Life-saving AEDs are rarely used in cases of cardiac arrest, a new study finds. Why that's a problem — and what you can do.

Defibrillators mounted in many public buildings can save the life of someone in cardiac arrest, but they’re almost never used, a new study finds. According to research funded by the National Heart, Lung and Blood Institute and due to be presented this week at an American College of Cardiology conference, automated external defibrillators, or AEDs were only used in 13 of almost 1,800 cases of cardiac arrest occurring outside of a hospital setting.

Why are these AEDs — credited with helping revive Buffalo Bills player Damar Hamlin during his on-field health scare last year — so rarely used? Ahead, experts explain why that’s leading to deaths that could have been prevented, and what they recommend doing in the event of an emergency.

What is an AED?

AEDs are portable versions of the defibrillators used to shock the heart back into a proper rhythm in hospitals. Laws pertaining to AEDs vary from state to state, but in much of the United States, schools, gyms, casinos, churches, airports, federal buildings and places where there are large public gatherings are required to have one. Each device consists of a screen that displays instructions, a battery and in some cases a speaker for audio instructions; they also contain connected defibrillation pads that can be adhered to the chest of a person in cardiac arrest, according to the Food and Drug Administration.

Once the pads have been applied to the chest, electrodes embedded in them send information about the heart rate to the main device, which determines whether the person is in cardiac arrest or having different type of dangerous arrhythmia, the FDA says. Depending on the result, the AED delivers an electrical charge that can shock the heart back into rhythm.

The survival rate for out-of-hospital cardiac arrests is just 8% to 10%; with defibrillation, that figure rises several times over, to 50% to 74%. And, because the device speaks and displays instructions and is almost entirely automated, you don’t need training to use an AED.

“It’s a modern medical miracle that anyone, regardless of skill level, can [use to] save a life,” Dr. Harlan Krumholz, a cardiologist and professor at the Yale School of Medicine, tells Yahoo Life.

So why aren’t AEDs being used?

It’s not entirely clear. The authors of the new study — which analyzed 1,799 cardiac arrests that took place either at home or in public settings in Kansas City, Mo., between 2019 and 2022 — wanted to know whether having an AED nearby would mean the devices were used more often, potentially saving more lives. But they were disappointed to find that proximity didn’t seem to have much effect on how often AEDs were used.

The vast majority of cardiac arrests — about 85% — happened when people were at home. About a quarter of those at-home incidents took place within a four-minute walk from a public AED, though the device was not used in a single case. (Someone other than a paramedic administered CPR in 42% of those at-home cardiac arrests, however.)

When cardiac arrests happened in public — half of which occurred within four minutes of a public AED — a bystander once again did CPR in 42% of cases, but an AED was used only about 7% of the time. “Percentages [of AED use] are highest the closer you are to an AED ... but these numbers are small,” Dr. Mirza Khan, lead study author and fellow in cardiovascular outcomes research at the University of Missouri-Kansas City and Saint Luke’s Health System, tells Yahoo Life.

“The findings are really disheartening, because the use of one of these automated defibrillators is vital to helping people who have cardiac arrest survive,” Krumholz says. “My hunch is that either people aren’t aware that there is a defibrillator nearby, or they don’t think about it.” He worries that, too often, bystanders freeze in the chaos of the moment and are not in a state of mind to check for an AED.

“I wouldn’t say that we need to scrap AEDs altogether, but we need to think more strongly about optimizing the location of them and how we can train and inform bystanders,” says Khan. He also suggests that identifying hotspots for cardiac arrest might improve AED placement and use.

What can you do?

You can prepare yourself to help in an emergency simply by looking around when you’re out and about. See if you can spot an AED at your local supermarket, library, gym or movie theater — all places where they are common. “That is mental preparation that a lot of us don’t do,” says Khan. “We think about it only after the fact, and we need to do a better job of it.”

Next, a simple mental exercise can help you avoid freezing in a crucial moment. “When I teach people about AEDs, I try to get them to think through what they would do, so they’ve at least thought it through once,” Krumholz says. “Just spend five minutes thinking about, ‘I’m going to seize the moment, jump in;’ See it as an opportunity to save a life, and don’t be afraid that you’re going to do something wrong, because the only wrong thing you can do is freeze and not do anything.”

He underscores how nearly foolproof AEDs are, because, once you turn them on, they give you instructions. But first you need to know how to recognize a cardiac arrest. According to Johns Hopkins Medicine, the most common signs are:

• Fatigue
• Dizziness
• Shortness of breath
• Nausea
• Chest pain
• Heart palpitations

“Oftentimes, someone is just not feeling right,” says Khan. “They may, all of a sudden, feel sick to their stomach or have a crushing kind of chest pain that may or may not radiate toward the jaw, the ear or the neck; they may be a little more flush and just not feel right or be a little restless.” Eventually, someone in cardiac arrest will faint, but if the person in distress is still standing, bending over or sitting up, help them safely lie down on the ground, Khan says. If other people are or might be in the vicinity, immediately start calling for help and asking others to call 911. If you are alone, you should call 911. Ideally, one person can call 911 and look for an AED while another begins CPR.

If an AED is available, it should be used immediately. Simply turn it on, open or pull up the person’s shirt to expose their bare chest and stick the pads on their chest (the device will instruct you where they should go). If you’re waiting on someone to find an AED, begin CPR.

“Start basic life support," Krumholz says, who advises everyone to get trained to perform CPR. "You may think you haven’t been trained, but do just do your best."