Automated External Defibrillators (AEDs) are now found in more and more places, from train stations to town halls and schools. An AED is a device which can issue a potentially lifesaving shock to a casualty who is in cardiac arrest – a malfunction in the electrical activity of the heart which rapidly leads to death. Although not all cardiac arrests are ‘shockable’, for those that are, quick use of an AED can greatly increase the casualty's chances of survival.

How big a problem is cardiac arrest?

Sudden cardiac arrest, when the heart stops beating normally due to an electrical fault, kills 100,000 people in Britain each year. While it’s more common for the elderly and those with chronic health conditions, children and apparently healthy people, even athletes, can also fall victim. When cardiac arrest happens outside of hospital, survival rates are astoundingly low – 7% on average in England.

However, this statistic can be improved – in Norway, the survival rate stands at 25%. For victims of cardiac arrest, speed is essential to their survival. CPR ensures blood and oxygen continues to flow around the body, delaying irreversible tissue death and brain damage, and can maintain a ‘shockable’ heart rhythm.  However, in most cases only defibrillation, either with an AED or by emergency services, can actually restore the heart to normal function and ensure survival. Without timely intervention, however, death becomes permanent within minutes. Cardiac arrest is a race against time. The chances of survival drop around 7-10% every minute without defibrillation.

Why are AEDs so useful?

AEDs, also known as Publically Accessible Defibrillators (PADs), are portable, battery-powered machines which are designed for use by untrained bystanders to defibrillate cardiac arrest victims before emergency services arrive. This is important as a victims' chances of survival deteriorate over time, even with good-quality CPR. While emergency services aim to reach the most serious casualties within 8 minutes, by this time a victim who has not received CPR has a very low chance of surviving, or surviving without significant brain damage. It’s not always possible for emergency services to meet this target either. The earlier a victim can be defibrillated, the better.

An AED can restore normal heart function before emergency services arrive, which gives casualties the best possible chance of survival. AEDs are typically found in train stations, shopping centres, and other busy public places. However, there is currently (as of 2019) no UK legislation obliging employers to have AEDs on their premises. Nonetheless, depending on your workplace and workforce, there may be compelling reasons to do so.

Should my workplace have an AED?

There are several factors employers should consider when it comes to investing in an AED. These are the number of staff and members of the public on site, known pre-existing health conditions, the average age of workers or visitors, the amount of strenuous physical activity undertaken on the site and the average response time for local emergency services. For example, an office with a large number of over 50s is at a higher risk of someone suffering a cardiac arrest than one with a younger workforce.  A gym is too, as exercise can precipitate cardiac arrest even in those that appear fit and healthy. As survival ultimately depends on timely defibrillation, a workplace in a remote location or one with congested roads should consider if emergency services are likely to be able to respond within 8 minutes.

Are AEDs safe?

AEDs analyse a casualty’s heart rhythm and if the shock is appropriate, depending whether the AED model is fully or semi-automatic, will either proceed to issue a shock or ask a rescuer to press a button to do so. The AED will command bystanders to avoid contact with the casualty at this time. An AED will only issue a shock to someone who is both in cardiac arrest and who has a ‘shockable’ heart rhythm which will respond to defibrillation. It is, therefore, not possible for the AED to issue a shock to someone who does not need it or wouldn’t benefit from it.

For a casualty who is in cardiac arrest with a shockable heart rhythm (either pulseless ventricular tachycardia or ventricular fibrillation), the casualty is clinically dead and has no chance of survival without help. It’s therefore impossible for an AED to do harm to a casualty in any circumstances, making them very safe. Should a casualty be in cardiac arrest with a non-shockable rhythm (asystole and pulseless electrical activity), the AED will direct rescuers to continue with CPR.

You can shop for AEDs from here.

About the author:

Dennis Outram is a senior first aid trainer and a Serving Brother in the Order of St John.
Find out more about Dennis.