Defibrillator FAQs

When considering an AED you will undoubtedly encounter questions, and you/your team may well have a few concerns. Below are typical questions we’ve encountered, grouped by topic for your ease-of-mind:

Sudden Cardiac Arrest (SCA)

  • What is the difference between a heart attack and a cardiac arrest?

    A heart attack can lead to a cardiac arrest but they are different. Heart attack is a sudden interruption to the blood supply to part of the heart muscle. It will cause chest pain and permanent damage to the heart. The heart will still pump blood around the body and the person remains conscious.

    A cardiac arrest is when the heart suddenly stops pumping blood around the body. The person will lose consciousness and stop breathing. Unless immediately treated by CPR this always leads to death within minutes.

  • How many people die of cardiac arrest in the UK?

    Sudden Cardiac Arrest kills over 100,000 people each year in the UK, that’s:

    • Over 1,900 people each week
    • Over 250 people every day
    • 1 person – every 5 minutes

    SCA can and does strike anyone, anywhere, anytime. In the UK 30,000 people fall victim to SCA outside of a hospital, where support is limited and our chance of survival is dramatically reduced, because we are isolated from immediate care. Out of Hospital SCA claims:

    • Almost 600 lives each week
    • Almost 100 lives every day
    • Almost 1 person – every 15 minutes


  • What causes cardiac arrest?

    The most common cause of a cardiac arrest if a life threatening abnormal heart rhythm called Ventricular Fibrillation (VF). This happens when the electrical activity of your heart becomes so chaotic that the heart stops pumping and quivers or ‘fibrillates’ instead.

  • Who suffers from cardiac arrest?

    SCA can affect anyone of regardless of their age, gender or race.

  • What is a cardiac arrest?

    A sudden, sometimes temporary, cessation of the hearts functioning. Your heart stops pumping blood around your body. If somebody has collapsed, are unresponsive and not breathing normally this means that they are in cardiac arrest.

Cardiopulmonary Resuscitation (CPR)

  • What do I do if I’m alone with this person? Do I call 999 first, use the AED or perform CPR?

    If you are alone with the person call 999 and put it on speakerphone and then begin to do CPR. If the AED is not close to you, get that first before anything else.

  • Is the AED going to help?

    If the patient has a shockable rhythm the AED enables you to shock the persons heart into a normal rhythm.  Early defibrillation is the single most effective treatment for SCA and defibrillation within 3 minutes of collapse can increase the chance of survival to over 70%.

  • How long do I have to perform CPR for?

    You perform CPR for two minutes at a time and then use the AED to check the person’s vital signs and this will tell you whether you need to use the AED, continue CPR or proceed with both.

  • Can I still do CPR whilst the electrodes are on the chest?

    Yes. The AED will continue to analyse the patients heart as you perform CPR. It will then advise you whether you need to shock or continue with CPR.

  • Do I still have to perform CPR, if so, why?

    For every minute that passes between collapse and defibrillation , survival rates from a witnessed VF SCA decrease 7 – 10% if no CPR is provided. However, when early and effective bystander CPR is provided, survival rates can double or triple.

    Start CPR as soon as possible. It provides some circulation of oxygen-rich blood to the victims heart and brain. This delays both brain death and the death of the heart muscle. CPR also makes the heart more likely to respond to defibrillation.

AEDs Explained

  • What is the difference between a fully automated AED and a semi, and who would use which device?

    A fully automatic AED means that all you have to do is turn the device on, place the pads on the chest and do CPR. The AED will then do the rest of the actions. It will administer a shock if needed – telling you to not touch the patient – and if not, then it will continue to monitor the patient for you.

    A semi-automatic AED means that you have to turn the device on, place the pads on and administer the shock to the patient by pushing the button. The AED will tell you when the shock is needed and will also monitor the patient for you.

    Both a fully automated and a semi automated AED can be used by anyone – without training – as both are designed with the lay rescuer in mind.

  • How do I know who to use the AED on?

    If you are unsure that someone has had a cardiac arrest you can shake them gently or shout at them to make sure they aren’t sleeping. NEVER shake a child – pinch them gently to check if they are awake. Then you can perform 2 minutes of CPR and attach the AED.

