Reasons for death in patients successfully resuscitated from out-of-hospital and in-hospital cardiac arrest

Introduction: There is no standard for categorizing reasons for death in those who achieve return of spontaneous circulation (ROSC) after cardiac arrest but die before hospital discharge. Categorization is important for comparing outcomes across studies, assessing benefits of interventions, and developing quality-improvement initiatives. We developed and tested a method for categorizing reasons for death after cardiac arrest in both in-hospital (IHCA) and out-of-hospital (OHCA) arrests.

Methods: Single-center, retrospective, cohort study of patients with ROSC after IHCA or OHCA between 2008 and 2017 who died before hospital discharge. Traumatic arrests and patients with "do-not-resuscitate" orders prior to their arrest were excluded. Two investigators assigned each patient to one of five predefined reasons for death. Interrater reliability was assessed using Fleiss' kappa. For final categorization, discrepancies were resolved by a third investigator.

Results: There were 182 IHCA and 226 OHCA included. There was substantial agreement between raters (kappa of 0.62 and 0.61 for IHCA and OHCA, respectively). Reasons for death for IHCA and OHCA were: neurological withdrawal of care (27% vs 73%), comorbid withdrawal of care (36% vs 4%), refractory hemodynamic shock (25% vs 17%), respiratory failure (1% vs 3%), and sudden cardiac death (11% vs 4%). The differences in reasons for death among the two groups were significant (p-value < 0.001).

Conclusions: Categorizing reasons for death after cardiac arrest with ROSC is feasible using our proposed categories, with substantial inter-rater agreement. Neurologic withdrawal of care is much less common in IHCA than OHCA, which may have implications for further research.