Defibrillators are life-support devices, which changes the standard for both testing and documentation. A monitor that fails intermittently is an inconvenience. A defibrillator that delivers 15% low energy is a patient safety event waiting for a code.
This is a practical reference for the checks that matter, the failures that actually occur, and the documentation that holds up in a survey.
The core test set
Every defibrillator PM should establish, at minimum, that the device delivers the energy it claims, in the time it claims, on the battery it carries.
Record measured values, not checkmarks. "Delivered 198 J at 200 J setting" is defensible. "Energy: PASS" is not.
- Delivered energy verification across the range — low, mid, and max settings, against a calibrated defibrillator analyzer
- Charge time to maximum energy on battery power (not mains) — this is where aging capacitors and batteries show up
- Synchronized cardioversion timing — verify the discharge lands on the R wave within specification
- ECG monitoring accuracy through the paddles or pads circuit
- External pacing output verification if the unit is equipped — rate and current, under load
- Battery capacity and runtime under a discharge cycle, not just a resting voltage reading
- Electrical safety testing per your facility standard
- Physical inspection: paddle surfaces, cable strain reliefs, pad expiration, case integrity
Energy output out of tolerance
Most manufacturers specify delivered energy within roughly ±15% of the setting, or a fixed joule tolerance at low settings — always work from the specific unit's service manual, not a remembered number.
When output reads low across all settings, the usual suspects are the high-voltage capacitor and the charging circuit. When it reads low only at high settings, suspect the capacitor or an undersupplied charging path. When it reads erratic, suspect the discharge relay or the paddle/pad cable.
- Repeat the measurement with a second analyzer or a second load setting before condemning the unit
- Verify the analyzer itself is in calibration — an out-of-cal analyzer has failed plenty of good defibrillators
- Test through both paddle and pad paths where the unit supports both; a cable fault presents as an output fault
- Remove the unit from service immediately on a confirmed out-of-tolerance result — do not leave it on the floor pending parts
Battery failures
Batteries cause the majority of defibrillator downtime. A defibrillator battery that reads full voltage at rest can still collapse under a charge cycle, which is exactly when it matters.
Test capacity with a real discharge cycle on the OEM-specified schedule, track battery age and cycle count in the device record, and replace on age even when capacity still passes. Batteries are cheap relative to a failed code.
AED self-test failures
AEDs run periodic self-tests and report failures with a status indicator or audible chirp. The three common causes, in order of frequency: expired or dried-out electrode pads, low battery, and an internal test failure.
- Check pad expiration date and package seal first — this is the single most common cause
- Check battery install date and indicator status
- Force a manual self-test after replacing consumables and confirm it clears
- If the internal test still fails, the unit goes to OEM — AED internals are generally not field-serviceable
- Verify the unit is logged back into the AED tracking program with new pad and battery expiry dates
Documentation standard for life-support devices
For defibrillators, the service record should let a surveyor reconstruct the entire test without talking to you: analyzer used and its calibration date, each setting tested, each measured value, pass criteria applied, battery data, and the return-to-service decision.
If the unit failed and was removed from service, the record should also show when it came off the floor and what replaced it in the interim. That gap is what surveyors ask about.