Abstract 18984: Discrepancy Between Originally Assigned and Adjudicated Causes of Out-of-Hospital-Cardiac-Arrest of “No Obvious Cause” in Young Patients

Abstract

Background: Death due to out-of-hospital cardiac arrest (OHCA) is most commonly attributed to “no obvious cause” after review of the prehospital and in-hospital documentation. To establish cause of death in younger patients, autopsy and toxicology data are important, especially in younger patients. We examined the probable cause of death in a large urban cohort of younger OHCA patients. Methods: A prospective population-based registry of all OHCAs attended by Emergency Medical Services (EMS) in the Toronto area was used to identify cases from 2009-2012. Identified OHCAs were cases aged 2-45 who died and assigned ‘no obvious cause’ based on abstracted data from ambulance call reports and in-hospital chart review, including narrative review and contributing factors compliant with the Resuscitation Outcomes Consortium Epistry Manual of Operations. Cases with inadequate information (coroners and/or EMS), or with expected death (e.g. DNR or long term care) or homicide were then excluded. The remaining cases were adjudicated by 3 reviewers using additional data from coroner investigative statements, autopsy, toxicology and police reports, and classified as primary cardiac or another non-cardiac etiology. Results: A total of 2048 OHCA cases with no obvious cause were identified; of these, 547 were excluded. Of the remaining 1501 cases with complete information, 48.2% were treated by EMS. Of the treated cases, 41.3 % (299/724) of those assigned to ‘no obvious cause’ had an adjudicated cardiac etiology. Of the untreated group, 21.2% (165/777) had an adjudicated cardiac etiology. The majority consisted of drug overdoses (214/425; 50.3%) and other non-cardiac causes (49.7%) including trauma (Figure 1). Conclusions: In younger OHCA patients who die, the category "OHCA of no obvious cause”, on detailed review, is most often due to a non-cardiac cause. This observation may contribute to a better understanding of the etiology of sudden cardiac death in younger patients.