Editing Automated external defibrillator (section)

==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=http://www.nhlbi.nih.gov/health/dci/Diseases/aed/aed_use.html|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>