Defibrillator FAQ's
Defibrillators are designed to be straightforward to use in a cardiac emergency. The following frequently asked questions explain what defibrillators do, who can use them, how they work and what is involved in owning and maintaining one.
Q. What is a Defibrillator?
A. A defibrillator is a medical device used when someone experiences sudden cardiac arrest. It analyses the electrical activity of the heart and, when an appropriate shockable rhythm is detected, can deliver an electrical shock to help restore a normal heart rhythm.
Public access and workplace defibrillators are commonly referred to as AEDs, meaning automated external defibrillators.
If you are looking to buy a defibrillator, browse our range of AED machines from leading manufacturers.
Q. What is sudden cardiac arrest?
A. Sudden cardiac arrest occurs when the heart suddenly stops pumping blood effectively around the body. The person will normally become unresponsive and will not be breathing normally.
It is different from a heart attack, although a heart attack can sometimes lead to cardiac arrest.
When cardiac arrest is suspected, emergency medical assistance should be called, CPR started and a defibrillator obtained as quickly as possible.
Q. Is defibrillator training required?
A. Formal training is not required before someone can use an AED in an emergency. The machines are designed to guide the user through each stage.
Training can, however, familiarise people with CPR, pad positioning, operation of the AED and the actions involved in responding to cardiac arrest. Practice with an AED Trainer.
Q. Can a defibrillator shock someone who does not need it?
A. An AED analyses the casualty's heart rhythm before a shock can be delivered. A shock is only enabled when the device detects a rhythm that it is designed to treat.
The user does not make the clinical decision about whether a shock is appropriate.
Q. What is the difference between fully automatic and semi-automatic defibrillators?
A. Both types analyse the heart rhythm and determine whether a shock is required.
A semi-automatic defibrillator instructs the user to press the shock button when a shock is required.
A fully automatic defibrillator delivers the shock automatically after giving appropriate warnings and allowing time for people to move clear of the casualty.
Both types continue to provide instructions throughout the rescue process.
Q. How do you use a defibrillator?
A. The exact process varies slightly between models, but an AED generally guides the user through the following stages:
- Switch on or open the defibrillator.
- Expose the casualty's chest.
- Attach the electrode pads in the positions shown on the pads or packaging.
- Allow the AED to analyse the heart rhythm.
- Make sure nobody is touching the casualty while analysis or shock delivery takes place.
- Follow the AED's instructions regarding shock delivery and CPR.
- Continue following the device prompts until emergency medical assistance takes over.
Current resuscitation guidance places defibrillation alongside early recognition of cardiac arrest, calling the emergency services and CPR.
Q. Can a defibrillator be used on children?
A. Many AEDs can be used with children, although the appropriate pads or paediatric mode depend on the age or size of the child and the particular defibrillator.
Some models use separate paediatric electrode pads, while others have a child mode or child key that adjusts the energy level delivered.
The instructions supplied with the specific AED identify its paediatric capabilities and compatible accessories.
Q. Can a defibrillator be used if the casualty is wet?
A. The casualty's chest should be sufficiently dry for the electrode pads to adhere properly.
If the casualty has been removed from water, the chest can be dried before the pads are attached. The AED instructions should then be followed as normal.
Q. Can a defibrillator be used on someone with a pacemaker or implanted device?
A. An AED can still be used when a casualty has an implanted pacemaker or defibrillator.
If an implanted device is visible or can be felt beneath the skin, the AED electrode pad should not be positioned directly over it. The pad can be positioned away from the implanted device while following the AED manufacturer's instructions.
Q. What if the casualty has a medication patch on their chest?
A. An electrode pad should not be placed directly over a medication patch. If a patch is in the required pad position, it can be removed and the area wiped before the AED pad is attached.
Q. What if the casualty has a very hairy chest?
A. AED pads need good contact with the skin. In cases where excessive chest hair prevents a pad from adhering properly, hair may need to be removed from the required pad area.
Some defibrillator rescue kits include a razor alongside other emergency accessories.
Q. Can anyone touch the casualty while a shock is being delivered?
A. Nobody should be touching the casualty while the AED is analysing the heart rhythm or delivering a shock.
AEDs provide warnings before analysis and shock delivery so that people can move clear.
Q. Where should a defibrillator be stored?
A. A defibrillator is normally stored somewhere that allows it to be located and accessed quickly.
Depending on the location, it may be kept in a wall bracket, carry case or dedicated defibrillator cabinet. Outdoor installations generally require a cabinet suitable for the environmental conditions in which it will be installed.
