The Chain of Survival is a five-step process for providing treatment to victims of sudden cardiac arrest (SCA) [1]. It was first developed by the American Heart Association (AHA) in 1990 after several decades of research into SCA and was designed in recognition of the fact that most episodes of SCA occur outside of a hospital, with death occurring within minutes of onset without treatment. Quick execution of each and every link is critical because the chances of survival decrease 7 to 10% with each passing minute.
Emergency systems that can effectively implement these links can achieve ventricular fibrillation cardiac arrest survival of almost 50%. Indeed, a recent study [2] of school-based AED programs found that the overall survival rate can be increased to over 70% and to nearly 90% among student-athletes resuscitated with an on-site AED.[2]
More people can survive SCA if the following steps occur in rapid succession:
The AHA developed the Chain of Survival concept to communicate this sequence in a useful and easy-to-understand way.
1. Immediate recognition that the victim has experienced a cardiac arrest, based on unresponsiveness and lack of normal breathing, immediate activation of the emergency response system (e.g. call 911 [3]), and get an AED/defibrillator.
2. Early CPR. Once an SCA victim collapses and a bystander calls 911, the next step in the Chain is to immediately begin chest compressions (Cardiopulmonary Resuscitation or CPR) [4]. The AHA now recommends[1] that all rescuers, regardless of training, or skill level, victim charactheristics, or available resources, should provide chest compressions to all cardiac arrest victims, with rescuers who are able adding ventilations (mouth-to-mouth) to chest compressions. Rescuers should start CPR immediately. The directive to "look, listen, and feel for breathing" is no longer recommended.
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. 3. Early Defibrillation. Most victims of SCA need an electric shock called defibrillation to restore the heart to a regular rhythm. When the AED arrives, apply the pads, if possible, without interrupting chest compressions and turn the AED on. The AED will analyze the rhythm and direct the rescuer either to provide a shock (i.e. attempt defibrillation) or to continue CPR.
4. Early Advanced Life Support. The fourth link in the Chain of Survival is advanced care. Paramedics and other highly trained EMS personnel provide this care, which can include basic life support, defibrillation, administration of cardiac drugs, and the insertion of endotracheal breathing tubes (intubation).
SCA accounts for at least 350,000 deaths each year in the United States and some authorities believe the number is much higher. Whatever the accurate number, cardiac arrest kills more people than all forms of cancer combined.
Following the Cardiac Chain of Survival dramatically increases the survival rates for SCA victims:
CPR and AED Used Within 8 Minutes: 20% Chance of Survival. When CPR and defibrillation are provided within eight minutes of an episode, a person's chance of survival increases to 20%.
CPR and AED Within 4 Minutes/EMS Within 8 Minutes: 40% Chance of Survival. When these steps are provided within four minutes and a paramedic arrives within eight minutes, the likelihood of survival increases to over 40%.
Defibrillation Within 5 To 7 Minutes: 49% Survival Rate. According to the AHA, the survival rate from SCA is as high as 49% where defibrillation occurs within 5 to 7 minutes of collapse.
Survival Rates As High As 64%. The AHA also reports that after AEDs were placed at Chicago's O'Hare and Midway Airports, 9 out of 14 SCA victims (64%) were revived with an AED and had no permanent neurological damage. Survival rates between 70 and 89% were recently reported at U.S. high schools with AEDs.[2]
If nothing is done for a cardiac arrest victim, he is probably going to die. Even with prompt CPR he is probably going to die before the ambulance arrives. Defibrillation applied shortly after his collapse gives him a fair chance of survival. What better reason could there be for implementing AED programs?
1. Travers AH, Rea TD, Bobrow BJ, et. al. 2010 American Heart Association Guidelines for Cardiopulminary Resuscitation and Emergency Cardiovascular Care Science. Part 4: CPR Overview. Circulation 2010;122:S676-S684.
2. Drezner JA, Toresdahl BG, Rao AL, et al. Outcomes from sudden cardiac arrest in US high schools: a 2-year prospective study from the National Registry for AED Use in Sports. Br J Sports Med. 2013:47:1179-1183 (originally published online October 11, 2013); doi:10.1136/bjsports-2013-092786.
Links:
[1] https://momsteam.com/node/361
[2] https://momsteam.com/node/6943
[3] https://momsteam.com/node/387
[4] https://momsteam.com/node/354
[5] https://momsteam.com/node/300
[6] https://momsteam.com/users/glenn-laub
[7] https://momsteam.com/health-safety/school-based-aed-programs-save-victims-of-sudden-cardiac-arrest-and-important-public-safety-measure-study-says
[8] https://momsteam.com/health-safety/many-us-high-schools-unprepared-cardiac-emergency