View source for Automated external defibrillator


{{short description|Portable electronic medical device}}
{{infobox medical equipment
| name = Automated external defibrillator
| acronym = AED
| synonym = defibrillator, defib
| image = File:AED_machine_medisource.jpg
| caption = AED machine
| alt = ViVest X1 Defibrillator (AED), charged and ready for use.
| image_size = 
| specialty = [[Cardiology]], [[emergency medicine]]
| intervention = 
| MedlinePlus = 
| eMedicine = 
| inventor = [[Frank Pantridge]]
| invention date = 
| manufacturer = 
| related = [[defibrillation#Types|Manual defibrillator]]
}}
An '''automated external defibrillator''' ('''AED''')  is a portable electronic device that automatically diagnoses the life-threatening [[cardiac]] [[Heart arrhythmia|arrhythmia]]s of [[ventricular fibrillation]] (VF) and [[pulseless ventricular tachycardia]],<ref name=AHA1>{{cite journal|title=Automatic External Defibrillators for Public Access Defibrillation|last=Kerber|first=Richard E |author2=Becker, Lance B |author3=Bourland, Joseph D |author4=Cummins, Richard O |author5=Hallstrom, Alfred P |author6=Michos, Mary B |author7=Nichol, Graham |author8=Ornato, Joseph P |author9=Thies, William H |author10=White, Roger D |author11=Zuckerman, Bram D |date= March 18, 1997 |volume=95|issue=1677–1682|journal=Circulation|publisher=American Heart Association|pmid=9118556|pages=1677–82| doi=10.1161/01.cir.95.6.1677}}</ref> and is able to treat them through [[defibrillation]], the application of electricity which stops the arrhythmia, allowing the heart to re-establish an effective rhythm.

With simple audio and visual commands, AEDs are designed to be simple to use for the layperson, and the use of AEDs is taught in many [[first aid]], [[certified first responder]], and [[basic life support]] (BLS) level [[cardiopulmonary resuscitation]] (CPR) classes.<ref>{{cite web|publisher=American Red Cross|url=http://www.redcross.org/services/hss/courses/adultcpraed.html|access-date=2007-06-28|title=CPR Adult Courses| archive-url= https://web.archive.org/web/20070703221912/http://www.redcross.org/services/hss/courses/adultcpraed.html| archive-date= 3 July 2007 | url-status= live}}</ref>

The portable version of the defibrillator was invented in the mid-1960s by [[Frank Pantridge]] in [[Belfast]], [[Northern Ireland]] and the first automatic, public-use defibrillator was produced by the Cardiac Resuscitation Company in the late 1970s. The unit was launched under the name Heart-Aid.<ref name="Heart-Aid Defibrillator">{{Cite web|title=Heart-Aid Defibrillator|url=https://emsmuseum.org/collections/archives/defibrillators/heartaid/|access-date=2021-07-13|website=EMS Museum|language=en-US}}</ref>

==Indications==
[[File:Chain of Survival.jpg|thumb|A diagram showing the [[chain of survival]]]]

=== Conditions that the device treats ===
An automated external [[defibrillator]] is used in cases of life-threatening cardiac [[Heart arrhythmia|arrhythmia]]s which lead to sudden [[cardiac arrest]], which is not the same as a heart attack. The rhythms that the device will treat are usually limited to:

# Pulseless [[Ventricular tachycardia]] (shortened to VT or V-Tach)<ref name=AHA1/>
# [[Ventricular fibrillation]] (shortened to VF or V-Fib)

In each of these two types of shockable [[cardiac arrhythmia]], the heart is electrically active, but in a dysfunctional pattern that does not allow it to pump and circulate blood. In ventricular tachycardia, the heart beats too fast to effectively pump blood. Ultimately, ventricular tachycardia leads to ventricular fibrillation. In ventricular fibrillation, the electrical activity of the heart becomes chaotic, preventing the [[ventricle (heart)|ventricle]] from effectively pumping blood. The fibrillation in the heart decreases over time, and will eventually reach [[asystole]].

AEDs, like all defibrillators, are not designed to shock asystole ('flat line' patterns) as this will not have a positive clinical outcome. The asystolic patient only has a chance of survival if, through a combination of CPR and [[cardiac stimulant]] drugs, one of the shockable rhythms can be established, which makes it imperative for CPR to be carried out prior to the arrival of a defibrillator.

