The chain of survival refers to a series of actions that, when put into motion, reduce the mortality associated with cardiac arrest. Like any chain, the chain of survival is only as strong as its weakest link.
The chances of survival following cardiac arrest are considerably improved if there is a rapid, coordinated response to the emergency, each component of the chain being only as strong as its supporting link.
The components in the chain of survival are:
- – early access to emergency services. Dialling 999 or 112
- – early CPR Even if it is only “Hands Only” CPR
- – early defibrillation, Automated External Defibrillator
- – early advanced cardiac life support ACLS
CPR (Cardiopulmonary Resuscitation)
Having recognised that a patient is in need of CPR it is most effective when it is started immediately. Early CPR provides rescue breathing and chest compressions to the Patient. It will help to keep the victims brain and heart supplied with blood and oxygen until medical help arrives. It also increases the amount of time that an electric shock from a defibrillator can be effective. Even in the worst cases where the patient does not survive CPR can keep the vital organs alive possible making them viable for organ transplantation later resulting in life continuing for someone else.
Defibrillation
Early defibrillation saves lives and involves trained personnel delivering an electric shock to the patients chest to help restore the normal function of the heart. It is the link in “The Chain of Survival” that is most likely to improve survival rates. Having a defibrillator on site within 2 minutes, there can be an 80% chance of survival. Every minute that passes survival rates are reduced by 7-10%. Studies show survival rates as high as 74% can be achieved if defibrillation is given administered within 3 minutes.
Automated External Defibrillator (AED)
An automated external defibrillator (AED) is a small, portable piece of equipment that can deliver an electric shock in order to convert Ventricular Fibrillation VF of the heart into its normal or usual rhythm Normal Sinus Rhythm NSR. The AED contains computer software which analyses a cardiac rhythm and will not deliver a shock if the heart does not require it. The time to defibrillation is the single most important determinant of survival after cardiac arrest otherwise known as time form “drop to shock”
CPR Facts and Statistics
Effective bystander CPR, provided immediately after cardiac arrest, can double a victims chance of survival. CPR helps maintain vital blood flow to the heart and brain and increases the amount of time that an electric shock from a defibrillator can be effective and reduces the amount of brain damage that may occur.
Approximately 95 percent of sudden cardiac arrest victims die before reaching the hospital. Death from sudden cardiac arrest is not inevitable. If more people were trained in CPR, more lives could be saved. Brain death starts to occur four to six minutes after someone experiences cardiac arrest if no CPR and defibrillation occurs during that time.
If bystander CPR is not provided, a sudden cardiac arrest victims chances of survival falls 7 percent to 10 percent for every minute of delay until defibrillation. Few attempts at resuscitation are successful if CPR and defibrillation are not provided within minutes of collapse.
What is the difference between Sudden Arrhythmic Death Syndrome (SADS) and Sudden Cardiac Death (SCD)? Sudden Cardiac Death (SCD)
is a dramatic and/or spontaneous death that is thought to be (and usually is) caused by a heart condition and may have been brought on by exercise
Sudden Arrhythmic Death Syndrome (SADS):
In one in every twenty cases of sudden cardiac death, no definite cause of death can be found, even after an expert cardiac pathologist has examined the heart. This is called Sudden Arrhythmic Death Syndrome. (In the past it has also been called Sudden Adult Death Syndrome or Sudden Death Syndrome but, because it affects children too, the term Sudden Arrhythmic Death Syndrome is now used.)
The Report of the Task Force on Sudden Cardiac Death
In 2004 the Department of Health set up a special taskforce to examine the issue of sudden cardiac death and its report was produced in March 2006. This report recommended increasing the numbers of people trained in CPR, a much greater provision of defibrillators in communities around Ireland and much quicker response times by emergency services. It also advised that screening should be carried out on the families of those who died and on those playing sport at a high level.
Reducing Time to Response
Survival rates following cardiac arrest are directly related to time to resuscitation and in particular defibrillation. If defibrillated within 5 minutes, survival rates are approximately 50% and potentially higher with younger patients. If time to defibrillation is 10 minutes or more, virtually no one survives without cardiopulmonary resuscitation (CPR). This increases to 10 to 20% if CPR is used. A speedy and effective response is required if the chances of survival are to be increased.
In the absence of an effective emergency response system, survival from cardiac arrest is less than 1%. Recent data confirms that when response systems are optimised, survival rates increase. Overall survival from cardiac arrest in a Belfast study was 7.2%. Where the arrest was witnessed and the emergency medical services arrived within 7 minutes and the rhythm was VF, the survival rate rose to 41%.
