Site variation in EMS Treatment, Transport and Survival in relation to Restoration of Spontaneous Circulation (ROSC) for Adult Out-of-Hospital Cardiac Arrest: The Resuscitation Outcomes Consortium (ROC) Epistry

Mohamud R. Daya, Oregon Health & Science University
Kent M. Koprowicz, University of Washington
Dana M. Zive, Oregon Health & Science University
Julie E. Cummins, Ottawa Health Res Inst
Gena K. Sears, University of Washington
Terri A. Schmidt, Oregon Health & Science University
Shannon W. Stephens, University of Alabama at Birmingham
Ian G. Stiell, University of Ottawa

Abstract

Introduction: EMS protocols outlining when to attempt and terminate resuscitation for non-traumatic out-of- hospital cardiac arrest (OHCA) vary substantially across North America. The ROC Epistry is a prospective population based cohort study with uniform Utstein-style data definitions from 11 sites in North America. The purpose of this study was to compare site variation in EMS treatment and transport percentages within the ROC Epistry. We also examined the differences in overall survival in relation to the presence of ROSC prior to transport. Methods: Analysis of ROC Epistry data from 7 sites for all patients > 20 years of age with OHCA between 12/1/05 and 11/30/06 who either a) received CPR by EMS and/or received any external defibrillation attempt (including lay AED) or b) were pulseless but received no EMS resuscitation. Survival is defined as discharge from hospital. Statistical analysis was performed using unadjusted and adjusted tests of heterogeneity across sites. The covariates adjusted for included age, gender, initial rhythm, location, EMS or bystander witnessed, bystander CPR and ALS care. Results: Data from 13,530 patients were analyzed. Overall, 55% of patients were treated by EMS (site range: 44-65%, p < 0.0001). Of the EMS treated patients, the overall transport rate was 59% (site range 49-93%; p < 0.0001). In this group, 59% (site range 15-83%; p < 0.0001) were transported prior to or in the absence of ROSC. Overall, 26% of patients transported post scene ROSC survived (site range 16-38%, p < 0.0001), while only 4% of those transported prior to scene ROSC survived (site range 3-15%, p <0.0001). Conclusions: There is significant inter-site variation in OHCA treatment and transport. Survival of patients transported by EMS prior to or in the absence of scene ROSC also vary and indicate the need to explore site- specific protocols for continuing or terminating resuscitation of OHCA to more accurately assess predictors of both prehospital ROSC and overall survival.