What is an AED?

AEDs play a critical role in the “Chain Of Survival” which can help save the lives of victims of sudden cardiac arrest (SCA). The Chain of Survival is a four-step intervention process developed by the American Heart Association.

1. Early Access — First, as soon as an emergency is recognized, call 9-1-1.
2. Early CPR — The critical link that buys time between the first link (call 9-1-1) and the third link (use the AED). Begin Cardiopulmonary Resuscitation (CPR).
3. Early Defibrillation — Most sudden cardiac arrest victims are in ventricular fibrillation (VF). Use an AED to Treat VF.
4. Early Advanced Care — The fourth is advanced care provided by highly trained EMS personnel called paramedics.

An automated external defibrillator (AED) is a portable device used to administer an electric shock to the heart and restore the heart’s normal rhythm during Sudden Cardiac Arrest. Ventricular Fibrillation (VF), the abnormal heart rhythm that most often leads to Sudden Cardiac Arrest, is treatable. If the heart can be shocked quickly with an AED, a normal heart rhythm may be restored.

In the past, defibrillators were complicated and cumbersome. Only medical professionals with extensive training in heart rhythm interpretation could use them. Today, defibrillators used in public places and in the home are automated, portable and easy to use. They are no longer limited to emergency rooms; and are now placed in airports, schools, gyms, and other public places, and most recently in homes.

An AED consists of a small computer (microprocessor), electrical circuitry and adhesive electrode pads. The electrodes collect information about the heart”s rhythm. The microprocessor interprets the rhythm. If the heart is in ventricular fibrillation, the microprocessor recommends a defibrillating shock. The shock is delivered by way of the electrode pads, through the victim’s chest wall, and into the heart. The shock stuns the heart momentarily, stopping all activity. This gives the heart a chance to restart normal electrical activity and resume beating effectively.

It is essential that defibrillation be administered immediately following the cardiac arrest. If the heart does not return to a regular rhythm within 5-7 minutes, this fibrillation could be fatal. If defibrillated within the first minute of collapse, the victim’s chances for survival are close to 90%. For every minute that defibrillation is delayed, survival decreases by 7 percent to 10 percent. If it is delayed by more than 10 minutes, the chance of survival in adults is less than 5 percent.