|What Is An AED?
An automated external defibrillator (AED) is a portable device (about the size of a laptop computer) that administers electric shock through the chest to the heart (image). It is used on people who collapse after sudden cardiac arrest (SCA) and their heart stops beating. The AED has a built in computer which assesses the patient's heart rhythm and determines if defibrillation (electric shock) is needed. If it is, it advises the rescuer by audio or visual prompts when to apply the shock. The chance of a person dying without immediate cardiopulmonary resuscitation (CPR) or defibrillation after SCA increases by 7 to 10 percent every minute. Ideally an AED needs to be used within 3 to 5 minutes to save a person's life. Unfortunately emergency service response is not usually quick enough; the average national American response time for an ambulance is 10 to 12 minutes and 6 to 8 minutes in the UK. Although this may sound fast, when a person has stopped breathing, it is an eternity.
What Is Sudden Cardiac Arrest?
In simple terms a sudden cardiac arrest is an 'electrical' problem and a heart attack is a 'plumbing' problem.
SCA is where the heart suddenly and unexpectedly stops pumping. Blood flow to the brain stops and the victim collapses and loses consciousness. Their breathing stops and they no longer have a pulse. This differs to a heart attack where the heart continues to pump but it does not receive enough blood due to a blockage in one of the major blood vessels supplying it. Without blood and oxygen during a heart attack the heart muscle starts dying and produces chest pain and other classic heart attack symptoms. While a heart attack is not SCA it can lead to it. SCA victims fall unconscious whereas most heart attack victims will stay awake and remain able to communicate. Most SCAs are caused by an abnormal heart beat called heart arrhythmia. The most common and dangerous arrhythmia is called ventricular fibrillation (VF) which is where the electrical impulses of the heart become chaotic. Death usually follows unless the heart rhythm can be restored within 3 to 5 minutes. An AED device restores the rhythm by the application of an electric shock. What prompts SCA? Drowning, electrocution, choking on something (asphyxia) and heart attacks are the most common causes.
Where Are AEDs Located?
The American Heart Association and American Red Cross are dedicated to helping business and other establishments install AED devices and train staff in their use to increase the survival rates for victims of SCA. Currently 250,000 people die of SCA every year before they reach hospital. The survival rate for SCA, without defibrillation is less than 5 percent. AEDs are increasingly being installed in workplaces and public places where people gather or where the incidence of a SCA might be high, such as nursing homes, shopping malls, sports stadiums, health clubs and airports. Look for a sign like this to indicate that an AED is available nearby:
What Is The Chain Of Survival?
This describes a sequence of events which ideally should take place in order to help a person survive cardiac arrest. The following steps are referred to as the Chain of Survival:
Early Access: Recognize that a cardiac medical emergency exists and immediately dial 911 for emergency assistance, or notify the local EMS (Emergency Medical Services).
Early CPR: Start cardiopulmonary resuscitation (CPR) immediately to circulate oxygen-rich blood to the brain and other vital organs. This buys time for the victim until defibrillation can be given.
Early Defibrillation: Apply defibrillation to the victim as soon as the equipment arrives.
Early Advanced Care: Trained healthcare or EMS providers arrive and administer advanced lifesaving interventions.
How Difficult Is An AED To Use?
An AED is simple to use, in mock SCA situations, 6th grade children were able to use AEDs without difficulty. The American Heart Association and other organizations run 4 hour courses which certify people for correct use.
How Do I Use An AED?
Using an AED to apply defibrillation (electric shock) to the heart stops ventricular fibrillation (VF), the underlying cause of SCA. Defibrillation is the only known treatment for VF. An AED only requires the user to attach pads to the patient's chest, turn the device on and then follow the audio instructions. They do not require the user to make a decision or to interpret the patient's symptoms. If an AED is installed in your workplace, certain personal will be trained in its use.
Why Should We Have An AED In The Workplace?
Every year in the United States nearly 7,000 workers die in the workplace. About 1200 of those are caused by heart attacks, 350 from electric shock and 300 from asphyxia (choking). Up to 60 percent of these people could be saved if AEDs were immediately available. Resuscitation rarely succeeds once 10 minutes has passed. Jobs where people work shifts, experience high levels of stress or are exposed to electrical or chemical hazards are particularly high risk areas.
Is AED Equipment Expensive?
The average initial cost of an AED ranges between $3,000 to $4,500. The Federal Occupational Health can help you purchase suitable equipment as well as provide information on training and support. It should be noted that a physician prescription is needed in order to purchase an AED (because of FDA rules). Most states also require a medical director or a medical personal to oversee the installation and running of an AED program. For more information, contact the FOH at:
Federal Occupational Health
Phone: (800) 457-9808
Can AEDs Be Used Around Water?
As AEDs use electricity, a victim should not be lying in a puddle of water nor should the rescuer be in kneeling in a puddle of water when AED is applied. However AEDs can be used in a variety of conditions including rain and snow.
What Is A Home Defibrillator?
This is an AED device which is suitable for home use. It may be recommended to patients at high risk of SCA, including those who have undergone heart transplant surgery or with high heart attack risk factors. It is only available on prescription, which means a doctor has to sign off the purchase. To read more about this check our article: Home Defibrillator.
See also, womens health questions, which includes the answers to:
When is CPR necessary?
How is hands only CPR performed?