IStock Photo 9368051 © BanksPhotos

Television loves its medical dramas and every TV medical drama loves its AED, or automated external defibrillator. Aside from nurses yelling “Stat!” the most common exclamation on ER or Grey’s Anatomy or House is the command to “Clear,” as a doctor uses those two metal paddles to shock a patient back to life. But, as with most things on TV, don’t believe everything you see. AEDs are designed for hearts that are fibrillating, not flat-lining. In other words, if there is no heartbeat, an AED is no help at all.

When used in the right situations, however, an AED can be a real lifesaver. Not counting hospitalized patients, 1 in 1,818 people experience sudden cardiac arrest in the US each year. This shouldn’t be confused with a heart attack.

A heart attack, or myocardial infarction, occurs when blood flow to the heart is cut off, usually by a clot or clogged arteries. Cardiac arrest, on the other hand, is when the heart itself starts misfiring in the form of fibrillation, when the heart’s usually steady rhythm is thrown out of whack.

During ventricular fibrillation, for example, the heart’s lower chambers flutter instead of beating with the powerful pulses needed to push blood through the body. This is a situation that calls for defibrillation, a jolt of electricity to reset a steady heartbeat.

According to the American Heart Association, only about 5% of people experiencing cardiac arrest with no immediate intervention survive the trip to the hospital. However, in cities where portable AEDs are readily available, as many as 45% make it alive to the hospital. And, as AEDs become more widespread, the odds just keep getting better.

There’s a 1 in 75.08 chance that someone experiencing cardiac arrest due to a pre-existing heart condition will be defibrillated by a quick-thinking bystander and a public-access AED. 1 in 1.32 (76%) of those victims will make it to the hospital, and 1 in 2 will live to be discharged. These are amazing numbers considering that when a cardiac arrest victim doesn’t receive the jolt from an AED, their odds of survival are only 1 in 15.63.

Luckily for any would-be life-saver, today’s AEDs come with explicit instructions. In fact, the machine monitors the victim’s heartbeat and tells you in its electronic voice whether or not the person needs a jolt. A study conducted at Chicago’s O’Hare airport found that even people with no prior experience using an AED were able to use the device properly. And a similar study aboard US aircraft found a 40% survival rate for passengers who were jolted out of cardiac arrest in-flight. So you don’t have to be a doctor, or even an actor that plays one on TV, to be able to grab the device, yell “Clear,” and save a life.