Abstract 411: Location of Collapse is Independently Associated With Initial Rhythm and Survival in Out-Of-Hospital Cardiac Arrest

Abstract

Introduction: Out-of-hospital cardiac arrest (OHCA) at a home location is associated with lower rates of shockable initial rhythm (SIR) and survival than OHCA at a public location. While this is generally attributed to unfavourable resuscitation characteristics, it might also be explained by differences in pre-existing disease or medication use between patients with OHCA at home and those in public. We compared medical history and medication use between home and public OHCA patients, and determined whether these factors explain the association between OHCA location and SIR or survival. Methods: Data from ARREST, an OHCA registry in the Netherlands, were used (Jan 2009 - Dec 2012). We assessed the association between OHCA location and a) presence of SIR and b) survival to hospital discharge in a multivariable regression analysis taking medical history, medication use, resuscitation characteristics and demographics into account. Next, the relative contribution of the abovementioned variables to variance in both outcome measures was estimated using the Nagelkerke test. Results: In total, 1724 patients were included (1278 [74.1%] home OHCA, 446 [25.9%] public OHCA). OHCA location was significantly associated with rates of SIR (home 39.1%, public 75.1%; P <0.01) and survival to hospital discharge (home 17.2%, public 47.3%; P <0.01). Adding resuscitation characteristics to models of SIR rate and survival rate resulted in the largest increase in explained variance (Figure 1A and 1B), whereas adding pre-existing disease or medication use to the models resulted in only a limited increase in explained variance (Figure 1A and 1B). Conclusions: Location of OHCA remains significantly associated with lower rates of SIR and survival, even when adjusted for medical history, medication use, resuscitation characteristics and demographics; an unexplained gap remains. Both medical history and medication use only explain a modest proportion of the variance of SIR and survival.