How do Defibrillators Work

An automated external defibrillator (AED) sends a burst of electrical energy through the chest wall to the heart. It is used on people suffering from life-threatening fast heart rhythms or when the cardiac muscles are working in an uncoordinated fashion (also known as ventricular fibrillation). The shock briefly stops electrical activity in the heart and, with any luck, enables it to return to a regular rhythm.

The defibrillator consists of a large capacitor that is charged by a battery. A typical AED has a capacitor that stores a massive 970 joules of energy and delivers 4,200 volts in a matter of milliseconds through the electrodes positioned on the patient’s chest.

A microprocessor inside the AED decides whether a shock should be administered based on the ECG (electrocardiogram) reading from the electrodes. In other words, it will not allow someone with a healthy heart rhythm to be shocked.

The electrodes should be securely attached to the victim, and they should not be touched during the shocking process. The use of CPR (cardiopulmonary resuscitation) chest compressions is advised before and after the AED is brought into action.

How do automated external defibrillator work

1. Display panel – This shows the operator diagrams illustrating how to assess the patient. This information is supplemented with text and voice prompts that guide the user throughout the process.

2. Electrode pads – There are two self-adhesive electrode pads. The anterior electrode is placed to the right on the bare upper chest, and the apex electrode on the bare left-hand lower chest.

3. Analysis – The AED analyses data from the patient and shows their ECG rhythm; it then determines whether or not a shock should be administered.

4. Shock delivery – Either the user is prompted to press a button to perform a shock or some AEDs automatically deliver the electric charge.

5. CPR – CPR chest compressions should be carried out on the patient before the AED arrives, and when prompted by the device.