When is a Cardiac Arrest Non-Cardiac?

Abstract

A Medline (US National Library of Medicine, National Institutes of Health; Bethesda, Maryland USA) search was performed using the subject headings "OHCA" and "Emergency Medical Services" (EMS). Studies were included if they reported prevalence of cardiac etiology among OHCA in the entire patient sample, or in all arms of a comparison study. Studies that either did not report etiology of OHCA, or that excluded all cardiac or non-cardiac etiologies prior to reporting clinical data, were excluded. Twenty-four studies were identified, containing 27 datasets of OHCA which reported the prevalence of presumed cardiac vs non-cardiac etiology. These 27 datasets were drawn from 15 different countries. The prevalence of cardiac etiology among OHCA ranged from 50% to 91%. No obvious patterns were found regarding database size, year of publication, or global region (continent) of origin. There exists significant variation in published rates of cardiac etiology among OHCAs. While some of this variation likely reflects different actual rates of cardiac etiologies in the sampled populations, varying definitions of cardiac etiology among prehospital personnel or varying implementation of existing definitions may also play a role. Different proportions of cardiac vs non-cardiac etiology of OHCA in a sample could result in entirely different interpretations of data. A more specific consensus definition of cardiac etiology than that which currently exists in the Utstein template may provide better guidance to prehospital personnel and EMS researchers in the future. Carter RM , Cone DC . When is a cardiac arrest non-cardiac? Prehosp Disaster Med. 2017;32(5):523-527.