=== Effect of delayed treatment ===
Uncorrected, these cardiac conditions (ventricular tachycardia, ventricular fibrillation, asystole) rapidly lead to irreversible [[brain damage]] and death, once cardiac arrest takes place. After approximately three to five minutes in cardiac arrest,<ref>{{cite web|publisher=American Red Cross|url=http://www.americanheart.org/presenter.jhtml?identifier=4483|access-date=2008-10-27|title=Cardiopulmonary Resuscitation (CPR) Statistics
| archive-url= https://web.archive.org/web/20081119200414/http://www.americanheart.org/presenter.jhtml?identifier=4483| archive-date= 19 November 2008 | url-status= live}}</ref> irreversible brain/tissue damage may begin to occur. For every minute that a person in cardiac arrest goes without being successfully treated (by defibrillation), the chance of survival decreases by 7 percent per minute in the first three minutes, and decreases by 10 percent per minute as time advances beyond ~three minutes.<ref>American Red Cross.  ''CPR/AED for the Professional Rescuer'' (participant's manual). Yardley, PA: StayWell, 2006. p. 63.</ref>

=== Requirements for use===
[[File:Medtronic aed training kit.jpg|thumb|right|Defibrillator training kit]]
AEDs are designed to be used by laypersons who may not have received AED training. However, sixth-grade students have been reported to begin defibrillation within 90 seconds, as opposed to a trained operator beginning within 67 seconds.<ref>{{cite journal|last=U.S. Department of Labor Occupational Safety and Health Administration|title=Cardiac arrest a automated external defibrillators (AEDs)|journal=OSHA Publication No. TIB 01-12-17|year=2001}}</ref> This is in contrast to more sophisticated manual and semi-automatic defibrillators used by health professionals, which can act as a [[artificial pacemaker|pacemaker]] if the heart rate is too slow ([[bradycardia]]) and perform other functions which require a skilled operator able to read [[electrocardiograms]].

Bras with a metal [[Underwire bra|underwire]] and piercings on the torso must be removed before using the AED on someone to avoid interference.<ref>{{cite web|title=How To Use an Automated External Defibrillator|url=https://www.nhlbi.nih.gov/health/defibrillators|work=National Heart Lung and Blood Institute|access-date=24 May 2011| archive-url= https://web.archive.org/web/20110623095339/http://www.nhlbi.nih.gov/health/dci/Diseases/aed/aed_use.html| archive-date= 23 June 2011 | url-status= live}}</ref><ref>{{cite news
 | last = de Vries
 | first = Lloyd
 | title = Breathing Easier
 | url = https://www.cbsnews.com/news/breathing-easier/
 | access-date = 2009-04-22
 | date = 2006-03-22
 | work = [[CBS News]]
 | quote = We got a short lesson in using an AED, which is an Automated External Defibrillator. We had the thrill of yelling, "Clear!" Unfortunately this also brought on a little anxiety when Sean mentioned if the patient were a woman with a metal underwire in her bra or with metal piercings on her torso, we'd have to remove them.| archive-url= https://web.archive.org/web/20090429132957/http://www.cbsnews.com/stories/2006/03/22/opinion/garver/main1429483.shtml| archive-date= 29 April 2009 | url-status= live}}</ref> The American television show ''[[MythBusters]]'' found evidence that use of a defibrillator on a woman wearing an underwire bra can lead to arcing or fire but only in unusual and unlikely circumstances.<ref>{{Cite web | url=http://dsc.discovery.com/fansites/mythbusters/db/human-body/underwire-bra-mess-with-defibrillator.html | title=Underwire Bra Can Mess with Defibrillator| date=2012-04-11}}</ref>

In a study analyzing the effects of having AEDs immediately present during Chicago's Heart Start program over a two-year period, of 22 individuals, 18 were in a cardiac arrhythmia which AEDs can treat. Of these 18, 11 survived. Of these 11 patients, 6 were treated by bystanders with absolutely no previous training in AED use.<ref>{{cite journal |vauthors=Caffrey SL, Willoughby PJ, Pepe PE, Becker LB |title=Public use of automated external defibrillators |journal=N. Engl. J. Med. |volume=347 |issue=16 |pages=1242–47 |date=October 2002 |pmid=12393821 |doi=10.1056/NEJMoa020932|doi-access=free }}</ref><ref>{{Cite web| url=http://beavermedic.wordpress.com/2010/02/10/look-for-me-in-airportshockey-arenas/| title=Look for me in airports/Hockey arenas| date=2010-02-10| access-date=2010-03-27| archive-date=2011-08-12| archive-url=https://web.archive.org/web/20110812074634/http://beavermedic.wordpress.com/2010/02/10/look-for-me-in-airportshockey-arenas/| url-status=dead}}</ref>

