Automatic external defibrillators (AEDs) are external devices that can be used by minimally trained laypersons in emergency situations. They are designed to read the heart rhythm patterns of the patient, signal if defibrillation is necessary, then deliver the appropriate electrical shock.  This significantly reduces the amount of training needed for their effective use and allows people with minimal training to perform defibrillation in emergency situations with little risk of additional injury to the patient.

The operator needs to do only four things:

The AED reads the patient’s heart rhythms to determine if a “treatable rhythm” exists. At the moment of collapse, most rhythms are treatable – but this becomes less likely as more time passes. If the patient does not have a “treatable rhythm,” the AED will not discharge the electrical shock.

Both the AED and cardiopulmonary resuscitation (CPR) are techniques that can be used in emergencies when someone has gone into cardiac arrest – an often-fatal condition in which the person loses consciousness as a result of the heart abruptly ceasing to pump blood to the body. Although CPR is a vital life-sustaining tool, it cannot restore the heart rhythm of the patient – defibrillation can. Research has consistently demonstrated that early defibrillation greatly increases the survival rate of patients in cardiac arrest.

Automatic defibrillation attempts should begin as quickly as possible after the onset of cardiac arrest. With each minute that passes, the chance for survival or significant recovery decreases, which is why many healthcare professionals advocate the widespread availability and use of AEDs.

Indeed, AEDs have become more common in ambulances and fire rescue vehicles, as well as public places, such as stadiums, airports, shopping malls, health clubs and golf courses. All U.S. airlines are now required to carry AEDs on all domestic and international flights.