Documented Use of Emergency Medical Dispatch Protocols is Associated with Improved Survival in Out of Hospital Cardiac Arrest

Abstract

Objective

There are over 300,000 out-of-hospital cardiac arrests (OHCA) annually in the United States (US) and despite many scientific advances in the field, the survival rate remains low. We seek to determine if return of spontaneous circulation (ROSC) is higher when use of emergency medical dispatch (EMD) protocols is documented for OHCA calls compared to when no EMD protocol use is documented. We also seek identify care-related processes that differ in calls that use EMD protocols.

Methods

This is a retrospective cohort study of U.S. adults with OHCA prior to emergency medical services (EMS) arrival using 2019 National EMS Information System data. The primary exposure was EMD usage during EMS call. The primary outcome was prehospital ROSC, and secondary outcomes included automated external defibrillator (AED) use before EMS arrival, bystander CPR, and end-of-event EMS survival (survival to the end of the EMS care at transport destination). Multivariable logistic regression adjusted for age, sex, race/ethnicity, primary insurance, rurality, initial rhythm, arrest etiology, and witnessed arrest.

Results

Of the 96,269 OHCA cases included, EMD use was documented in 73%. Overall, 26% of subjects achieved ROSC in EMS care. EMD subjects were more likely to achieve ROSC (27.2% vs. 23.5%, uOR 1.22, 95%CI 1.18 − 1.26) even after adjusting for subject and arrest characteristics (aOR 1.13, 95%CI 1.08 − 1.17). EMD subjects also had higher end-of-event survival (19.1% vs. 16.4%, aOR 1.20, 95%CI 1.15 − 1.25). AED use before EMS arrival was more common in the EMD group (28.3% vs. 26.3% %diff 2.0, 95%CI 1.4 to 2.6), as was CPR before EMS arrival (63.8% vs. 55.1%, difference 8.6%, 95%CI 7.9 to 9.3%).

Conclusions

In this retrospective analysis, the rate of ROSC was higher in adult OHCA patients when EMD protocol use was reported compared to when it was not reported. The group with documented EMD use also experienced higher rates of bystander AED use, bystander CPR, and end-of-event survival.

Acknowledgments

Data included in this study were provided by the National Highway Traffic Safety Administration (NHTSA) and National Emergency Medical Services Information System (NEMSIS). The content reproduced from the NEMSIS database remains the property of NHTSA. NHTSA is not responsible for any claims arising from works based on the original data, text, tables, or figures.

Credit Authorship Contribution Statement

Alexander Colgan: Conceptualization, Methodology, Writing – original draft. Morgan Swanson: Conceptualization, Methodology, Formal Analysis, Writing – original draft, review & editing. Azeemuddin Ahmed: Conceptualization, Methodology, Supervision, Writing – original draft, review & editing. Kari Harland: Methodology, Writing – review & editing. Nicholas Mohr: Conceptualization, Methodology, Formal Analysis, Writing – original draft, review & editing.

Disclosure Statement

The authors report no conflicts of interest.

Presentations

This work was presented at the American College of Emergency Physicians Scientific Assembly in October 2021 in Boston, MA.

Additional information

Funding

The University of Iowa Department of Emergency Medicine provided financial support for this study.