- An automated external defibrillator (AED)
is a portable automatic device used to restore normal heart rhythm to
patients in cardiac arrest.
An AED is applied outside the body. It automatically analyzes the
patient’s heart rhythm and advises the rescuer whether or not a shock is
needed to restore a normal heart beat. If the patient’s heart resumes
beating normally, the heart has been defibrillated.
When isit used?
An AED is used to treat cardiac arrest. It is a life-saving device
because cardiac arrest is a sudden condition that is fatal if not
treated within a few minutes.
Heart attacks and other conditions can cause ventricular fibrillation.
In ventricular fibrillation, the electrical signals in the lower part of
the heart are uncoordinated and ineffective. Very little blood is pumped
from the heart to the body or the lungs. If ventricular fibrillation is
not treated, it will result in Cardiac Arrest.
You can find AEDs in public places, such as airports and office
buildings (public access AEDs). Doctors sometimes recommend home
defibrillators for patients with heart disease.
How doesit work?
An AED consists of a small computer (microprocessor), electrodes, and
electrical circuitry. The electrodes collect information about the
heart’s rhythm. The microprocessor interprets the rhythm.
If the heart is in ventricular fibrillation, the microprocessor
recommends a defibrillating shock. The shock is delivered by adhesive
electrode pads, through the victim’s chest wall, and into the heart.
There are special low-power electrode pads for use on children.
What will it accomplish?
The AED delivers an electric shock that stuns the heart momentarily;
stopping all activity. This gives the heart a chance to restart normal
electrical activity and resume beating effectively.
What are the risks?
Most trained users can operate AEDs safely. There is some risk of
electric shock to the operator and others if the operator has not been
trained to avoid touching the patient. Other risks include skin burns
from the electrodes, abnormal heart rhythms, and blood clots.
When should it not be used?
The device should not be used in a patient who has a pulse. It should
also be avoided under conditions where the patient cannot be isolated
from other people (for example, in the standing water of a rowboat that
is filled with passengers who are either touching the patient or the
water).
