What is an AED? Complete Guide — How to Use, Who Needs One

What is an AED?

AED stands for Automated External Defibrillator — a portable medical device designed for use by anyone, not just medical professionals.

When someone experiences Sudden Cardiac Arrest (SCA), the heart develops an abnormal rhythm and stops pumping blood effectively. Without intervention within 3-5 minutes, survival rates drop rapidly — approximately 7-10% per minute (AHA, 2020).

An AED analyzes the heart's rhythm through electrode pads placed on the patient's chest. If it detects a shockable rhythm, it delivers an electrical shock to reset the heart back to normal rhythm.

Key point: An AED only delivers a shock when necessary. If the heart rhythm is normal, no shock is given — making it safe for non-medical users.

According to the American Heart Association, AHA (2020): "AEDs are designed to be used safely and effectively by laypersons with no medical background, guided by step-by-step voice instructions."

Read more: Why does time matter? See the minute-by-minute timeline in our Cardiac Arrest Emergency Guide, or compare AED brands in our AED Comparison guide.

How Does an AED Work?

Modern AEDs use biphasic waveform technology, sending electrical current in two directions. This is more effective than older monophasic designs, requiring less energy and reducing potential heart muscle damage.

How an AED works step by step:

1. Power on — The device immediately begins voice guidance in Thai and English
2. Rhythm analysis — Reads ECG signals through electrode pads to determine the type of arrhythmia
3. Decision — If Ventricular Fibrillation (VF) or pulseless Ventricular Tachycardia (VT) is detected, the AED advises a shock
4. Shock delivery — Up to 360 joules (Amoul i-Series) delivered through electrode pads
5. CPR guidance — After the shock, the device prompts chest compressions for 2 minutes before re-analyzing

AEDs come in two types: - Semi-Automatic — analyzes and advises, but the user presses the shock button - Fully Automatic — analyzes and delivers the shock automatically, ideal for locations where users may be hesitant

AEDs are one type of defibrillator — the category includes everything from public-access AEDs to implantable ICDs.

How to Use an AED — 5 Simple Steps

Using an AED is easier than you think. The device provides voice guidance at every step — just follow along.

Step 1: Call 1669 Before using the AED, call 1669 (Thailand's emergency medical hotline), or assign someone else to call while you help the patient.

Step 2: Turn on the AED Press the power button (some models turn on automatically when the cover is opened). Voice guidance begins immediately in Thai.

Step 3: Apply electrode pads to the patient's chest Remove the patient's shirt, dry the chest, and apply electrode pads as shown in the diagrams on the pads: - Pad 1: Below the right collarbone - Pad 2: On the left side of the torso, below the armpit

Step 4: Don't touch the patient — let the AED analyze The device will say "Do not touch the patient" and analyze the heart rhythm. This takes about 5-15 seconds.

Step 5: Press the shock button (if advised) If a shockable rhythm is detected, the device will prompt you to press the shock button. Ensure no one is touching the patient, then press. Afterward, the AED will guide you to perform CPR.

Key reminders: - The AED will not shock a normal heart rhythm — it's impossible to harm someone by using it incorrectly - Perform CPR while waiting for the AED to arrive, as chest compressions help maintain blood flow to the brain - Pediatric electrode pads are different from adult pads — check before use

Read the full step-by-step guide at How to Use an AED.

Who Should Have an AED?

Sudden Cardiac Arrest can happen anywhere, regardless of age or health. Over 70,000 Thais die from cardiovascular disease annually, with a portion being out-of-hospital SCA events.

Locations that should have an AED: - Hospitals and clinics — minimum standard, required on every patient floor - Airports and transit stations — high density, frequent elderly travelers - Shopping malls and office buildings — large gatherings of people - Hotels and resorts — elderly international guests, slower EMS access - Schools and universities — including sports facilities - Factories and construction sites — risk from physical exertion in heat (see AED guide for offices & workplaces) - Condominiums and housing estates — elderly residents - Sports venues and fitness centers — athletes at risk from intense exercise - Emergency vehicles — EMS, fire trucks, police cars

Many countries mandate AED installation in public buildings. Japan has over 600,000 AEDs nationwide; the US requires them in all airports. Thailand doesn't yet have mandatory AED laws but is increasingly promoting public access.

AED Regulations in Thailand

Thailand currently has no mandatory AED installation law for public buildings, but several regulations apply:

Medical Device Act B.E. 2551 (2008) — AEDs are classified as medical devices requiring import authorization from the Thai FDA (Food and Drug Administration). Importers must hold proper licenses and devices must meet standards.

Good Samaritan Law — Thailand's Emergency Medical Act B.E. 2551 protects individuals who provide emergency assistance in good faith. Non-medical personnel using an AED are legally protected.

Relevant standards: - IEC 60601-1 — Electrical medical device safety standard - IEC 60601-2-4 — Specific standard for defibrillators - CE Marking — European conformity certification - Thai FDA — All AEDs sold in Thailand must be FDA-approved

Future outlook: The Ministry of Public Health promotes public AED placement, especially in high-traffic areas. Clearer regulations are expected in the coming years.

For a comprehensive overview of Thai AED laws and international standards, see our AED Standards & Law in Thailand guide.

AED Maintenance

AEDs must be ready for use at all times. Maintenance is straightforward but requires regular checks.

Monthly checks: - Status Indicator light — green flashing = normal, red or no flash = requires attention - Electrode pad expiry date — pads last 2-3 years; expired gel may dry out, reducing conductivity - External condition — device, cables, storage case free from damage

Scheduled replacements: - Battery: 3-5 year lifespan (model dependent), replace before expiry - Electrode pads: 2-3 year lifespan, replace immediately after use or upon expiry - Pediatric pads: Keep separate if children are present at the location

Remote monitoring: Modern AEDs like the Amoul i-Series feature an AED Network Management Platform for automatic status monitoring. The system alerts when batteries are low, pads are nearing expiry, or other issues arise — reducing manual inspection burden.

Maintenance log: Maintain an AED maintenance log at the installation location. Record inspection dates, inspector name, status, and replacement dates. Essential for regulatory audits.

Read the full guide and download a free inspection form at our AED Maintenance Checklist.

How to Choose the Right AED

Different AED models suit different environments. Match the features to your location and users.

Factors to consider:

1. Semi-automatic vs fully automatic

1. IP rating (water/dust protection)

1. Display type

1. Voice language

1. Remote management

1. After-sales service

AEDs from Thunder Venture Group: We distribute the Amoul AED i-Series (i7 and i9 models), covering all requirements — from entry-level graphic display to 7" HD color screen, both semi-automatic and fully automatic, IP65 rated, Thai voice support, and AED Network Management.

Read our AED Comparison guide for a detailed spec-by-spec comparison, or see head-to-head matchups: Amoul vs Zoll | Amoul vs Philips

Frequently Asked Questions