Having just finished her shift, Dahl dropped what she was doing at the hospital and ran down five flights of stairs to the street.
"It was right during a huge storm, so it was raining, and I was trying to figure out where they would be," she said. "And then I saw Zach was bent over somebody on the ground, so I ran over."
Zach Forcade, a 27-year-old medical student, hovered above a man beside a bus stop outside the hospital. Forcade had seen Stephen DeMont fall to the ground and shouted to a passer-by to dial 911 before he performed chest compressions, trying to keep DeMont's heart beating.
That same 911 call triggered an alert that Dahl and 40 other people nearby received. All 41 had three things in common: They knew CPR, they had downloaded an app known as PulsePoint, and they could have been close enough to help.
"I didn't really know if it would work," said Dahl, who had never received a PulsePoint alert before DeMont collapsed. "I mean, it sounds like a crazy idea, but then I received an alert, and a little map came up and showed me where he was ... and there he was!"
Though she herself didn't perform CPR, she helped Forcade by making sure DeMont's air passage remained clear and by counting compressions.
DeMont doesn't remember any of it.
"I rolled into the bus stop, stopped the bike, swung my leg over, stood up and got real light-headed," said DeMont, 60, a technical writer. "The next thing I remember is, I'm in ICU."
First responders hiding in plain sight
As described by the American Heart Association, sudden cardiac arrest
is when the heart suddenly stops beating, resulting in a lack of blood flow to the brain and other vital organs. If the heart stops, real damage can result.
Every year, more than 350,000 cardiac arrest incidents occur outside a hospital, yet only 46.1% of those people receive bystander CPR, and just 12% of the total 350,000 patients survive, the American Heart Association says.
"If you don't get chest compressions -- if you don't get high-quality CPR -- your heart starts to die, but so do all your other organs, and a lot of that damage is permanent," Dahl said. The result can be "very, very severe brain damage. Some people are never the same again and are unable to recover from that injury."
By comparison, effective bystander CPR, provided immediately after sudden cardiac arrest, can double or triple a person's chance of survival, according to the heart association. In a new guideline issued this month, the association recommends that cities consider using apps and mobile phones to connect those in cardiac arrest with nearby CPR-trained rescuers.
One such app is PulsePoint
, which allows 911 operators to alert people within about a quarter-mile of where CPR assistance is needed. The app also signals the location of the nearest portable defibrillator.
DeMont knows that he is one of the lucky ones. Waking in the ICU two and a half hours after his collapse, he recalls telling himself, "I'm thinking straight, so there must not be any brain damage." Later, a doctor would confirm that no brain function was lost.
DeMont feels grateful to Forcade and Dahl for the immediate CPR he received.
An idea brought to life
PulsePoint is the brainchild of Richard Price, a former fire chief, who tells a story of having lunch in a deli in San Ramon, California. Hearing sirens, he followed the sound until emergency workers pulled up just outside. Less than 30 feet from where Price was sitting, someone was lying unresponsive.
"It was very jarring to have an event happen so close to me where I could have made a big difference in the outcome," Price said.
There and then, he decided that there should be a communication system to alert CPR-trained people. Naturally, he thought of using cell phones and creating an app, but how? He worked with plenty of IT people, but he didn't know any app developers.
He discovered that Northern Kentucky University had a mobile app development program, with a graduation requirement for students to make a real world app.
"So I pitched them this idea," Price said. "I ended up bringing out about six students out to California, where I paid them in Doritos and Pepsis and made a little sort of startup to build the app."
The students wrote code and built an initial proof-of-concept app. (Some eventually took jobs at a nearby company, Workday, which continues to provide IT support for the app on a volunteer basis.)
There were many questions, said Price, who listed just a few: "Would people carry the app? Would they respond? Would they beat first responders to the scene?" But all of these questions were resolved almost immediately, he said.
"One of our very first activations occurred in San Ramon," said Price. "When our crews got there, eight people had responded, and two people were doing CPR. It was sort of remarkable to us."
'I'm very grateful'
Nearly 2,000 emergency centers in 28 states and Canada use PulsePoint. Approximately 900,000 people have downloaded the app, which is open to anyone who's certified in CPR and wants to help. More than 13,000 alerts have been issued, and nearly 35,000 people have responded to an alarm, appearing on the scene, ready to help.
"We've activated the system 155 times since we went live back in March," said Dr. Michael Sayre, medical director of the Seattle Fire Department and a professor at the University of Washington. Of those cases, 28 people were receiving CPR when the EMS crew arrived.
Only about a quarter of the 155 activations involved someone in cardiac arrest, Sayre said. People who call 911 may be too excited to accurately describe a medical emergency, he explained, but he prefers to err on the side of caution and activate the system even in situations where it might not be needed.
The app also raises privacy issues, Sayre noted. The majority of cardiac arrest cases happen at home, yet PulsePoint has been activated only for cardiac events happening in public places, he said.
"We do not know how residents of Seattle would feel about a system that would send their neighbors to help provide CPR in an emergency," Sayre said. "Some likely would welcome the assistance. Others may not like it."
When a patient does receive CPR before an emergency services team arrives, it's difficult to know whether PulsePoint sent them. As Sayre explained, some 911 callers are persuaded by a dispatcher to attempt CPR, while in other cases, bystanders jump in on their own. Emergency teams are too busy with life-saving to get the details of how help arrived.
Still, Sayre has found two cases where he could make a connection directly back to PulsePoint. One was DeMont, and the other was Doug Stine, 36, an employee at Lamar Advertising whose heart stopped one morning when he and some co-workers were headed to work.
Though he does not remember anything -- Stine was immediately and completely unconscious when his heart "flatlined"-- his co-workers have explained to him that, seeing him slump in his seat, they stopped the truck. Next, they pulled him out and immediately called 911.
They performed CPR until an off-duty ER doctor who had received a PulsePoint alert arrived from his house just two blocks away. The doctor took over CPR duty until emergency services arrived.
One month later, Stine has no loss of memory or brain function, even if his ribs still hurt.
"I'm very grateful for the PulsePoint app and everything that happened," he said.