Modeling the Impact of How Volunteer Responders Can Reduce Cardiac Arrest Response Times in Rural Ontario

Out-of-hospital cardiac arrest (OHCA) is one of the most time-critical emergencies, with survival dropping 7–10% for every minute without defibrillation. Emergency medical services (EMS) are often delayed in rural regions, limiting survival. Community First Responders (CFRs), trained volunteers activated through smartphone applications, offer a potential way to bridge this gap. This project evaluates how CFR recruitment could reduce response times in Kingston and Frontenac County, aligning with the “Neighbours Saving Neighbours” initiative. Spatial modeling was conducted in QGIS using a gridded approach to study the relationship between responder distribution and response times. The study area was divided into 5 × 5 km squares (25 km² each), with each cell representing a potential recruitment zone. Two maps were generated: one showing historical OHCA incidence hotspots, and another showing EMS median response times, which were faster in Kingston and slower in northern rural areas. Squares with no OHCAs (grey cells) were excluded. To refine the model, 5 × 5 km cells were later subdivided into 1 × 1 km cells and merged with census data to explore how population density might guide recruitment. Simulations were run by randomly placing responders in the grid while systematically increasing the number of volunteers in increments of 4 (from 0 up to 40). Under assumptions of a 0.5 alert acceptance rate and a 0.5 travel success rate, outcomes included median response time (the “typical” case where half of OHCAs were reached faster and half slower), 90th percentile response time (the longest 10% of cases), and the share of OHCAs reached within 6, 10, and 15 minutes. Results show that median response time decreased from ~9 minutes to ~7 minutes, while the 90th percentile improved from ~16 to ~13 minutes. Early coverage improved most sharply: the proportion of OHCAs reached within 6 minutes increased from ~2% to over 35%, while 10-minute coverage rose from ~50% to nearly 70%. Fifteen-minute coverage plateaued near 100%, indicating diminishing returns once the volunteer pool exceeded ~30. This grid-based modeling demonstrates that even modest CFR recruitment significantly shifts the response time distribution, particularly in rural areas where EMS travel times are longest. By showing where cardiac arrests occur, how fast current response times are, and how many responders are required per grid square, this framework highlights the potential of CFR expansion. Findings suggest that scaling initiatives like “Neighbours Saving Neighbours” could meaningfully improve the chance of survival in Kingston.