How does a defibrillator work?

Automated external defibrillators are devices that deliver a controlled electrical shock through electrodes. The aim is that the cardiac arrhythmia that causes cardiorespiratory arrest is reverted to a normal rhythm. Its use is very simple and safe, and it can be used by non-medical personnel with minimal training.

In this article we want to explain how a defibrillator works and how it should be used in an emergency.

The first step is to start the defibrillator. Some will do it automatically when you open the lid, in others you must press the “ON” button. If someone is performing Basic Life Support when reaching the victim with the defibrillator, the compressions should be continued while the electrodes are placed on the chest.

We will place the electrodes on the victim’s bare chest, normally they have their position labeled: One, on the right side of the thorax under the clavicle, next to the sternum. The other, on the left side, under the chest, in the rib area. Once placed, the defibrillator will analyze the heart rhythm, during this process it is very important that no one touches the victim.

If the defibrillator tells us that we have to deliver a shock, we will make sure that no one touches the victim, and we will press the shock button. Immediately afterwards, we will start Basic Life Support. If the defibrillator tells us NOT to deliver a shock, we will immediately start Basic Life Support again. Every 2 minutes, the defibrillator will make us stop Basic Life Support to re-analyze the rhythm, and perform or not a shock (as indicated by the device).

It is essential that we continue with the resuscitation techniques until: the victim breathes normally, opens his eyes or moves, a health professional tells us or we are exhausted.