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Chain of Survival for Sudden Cardiac Arrest

Quick execution improves survival odds

    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.

  • Defibrillation outcomes improved when interruptions in chest compressions kept to minimum.
  • Most critical link: Although CPR can sustain life for a short time, it must be followed within minutes by early defibrillation.
    • Each minute that defibrillation is delayed reduces the victim's chance of survival by about 10 percent.
    • Not all rescues involving an AED are successful, but where AEDs are deployed widely and used quickly, survival rates of 50% or higher have been reported - a far cry from the 2-5% survival rates for CPR alone.
    • Early defibrillation is thus recognized as the most critical step in restoring cardiac rhythm and resuscitating a victim of SCA.
  • Strength of link depends on AED availability. Almost a third of the deaths from sudden cardiac arrest can be prevented if an AED id available for immediate use at the time of the emergency. Unfortunately, AEDs are not yet widely in use, especially in schools and by youth sports programs. As a result, many youth sports athletes die each year that might have been saved by an AED. 

   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).

  • Helps maintain normal heart rhythm after defibrillation: Advanced care can help the heart in VF respond to defibrillation and maintain a normal rhythm after successful defibrillation.
  • Allows monitoring on way to hospital: The trained EMS personnel monitor the patient closely on the way to the hospital, where more definitive diagnostic evaluation can occur.
   5. Integrated post-cardiac arrest care.

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.