Recognize an Emergency.
First, you or other witnesses must recognize the emergency. You must recognize the warning signs of a heart attack, cardiac arrest, stroke, or choking. Anyone who is unresponsive should receive emergency care. Heart attack, cardiac arrest, stroke, and foreign-body airway obstruction can each cause unresponsiveness. Although many conditions — not just cardiac arrest — can cause unresponsiveness, all unresponsive victims will benefit from activation of the Chain of Survival.

Call 911 (or the EMS system in your area).
As soon as an emergency is recognized, call 911. When you or another rescuer calls 911, let the dispatcher ask you questions. While the dispatcher interviews you, he or she will enter the data on a computer. The information you give will be relayed to a response team. Answer in short, specific replies, giving only the requested information. The dispatcher will probably ask:

• "What is your emergency?" You might answer, "A customer had sudden chest pain and has now collapsed."
• "What's happening now?" "My friend is giving cardiopulmonary resuscitation. We have an automated external defibrillator."
• "Where is the patient located?" "We are at the Evergreen Company, here at 1234 Fifth Avenue NE, in the back hall."
• "What number are you calling from?" "The number is 555-1313."

At this point the dispatcher may give you directions such as "Stay on the line until I tell you to hang up. Rescuers are being sent to your location. Please meet them and direct them to the scene."

Remember, though, if you are alone, you must immediately begin performing CPR, the next link in the chain.

Begin Cardiopulmonary Resuscitation (CPR).
CPR is the critical link that buys time between the first link (call 911) and the third link (use the AED). The earlier you give CPR to a person in cardiac or respiratory arrest, the greater their chance of survival. CPR keeps oxygenated blood flowing to the brain and heart until defibrillation or other advanced care can restore normal heart action.

Dispatcher-Assisted CPR and Defibrillation and Enhanced 911. In many areas of the country emergency dispatchers are taught how to help callers give emergency care. With help from the dispatcher, callers can give CPR (and use an AED). The instructions are basic and simple, but they will help the victim until EMS personnel arrive. Remember, CPR needs to be started immediately!

Using a prepared list of instructions, the dispatcher can coach you through the basic steps of CPR. At a worksite you will usually have help.

Use this approach:

• Repeat the dispatcher's instructions loudly to the other rescuers and confirm that they are following that step.
• If the patient vomits or other complications arise, tell the dispatcher. Do not expect that you will perform perfectly in such a crisis.
• Be sure that rescuers follow each instruction, even if it takes extra seconds.
• Ensure rescuer safety at all times.
• When EMS personnel arrive at the victim's side, the dispatcher will tell you that he or she is hanging up.
• You hang up last.

Find Out if Your Community Has Enhanced 911.
In enhanced 911 a computer automatically confirms the caller's address. Also ask if your 911 dispatchers are trained to offer prearrival instructions to rescuers. This means that they can give instructions for immediate care based on the clinical criteria of the emergency. If not, become a vocal advocate for such services in your community. Enhanced 911 can save precious seconds, minutes, and even lives.