==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=AED Renewal and Maintenance|url=https://www.vitalaed.com/pages/aed-renewal-maintenance/|access-date=2025-05-20|website=Vital AED Solutions|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.<ref>AED.com. (17 June 2019). ''Replacing a not so life-saving AED.'' https://www.aed.com/blog/replacing-a-not-so-life-saving-aed/?srsltid=AfmBOoriS-T3ztjQQJuqzzr1FYmsYIlVPFuwo4fQToAeVaMu1NnQnugw</ref>

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=https://www.vitalaed.com/products/zoll-aed-plus|title=ZOLL® AED Plus® Package w/Voice Recording |website=Vital AED Solutions|access-date=2025-05-20}}</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>

==Usage==
===Simplicity of use===
[[Image:Defibrilation electrode placement svg hariadhi.svg|thumb|right|200px|Usual placement of pads on chest]]
Unlike regular [[defibrillator]]s, an automated external defibrillator (AED) requires minimal training to be used (or even no training). That is possible because all AEDs approved for use in the [[United States]] and many other countries use an electronic voice to prompt users through each step. Many AEDs now include visual prompts in case of a [[hearing impairment|hearing impaired]] user. Most units are designed for use by non-medical operators. Their ease of use has given rise to the notion of public access defibrillation (PAD).

An AED automatically diagnoses the heart rhythm and determines if a shock is needed. Automatic models will administer the shock without the user's command. Semi-automatic models will tell the user that a shock is needed, but the user must tell the machine to do so, usually by pressing a button. In most circumstances, the user cannot override a "no shock" advisory by an AED. Some AEDs may be used on children – those under 55&nbsp;lbs (25&nbsp;kg) in weight or under age 8. If a particular model of AED is approved for pediatric use, {{failed verification span|all that is required is the use of more appropriate pads|date=January 2024}}.<ref>{{cite web| url=https://www.seton.co.uk/aeds |title= AEDS Guide }} Monday, March 16, 2020</ref>

===Benefit===
Observational studies have shown that in out of hospital cardiac arrest, public access defibrillators when used were associated with 40% median survival. When operated by non-dispatched lay first responders they have the highest likelihood of leading to survival.<ref>{{cite journal|title=The Effects of Public Access Defibrillation on Survival After Out-of-Hospital Cardiac Arrest: A Systematic Review of Observational Studies|last1=Bækgaard|first1=Josefine S.|last2=Viereck|first2=Søren|last3=Møller|first3=Thea Palsgaard|last4=Ersbøl|journal=Circulation |year=2017 |volume=136 |issue=10 |pages=954–965 |doi=10.1161/CIRCULATIONAHA.117.029067 |pmid=28687709|s2cid=21249432 |doi-access=free}}</ref>

===Liability===
====United States====
Automated external defibrillators are now easy enough to use that most states in the United States include the "good faith" use of an AED by any person under [[Good Samaritan law]]s.<ref>[http://webarchive.loc.gov/all/20021016123247/http://www.ncsl.org/programs/health/aed.htm Laws on Cardiac Arrest and Defibrillators, 2013 update.] National Conference of State Legislatures.   Retrieved on 2013-03-18.</ref> "Good faith" protection under a Good Samaritan law means that a volunteer responder (not acting as a part of one's occupation) cannot be held civilly liable for the harm or death of a victim by providing improper or inadequate care, given that the harm or death was not intentional and the responder was acting within the limits of their training and in good faith. In the United States, Good Samaritan laws provide some protection for the use of AEDs by trained and untrained responders.<ref>{{Cite web |url=http://www.ncsl.org/programs/health/aed.htm |title=Archived copy |access-date=2007-07-22 |archive-url=http://webarchive.loc.gov/all/20021016123247/http://www.ncsl.org/programs/health/aed.htm |archive-date=2002-10-16 |url-status=dead }}</ref> AEDs create little liability if used correctly;<ref>[http://www.ncsl.org/default.aspx?tabid=14506 Laws on Cardiac Arrest and Defibrillators]</ref> NREMT-B and many state [[Emergency Medical Technician]] (EMT) training and many CPR classes incorporate or offer AED education as a part of their program.

