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What This Guide Helps With
Troubleshooting absent, delayed, interrupted, or incomplete ECG rhythm analysis caused by electrode contact, accessories, motion, interference, power, or device faults.
Step-by-Step Troubleshooting
1. Ensure Patient Safety First
Do not perform extended troubleshooting on a LIFEPAK CR2 that is required for an active cardiac arrest response.
If ECG analysis does not start or complete during actual patient use:
- Follow the device’s voice and visual prompts
- Continue resuscitation according to the facility’s emergency-response protocol
- Obtain another verified AED/defibrillator immediately when available
- Do not delay CPR or higher-level emergency response while attempting equipment troubleshooting
Expected: Patient care is not dependent on an AED with unresolved rhythm-analysis performance.
Why it matters: Failure to complete rhythm analysis may prevent the device from reaching an appropriate shock decision. Troubleshooting beyond immediate external corrections should occur off patient.
If another verified defibrillator restores safe emergency-response capability, remove the affected CR2 from clinical reliance and continue evaluation in a controlled setting.
2. Confirm the Exact Failure Behavior
Determine precisely what Clinical Engineering can reproduce.
Check whether:
- Analysis never appears to begin
- The unit repeatedly instructs the user to attach electrodes
- Analysis begins but repeatedly restarts
- Analysis remains prolonged
- Analysis is interrupted by motion or contact prompts
- The unit progresses through CPR prompts but not expected rhythm analysis
- The problem occurs only with one electrode set
- Voice prompts stop or the operating sequence freezes
- The device unexpectedly powers off or restarts
Record all audible prompts, indicator behavior, and sequence timing.
Expected: The complaint is narrowed to an electrode-recognition, signal-quality, operating-sequence, power, or device-level problem.
If the reported behavior cannot be reproduced, continue with accessory, readiness, and controlled functional checks before returning the unit to service.
3. Verify the Correct Operating Sequence
Using an approved non-patient test method, verify that the CR2 is being activated through its normal operating sequence.
Check that:
- The lid opens normally
- The device powers on
- Voice prompts begin
- The device advances through the expected rescue sequence
- No startup fault or abnormal readiness indication is present
Do not assume the device should enter rhythm analysis immediately upon power-up. Analysis depends on progression through the AED rescue sequence and acquisition of an acceptable ECG signal through the electrodes.
Expected: The CR2 powers on normally and proceeds through its expected prompt sequence.
If startup is abnormal, prompts are missing, or the sequence freezes before electrode evaluation, stop and escalate the device for bench evaluation.
4. Check Electrode Connection and Deployment
Inspect the installed QUIK-STEP electrode assembly and associated connection points externally.
Check for:
- Electrode package damage
- Open or compromised packaging
- Expired electrodes
- Partially deployed electrodes
- Visible cable damage
- Pinching or severe bends
- Loose connection at any user-accessible interface
- Evidence of fluid contamination
Ensure the electrode system is installed and routed as intended for the CR2.
Expected: The electrode assembly is intact, in date, correctly installed, and free of obvious physical damage.
If correcting an obvious seating or deployment problem restores the expected analysis sequence, document the finding, complete required testing, and stop.
5. Verify Electrode Pad Condition and Contact
For controlled troubleshooting, use only an approved test setup appropriate for AED evaluation. Do not test rhythm analysis on a healthy person.
If reviewing a clinical event, determine whether the pads may have had:
- Incomplete adhesion
- Folded edges
- Dried or contaminated conductive surface
- Heavy chest hair preventing contact
- Moisture between the pad and skin
- Incorrect placement
- Pads touching or overlapping
- Partial removal during movement or CPR
Expected: Both pads can provide stable contact through an approved simulator/test arrangement or were documented as properly applied during the event.
Why it matters: The CR2 obtains ECG information through its therapy electrodes. Poor contact can prevent dependable signal acquisition and interfere with analysis.
If a known-good compatible electrode set resolves the problem during approved testing, replace the defective or suspect electrode assembly and complete post-service verification.
6. Substitute a Known-Good Compatible Electrode Set
When permitted by facility procedure and manufacturer requirements, repeat the controlled test with a known-good, in-date, compatible electrode set.
Do not use visibly damaged, expired, previously deployed, or questionable electrodes for comparison.
Expected: The device progresses into and completes the expected analysis sequence with the known-good electrode set.
If the problem disappears, the original electrode assembly is the likely cause.
Remove the suspect electrodes from service, replace them, document the failure, and complete the required readiness check.
7. Eliminate Motion and Mechanical Disturbance
During controlled analysis testing:
- Keep the simulator/test arrangement stationary
- Avoid moving the device
- Prevent electrode cables from being pulled
- Do not manipulate connections during analysis
- Ensure the test setup is mechanically stable
When reviewing an actual event, consider:
- Patient movement
- Ongoing transport vibration
- Repositioning
- Repeated pad disturbance
- Mechanical CPR-related conditions
- Rescuer contact during a requested hands-off analysis period
Expected: Analysis completes when the ECG input and test setup are stable.
If analysis succeeds only when movement stops, document motion or unstable contact as the likely contributor rather than assuming an internal AED failure.
8. Check for Electrical or Electromagnetic Interference
Move the CR2 and approved test setup away from potential high-interference sources when practical.
