Chain of survival

The chain of survival refers to a series of actions that, properly executed, reduce the mortality associated with cardiac arrest. Like any chain, the chain of survival is only as strong as its weakest link. The four interdependent links in the chain of survival are early access, early CPR, early defibrillation, and early advanced cardiac life support

The "chain of survival" metaphor was first published in the March 1981 newsletter of CPR for Citizens in Orlando, Florida. James O. Page, JD, requested permission to use it and that permission was granted. It was further developed by Mary M. Newman, MS, of the Sudden Cardiac Arrest Foundation, and used as a slogan for the 1988 Conference on Citizen CPR, and described in an article she wrote for the Journal of Emergency Medical Services in 1989, and in an editorial she wrote for the first issue of Currents in Emergency Cardiac Care in 1990. The American Heart Association adopted the concept and elaborated on it in its 1992 guidelines for cardiopulmonary resuscitation and emergency cardiac care, The International Liaison Committee on Resuscitation (ILCOR) echoed the concept in 1997.

Ideally, someone must recognize an impending cardiac arrest or otherwise witness the cardiac arrest and activate the EMS system as early as possible with an immediate call to the emergency services. Unfortunately, many persons experiencing symptoms (for example, angina) that may lead to a cardiac arrest ignore these warning symptoms or, recognizing these warning symptoms correctly, fail to activate the EMS system, preferring to contact relatives instead (the elderly often contact their adult offspring rather than contact emergency services).

To be most effective, bystanders should provide CPR immediately after a patient collapses. Properly performed CPR can keep the heart in a shockable ventricular fibrillation for 10–12 minutes longer.

Most adults who can be saved from cardiac arrest are in ventricular fibrillation or pulseless ventricular tachycardia. Early defibrillation is the link in the chain most likely to improve survival. Public access defibillation may be the key to improving survival rates in out-of-hospital cardiac arrest, but is of the greatest value when the other links in the chain do not fail.

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