Health

Effectiveness of Heart Defibrillators Seen in Two Studies

By CBSNews.com staff CBSNews.com staff

January 31, 2002 / 8:40 AM EST / CBS

With new technology comes an opportunity for people to save the lives of those around them in the case of emergency. Today's issue of the New England Journal of Medicine includes results of two studies that indicate the effectiveness of 'lay personnel' using publicly available automated external defibrillators (called AEDs) to restart a heartbeat once someone goes into cardiac arrest.

CBS News Health Correspondent Dr. Emily Senay demonstrated how these devices on Thursday's Early Show.

People trained in the use of AEDs can intervene effectively and increase the survival rate among victims of cardiac arrest by 26 to 40 percent. The studies show the value of placing AEDs in non-hospital settings, where cardiac arrests can occur.

Of 105 people who had sudden cardiac arrest in casinos, more than half survived to be discharged from the hospital when trained security guards used an Automated External Defibrillator or AED device to jolt the person's heart into a normal rhythm. In another study of the use of AEDs on airlines, 40 percent of people survived. Compare this to current overall average of 5 percent survival and you can see the benefit, Senay says.

The key to success with AEDs is timing--the faster the better. In the casino study, the best results were obtained when the device was used within three minutes of a witnessed heart attack. In fact, the survival rate for those who received a shock within three minutes was as high as 75 percent. Ambulances obviously take longer than three minutes, which is often too late to really save anybody, Senay says. This is why having defibrillators in public areas is crucial.

How Do AEDs Work?

Senay and Early Show co-host Bryant Gumbel demonstrated how to use an AED on a dummy. In an emergency, even people who are not trained can follow the instructions on the AED, Senay says, and one study showed that sixth graders can do it effectively.

Should people be concerned that they would hurt themselves or make the situation worse? The fact is it is almost impossible to hurt yourself or cause a person damage using this device, Senay says, because the computerized system won't let you. It only shocks under highly specific situations so while many people may have that fear, it is unfounded.

Training is recommended, however. It takes just four hours of your time and you can get trained in cardiopulmonary resuscitation (CPR) at the same time. Call either the American Heart Association, the American Red Cross, or the National Safety Council to find courses in your area.

An initial barrier to placing AEDs in business locations was the fear of liability. This concern has been effectively addressed by legislation in almost all states. For the states without their own legislation, there is the proposed Cardiac Arrest Survival Act that would prtect the many thousands of people who either work in or pass through federal buildings nationwide. The act is still pending.

Cardiovascular Disease Facts and Statistics

Cardiovascular disease is the No. 1 killer in the United States, taking more than 950,000 lives annually. Cardiovascular diseases claim more lives than the next seven leading causes of death combined, including cancer, accidents, pneumonia, influenza, diabetes and suicides.
More than 95 percent of sudden cardiac arrest victims die before reaching the hospital. Sudden cardiac arrest claims about 225,000 adults in the U.S. each year. More than 600 Americans die of sudden cardiac arrest each day.
Sudden cardiac arrest is caused by a life-threatening abnormal heart rhythm that can result from heart attack, respiratory arrest, electrocution, drowning, choking or trauma or it can have no known cause. Brain death and permanent death start to occur in just four to six minutes after someone experiences sudden cardiac arrest.
Survival is directly linked to the amount of time between the onset of sudden cardiac arrest symptoms and defibrillation (electric shock to the heart). Chances of survival are reduced by 7 to 10 percent with every minute that passes. Few attempts at resuscitation are successful after 10 minutes.
Death from sudden cardiac arrest is not inevitable. If more people react quickly by calling 9-1-1 and performing CPR, more lives could be saved. CPR is important, but it is not a substitute for defibrillation. CPR can help keep a sudden cardiac arrest victim alive until defibrillation - the only treatment that can restart the heart - can be administered.
The American Heart Association is helping businesses and other facilities develop programs to make automated external defibrillators, or AEDs, and AED-trained people more readily available. These programs, called "public access defibrillation" or PAD, encourage the purchase of AEDs, medical supervision in creating and overseeing the program, the training of personnel who will use AEDs, proper maintenance of AED equipment, and coordination of the program with local emergency medical service personnel.
About 80 percent of all sudden cardiac arrests happen at home, so knowing how to give effective cardiopulmonary resuscitation (CPR) may mean the difference between life and death for a loved one.
In cities where defibrillation is provided within five to seven minutes, the survival rate from sudden cardiac arrest is as high as 15 percent. If every community could achieve a 20 percent sudden cardiac arrest survival rate, at least 50,000 people could be saved each year.