Abstract Body: Introduction
PulsePoint is a mobile application that can notify volunteers about nearby out-of-hospital cardiac arrest events, allowing them to respond and provide cardiopulmonary resuscitation (CPR) and an automated external defibrillator (AED), lowering downtime prior to Emergency Medical Services (EMS) arrival. The use of PulsePoint is predominantly for public OHCA events, but the incorporation of a registered / vetted tier of volunteers can facilitate its use for residential OHCA alerts. We sought to describe system performance characteristics in the early phase of transitioning a county-level PulsePoint deployment to include registered responders capable of residential response.

Hypothesis
Number of responders alerted, bystander CPR (BCPR) rates, and use of AEDs (BAED) would differ between public and private locations when the system incorporates registered volunteers.

Methods
PulsePoint alert records for the City of Pittsburgh, Pennsylvania were obtained via the PulsePoint Central dashboard for the capture period of January 1, 2024, to April 30, 2025, covering all events that met dispatch determinant criterion for a PulsePoint alert (absent or agonal breathing). This criterion will trigger an alert if a PulsePoint volunteer is with a qualifying distance of the caller’s location (Public OHCA: 0.25mi; Private OHCA: 0.5mi). Each record summarized whether an alert was triggered, the type of response, number of responders notified, number of AEDs within radius, and event timing. We obtained EMS records to determine medical category, presence of BCPR, and BAED. We calculated percentage of qualifying events resulting in an alert, resultant medical categories, proportion private/public, and layperson bystander intervention rates.

Results
Of a total of 1,007 qualifying PulsePoint events (30.7%Public vs 69.3%Private), 311 resulted in an alert (83.3%Public vs 16.7%Private). Most common medical categories among these were: [No Patient 32.4%] [Cardiac Arrest 13.5%] [Drug Overdose 9.6%]. Among confirmed OHCA, 26.3% were private. Overall BCPR rate for those alerts with confirmed OHCAs was 26.3%, while overall BAED use rate among the same was 5.3%. The maximum number of residential-eligible responders (60) was low relative to the number of public-eligible responders (5,107) during this early phase.

Conclusions
In the early phase of incorporating residential alerts into PulsePoint deployment, event characteristics differed between private and public location events.