====Canada====
In addition to Good Samaritan laws, Ontario, Canada also has the "[[Chase McEachern]] Act (Heart Defibrillator Civil Liability), 2007 (Bill 171 – Subsection N)", passed in June, 2007,<ref>[http://www.e-laws.gov.on.ca/html/statutes/english/elaws_statutes_07c10_e.htm Health System Improvement Act, 2007] Retrieved on 26 June 2007</ref> which protects individuals from liability for damages that may occur from their use of an AED to save someone's life at the immediate scene of an emergency unless damages are caused by gross negligence.

====Australia====
Legislation in Australia varies by state, with separate liability issues relating to providing and using AED equipment.  
Each state and territory has enacted "Good Samaritan" laws that offer legal protection to a person who gives assistance in a medical emergency - the standard of care expected corresponds to their training (or lack of training).<ref>{{cite web |title=Legal and Ethical Issues Related to Resuscitation - Section 10: Guideline 10.5 |url=http://resus.org.au/download/section_10/guideline-10-5-nov-2015.pdf |publisher=Australian Resuscitation Council |access-date=16 October 2020 |date=2015}}</ref>
In New South Wales, the Work Health and Safety Regulation (2011) requires an employer to use a risk assessment to ensure that there is adequate provision for first aid; when there is a sufficient risk it warrants providing a defibrillator.<ref>{{cite web |title=Work Health and Safety Act 2011 No 10 |url=https://www.legislation.nsw.gov.au/view/html/inforce/current/act-2011-010 |website=legislation.nsw.gov.au |access-date=16 October 2020}}</ref>

===Reliability===
In 2012, AED's (automated external defibrillators) were under scrutiny by the U.S. [[Food and Drug Administration]] (FDA) which considered reclassifying AEDs as class III [[premarket approval]] devices. Technical malfunctions likely contributed to more than 750 deaths in the 5-year period between 2004 and 2009, in most cases by component failures or design errors. During the same period, up to 70 types of AEDs were recalled, including recalls from every AED manufacturer in the world. 
<ref>{{cite web|title=The Shocking Truth About Defibrillators|publisher=[[IEEE Spectrum]], March 2012. Retrieved 2012-07-28|url=https://spectrum.ieee.org/biomedical/devices/the-shocking-truth-about-defibrillators/0|archive-url=https://archive.today/20130415062356/http://spectrum.ieee.org/biomedical/devices/the-shocking-truth-about-defibrillators/0|url-status=dead|archive-date=April 15, 2013|date=2012-02-27}}</ref>

In January and February 2015, the FDA issued this news release: "The FDA issued a final order that will require AED manufacturers to submit premarket approval applications (PMAs), which undergo a more rigorous review than what was required to market these devices in the past. The agency's strengthened review will focus on the critical requirements needed to ensure the safety and reliability of AEDs and their necessary accessories, including batteries, pad electrodes, adapters and hardware keys for pediatric use."<ref>{{cite web|title=FDA takes steps to improve reliability of automated external defibrillators|publisher=[[FDA News Release]], January 2015. Retrieved 2017-07-15|url=https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm431907.htm|archive-url=https://web.archive.org/web/20150131045045/http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm431907.htm|url-status=dead|archive-date=January 31, 2015}}</ref><ref>{{cite web|title=Effective Date of Requirement for Premarket Approval for Automated External Defibrillator Systems; Republication|publisher=[[Federal Register]], February 3, 2015. Retrieved 2017-07-15|url=https://www.federalregister.gov/documents/2015/02/03/2015-02049/effective-date-of-requirement-for-premarket-approval-for-automated-external-defibrillator-systems|date=2015-02-03}}</ref>

In the United Kingdom there is concern that poor maintenance may make public defibrillators unreliable. Regular inspections and readiness checks are essential to maintaining AED effectiveness over time. The ''[[Henley Standard]]'' reported on 21 July 2017 that more than half the defibrillators in [[Henley-on-Thames]] and the surrounding area were at risk of failing, either because of low battery power or because adhesive pads had deteriorated.

