Essentia / Devices / Defibrillator

Device Lab 19

Defibrillator

This device spends years in a box on a wall, doing nothing, and then has to work perfectly in the hands of a frightened stranger. That combination, years of nothing followed by one attempt with no second chance, shapes everything about how it is built, tested and stored.

Also called: Defib, Aed, Automated External Defibrillator. Arabic: جهاز إزالة الرجفان. Device Lab 19 of 69 in BMEssentia Medical City, 6 configurations.

How it works: the main parts

What each part does, from the Defibrillator lessons in the 3D Device Lab.

Display

There is no ECG trace here and that is deliberate. A manual defibrillator shows a clinician a waveform because a clinician can interpret one.

Controls

Count the controls. There are almost none, and that is the single most important design decision in this device.

Battery

This battery will sit unused for years and must then supply a full resuscitation without warning. No other battery in this device family has that duty.

Therapy

On this device the therapy cable is usually already connected, and that is a decision about users rather than about engineering. A cable a bystander has to plug in correctly, under stress, is a step that can be got wrong.

Right Pad

This pad has to be placed correctly by somebody who has never done it, is not being supervised, and is reading a picture. Everything about it, its size, its backing, the diagram printed on it, exists to make a correct placement the obvious one.

Left Pad

The second pad completes the circuit, and where it goes decides what the shock reaches. Two electrodes do not deliver therapy to a place; they deliver it along a path between them.

Capacitor

This store holds enough energy to stop a heart, inside a device that a member of the public opens on a wall. That it can be operated safely by an untrained person is a claim resting entirely on the fact that they can never reach this component, and that the device decides when it is charged.

Charger

This converter has to take a standby battery to defibrillation voltage in the seconds after the device decides to treat, having done almost nothing for years beforehand. It is the least exercised assembly in the device and one of the most critical, which is why the self-test runs it deliberately.

Common faults and what to check

Most reported device problems (FDA MAUDE)

Raw counts of adverse event reports for this device type (FDA product code MKJ, LDD, DRK, NSA), all years. Not adjusted for the number of units in use, so they show what gets reported, not failure rates. Report text is never copied.

Standards engineers test against

Recent FDA recalls

From the FDA recall database (openFDA), newest first, imported 2026-10-22. 369 recalls on record for this device type. Recall text is the FDA's public text; each recall links to the official record.

Learn it, see it in 3D, ask about it

• Ask Essentia about the Defibrillator: answers from named sources, with the device open in its 3D Device Lab beside the answer.
• The Defibrillator on the BMEssentia Platform: the Device Library course, 13 sections from physics to maintenance.
• BMEssentia Medical City: Device Lab 19, the Defibrillator fully assembled in 3D, with lab tasks and the simulations.

Previous: Autoclave. Next: EP Mapping System. All 69 devices.