Consider nearby:
- Electrosurgical equipment
- High-power radio transmitters
- Certain telemetry or communication equipment
- Large motors
- Damaged electrical equipment
- Other equipment producing substantial electromagnetic interference
Repeat the controlled test in a different location.
Expected: Analysis performance remains stable regardless of location.
If the problem occurs only near a specific interference source and clears elsewhere, document the environmental relationship and investigate the source before condemning the AED.
9. Verify Battery and Power Stability
Inspect the LIFEPAK CR2 battery externally.
Check for:
- Low-battery indications
- Abnormal readiness status
- Battery not fully seated
- Physical battery damage
- Contaminated accessible contacts
- Unexpected shutdown
- Restart during the rescue sequence
- Intermittent operation when the unit is moved
Reseat the battery only when permitted by facility procedure and with the device removed from patient use.
Expected: The CR2 remains continuously powered through startup, prompts, ECG acquisition, and analysis testing.
If power instability is present, address the battery/power complaint before evaluating analysis performance further.
10. Review Readiness and Self-Monitoring Status
Check the CR2 readiness indication and any available device-management status information used by the facility.
Look for:
- Not-ready indication
- Battery alerts
- Electrode alerts
- Failed or abnormal self-monitoring status
- Unresolved maintenance notifications
Connected CR2 deployments may also provide readiness information through the facility’s configured AED management workflow.
Expected: The unit indicates ready status with no unresolved battery, electrode, or device fault.
If the AED is not ready or reports a persistent fault, remove it from service and escalate rather than attempting repeated patient-use simulations.
11. Test With an Approved AED/ECG Simulator
Use a manufacturer-compatible or facility-approved AED analyzer/simulator according to Clinical Engineering procedure.
Verify whether the LIFEPAK CR2:
- Recognizes the connected test load
- Enters the expected analysis sequence
- Completes analysis on a stable simulated rhythm
- Produces an appropriate shock/no-shock decision for the test condition
- Repeats the sequence consistently
Use only approved test equipment and established procedures. Do not improvise a live-person test.
Expected: The device consistently completes analysis and responds appropriately to the controlled simulated rhythm.
If analysis repeatedly fails with a known-good electrode setup and approved simulator, the likelihood of an internal device fault increases.
12. Repeat the Test for Intermittent Failure
If the first controlled test passes, repeat the sequence enough times to evaluate the reported intermittent behavior.
Observe for:
- Random analysis interruption
- Freezing at the same stage
- Delayed recognition
- Unexpected restart
- Prompt sequence failure
- Sensitivity to minor device movement
- Failure after warming during repeated operation
Expected: Analysis starts and completes consistently across repeated controlled tests.
If failure is intermittent but reproducible, remove the unit from service. An intermittent AED analysis problem should not be returned to service solely because one test passed.
13. Inspect for External Physical Damage
Inspect the CR2 externally for:
- Cracked enclosure
- Evidence of impact
- Liquid intrusion
- Corrosion
- Damaged lid mechanism
- Damaged battery compartment
- Contaminated accessible connections
- Unusual heat
- Burn odor
- Loose internal-sounding components when handled normally
Do not open the enclosure unless specifically authorized, trained, and following approved service documentation.
Expected: No external condition suggests compromised reliability.
If impact, fluid intrusion, overheating, or significant damage is found, stop troubleshooting and escalate for repair evaluation.
14. Determine Whether the Failure Is Accessory-Related or Device-Related
Review the results of all controlled substitutions and observations.
Accessory-related failure is more likely when:
- A known-good electrode set resolves the problem
- The original electrodes are damaged or expired
- Analysis succeeds after correcting pad/contact conditions
- The problem follows one specific electrode assembly
Device-related failure is more likely when:
- Multiple known-good compatible electrode sets fail
- The approved simulator/test setup is verified
- Power remains stable
- Motion and interference have been ruled out
- The analysis sequence repeatedly freezes or fails
- Readiness or self-monitoring status is abnormal
Expected: The fault is isolated as far as possible without unnecessary internal disassembly.
If the issue is resolved externally, complete all required post-service testing and stop.
If the Problem Persists
If ECG analysis still will not start or complete after verifying:
- Patient safety
- Normal startup sequence
- Correct electrode installation
- Electrode condition
- Known-good compatible electrodes
- Stable contact
- Motion conditions
- Environmental interference
- Battery stability
- Readiness status
- Approved simulator performance
then common external causes have been reasonably ruled out and the problem is likely internal or requires manufacturer-level evaluation.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or controlled bench evaluation
- Evaluated according to approved Stryker service procedures and facility policy
Possible internal categories may include ECG acquisition circuitry, electrode detection, internal connections, processing, software, or other device-level faults. Do not continue into board-level troubleshooting without authorized service documentation, appropriate training, and required test equipment.
Knowing when to stop is proper troubleshooting. A defibrillator with unresolved rhythm-analysis performance should not be returned to clinical service based on an intermittent pass or inability to reproduce the failure once.
Clinical Use Tip
Never perform extended troubleshooting on an active cardiac-arrest patient.
If the LIFEPAK CR2 cannot reliably begin or complete analysis:
- Continue resuscitation according to emergency protocol
- Obtain another verified AED/defibrillator immediately when available
- Follow the device’s prompts
- