Virginia Via Research Day Book 2026

Graduate Student Research Public Health

03 EARLY INTERVENTIONS AND RETURN OF SPONTANEOUS CIRCULATION IN A NATIONAL EMERGENCY SERVICES DATABASE

Carter Bohart, NREMT, Laura Hungerford, DVM, NREMT, MPH, PhD, CPH, FNAP Corresponding author: cjbohart@vt.edu

Virginia Tech Department of Population Health Sciences, Blacksburg, Virginia

received an EMS response for a cardiac arrest were subsetted and those with missing data on key variables were omitted. The relationship of time of arrest, CPR initiation, AED placement, and witnessed status with achievement of ROSC was analyzed by determining relative risks (RR) with their 95% confidence intervals (CIs) and statistical significance through mid-P Exact tests utilizing OpenEpi with an alpha value of 0.05. The difference in EMS response times between those who achieved ROSC and those who did not was compared using a Wilcoxon test utilizing RStudio programs. Deidentified public-use data were accessed through a data-sharing agreement with NEMSIS under the provisions of their IRB. Results: There were a total of 976,843 cardiac arrest patients, with complete information available for 353,178 patients. Among these, 137,082 were patients who had ROSC obtained following their arrest, and 216,096 were patients who did not obtain ROSC. These patients were predominantly white, from a suburban area, with a mean age of 61 years. Sex of the patient was not available in NEMSIS at this time. Arresting prior to EMS arrival (RR=0.84, 0.83-0.85) and AED initiation prior to EMS arrival (RR=0.98,

0.97-0.99) were associated with a significantly reduced probability of obtaining ROSC while witnessed cardiac arrest (RR=1.65,1.64-1.67), CPR prior to EMS arrival (RR=1.04, 1.03-1.05), and a shorter EMS response time (median difference of 0.18 minutes) were associated with a significantly increased probability of obtaining ROSC. Conclusion : Early intervention, whether it be by EMS or bystanders, is crucial to ensure a greater probability of ROSC, with emphasis on the importance of CPR. However, further research is needed to understand why use of an AED before EMS arrival did not have a beneficial effect. Further research will expand on the initial findings to take a multivariable approach while considering confounding and effect modifiers which influence the understanding of cardiac arrests.

Context: Emergency medical service (EMS) response is important in the chain of survival for cardiac arrest patients. Early cardiopulmonary resuscitation (CPR) and automatic external defibrillator (AED) placement are key to obtaining return of spontaneous circulation (ROSC). Literature suggests that earlier interventions are important to survival but it is not certain which aspects have the greatest effect. Recognizing the association of survival with actions that occur before and after EMS arrives can help strengthen recommendations about care for cardiac arrest patients. Current viewpoint assumes early intervention is the key to cardiac arrest survival. Objective: The two exposures of interest understanding EMS's impact are the time of arrest and EMS response time to scene. Exposures such as CPR initiation, AED placement, and witnessed status were also examined to see how factors such as bystander participation in the chain of survival impact arrest results along with EMS. Methods: This study utilized nationwide data from the 2023 National Emergency Medical Services Information System (NEMSIS) dataset. Patients who

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2026 Research Recognition Day