Automated External Defibrillators

Nearly 350,000 Americans die from sudden cardiac arrest each year. Cardiac arrest may occur when the heart’s rhythm goes into an uncoordinated electrical activity called fibrillation. The heart cannot pump blood effectively and permanent brain injury and death can result within 10-12 minutes. The victim's chance of survival decreases by 7 to 10 percent for each minute that passes without defibrillation.

In most cases, a "rescue" is possible with defibrillation—an action that stops an uncontrolled heart rhythm and allows the normal rhythm to resume. Experts estimate that 100,000 lives could be saved each year if automated external defibrillators (AEDs) were widely available.

Without the aid of an AED, the chances of surviving a sudden cardiac arrest are 1 in 20. With an AED, however, chances of survival improve dramatically to 1 in 3. Many safety and health associations strongly encourage businesses and organizations to establish AED programs in their facilities. AED use is an important step in reducing time to defibrillation and improving the sudden cardiac arrest survival rate of employees and the public.

AED Functions and Operation

An AED is a device that administers an electric shock through the chest wall to the heart. Built-in computers assess the patient's heart rhythm, determine if defibrillation is needed and administer the appropriate level of shock.

Audible and visual prompts guide users through the process, so they need not fear forgetting how to use the AED during an emergency situation. Since the AED analyzes the victim's heart rhythm and advises whether or not a shock is needed, the operator is not faced with the decision of how to correctly administer emergency care.

AEDs do not always resuscitate someone in cardiac arrest; they only treat a heart in ventricular fibrillation—an irregular heart rhythm. In cardiac arrest without ventricular fibrillation, the heart does not respond to electrical currents and, instead, needs medication.

If an AED shock is not advised, CPR should be started immediately. AEDs are also less successful when the victim has been in cardiac arrest for more than a few minutes, especially if CPR has not been administered.

Where Should AEDs be Provided?

AEDs should be located in places where large groups of people gather and the risk of a sudden cardiac arrest incident is more likely. AEDs can be found in corporate offices, shopping malls, airports, sports stadiums, schools and community centers. The number of devices available in public areas continues to grow as more organizations realize the importance of AEDs and AED training.

The American Red Cross has a vision of all Americans being within 4 minutes of an AED and someone trained to use it. All businesses and organizations should seriously consider purchasing an AED and providing CPR and AED training to multiple employees.

According to Food and Drug Administration (FDA) rules, a physician's prescription is required to purchase an AED (there are some exceptions for models purchased for home use). This means that the medical director of a facility, or a physician used by a facility, must prescribe and oversee an AED program at any workplace or other facility that houses an AED.

The cost of an AED varies among manufacturers, but averages about $1,5000-$2,000 per unit. This is a small price to pay for the comfort of knowing that victims of sudden cardiac arrest are nearly 7 times as likely to survive.

AED Training

Although AEDs are designed for ease of use, training is necessary to understand the role of defibrillation in the broader context of the cardiac chain of survival. Training in CPR and AED enables the rescuer to use all the steps in the cardiac chain of survival, significantly increasing the victim's chance of survival.

Organizations such as the American Heart Association and American Red Cross provide CPR and AED training classes. These organizations generally offer half-day courses that teach CPR and AED skills and comprehensive, daylong sessions that also include first aid training.

It is important that rescuers be trained in both CPR and AED, since both are required in the cardiac chain of survival. Most CPR training courses now routinely incorporate AED training due to the increasing presence of AEDs in public areas.

In most cases, EMTs and first responders (police and firefighters) are required to know how to use an AED as part of their job responsibilities. All 50 states now have AED Good Samaritan provisions that help protect rescuers from liability. Additional information regarding Good Samaritan protection can be obtained from local or state emergency medical services (EMS) departments.

Cardiac Chain of Survival

The cardiac chain of survival is the best treatment for victims of sudden cardiac arrest. This series of four critical steps must be followed to help ensure survival.

Step 1: Early access to emergency care (calling 911 or another emergency number)

Step 2: Early CPR

Step 3: Early defibrillation

Step 4: Early advanced life support as needed

The third step is recognized as the most critical step in restoring cardiac rhythm and resuscitating a victim of sudden cardiac arrest. Without the use of an AED, early defibrillation is generally not possible.