Abstract Body: Introduction: Pediatric cardiac arrest is associated with high mortality and morbidity. Timing and modes of death after pediatric out-of-hospital cardiac arrest (OHCA) varies across centers. Causes of death for children with in-hospital cardiac arrest (IHCA) have not been described.

Aims: We sought to determine and compare timing and modes of death in children admitted to a PICU following return of circulation (ROC) after IHCA and OHCA.

Hypothesis: Among children with ROC who did not survive to hospital discharge (SHD), we hypothesized that children with IHCA would more commonly die from withdrawal of life sustaining therapy (WLST) and children with OHCA would more commonly die from brain death (BD).

Methods: Single center retrospective study of children <18 years old who received >1 minute of chest compressions, achieved ROC for >20 minutes, and were admitted to the PICU from January 2017 - March 2023. We compared modes of death classified as: a) BD, b) WLST, c) circulatory death from recurrent arrest or d) recurrent arrest without attempted resuscitation (DNAR) between IHCA and OHCA using chi squared or Fisher’s exact test. Reason for WLST was categorized from physician notes. Time to death, defined as number of days between arrest and death, was compared between IHCA and OHCA by Wilcoxon rank-sum.

RESULTS: 857 children (median age 1.3 years [IQR 0.4, 8.8], 43% female, 553 (65%) IHCA and 304 (35%) OHCA) were included. In the IHCA cohort, 163/553 (29%) did not SHD (BD 7 [4%], WLST 92 [56%], recurrent arrest 28 [17%], DNAR 34 [21%]). The primary reasons for WLST were poor cardiovascular prognosis (42 [46%]) and poor neurologic prognosis (33 [36%]). In the OHCA cohort, 111/304 (37%) did not SHD (BD 55 [50%], WLST 42 [38%], recurrent arrest 7 [6%], DNAR 7 [6%]). The primary reason for WLST was poor neurologic prognosis (35 [83%]). The median time to death was longer for IHCA vs. OHCA (6 [0,30] vs 2 [1,5] days, p<0.001). After IHCA, children were less likely to die from BD (p<0.001) and more often underwent WLST due to poor cardiovascular prognosis (p<0.01) than children with OHCA.

CONCLUSIONS: Non-survivors after IHCA more frequently died due to WLST and circulatory death in the setting of care limitations, while non-survivors following OHCA died earlier and more frequently from BD. Understanding the timing and mode of death after OHCA and IHCA is critical for framing prognostic, goals-of-care conversations.