When and why should a defibrillator be used?

An Automated External Defibrillator (AED) and effective CPR is the only definitive treatment for a victim of sudden cardiac arrest (SCA).

A defibrillator is a device that gives a high energy electric shock to the heart, through the chest wall to someone who is in cardiac arrest in an attempt to restart the heart in a regular rhythm. 

If you suspect that someone has had a cardiac arrest, it is vital you call 999 and immediately start CPR. Then, you must find out if there is a defibrillator close by. Defibrillators are becoming increasingly available in public places such as train stations, shopping centres, airports and leisure centres. These defibrillators are known as public access defibrillators (PAD) as anyone can use them in an emergency situation to provide a potentially life-saving shock to a victim of SCA.

Chain of Survival

When someone suffers an out of hospital cardiac arrest, their chance of survival is increased if certain actions are carried out in order. This is known as the ‘Chain of Survival’.

The Chain of Survival is made up of four links. Three of which, can be performed by members of the public who act fast, applying basic life-saving knowledge to the situation:

1. Early access, recognition and call for help. Being able to recognise that someone is in cardiac arrest is the first step in assuring they receive the necessary treatment.
2. Early CPR. Performing chest compressions can keep the heart going until a defibrillator is present. Research has found that CPR can double a person’s chance of survival.
3. Early defibrillation. For every minute that goes by without treatment from a defibrillator, the victim’s chance of survival can decrease by 10%.
4. Post-resuscitation care. To restore quality of life relating to the response of highly trained and equipped paramedics who can effectively respond to the victim.

In order for the patient to have the best chance of surviving an out of hospital cardiac arrest, CPR and early defibrillation must be provided within the first 3-4 minutes of the cardiac arrest, followed by advanced life support within the first 8 minutes of the arrest. Knowing the steps to take after someone has suffered a cardiac arrest could be the difference between life and death.

How to use a defibrillator

Unfortunately, many lives are lost as a result of a cardiac arrest because bystanders are often unsure about what to do in an emergency situation. You do not need training to be able to save someone’s life with the use of a defibrillator. After the electrode pads have successfully been applied to the patient’s chest, the device will begin by analysing the victim's heart rhythm and will then guide the rescuer through each step with visual and/or voice prompts.

A standard rescue process could look something like this:

• Once you have called for an ambulance, begin to give CPR until someone arrives to the scene with a defibrillator.
• As soon as you have the AED, switch it on and it will straightaway begin to give you a series of visual and/or verbal prompts informing you of what you need to do.
• Take the pads out of the sealed pack. Remove any obstructions to the chest including clothing, excess hair and sweat.
• Remove the backing paper and attach the pads to the victim.
• Place the first pad on the upper right side of the victim, just below their right collarbone.
• Then place the second pad on their left side, lengthways, just below the armpit.
• The device will then begin to analyse the heart rhythm and decide whether a shock is necessary. During this time, do not touch the patient and continue to follow the prompts until help arrives.

A defibrillator will only deliver a shock if one is required by the patient. The information relayed from the electrode pad’s analysis of the patient’s heart will help the device decide whether a shock is required or not. If no shock is required, no shock will be delivered and on semi-automatic devices – devices that require the rescuer to deliver a shock by pressing a button – even if the button is pressed, no shock will be delivered.

Stay Heart Safe

Do you know how to use a defibrillator? Remember that anyone can use an AED to provide potentially life-saving treatment to a victim of sudden cardiac arrest. Voice prompts and visual cues on the device will guide the rescuer, ensuring the process is made as simple as possible.

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