The sound of a phone ringing has put Surrey resident Esmeralda Gomez on edge for weeks.

Back in July, she received the kind of call every parent dreads. Her son Alex had been rushed to hospital after collapsing at the gym.

"It was the worst feeling," Gomez said. "We got the phone call saying your son has collapsed, he may not make it so you need to get over here."

Alex, who was then just 14 years old, had unexpectedly gone into cardiac arrest. He would spend the next 12 hours in a coma.

And Gomez said her son might not have survived at all if it hadn't been for the lifeguards from an adjoining pool who rushed into the gym, used an automated external defibrillator (AED) on him and then performed CPR.

"The doctors at (BC Children's Hospital) said if he didn't have the AED machine used, he wouldn't be here today," Gomez said.

Before the incident, the family had no reason to suspect there was anything wrong with Alex. They described him as an athletic high schooler who played competitive soccer.

To their dismay, the cause of his episode is still unclear almost two months later.

"Tests all come back normal. They can't find anything so we're waiting for the genetic tests to come back," Gomez said.

In the meantime, they're terrified he could suffer another cardiac arrest somewhere that doesn't have the kind of life-saving technology that spared their family a tragedy the first time – including at his school.

"We were extremely shocked to find out the school didn't carry an AED machine," Gomez said. "North Van has them, Coquitlam has them, why not Surrey?"

The provincial government doesn't currently require schools across the province to stock an AED, something Gomez would like to see changed. The Ministry of Education told CTV News it follows the advice of B.C.'s provincial health officer, who currently supports the installation of AEDs in schools where there are children or staff with medical conditions that could require them.

There is also a private member's bill in the works to create clear regulations around AEDs for the entire province, and to improve accessibility.

But the Surrey school district said for now, it's facing issues around funding and maintenance.

“It’s not as simple as saying let’s put an AED in the school. I think there’s a number of things, a number of considerations outside the reach of the school district," spokesperson Doug Strachan said.

Strachan promised the district will be addressing the situation with Gomez's family, however.

"We will work with the family if there’s a need identified by a medical professional," he said.

Gomez and her husband hope something will be done quickly. Experts caution that just 15 per cent of British Columbians who suffer cardiac arrest manage to survive.

"For every minute that goes by, your survival reduces by 10 per cent, so there's really a small time frame where doing CPR and using an AED are extremely important," said Gillian Wong of the Heart and Stroke Foundation.