfunction or anoxic brain injury. Prior studies have reported factors associated with outcomes in OHCA. However, these studies do not address early prognostication factors in the first 24 hours of admission. Outcome predictors available in the initial 24 hours may be helpful in deciding candidacy for advanced therapies such as ECMO and in informing families about potential outcomes.

Research question:
Evaluate parameters available in the initial 24 hours after hospitalization and their relation to outcomes of children admitted to the Pediatric Intensive Care Unit (PICU) after OHCA.

Methods:
Single center retrospective study of PICU admissions after OHCA from 2018 to 2024. Data sources were the local Virtual Pediatric Systems registry and the electronic medical records. Pertinent categories included demographics, etiology of OHCA, CT Head findings on admission, neurological pupillary index (NPi) at 0, 6, 12 and 24-hours from admission, serum lactate, base deficit, illness severity score, CPR characteristics, and Pediatric Cerebral Performance Category (PCPC) score. Poor outcome was defined as change in PCPC ≥ 2. Factors associated with outcomes are presented using descriptive statistics, and the sensitivity, specificity, positive and negative predictive values of their association with outcomes were evaluated. Nominal and ordinal variables were compared using Fisher’s exact test and Mann Whitney U test respectively.

Results:
In this cohort of 218 patients, median age was 2.2 years (0.6, 9.7), 57.3% were males and mortality was 39%. Of the 123 head CTs obtained upon admission, 50 showed cerebral edema (CE), and 88% had poor outcomes (specificity 88.2%, positive predictive value (PPV) 88%). Of the poor outcomes, 80% died and 8% survived. Similarly, a NPi of 0 at all time intervals (0, 6, 12 and 24 hours) was associated with poor outcomes (specificity 96-97% and PPV 96-97%). A cardiac etiology of arrest was associated with survival (79%, p=0.04). Non-survivors had higher illness severity, more epinephrine doses, worse lactate and base deficit values, and higher vasoactive scores.

Conclusion:
Clinical characteristics in the first 24 hours after OHCA are associated with outcomes. CE on initial head CT and NPi=0 during the initial 24 hours had high specificity and PPV for poor outcomes.