ESI Update:
Last month, Mary was enjoying a day in New York City with her daughter, Debbie. While they were strolling through a gallery at the photography museum, she developed chest pain, fell down and was unresponsive. Debbie quickly asked the security guard for help and began CPR. Within minutes the museum's health service had located its automated external defibrillator and placed it on Mary. Three shocks were indicated and delivered and Mary was transported o the nearest hospital. Today she has been discharged from the hospital and is at home.

It is estimated that in the United States 225,000 people will die suddenly from coronary disease before they reach the hospital. In adults the most common cause for collapse is a cardiac arrhythmia in the setting of a heart attack. To improve outcomes in such instances, the American Heart Association (AHA) has developed the "Chain of Survival" which includes the following four steps: rapid activation of the emergency medical service system, the initiation of cardiopulmonary resuscitation (CPR) until advanced help arrives, evaluation of the heart rhythm with prompt defibrillation when indicated, and airway protection and medical therapy. When CPR is started within four minutes after collapse, the likelihood of a victim's survival to hospital discharge doubles. However, CPR's main benefit is allowing a defibrillator to reach the patient in time to be effective. CPR instructions are provided at www.learncpr.org. If an AED is immediately available its use takes precedence over CPR.

Certain cardiac rhythms can only be treated by rapid defibrillation. An automatic external defibrillators (AEDs) are designed to accurately analyze the heart's rhythm. When the rhythm is one amenable to defibrillation the AED delivers an electrical impulse in an effort to restore a normal rhythm. In some circumstances this may require multiple shocks, and in other instances a shock may not be beneficial so the AED will advise that CPR be performed. If the AED has delivered three shocks without the resumption of a normal heart rhythm, CPR should be resumed.

AEDs have been available for over a decade, and are now in many public locations including shopping malls, stadiums casinos, train stations, exercise facilities, office buildings, airplanes and airports. Organizations such as the AHA encourage public access to AEDs and most states have passed legislation limiting liability associated with the use of AEDs to encourage their use. Such efforts have increased the success of resuscitation. Since gambling casinos purchased AEDs they have found that victims with a sudden cardiac arrest who receive their first defibrillation within three minutes have a spectacular 74 percent survival rate to hospital discharge.