==History==
The first use of an external defibrillator on a human was in 1947 by Claude Beck.<ref>{{cite web|url=http://www.case.edu/artsci/dittrick/site2/museum/artifacts/group-c/c-8defrib.htm |title=Claude Beck, defibrillation and CPR |publisher=Case Western Reserve University |access-date=2007-06-15 |url-status=dead |archive-url=https://web.archive.org/web/20071024145652/http://case.edu/artsci/dittrick/site2/museum/artifacts/group-c/c-8defrib.htm |archive-date=2007-10-24 }}</ref> The portable version of the external defibrillator was invented in 1957 by [[Frank Pantridge]] in [[Belfast]], [[Northern Ireland]], a pioneer in emergency medical treatment.<ref>{{cite journal|last1=Shurlock|first1=B|title=Pioneers in cardiology: Frank Pantridge, CBE, MC, MD, FRCP, FACC|journal=Circulation|date=18 December 2007|volume=116|issue=25|pages=f145–48|pmid=18086933|doi=10.1161/CIRCULATIONAHA.107.187677|doi-access=free}}</ref><ref>{{cite journal|last1=Evans|first1=Alun|title=Frank Pantridge|journal=BMJ|date=April 2, 2005|volume=330|issue=7494|page=793|pmc=555899|doi=10.1136/bmj.330.7494.793}}</ref> Pantridge's defibrillator required a trained operator to perform the shock procedure and charted a course for many new innovations in external defibrillation.<ref>{{Cite web|title=EMS Innovators|url=https://emsmuseum.org/collections/ems-innovators/|access-date=2021-07-13|website=EMS Museum|language=en-US}}</ref>

In the late 1970s the Heart-Aid was developed as the first truly automated external defibrillator that was designed for the public. The principles of ABC assessment and a human voice relaying instructions helped bystanders respond to a sudden cardiac event while waiting for the first responders to get to scene.<ref name="Heart-Aid Defibrillator"/> Many of the early innovations in the Heart-Aid model are still part of the current generation of AEDs, although some innovations, like the airway electrode have fallen from use.

==Case studies==

In a study published in 2017, researchers in Poland selected the main entrances of buildings which had AEDs, although the researchers themselves did not know the exact locations of the devices.  In mock cardiac arrest scenarios, the average time to bring the AED to the patient was 96 seconds, with a time that ranged from 52 to 144 seconds.  This met the three minute goal.  In some cases, the use of the AED required the continuous presence of building personnel.  Future improvements include more obvious signage and public-access AEDs which do not require a staff member of the building to either retrieve or use the device.<ref>{{cite journal| pmid=29168550 | doi=10.5603/KP.a2017.0199 | volume=76 | title=Automated external defibrillator use in public places: a study of acquisition time | year=2018 | author=Telec W, Baszko A, Dąbrowski M, Dąbrowska A, Sip M, Puslecki M, Kłosiewicz T, Potyrała P, Jurczyk W, Maciejewski A, Zalewski R, Witt M, Ladny JR, Szarpak L | journal=Kardiol Pol | issue=1 | pages=181–185| doi-access=free }}</ref>
<ref>[https://www.aedmaster.nl/ AED master]</ref>

==See also==
{{Portal|Electronics|Medicine}}
*[[Cardiopulmonary resuscitation]]
*[[Defibrillation]]
*[[Advanced cardiac life support]]
*[[Cardioversion]]

==References==
{{reflist}}

== External links ==
{{Commons category|Automated external defibrillators}}
* [http://www.sca-aware.org Sudden Cardiac Arrest Foundation]
* [http://www.heart.org/HEARTORG/ American Heart Association: Learn & Live] 
* [http://www.redcross.org/prepare/location/workplace/easy-as-aed American Red Cross: Learn About Automated External Defibrillators ]
* [http://www.resus.org.uk Resuscitation Council (UK)]
* [https://mhf.life/ Sudden Cardiac Arrest Foundation (AU)]
* [https://www.emsmuseum.org The National EMS Museum]
* [https://openaedmap.org OpenAEDMap]

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[[Category:Cardiac electrophysiology]]
[[Category:Emergency medical equipment]]