AED stands for automated external defibrillator. It is a computerized medical device that can be used to treat a victim of cardiac arrest. An AED evaluates a sudden cardiac arrest victim's heart rhythm, determines if shock is needed and delivers an electric shock through the chest wall to the heart. Audio and/or visual prompts guide the user through the process.

How does an AED work?
Adhesive electrode pads, connected to the AED by cables, are placed on the victim's chest. The pads capture the victim's heart rhythm and transmit the rhythm to the AED. A computer inside the defibrillator analyzes the victim's heart rhythm and advises the operator whether a shock is needed.AED's advise a shock only for a "shock able" rhythm, most often ventricular fibrillation (VF).

When are AED's used?
AED's are used to treat sudden cardiac arrest, most often caused by VF. VF is a life-threatening abnormal heart rhythm in which the heart's electrical impulses become chaotic, causing the heart to quiver and stop pumping blood. Victims become unresponsive and can't breathe normally. If the shock is effective, it will stop the abnormal heart rhythm, allowing the heart's normal rhythm to resume.

Why are AED's important?
The treatment for sudden cardiac arrest caused by VJ is defibrillation within minutes.AED's are important because they can reduce the time to defibrillation for victims of sudden cardiac arrest. Communities can implement community AED programs to help make sure that sudden cardiac arrest victims receive immediate bystander CPR and defibrillation within minutes.

Who can use an AED?
AED's can be used by non-medical personnel such as police, fire service personnel, flight attendants, security guards and other trained lay rescuers.

Why does someone having a heart attack need an AED?
Not everyone having a heart attack needs an AED. However, some victims of heart attack can develop VF sudden cardiac arrest. When VF develops, the heart quivers ineffectively and can't pump blood. The AED delivers a shock to the heart muscle, stopping all electrical activity. This gives the heart a chance to resume a normal rhythm.

Should the use of AED's replace CPR?
No. CPR is an important part of treating sudden cardiac arrest because it can double a victim's chance of survival if it's provided from the moment of collapse until the AED is ready to deliver a shock. CPR may also be needed if the AED alone is not successful in restoring normal heart rhythm and further treatment is necessary.

Will an AED always resuscitate someone in sudden cardiac arrest?
No. An AED only recommends a shock when it detects a "shock able" rhythm. A shock can eliminate VF but it will not "restart" the heart. sometimes the abnormal rhythm is eliminated, but the heart's own rhythm does not return and restore normal circulation. CPR can be used between shocks and until advanced care arrives.

Is an AED safe to use?
An AED is safe to use by anyone who's been trained to operate it. AED's are designed with multiple safeguards before any shock is delivered. AED's deliver a shock only when they have detected VF of other "shock able" rhythm and when the operator presses the "Shock" button. The AED will not deliver a shock (even if the operator presses the "Shock" button) if it does not detect a "shock able" rhythm.

Are AED's safe to use on children?
At this time, the American Heart Association does not recommend using AED's for children younger than 8 years old or who weigh less than 55 pounds.

Will I get shocked if I shock a victim in rain or near water?
It's very unlikely that you can get shocked or will shock bystanders when you use an AED safely. However, if the victim is lying in standing water, particularly if water is on the victim's chest, you should move the victim to a dry area, open or remove the victim's shirt and dry the chest.

When an AED is analyzing the victim's heart rhythm and delivering an electric shock, no one, including you (the AED operator) should touch the victim.

Can an AED make mistakes?
It's unlikely that an AED will make a mistake. Studies have shown that AED's interpret the victim's heart rhythm more accurately and more quickly that trained emergency professionals. If the operator has attached the AED to an adult victim who's unresponsive, not breathing normally, with no signs of circulation (cardiac arrest), the AED is very accurate in determining if the victim has a "shock able" or a "non-shock able" rhythm.

If AED's are so easy to use, why is formal training needed?
Commercially available AED's are user-friendly and contain prompts to guide a rescuer. However, using an AED safely requires more than operating it.

The American Heart Association recommends that anyone who might use an AED take its Heart Saver AED course. Training will help rescuers know how to recognize the signs of sudden cardiac arrest, when to activate he EMS system, how to provide CPR, when to attach an AED and how to safely operate and troubleshoot the AED. It's also important to receive formal training on the specific AED that will be used. This helps a user successfully operate it in an emergency.

Training also teaches the user how to respond to special situations such as placing AED electrode pads when the victim has an implanted pacemaker, a very hairy chest or a medication patch. Finally, training helps the rescuer be skilled in performing CPR and efficient in delivering the shock in the shortest time possible. These factors can improve survival from VF sudden cardiac arrest.

Where can I get AED training?
AED training is part of the Heart Saver AED course. Call toll free: 1-877-242-4277 to find a training center near you.