Editing Automated external defibrillator (section)

==Implementation==
===Placement and availability===
[[Image:AED Oimachi 06z1399sv.jpg|thumb|upright|An AED at a railway station in [[Japan]]]]
Automated external defibrillators are generally either kept where health professionals and first responders can use them (health facilities and ambulances) as well as public access units which can be found in public places including corporate and government offices, shopping centres, restaurants, hotels, public transport, and any other location where people may congregate.
[[Image:ISO 7010 E010.svg|130px|thumb|The universal AED sign, developed by the [[International Liaison Committee on Resuscitation]] and adopted as [[ISO 7010]] E010]]

In order to make them highly visible, public access AEDs are often brightly coloured and are mounted in protective cases near the entrance of a building. When these protective cases are opened or the defibrillator is removed, some will sound a buzzer to alert nearby staff to their removal, though this does not necessarily summon emergency services; trained AED operators should know to phone for an ambulance when sending for or using an AED.  In September 2008, the [[International Liaison Committee on Resuscitation]] issued a 'universal AED sign' to be adopted throughout the world to indicate the presence of an AED, and this is shown on the right.<ref>{{cite web|title=ILCOR presents a universal AED sign|publisher=[[European Resuscitation Council]]|url=http://www.erc.edu/index.php/newsItem/en/nid=204/|access-date=2019-10-07|archive-url=https://web.archive.org/web/20160811024215/https://www.erc.edu/index.php/newsItem/en/nid=204/|archive-date=2016-08-11|url-status=dead}}</ref>

A trend that is developing is the purchase of AEDs to be used in the home, particularly by those with known existing heart conditions.<ref>{{cite web|url=http://www.heartstarthome.com/content/why_defibrillators/why_defibs2_detail.asp|title=Heartstart Home Defibrillator|publisher=Philips Electronics|access-date=2007-06-15| archive-url= https://web.archive.org/web/20070613234818/http://www.heartstarthome.com/content/why_defibrillators/why_defibs2_detail.asp| archive-date= 13 June 2007 | url-status= live}}</ref> The number of devices in the community has grown as prices have fallen to affordable levels. There has been some concern among medical professionals that these home users do not necessarily have appropriate training,<ref>{{cite news|url=https://www.nytimes.com/2005/05/03/business/03jolt.html|title=Do It Yourself: The Home Heart Defibrillator|last=Barnaby|first=Barnaby J|date=2005-05-03|access-date=2007-06-15|work=New York Times}}</ref> and many advocate the more widespread use of community responders, who can be appropriately trained and managed.

Typically, an AED kit will contain a [[Pocket mask|face shield]] for providing a barrier between patient and first aider during rescue breathing; a pair of [[nitrile rubber]] gloves; a pair of [[trauma shears]] for cutting through a patient's clothing to expose the chest; a small towel for wiping away any moisture on the chest, and a razor for shaving those with very hairy chests.<ref>''CPR/AED for the Professional Rescuer'', ''supra'', p. 65 ("[a] safety surgical razor should be included in the AED kit.")  The other items not directly mentioned in this text but are used in AED preparation, such as the gloves (used throughout patron assessment) and the towel, as the chest should be dried prior to AED pad attachment (id, at p. 64).</ref>

===Preparation for operation===
Most manufacturers recommend checking the AED before every period of duty or on a regular basis for fixed units. Some units need to be switched on in order to perform a self check; other models have a self check system built in with a visible indicator.

All manufacturers mark their electrode pads with an expiration date, and it is important to ensure that the pads are in date. The typical life expectancy of AED pads are between 18 and 30 months.<ref>{{Cite web|title=Why Do AED Defibrillator Pads Expire|url=https://www.aedbrands.com/resources/maintain/why-do-aed-pads-expire/|access-date=2021-07-28|website=AED Brands|language=en-US}}</ref> This is usually marked on the outside of the pads. Some models are designed to make this date visible through a 'window', although others will require the opening of the case to find the date stamp.{{Citation needed|date=December 2007}}

