Title: Effect of Designated First-Responder Cardiopulmonary Resuscitation on Survival Outcomes after Out-of-Hospital Cardiac Arrest Occurred During Exercise in Public Place
Introduction
Deployment of a designated first-responder in public place is one of interventions for improving survival outcomes through rapid response for early cardiopulmonary resuscitation (CPR) prior to emergency medical services arrival in out-of-hospital cardiac arrests (OHCA). We studied the association between first responder versus layperson CPR and survival of OHCA patients that occurred during period of exercise in public place.
Methods
All adult OHCAs of presumed cardiac etiology that occurred during period of exercise in public place and who were witnessed by a bystander between 2013 and 2015 in Korea were analyzed. The main exposure of interest was characteristics of the bystander (first responder vs. layperson). First responders were designated by EMS Act in 2008. The endpoints were bystander CPR and survival with good neurological recovery. Multivariable logistic regression analysis was performed, adjusting for patient and arrest-environmental factors.
Results
A total of 870 patients had a cardiac arrest during period of exercise in public place, and 58 (6.7%) patients witnessed by the first responder. The OHCAs witnessed by first responders were more likely to receive bystander CPR (89.7%) than the patients witnessed by laypersons (75.4%) (AOR (95% CI): 3.12 (1.30–7.47)). In terms of good neurological recovery, the OHCAs group witnessed by first responders has a higher good neurological recovery rate (37.9%) than the group witnessed by laypersons (24.0%) (AOR (95% CI): 1.87 (1.04–3.37)). 
Conclusions
Patients that occurred during period of exercise in public place and who were witnessed by first responders were more likely to receive bystander CPR and have neurologically intact survival compared to patients who were witnessed by laypersons.

Effect of First-Responder Cardiopulmonary Resuscitation on Survival Outcomes after Out-of-Hospital Cardiac Arrest Occurred During Exercise in Public Place