In public access defibrillation, automated external defibrillators are placed in busy public places such as malls and office buildings or in hard-to-reach locations such as ships and aircraft. The idea is to be able to attempt to re-start the heart of a person after a cardiac arrest as soon as possible. This is made possible by the microprocessor-controlled operation of automated external defibrillators.

All automated external defibrillators approved for use in the U.S. use a synthesized voice to prompt users through each step. Most units today are designed for use by non medical operators. Experts agree that public access defibrillation has the potential to be the single greatest advance in the treatment of out-of-hospital cardiac arrest since the invention of CPR.

Procedure

Defibrillation is the "D" part on the "ABCD" life-saving sequence (Airways, Breath, Circulation, Defibrillation. See CPR)

Defibrillation is an electric shock which re-initialises the cells of the heart and allows cardiac nervous pulsations to re-take control of the heart and restart normal heart beats. Modern semi-automatic defibrillators can monitor a patient's heart and decide wether a shock is recommended or not. They can be used over a pace-maker. The system begin very safe, it can be used by trained non-professional personel. Defibrillation is an essential part of the CPR : survival chances of a fibrillating patient start at 90% if defibrillated immidiately, and decrease by 10% every minute.

Defribrillation operations start by removing all metallic parts of the patient (jewelery, nipple piercings, etc.), shaving the breasts of exceptionally hairy patients, and placing defibrillation patches : one on the left side, under the heart, and the other over the right breast. The defibrillator will then start monitoring the patient to determine wether a shock is appropriate.

CPR must be stopped for the examination. In all cases, defibrillation has a priority on CPR.

If the defibrillator advises a shock, the operator will shout "Warning, shocking ! Clear !" while waving his hand all over the patient. Touching the patient is dangerous when the shock is aministrated. If all is clear, the shock is administrated by pressing the appropriate button.

Do not shock if

• The patient is close to explosive or inflammable material.
• The patient is wet.

If necessary, protect the patient from water and dry him, or displace the patient a few meters between each CPR cycle until the area is safe for defibrillation.

Defibrillators can also be used for monitoring and recording purpose only; a different set of patches is availlable (two or three small round patches). Should fibrillation occure when the monitoring patches are on, the defibrillator will ask the operator to change patches.

External links

• [1] http://circ.ahajournals.org/cgi/content/full/102/suppl_1/I-1?ijkey=0ea84b1fa73ef
  72b72aef923e0f1adc6d4fd6ba5&keytype2=tf_ipsecsha .