A smartphone application designed to mobilise nearby volunteers during cardiac emergencies did not significantly increase bystander cardiopulmonary resuscitation (CPR) or automated external defibrillator (AED) use. This was the main finding of a randomised study conducted in Canada and the United States. The results, presented at the American Heart Association's Resuscitation Science Symposium 2026, raise questions about the effectiveness of digital volunteer alert systems in communities where bystander intervention rates are already relatively high.
During an out-of-hospital cardiac arrest, immediate CPR and early defibrillation are critical interventions. Although emergency medical services (EMS) can respond within minutes, delays before professional assistance arrives may affect a patient's chances of survival.
Smartphone applications that notify nearby volunteers have been developed to shorten the interval between cardiac arrest and the start of resuscitation. These systems use location-based notifications to connect people experiencing an emergency with individuals willing to provide assistance. However, the effectiveness of these applications depends on several factors, including volunteer availability, emergency response times and existing levels of bystander intervention.
Randomised trial in two regions
Researchers in British Columbia, Canada, and Columbus, Ohio, evaluated PulsePoint Respond, a smartphone application developed by the nonprofit PulsePoint Foundation. The system connects with participating emergency dispatch centres and sends notifications to nearby volunteers when a suspected cardiac arrest occurs in a public location. Volunteers receive information about the emergency location and nearby AEDs while professional responders are dispatched.
Between June 2021 and March 2026, researchers randomly assigned 17,547 emergency calls involving suspected cardiac arrests to either standard emergency dispatch or standard dispatch supplemented by PulsePoint notifications. The primary analysis included 355 confirmed cardiac arrest cases that met the study's eligibility criteria. Of these, 178 were assigned to receive volunteer alerts and 177 to standard dispatch alone. All included incidents occurred in public locations where at least one registered PulsePoint user was within 400 metres when the emergency call was received.
No significant improvement
The researchers found that bystanders provided CPR or used an AED before professional responders arrived in 69 percent of cases where PulsePoint alerts were activated. In the standard dispatch group, this occurred in 72 percent of cases. The difference was not statistically significant. When analysed separately, bystander CPR occurred in 70 percent of patients in the alert group, compared with 73 percent in the control group. AED use was recorded in 15 and 17 percent of cases, respectively.
Survival to hospital discharge was approximately 21 percent in both groups. The median interval between the emergency call and EMS arrival was 5.6 minutes in the alert group and 5.9 minutes in the control group. According to senior lead author Steven Brooks, professor of emergency medicine and public health sciences at Queen's University in Canada, the already high rate of bystander CPR may have limited the additional benefit achievable through smartphone notifications.
In the control group, 73 percent of patients received CPR before professional responders arrived. The findings therefore do not necessarily indicate that volunteer alert systems are ineffective in all circumstances. Rather, the intervention did not produce a measurable improvement under the conditions examined.
Volunteer availability
The researchers identified several factors that may have influenced the results. Most cardiac arrests included in the analysis occurred in urban environments, accounting for 91 percent of cases. Professional emergency response times were also relatively short. Furthermore, the number of nearby registered volunteers was often limited. In 57 percent of incidents where alerts were activated, only one PulsePoint user was located within 400 metres. In 91 percent of cases, no more than four volunteers were nearby.
These findings suggest that the size and geographical distribution of volunteer networks are relevant considerations when evaluating location-based emergency response systems. The study also focused exclusively on cardiac arrests in public locations. Its findings cannot automatically be applied to emergencies occurring in private homes, where most out-of-hospital cardiac arrests take place. The researchers note that further investigation is needed in rural areas, high-rise buildings and communities with longer emergency response times or larger volunteer networks.
Implications for digital emergency care
The study illustrates the importance of evaluating digital healthcare interventions against existing emergency response practices. Although smartphone alerts offer a technically feasible way to mobilise volunteers, their availability does not necessarily translate into earlier intervention or improved survival. The results also demonstrate why local circumstances matter. A digital notification system may have limited additional value where bystander CPR is already common and emergency services arrive relatively quickly.
For healthcare organisations and policymakers considering similar technologies, the findings underline the need to assess volunteer coverage, existing response times and actual clinical outcomes rather than relying solely on the ability to send alerts. The researchers plan further analyses of how PulsePoint Respond operated during the trial, including the influence of volunteer availability and local conditions.
The findings remain preliminary, having been presented at a scientific conference. Further publication and peer review will be important for assessing the results and their implications for emergency care. For now, the study provides evidence that adding smartphone alerts to established emergency dispatch systems does not automatically improve bystander resuscitation rates, even when nearby volunteers are available.
References
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