In 1987, the Citizen CPR Foundation first used the "Chain of Survival" metaphor in a promotional brochure, listing the four major links that must coexist to maximize the chance of survival in a victim of SCA. Early defibrillation is an essential link in this process.

STEP 1 Early Access: Arrive and assess the scene. Notify Emergency Services. Check to see if victim is unresponsive, i.e., no breathing or pulse. Have someone retrieve AED.	STEP 2 Early CPR: This combination of rescue breaths and chest compressions provides limited oxygen to help keep brain tissue alive until defibrillation can occur.	STEP 3 Early Defibrillation: This is the biggest factor in saving a victim of SCA. Defibrillation must occur within minutes (less than five is optimal) or else the patient will not survive.	STEP 4 Early Emergency Care: The final critical link. The AED may get the patient's heart going again, but advanced medical care, such as stabilizing medications, is essential to ensure long-term survival.

The Third Step: Early Defibrillation
Once the first two steps of the "Chain of Survival" are completed, it's time to use your AED. Place the machine next to the victim and make sure it is on and operating (some machines will automatically come on when opened; others must be turned on manually). It will begin to give vocal instructions to coach you through the process.

First, the chest is completely bared. Cut or rip through the victim's clothing to save time.

Next, prepare the chest - if it's wet or sweaty, dry it off.

When the chest is ready, place the self-sticking defibrillation pads on the victim as shown above. Good, solid contact with the skin is essential for an effective shock. One pad goes on the upper right side of the patient's chest, just below the collarbone. The other pad is placed on the left side, below the left breast, over the ribcage. Most AEDs have graphics depicting exactly where to place the pads and/or a vocal message that takes you carefully through the process. If chest hair prevents the pads from sticking, quickly shave it (it is recommended that a razor be kept in the AED kit for this purpose).

Once the patient is attached, an AED will automatically begin to analyze the heart rhythm. While the AED is analyzing, clear the victim - make sure no person or other object is touching them. The AED may automatically shock the victim if they need it, or it may advise you to press a "shock" button.

Learn even more about AEDs and Sudden Cardiac Arrest. Continue on or click any of the links below to go directly to that topic.