Automatic external defibrillator

Automatic external defibrillator (AED) is an electronic device which can give electrical countershock to revive a person in cardiac arrest. When the electrode patches of the device are applied to the chest and the device switched on, it detects the heart rhythm and gives audio prompts for action. If it is a shockable rhythm, it advises a shock and delivers one if activated. Otherwise it will advise the continuation of cardiopulmonary resuscitation (CPR).

Where are AEDs usually deployed?

AEDs are usually deployed in public areas where large number of people are likely to come like airports, railway stations and malls. Even though cardiac arrest is rare in the healthy general public who move around in these areas, the large number of people moving in an out makes the probability of a cardiac arrest fair.

Where are the AED patches applied?

One patch is applied just below the right collar bone, above the right right nipple. Second patch is applied on the left side of chest below the breast area. This ensures that heart comes in the electrical path of the shock to be delivered. If there is a pacemaker of an implanted defibrillator (ICD), that area should be avoided while placing the patch. In such situations and in infants, one patch can be placed over the front of the chest and another on the back. Giving a shock over and implanted device can cause serious damage to the device.

Do you need training to use an AED?

Instructions to use an AED are generally written down in places where they are stored. But some basic training comes in handy because your actions have to be very prompt to be useful in a dire emergency like cardiac arrest. Training to use an AED is now part of all basic life support (BLS) courses. BLS courses are widely available and are being taken by people employed in regions where AEDs are deployed as well as quite a number of general public and volunteers.

Can AED be used when the victim is in water?

Using an AED while the victim is in water and with the bystanders in contact with water can cause harm to bystanders as they may get a shock. Move the victim quickly out of water to a dry area before applying the shock. Moreover a shock may be ineffective if the chest is wet. The shock instead of going through the heart, can get short circuited through the water on the surface, especially if it is salty.

What to do if an AED does not advice a shock?

If an AED does not advice a shock, it means that it is not a shockable rhythm. CPR has to be continued. But AED will check for the rhythm again after 2 minutes and advice shock if there is a shockable rhythm.