What Is A Cardiac Arrest?

Cardiac arrest means that the heart has stopped pumping blood around the body. This may occur for many reasons, but loss of the electrical coordination that controls the normal heartbeat is usually responsible. 

The most likely cause is ventricular fibrillation, in which the normal orderly electrical signal that controls the heartbeat becomes completely disorganised and chaotic, and the heart is unable to act as a pump. Ventricular fibrillation can be treated with a defibrillator that delivers a high energy shock to restore the heart’s normal rhythm

How Do I Recognise A Cardiac Arrest?

When the heart stops, blood supply to the brain also stops. The victim will collapse unconscious and will be unresponsive. Breathing also stops, although it may take a few minutes to stop completely. For the first few minutes the victim may take noisy, infrequent or gasping breaths.

The key features of cardiac arrest are therefore someone who is unconscious, unresponsive and NOT BREATHING NORMALLY. Noisy, infrequent or gasping breaths is not normal breathing.

If you have any doubt whether someone is breathing normally or not, assume it is it NOT normal: call 999 immediately and start CPR. 

What Is CPR?

The letters CPR stand for cardiopulmonary resuscitation. The term embraces all the procedures, from basic first aid to the most advanced medical interventions that can be used to restore the breathing and circulation in someone whose heart and breathing have stopped. 

For lay people and first aiders, CPR refers to the basic first aid procedures that can be used to keep someone alive until the emergency medical services can get to the scene. The most important skills are chest compressions to pump blood around the body, and rescue breaths to provide oxygen. Rescue breaths are also known as the ‘kiss of life’.

What Is An AED?

An automated external defibrillator (AED) is a portable electronic device that automatically diagnoses the life-threatening cardiac arrhythmias of ventricular fibrillation and pulseless ventricular tachycardia, and is able to treat them through defibrillation, the application of electricity which stops the arrhythmia, allowing the heart to reestablish an effective rhythm.

With simple audio and visual commands, AEDs are designed to be simple to use for the layperson, and the use of AEDs is taught in many first aid, certified first responder, and basic life support (BLS) level cardiopulmonary resuscitation (CPR) classes

Unlike the defibrillators seen on medical TV shows, AEDs are small, lightweight and very easy to operate. They are about the size of a lunch box and have adhesive electrode pads that rescuers attach to the person's chest.

How Does An AED Work?

An AED is programmed to tell rescuers exactly what to do using voice and visual prompts. Rescuers attach adhesive electrode pads to the person's chest. Through these electrodes, the AED is designed to automatically analyze the electrical activity of the heart to determine if a "shockable" rhythm is present. An AED is so easy to use even untrained school children can operate one quickly and correctly.

With voice prompts and pictures the AED guides rescuers through the resuscitation process, advising when to give CPR. If the AED determines the person's heart needs a shock, it tells rescuers to stand back so a shock can be safely given through the adhesive electrode pads affixed to the person's chest.

Some AED models will tell the user to push a button to shock and then ‘stand clear’ of the victim (semi automatic), while others are fully automatic and will automatically give the shock after giving rescuers a 'stand clear' warning.

The delivery of an electrical shock to a heart experiencing SCA briefly stops all electrical activity in the heart. This brief break from the previous electrical chaos can be enough for the heart to restart with a normal rhythm.

Not everyone can be saved from SCA, even with defibrillation. But early defibrillation, especially when delivered within three to five minutes of a person's collapse from SCA, does provide the best chance for survival.

What Is The Chain of Survival?

The Chain of Survival describes a sequence of steps that together maximize the chance of survival following a sudden cardiac arrest.

  1. The immediate recognition of cardiac arrest and calling for help.

  2. The Initiation of CPR.

  3. Performing defibrillation as soon as possible.

  4. Optimal post resuscitation care.

    Like any chain, it is only as strong as its weakest link, so if one stage is weak the chances of successful resuscitation are compromised.