Automated External Defibrillator (AED) & Defibrillator Overview | Wellbeing

1. What is Cardiac Arrest?

Cardiac arrest (or circulatory arrest) occurs when the heart stops beating. The danger lies in the fact that cardiac arrest can strike anyone—even healthy individuals with no prior medical history—at any time and in any place. The most common cause is an abnormal heart rhythm, specifically Ventricular Fibrillation. This abnormality often occurs when the heart muscle is damaged due to a myocardial infarction (heart attack) or when the heart is deprived of sufficient oxygen.

2. What is a Defibrillator?

A defibrillator is a medical device used to deliver a therapeutic dose of electrical energy to the heart. It is commonly used in surgery and intensive care units. Because of its effectiveness and ability to deliver immediate results, it is a standard equipment for treating various cardiac emergencies.

3. What is an Automated External Defibrillator (AED)?

An Automated External Defibrillator (AED) is a portable device used to correct the heart rhythm via an electric shock. It is specifically designed to allow people with absolutely no medical experience or knowledge to use it, thereby increasing the survival chances of cardiac arrest victims in both hospital and out-of-hospital settings.

4. Steps to Use an AED

1. Power on the AED and remove the electrode pads from their sealed package.

2. Remove or cut through clothing and wipe away any sweat from the victim's chest.

3. Tear open the pad packaging, peel, and attach the pads to the victim's chest at the indicated positions.

4. Place the first pad on the upper right side, directly below the victim's collarbone.

5. Place the second pad on the left side, directly below the victim's armpit (as shown in the diagram). Ensure the pad is aligned vertically along the body's axis.

6. The AED will begin analyzing the heart rhythm. Ensure no one is touching the victim. Strictly follow the visual and/or verbal instructions provided by the machine.

5. Important Precautions When Using an AED

5.1. Always Remember: Perform CPR Immediately! For every minute that passes, the victim's chance of survival drops by 7% to 10%. Therefore, perform Cardiopulmonary Resuscitation (CPR) immediately to circulate oxygenated blood. Do not waste time looking for an AED alone; if bystanders are present, instruct them to retrieve the AED while you continue CPR.

5.2. Beware of "AED Trainers" AED Trainers are non-shocking units created solely for training purposes. While their appearance and operation steps mimic real AEDs, their functions are simulated. Crucially, AED Trainers cannot deliver a shock. Using a Trainer in a real emergency will be ineffective.

• Check the Label: AED Trainers are clearly labeled "For Training Purposes Only" or "Not for Clinical Use." Real AEDs (Live units) will not have these labels.

5.3. Monitor Shock History An AED battery has enough energy for a specific number of shocks. For example, the Philips HS1 battery can deliver up to 200 shocks per cycle. If an AED has exceeded this limit, the remaining battery power may be insufficient.

• Action: If the machine fails due to low battery, focus on continuous CPR. Do not abandon the victim to find another machine unless a second rescuer can do so.

5.4. Battery Replacement History Battery power depletes over time even without use. Low battery levels slow down the analysis speed. Manufacturers typically recommend replacing the battery every 5 years (depending on the model). Always check the replacement date label on the battery to ensure the device is ready for use.

5.5. Pediatric vs. Adult Electrodes Shock energy differs for adults and children (aged 1-8 or weighing <25 kg). Ensure you are using the correct pads.

• Note: For AEDs with universal pads (e.g., Zoll AED 3, Nihon Kohden), ensure you verify the Child Mode switch/button is set correctly before proceeding.

5.6. Ensure Optimal Conditions on the Victim

• Remove Metal: Remove watches, belts, necklaces, and mobile phones, as they can interfere with analysis and shock delivery.

• Shave Chest Hair: If excessive hair prevents good pad contact, shave the area.

• Dry the Victim: Sweat or water reduces shock efficiency. Wipe the chest dry before applying pads.

5.7. DO NOT Touch the Victim During Analysis or Shock

• During Analysis: Touching the victim causes motion, which can lead to incorrect diagnosis by the machine.

• During Shock: The high-voltage current can stop a healthy heart. It is dangerous for the rescuer to be in contact with the victim during discharge. Stand clear!