Clear AED signage can also make the location easier to identify.
Q. Do defibrillators need electricity?
A. Portable AEDs operate from their own battery and do not need to be connected to mains electricity during use.
Some defibrillator cabinets use electricity for features such as heating, lighting or electronic access systems, but this is separate from operation of the AED itself.
Q. How long do defibrillator batteries last?
A. Battery life varies considerably between manufacturers and AED models.
Manufacturers normally specify both a standby life and operating capacity. Environmental conditions, device use and self-testing can also affect battery life.
Replacement batteries should be compatible with the particular make and model of defibrillator.
Q. Do defibrillator pads expire?
A. Yes. AED electrode pads contain conductive adhesive gel and carry an expiry date.
Pads should be replaced when they reach their expiry date and normally after they have been used. Replacement pads must be compatible with the particular defibrillator model.
Q. What maintenance does a defibrillator require?
A. Modern AEDs usually perform automatic self-tests and display a visual status indicator showing whether the device is ready for use.
Routine checks normally include confirming that:
- the AED indicates it is ready for use;
- electrode pads are present and within their expiry date;
- the battery remains within its specified service life;
- any rescue accessories are present and serviceable; and
- the AED and cabinet have not been damaged or interfered with.
Maintenance requirements vary by manufacturer and model.
Q. What happens after a defibrillator has been used?
A. After use, the electrode pads will normally require replacement. The AED should also be checked to confirm it is ready to return to service.
Depending on the model, rescue information may be stored electronically and can sometimes be downloaded for clinical review.
Any components used during the incident should be replenished before the AED is returned to its normal location.
Q. Is it a legal requirement to have a defibrillator?
A. Requirements depend on the setting and circumstances. There is not a single general requirement that makes an AED compulsory for every workplace or organisation.
Defibrillator provision may form part of wider first aid, health and safety or premises considerations, while particular sectors or settings can be subject to additional requirements
Q. How many defibrillators does a site need?
A. There is no single number appropriate for every premises.
Relevant factors include the size and layout of the site, number of buildings or floors, number of people present, operating hours and the time required to retrieve an AED from different parts of the premises.
Large or geographically spread sites may therefore have more than one defibrillator.
Q. Can a defibrillator be kept outside?
A. Yes. Defibrillators can be located outside when stored in a cabinet designed to protect the AED from the expected environmental conditions.
Outdoor cabinets may include heating, insulation, weather protection, lighting or controlled access depending on the installation.
The operating and storage temperature requirements of the particular defibrillator remain important because these vary between models.
Q. Should a defibrillator cabinet be locked or unlocked?
A. Both locked and unlocked AED cabinets are available.
Unlocked cabinets provide direct physical access to the AED. Locked or coded cabinets control access and normally require an access code or other unlocking method.
The most appropriate arrangement depends on the location, accessibility requirements and the way the AED is managed.
Q. What is normally supplied with a defibrillator?
A. Contents differ between products, but an AED package will commonly include:
- the defibrillator;
- a battery;
- adult electrode pads;
- a carry case or protective bag on some models; and
- operating documentation.
- Paediatric pads, spare batteries, cabinets, signage and rescue kits may be supplied separately unless specifically included in the package.
Q. What is an AED rescue kit?
A. A rescue kit contains items that may be useful when preparing a casualty for AED use and CPR.
Typical kits can include gloves, scissors, a razor, a face shield or CPR mask, wipes and a towel. Contents vary between manufacturers.
Q. How often should a defibrillator be replaced?
A. There is no universal replacement period for all AEDs.
The service life depends on the manufacturer, model, condition of the device, availability of compatible pads and batteries, manufacturer support and any applicable warranty or service arrangements.
Individual consumables such as pads and batteries normally require replacement more frequently than the AED itself.
Q. What should be considered when comparing defibrillators?
A. AEDs perform the same core function but differ in features and specification. Differences can include:
- fully automatic or semi-automatic shock delivery;
- paediatric capability;
- pad and battery life;
- CPR feedback;
- screen or visual guidance;
- resistance to water and dust;
- operating and storage temperatures;
- connectivity and remote monitoring;
- warranty length;
- size and weight; and
- ongoing replacement pad and battery costs.
These differences allow AEDs to be selected for environments ranging from homes and offices to schools, sports facilities, public locations, healthcare settings and outdoor sites. Choose a defibrillator by setting.