It is also important to ensure that the AED unit's batteries have not expired.  The AED manufacturer will specify how often the batteries should be replaced. Each AED has a different recommended maintenance schedule outlined in the user manual. Common checkpoints on every checklist, however, also include a monthly check of the battery power by checking the green indicator light when powered on, condition and cleanliness of all cables and the unit, and check for the adequate supplies.<ref>{{cite web|author1=Northwest Health |author2=Safety Inc. |title=AED Universe: A Northwest Health and Safety Company|url=http://www.aeduniverse.com/AED_Maintenance_s/115.htm|access-date=21 January 2013}}</ref>

===Mechanism of operation===
[[Image:Defib Checks.jpg|thumb|right|The use of easily visible status indicator and pad expiration date on a Cardiac Science G3 AED]]
An AED is "automatic" because of the unit's ability to autonomously analyse the patient's condition. To assist this, the vast majority of units have spoken prompts, and some may also have visual displays to instruct the user.

"External" refers to the fact that the operator applies the electrode pads to the bare [[chest]] of the victim (as opposed to [[implantable cardioverter-defibrillator|internal defibrillators]], which have [[electrode]]s surgically implanted inside the body of a patient).

When turned on or opened, the AED will instruct the user to connect the electrodes (pads) to the patient. Once the pads are attached, everyone should avoid touching the patient so as to avoid false readings by the unit. The pads allow the AED to examine the electrical output from the heart and determine if the patient is in a shockable rhythm (either ventricular fibrillation or ventricular tachycardia). If the device determines that a shock is warranted, it will use the battery to charge its internal [[capacitor]] in preparation to deliver the shock. The device system is not only safer - charging only when required, but also allows for a faster delivery of the electric current.

When charged, the device instructs the user to ensure no one is touching the patient and then to press a button to deliver the shock; human intervention is usually required to deliver the shock to the patient in order to avoid the possibility of accidental injury to another person (which can result from a responder or bystander touching the patient at the time of the shock). Depending on the manufacturer and particular model, after the shock is delivered most devices will analyze the patient and either instruct CPR to be performed, or prepare to administer another shock.

Many AED units have an 'event memory' which store the ECG of the patient along with details of the time the unit was activated and the number and strength of any shocks delivered. Some units also have voice recording abilities<ref>{{Cite web|url=http://www.aedsuperstore.com/zoll-medical-aed-plus-package-with-voice-recording.html|title=ZOLL® AED Plus® Package w/Voice Recording |website=AED Superstore|access-date=2016-05-12}}</ref> to monitor the actions taken by the personnel in order to ascertain if these had any impact on the survival outcome. All this recorded data can be either downloaded to a computer or printed out so that the providing organisation or responsible body is able to see the effectiveness of both CPR and defibrillation. Some AED units even provide feedback on the quality of the compressions provided by the rescuer.<ref>{{Cite web |url=https://www.elecotek.com/zoll-aed-plus-21000010102011010.html |title=Zoll AED Plus Provides Compression Feedback |access-date=2018-08-21 |archive-date=2021-03-07 |archive-url=https://web.archive.org/web/20210307064043/https://www.elecotek.com/zoll-aed-plus-21000010102011010.html |url-status=dead }}</ref><ref>[https://www.htmmedico.com.sg/products/heartsine-aed/ HeartSine AED CPR Advisor detects Compressions depth and rate feedback]</ref>

The first commercially available AEDs were all of a monophasic type, which gave a high-energy shock, up to 360 to 400 [[joules]] depending on the model. This caused increased cardiac injury and in some cases second and third-degree burns around the shock pad sites.  Newer AEDs (manufactured after late 2003) have tended to utilise biphasic algorithms which give two sequential lower-energy shocks of 120–200 joules, with each shock moving in an opposite polarity between the pads.  Others may give a stepped approach to energy delivery, usually in a 200J, a second 200J, then 300J, and finally 360J shock, with any further shocks also being 360 Joules. This lower-energy waveform has proven more effective in clinical tests, as well as offering a reduced rate of complications and reduced recovery time.<ref>{{cite web|url=http://www.zoll.com/product_resource.aspx?id=728|title=AED Plus Biphasic Waveform|publisher=ZOLL Medical Corporation|access-date=2008-10-27|archive-url=https://web.archive.org/web/20090429210326/http://www.zoll.com/product_resource.aspx?id=728|archive-date=2009-04-29|url-status=dead}}</ref>