Chain of survival


The chain of survival refers to a series of actions that, properly executed, reduce the mortality associated with sudden 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.

Background

The "chain of survival" metaphor was developed by Mary M. Newman in 1987. It was used as a slogan for the 1988 Conference on Citizen CPR, described in an article she wrote for the Journal of Emergency Medical Services in 1989, and promoted in an editorial she wrote for the first issue of Currents in Emergency Cardiac Care in 1990. The American Heart Association later adopted the concept and elaborated on it in its 1992 guidelines for cardiopulmonary resuscitation and emergency cardiac care, The International Liaison Committee on Resuscitation echoed the concept in 1997. The links of the Chain of survival are described below.

Early access

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 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.

Early CPR

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

Early defibrillation

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 defibrillation 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.

Early advanced care

Early advanced cardiac life support by paramedics is another critical link in the chain of survival. In communities with survival rates > 20%, a minimum of two of the rescuers are trained to the advanced level.