    If you are still unsure if they are suffering from a cardiac arrest then you can attach the pads to the patients chest and AED will analyse their rhythm and it will tell you if they are suffering from a sudden cardiac arrest.

  • How long, after I have attached the pads, does the AED take to work?

    The AED will take about 5-10 seconds to analyse the patient’s heart.  After that time, the AED will instruct you on what action is required.

  • What is an AED?

    An AED is an Automated External Defibrillator. It is device that looks for shockable heart rhythms and advises the rescuer on what to do next.

  • How do I use it?

    The AED will give you audible prompts to help you use it effectively. Before you use the AED make sure to remove any metal from the patient i.e. necklaces or bras. The metal is a conductor for the electrodes and could cause burns to the patient. if the person has piercings or an internal device i.e. pacemaker make sure you move the pads at least 1 inch from the device or piercing so that the electric current can flow freely between the pads.

AED Usage Worries

  • Are they dangerous?

    If used correctly they are not dangerous. If the person does not need to be shocked then the AED will not let you administer the shock.

  • Can I use the AED on someone who is pregnant or who has a pacemaker?

    Yes. Never withhold treatment from someone who is suffering from SCA. Make sure that if the person has a pacemaker that you place the pads at least one inch away so that the electric current can flow freely between the pads.

  • Can I hurt myself when using the AED?

    No. When the device is used properly and you follow the instructions, the AED is very safe to use. Make sure you stand clear of the patient when administering the shock and you will be safe from harm.

  • Can I use the AED on people of all ages?

    Yes. The AED can be used on people of all ages. However, it is recommended that children under 8 have the specific AED electrodes for their age because the shock it gives its more suitable.

  • Will I hurt the person if I use an AED on them?

    If the person is unresponsive and not breathing and the AED is used in the correct way, the device is extremely safe. It will only deliver a shock if it is needed so there is no chance of you hurting the person.

Lay Rescuer Basics

  • What is a lay rescuer?

    In simple terms, a lay rescuer is someone who is not medically trained but can perform CPR or adults and children. Also, lay rescuers do not check for a pulse. Lay rescuer CPR is likely to be needed by teachers, constructions worker and general workplaces.

  • What if I forget how to use the AED after training?

    Don’t worry about it. Our AEDs has audible instructions to guide you through the process and responds to interaction, repeating steps if necessary – you can’t do it wrong. If the AED decides that the person does not need a shock, it will not give one.

  • What if the pads do not stick fully to the chest?

    If the pads are not sticking wipe and clean the chest. If the chest is hairy then shave and clean it and try again.

  • Will I hurt the person I use the AED on?

    You cannot hurt the patient when using an AED. The AED will be able to tell if the person needs to be shocked. If the person does not need a shock, the AED will not enable a shock to be administered.

  • Does it come with a razor?

    The AED does not come with a razor but a separate pack is available to buy with all the equipment you will need to treat your patient effectively.

Costs & Services

  • If the AED is so easy to use, why do I need training?

    An AED operator must be able to recognise the signs and symptoms of a sudden cardiac arrest along with being able to perform CPR. The operator will be taught how to use the specific AED they are given. It will enable them to operate it effectively and also be able to avoid potentially hazardous situations.

  • What maintenance do I need go carry out on my AED?

    On a weeky basis, verify that the Status Indicator is flashing green approx. every five seconds. If is is not flashing green or is flashing red, a problem has been detected.

    We offer maintenance for you if you are unsure or do not want to worry about the maintenance on your machine.

  • Can you install it for me?

    Yes, we can install it for you.

  • How much will it cost me?

    We have a range of industry leading AEDs, with Service options – take a look at our Shop or Packages page for more information.

    We also offer a pack to assist with the defibrillator. It includes scissors, wipes, gloves etc to make the process easier.

  • How long is the defibrillator battery life?

    The battery in your defibrillator can last up to five years. The pads available in both adult and paediatric should be replaced every two years and the expiry date should be found on the packaging.