Chain of Survival for Sudden Cardiac Arrest

More people can survive SCA if the following steps occur in rapid succession:

1. Early warning signs are recognized;

2. The emergency medical system is activated;

3. Basic cardiopulmonary resuscitation (CPR) is started;

4. Defibrillation occurs;

5. The victim is intubated; and

6. Intravenous medications are administered.

The AHA developed the Chain of Survival concept to communicate this sequence in a useful and easy-to-understand way

Four links in chain of survival:

1. Recognize a medical emergency and call 911.

   • Immediate call crucial. The sooner 911 or your local emergency number is called the sooner early advanced life support arrives. A delay of just a few minutes could prove fatal.

   • Sets Chain of Survival in motion. Calling 911 gives the next two links, CPR and Early Defibrillation, the greatest opportunity for success.

2. Early CPR. Once an SCA victim collapses and a bystander calls 911, the next step in the Chain is to perform Cardiopulmonary Resuscitation (CPR) if you are trained, or to find someone who is.

   • Buys time: During SCA, the heart twitches irregularly, most often due to ventricular fibrillation (VF), and cannot pump oxygenated blood efficiently to the brain, lungs, and other organs. The victim quickly stops breathing and loses consciousness. Prompt CPR can help sustain life during VF. The mouth-to-mouth breathing and chest compressions help oxygenated blood flow to the person's brain and heart until an AED can be used to attempt to restore normal heart pumping or advanced medical personnel arrive.

   • Ineffective by itself: Only when combined with early defibrillation and early advanced care can CPR significantly increase an SCA victim's chance for long-term survival.

     • CPR alone cannot fully resuscitate a person in SCA because it does nothing to restore normal heart rhythm

     • While better than no treatment, the survival rate for victims in SCA treated by CPR alone is very small (between 2 to 5%);

     • The longer CPR is performed, the less the chance of survival.

   • Strength of link depends on increased training. Lay people initiate CPR in more than half of SCA cases in which someone has witnessed the incident. The strength of this link is dependent on the number of lay people trained in CPR and the number of training programs in your schools and community.

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