AED Basics

Automated External Defibrillators (AEDs) look like colorful, overly inflated laptop computers. They can be used by lay people who have gone through minimal training to revive people who suffer cardiac arrest. The AED consists of the actual device which has only one or two control buttons and a pair of self-stick pads called electrodes that are placed on the victim’s bare chest. One is placed about halfway between the right nipple and the right collarbone and the other is placed on the left side about two inches below the left armpit.
As soon as the pads are placed, the AED begins analyzing the victim’s heart rhythm. This takes only a matter of seconds. If the AED senses that cardiac arrest is occurring, it will advise you to push a button to deliver a shock.

An AED Speaks to You

From the moment it is turned on, the AED begins giving you directions. All of them provide spoken directions and most of them give text directions via a faceplate on the AED. Thus, as long as you turn the AED on, it will tell you what to do next. And it won’t go to the next step until you have completed the last step. Because its sequence is so logical, well defined, and well illustrated it has a calming effect on rescuers who are inexperienced in responding to cardiac emergencies.

An AED is Foolproof

AEDs will not allow a shock to be administered unless the person is really in cardiac arrest. You cannot shock a person who doesn’t need to be shocked making AEDs the next thing to foolproof. The only mistake you can make is to forget to turn the AED on.

People are familiar with defibrillators from the many hospital and rescue shows on television. Usually, a handsome or beautiful physician calls out a setting, makes sure no one is touching the unconscious victim, and holds a set of paddles on the victim’s chest while someone else presses the shock button. AEDs do the same thing except the machine determines how strong a shock is given, the sticky pads take the place of the paddles, and you press the ‘Shock’ button after making sure no one is touching the victim. The important decisions are made by the AED differentiating them from the manual defibrillators used by paramedics and physicians.

The Cardiac Chain of Survival

Following the Cardiac Chain of Survival will lead to dramatic increases in the survival rates of cardiac arrest victims.

The first step is to summon skilled help by calling 911 as soon as a cardiac arrest is suspected. The second step is to begin CPR to get oxygen-rich blood circulating through the victim’s body. Early defibrillation is the third step while the fourth step is to relinquish care of the victim to EMTs and paramedics once they arrive.

Why Are They Important?

Sudden cardiac arrest accounts for at least 350,000 deaths each year in the United States and some authorities believe the number is much higher. Whatever the accurate number, cardiac arrest kills more people than all forms of cancer combined.

What Is Cardiac Arrest?

Cardiac arrest results from a defect in the electrical impulses that control the heart’s rhythm. It is not a synonym for heart attacks that are usually caused by blockage of the veins and arteries leading to and from the heart. The analogy is that cardiac arrest is an electrical defect whereas heart attacks result from problems with the plumbing. People who suffer heart attacks often remain conscious during and after the attack and they are able to breathe on their own. Cardiac arrest victims lose consciousness, stop breathing and their hearts beat erratically. If intervention isn’t rapid, they usually die.

For the past twenty years, CPR has been the treatment of choice for cardiac arrest. Oxygen is provided to an unconscious person and chest compressions pump blood around his body. While better than no treatment, cardiac arrest victims treated by CPR alone survive only two to five percent of the time. CPR buys time until more effective treatments can be administered.

AED Can Restore Normal Heart Rythm

AEDs provide rescuers with these more effective treatments. The most common rhythm problem leading to cardiac arrest is ventricular fibrillation. This quivering of the heart muscle (likened to shaking  a bowl of Jell-O) causes the heart to stop circulating blood to the brain. Breathing stops and shortly thereafter the heart stops as well.
Unfortunately, CPR does nothing to restore normal heart rhythm and the longer CPR is performed, the less the chance of survival.

An AED Increases Chance of Survival

The same CPR rescuer, equipped with an AED, has a chance to improve the odds of survival significantly. If the AED senses ventricular fibrillation, it authorizes a shock to be given. The shock causes the heart to stop for a millisecond after which the victim’s own electrical system may cause it to start beating normally. Not all rescues involving an AED are successful, but where they are deployed widely and used quickly, survival rates of 50% or higher have been reported – a far cry from the 2-5% survival rates of CPR alone.

Defibrillation is most effective when used as soon after an arrest as possible. The chance of success decreases by seven to ten percent for every minute of delay.

Rescuers must remember that if nothing is done for a cardiac arrest victim, he is probably going to die. Even with prompt CPR he is probably going to die before the ambulance arrives. Defibrillation applied shortly after his collapse gives him a fair chance of survival.
What better reason could there be for implementing AED programs?