What is Automated External Defibrillator: How Does it Work, Who Can Use It

A defibrillator is an apparatus used to control heart fibrillation by application of an electric current to the chest wall or heart. An automated external defibrillator (AED) is a lightweight, portable device that delivers an electric shock through the chest to the heart. Using an automated external defibrillator on a person who is having sudden cardiac arrest (SCA) may save the person’s life. Most sudden cardiac arrest (SCA) result from a ventricular fibrillation (v-fib) which is the most serious cardiac rhythm disturbance and is fatal if not handled properly. In a v-fib, the lower chambers quiver and the heart can’t pump any blood, causing cardiac arrest. An automated external defibrillator checks the heart rhythm and can send an electric shock to the heart to try to restore a normal rhythm. Automated external defibrillators are used to treat sudden cardiac arrest (SCA).

Automatic external defibrillators are small computerized devices that analyze heart rhythms and provide the shock needed for defibrillation. Through electrodes placed on a patient’s chest a processor inside the automated external defibrillator analyzes the victim’s heart. The machine will not shock unless it is necessary; automated external defibrillators are designed to shock only when VF is detected. After the processor analyzes the heart rhythm and determines a shock is required, an electric current is delivered to the heart through the victim’s chest wall through the adhesive electrode pads. The shock delivered by a cardiac defibrillator interrupts the chaotic rhythm and allows it to return to normal.

Automated external defibrillators can be used by anyone, anytime, or anywhere to administer a lifesaving shock to victims of Sudden Cardiac Arrest (SCA). Audio and visual prompts guide the user step by step through the rescue process.

Non-medical personnel such as police, fire service personnel, flight attendants, security guards and other rescuers who have been trained in CPR can use automated external defibrillators. Although formal training in the use of an automated external defibrillator is not required, it is recommended to help the rescuer increase their comfort and level of confidence. However, automated external defibrillators or AEDs are intended for use by the general public. Most AEDs use audible voice prompts to guide the user through the process.

Given below are the five most important places where automated external defibrillators must be placed.

• High rise buildings
• The workplaces
• Schools
• Sporting events
• Fitness centers

Other than the above-mentioned places, all first-response vehicles including ambulances, law-enforcement vehicles and many fire engines should have automated external defibrillators or AEDs. They should also be placed in public areas such as shopping malls, airports, airplanes, convention centers, businesses, hotels etc.

The American Heart Association offers CPR and AED training through training centers. To locate a training center near you, call your nearest AHA office or 1-888-AHA-4CPR. You may also visit heart.org/cpr.

In conclusion, with CPR alone, the chance of survival after SCA is less than 5 percent; when CPR is combined with the use of a cardiac defibrillator within the first few minutes, the chance of survival can increase dramatically to more than 75 percent. Having an automated external defibrillator or AED on the premises gives victims of SCA the best chance of survival until paramedics arrive and take over care.