Understanding Automated External Defibrillators (AEDs)
Defibrillation is the definitive treatment for sudden cardiac arrest
commonly caused by ventricular fibrillation.
This in turn arises from a heart attack, drowning, electric
shock or other problems.
It is important that defibrillation be done soon and
defibrillators (AED) are made to be readily available and easy
to use. They are
designed to be less expensive than traditional defibrillators and
have voice guided prompting to encourage their use by non-medical
personnel. AEDs work by
analyzing the patients’ electrocardiogram which is sensed through
the adhesive defibrillator pads and prompting the operator through
the necessary steps from applying the pads to performing CPR if
needed. AEDs look for
ventricular fibrillation and rapid ventricular tachycardia
associated with a pulse-less unresponsive patient.
Biphasic defibrillation waveforms are most commonly
administered by most AEDs.
Some models make a distinction between being automatic and
semi-automatic. Semi-automatic in this instance refers to the user
having to manually push the shock button.
Truly automatic units will administer the shock without
needing an operator.
Some units will feature a monitor that will display the
will vary in the amount of coaching and prompting they provide for
the user through the CPR process.
Those AEDs which feature more prompting may be more suitable
for so-called “Public Access Defibrillation” where users untrained
in life support would be using them.
Adult Cardiopulmonary Resuscitation (CPR) with AED:
Be sure to check with the American Heart Association for the latest
Adult CPR is for victims aged 8 and older.
CPR basically involves giving chest compressions and breaths
to the victim. When an
AED is available, the rescuer will usually be guided through this
process by the AED. The
AED will instruct on CPR application and will also analyze and
advise on shocking the patient when appropriate.
Currently, the recommendation
for adults is to give 2 breaths followed by 30 compressions.
The compression rate is 100 per minute with a chest
compression depth of 1.5 to 2 inches.
The entire CPR process with an AED comprises several steps in a specific
sequence which most AEDs will prompt you through:
Securing the area.
Checking for patient responsiveness.
Calling for help if the patient is non-responsive or in trouble.
Check breathing. (Tilt
back head to open the airway and watch for signs of breathing).
Give 2 breaths if the victim is not breathing.
Give 30 chest compressions.
Repeat these last 2 steps until an AED is connected or the
victim starts to move.
Apply adhesive defibrillation pads.
Wait for the AED to analyze the electrocardiogram.
Shock the patient if the AED indicates to do so.
erform 2 minutes of CPR.
After 2 minutes, stop CPR and allow the AED to analyze the
Repeat step number 10 and 11 or if no shock advised, start CPR
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