When a man collapsed at a bus stop in Seattle due to cardiac arrest, an application called PulsePoint installed on his smartphone created an alert for medical staff within the vicinity to help him, saving his life.

The mobile app was created by a former fire chief in Northern Carolina, Richard Price, and works through a city's 911 system. Whenever there is a call coming in, the operators can alert people within a specific radius, who can offer CPR assistance and save people's lives before the ambulance gets there. In this case, the operators pointed to the nearest defibrillator and helped save the man's life.

"We notify them and provide them a map so they can see where the patient is located. We also show any nearby access to public defibrillators, AEDs, so they can either start CPR or use that AED while the professional responders are on their way to the scene," said Price.

The incident, the second in Seattle this month, does not occur that rarely. Because of the frequency, involving citizens in the rescue process is essential, according to the app developer.

Before the medical team arrived at the place of emergency, a medical student was already there, performing chest compressions. Another medical professional, a nurse who had just finished her shift, happened to be around and rushed there to help, until the paramedics arrived.

"If the cardiac emergency is in a public place, the location-aware application will alert trained citizens in the vicinity of the need for bystander CPR simultaneous with the dispatch of advanced medical care," states the official website of the mobile application.

Civic engagement is one of the purposes of this software, aiming to notify the right people to intervene quickly.

As the locations where these emergencies happen are not always traffic-free and near hospitals, it may take a while before the medical team gets to the emergency site. In cases such as one involving a 60-year-old patient, the success or failure of a rescue can spell the difference between life and death in a matter of seconds.

Approximately 34,000 medical professionals and citizens have downloaded the app in the U.S., and more than 13,000 cardiac events have been alerted through it, according to Price.

The idea came to him in 2009, when he witnessed an emergency while in a restaurant. As it turned out, the sirens of the ambulance were headed to the place he was eating in.