What is an Automated External Defibrillator

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An automated external defibrillator is a device that is used to check the rhythm of the heart. The device is used to restore the rhythm back to normal as well, if required in an emergency situation. While training for CPR, you must have heard about AED which is used to restore the heart that is not beating in order to start a pulse. Let’s look at it in more detail so that you can understand the function of AED more clearly.

What does an AED do?

When an AED is used within the first 5 minutes of a cardiac arrest, it can drastically increase the victim’s chances of survival from 5% to 70% or higher. The electric shock generated by the AED restores the normal rhythm of the heart in a Sudden Cardiac Arrest (SCA) situation.

An AED can automatically check if the heart is beating and initiate a shock if it detects no pulse. That is, if the person is in Ventricular Fibrillation (VF) or Ventricular Tachycardia (VT), the device attempts to generate a shock to the patient’s heart in order to restore the normal rhythm. Therefore, it will not work with patients whose hearts are beating normally.

Heart Rythms for Ventricular Fibrillation
Heart Rythms for Ventricular Fibrillation. AED’s can effectively return the heart to regular cardiac rhythms.

How does an AED work

During VF, the heart still receives nerve impulses from the brain. It is not dead or at a halt, it is just not beating normally. The nerve impulses sent by the brain are haphazardly or erratically transferred to the heart in bursts; therefore the heart is not able to produce a normal beat. As a result, it is not able to supply the vital organs of the body with blood and hence, sufficient oxygen to perform their various functions. If the brain cells are starved of oxygen for more than 6 minutes, they will start to die.

Therefore, the heart will continue with its uncoordinated tremors until the brain is no longer able to send impulses when it eventually dies. The whole system stops together and the victim dies in the process. This can be, however, reversed, if prompt action is taken and an AED is brought into the situation. The AED stops the heart from twitching by simply shocking it. The heart stops momentarily and while it has stopped, the sinoatrial node, which is a small piece of tissue responsible for the normal transfer of impulses across the heart, generates a heartbeat. The heart functions properly when electrical impulses are sent from the top of the heart to the bottom of the heart. Once this system is restored, the heart starts to beat normally.

Therefore, the only treatment to reverse Ventricular Fibrillation is defibrillation which can only be achieved using an Automated Electrical Defibrillator.

Pay attention

It is important that you realize that an AED is not fail-safe. Remember that an AED will only work when a person is going through a Sudden Cardiac Arrest or is suffering due to the heart not beating in the correct rhythm, the heart beating too fast or too slow. If this is not the case, then the AED will not work and will not save the person’s life. An AED can increase a person’s chance of survival during an emergency situation if prompted to treatment; however, it cannot guarantee the person’s life. Make sure you pay attention during your CPR classes and listen to the instructions carefully that are coming from the device. An AED can only save a victim’s life if used in the correct manner.

Automated External Defibrillator Video

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