Of all the resuscitation devices that modern medicine can offer, the defibrillator is probably the most widely used and well known. This device is used for restoring the heart rhythm of the patient. And this is performed by making a discharge of high voltage. This discharge is produced by specially constructed electrodes that are connected to the control part of the defibrillator device. The Control part of the device also contains a special power unit that provides high voltage for the discharge. For lack of a better illustration it's kind of like "jump-starting" a dead battery.
The construction of the defibrillator electrodes can be different. The two major types are in wide use today. One is external metal electrodes with special handles (insulated from discharge area). To use such electrodes doctors need to apply a specially made gel to increase conductivity from electrodes to patient's body.
Another type of electrodes doesn't need that gel for the correct work. Instead of conductivity gel these electrodes have special adhesive pads. Defibrillator with such electrodes is usually connected to the patient's body for a long time and when the device detects cardiac problem it can perform defibrillation with no need to apply gel(in some cases that procedure can even be performed automatically).
Defibrillators can also be divided into internal and external devices. Unlike external defibrillators (which are more common) with internal defibrillators discharge is applied directly to the patient's heart. Such techniques allow using lower voltages for the defibrillation. Some of the internal defibrillators can also be implanted into patient's body - these are implantable defibrillators. Implantable defibrillators are used for people with a high risk of ventricular fibrillation (VF) or ventricular tachycardia (VT). Implantable defibrillators constantly control heart condition by ECG.
And if any problem with heart rhythm occurs implantable defibrillators can perform defibrillation automatically and thus save a person from sudden death. Lately implantable defibrillators have become much more advanced thanks to the latest achievements of electronic technology.
And in group of external defibrillators there is a type of devices that can be singled out. These devices are called automated external defibrillators. Their construction allows them to be used by almost anyone without special education. The control unit of automated external defibrillators is computer operated and functions are similar to control unit of implantable defibrillators - it measures ECG of the patient when electrodes are attached to the patient's body.
When ventricular tachycardia or ventricular fibrillation appears this device tells the user to stand clear to perform defibrillation. And in semi-automatic automated external defibrillator user also needs to push special button to make a discharge. Today there are many places like airports where you can meet automated external defibrillators as long as pretty cheap and easy to operate models are available. Some people even have such automated external defibrillators for the home use.