How to Use an AED in 4 Simple Steps — A Guide for Everyone

When Should You Use an AED?

Use an AED when you find someone with these signs:

• Unresponsive — does not react when called or when shoulders are tapped
• Not breathing or gasping abnormally
• No pulse — if unsure whether there is a pulse, start CPR and use the AED immediately

The AED analyzes the heart rhythm automatically and will only deliver a shock if it detects Ventricular Fibrillation (VF) or pulseless Ventricular Tachycardia (VT). If the heart rhythm is normal, no shock is delivered — you cannot shock someone by mistake.

Remember: every minute without an AED reduces survival by 7-10% (AHA, 2020). Use it as fast as possible. Do not wait for an ambulance.

According to the International Liaison Committee on Resuscitation (ILCOR, 2020): "Defibrillation within 3-5 minutes of collapse can produce survival rates as high as 50-70%." Having an AED within easy reach is the decisive factor between life and death.

How to Use an AED: 4 Steps

1. Power on the AED — Press the power button (some models activate automatically when the lid is opened). The device immediately starts voice guidance in Thai and English. Listen and follow the instructions.

1. Place electrode pads on the patient's bare chest — Remove the patient's clothing. Wipe the chest dry. Peel pads from their packaging and place as shown on the diagrams: Pad 1 below the right collarbone, Pad 2 on the left side below the armpit. Press firmly so pads adhere fully to the skin.

1. Let the device analyze — The AED will announce "Analyzing heart rhythm, do not touch the patient." Do not touch the patient during analysis. This takes approximately 5-15 seconds.

1. Press the shock button (if advised) — If the AED detects a shockable rhythm, it will announce "Shock advised, press the shock button." Ensure no one is touching the patient, then press the flashing orange or red shock button. For fully automatic models, the device shocks automatically — no button press needed.

After the shock, the AED will instruct you to continue CPR for 2 minutes, then re-analyze. Follow the device's guidance until the ambulance arrives.

Correct Electrode Pad Placement

Correct pad placement is critical. Incorrectly placed pads may not deliver the electrical current through the heart effectively.

Standard placement (Anterior-Lateral): - Pad 1 (upper right): Below the right collarbone, to the right of the sternum - Pad 2 (lower left): On the left side of the chest, below the armpit, at nipple level

Prepare the chest before placing pads: 1. Remove clothing — use scissors if necessary (included in the AED kit) 2. Dry the chest — if wet from sweat or water, wipe dry first 3. Shave chest hair — if excessively hairy, use the razor in the AED kit. Hair prevents proper pad adhesion 4. Remove medication patches — if nicotine or pain patches are present, peel them off and wipe the area

Important warnings: - Do not place pads on top of each other - Do not place pads directly over an implanted pacemaker/defibrillator (visible as a lump under the skin) — position the pad at least 2.5 cm away - Electrode pads are single-use only — never reuse them

Special Scenarios — Children, Wet Surfaces, Pregnant Patients

Children aged 1-8: - Use pediatric electrode pads if available — they reduce shock energy to appropriate levels - If no pediatric pads are available, use adult pads in Anterior-Posterior placement: Pad 1 on the chest, Pad 2 on the back - For infants under 1 year, call 1669 and consult the dispatcher first

Wet surfaces or water: - Move the patient out of water first (just enough so the body is not submerged) - Dry the chest - AEDs with IP65 rating like the Amoul i-Series resist water spray, but the patient must be dry - If it's raining, shield the AED but do not delay — use it immediately

Pregnant patients: - Use the AED normally. No change in pad placement needed - Saving the mother's life is saving the baby's life

Patients with implanted pacemaker/ICD: - Look for a visible lump under the skin on the upper chest (usually on the left side) - Place electrode pads at least 2.5 cm away from the lump - Use the AED normally

Patients with excessive chest hair: - Press pads down firmly. If the AED warns "check electrode pads," rip the first set of pads off forcefully (this removes hair), then apply a second set - If a razor is included in the AED kit, shave the pad placement areas

CPR Combined with AED — How It Works Together

AED and CPR work together. CPR (chest compressions) pumps blood to the brain and organs temporarily. The AED corrects the abnormal heart rhythm. Both are essential — CPR alone is not enough, and AED alone is not enough.

Emergency response sequence per Chain of Survival (AHA, 2020):

1. Recognize — Notice that the person is unresponsive and not breathing
2. Call 1669 — Report the emergency, state your location
3. Start CPR — Compress the chest 100-120 times per minute, 5-6 cm deep, allowing full chest recoil
4. Use AED — When someone brings an AED, power it on and follow voice guidance
5. Handoff to paramedics — Continue CPR and AED use until medical professionals take over

Correct CPR technique: - Compress the center of the chest, on the sternum - Use both hands stacked, arms straight - Push 5-6 cm deep at 100-120 compressions per minute - Allow full chest recoil between compressions - If unwilling to give rescue breaths, Hands-Only CPR (compressions only) is still far better than doing nothing

When AED arrives during CPR: - Do not stop CPR until the AED is ready to analyze - Power on the AED, attach pads, then stop CPR only when the device announces "analyzing" - After a shock (or after "no shock advised"), resume CPR immediately for 2 minutes

Semi-Automatic vs Fully Automatic AED — Usage Differences

AEDs come in 2 types with a slight difference at step 4:

Semi-Automatic AED: - Device analyzes heart rhythm automatically - When a shock is needed, it announces "Shock advised, press the shock button" - The user must press the button — advantage is time to confirm no one is touching the patient - Models: Amoul i7, Amoul i9, Zoll AED Plus, Philips FRx, Philips HS1

Fully Automatic AED: - Device analyzes heart rhythm automatically - When a shock is needed, it announces "Do not touch the patient, shock will be delivered" - Device shocks automatically with no button press — reduces user hesitation - Models: Amoul i7 Plus, Amoul i9 Plus, Zoll AED 3 (select variants)

Which type to choose? - Public spaces where laypersons will be the users → Fully Automatic (no decision to press a button) - Medical institutions or locations with trained staff → Semi-Automatic (control over shock timing)

See detailed model comparisons at our AED Comparison page.

After Using an AED — What Happens Next

While waiting for the ambulance: - Continue CPR as directed by the AED - Do not remove the electrode pads from the patient - Do not power off the AED - The device will re-analyze heart rhythm every 2 minutes and may deliver additional shocks if needed

When paramedics arrive: - Inform them how many times the AED was used, how many shocks were delivered, and how long CPR was performed - Hand the patient over to the medical team

After the event: - Replace electrode pads immediately (used pads cannot be reused) - Replace the battery if the level is low - Clean the AED following manufacturer guidelines - Document the event: date/time, number of shocks, operator name - Some AED models (such as the Amoul i-Series) store ECG data and event logs internally, which can be shared with the medical team later

See full post-use maintenance details at our AED Maintenance Checklist.

Frequently Asked Questions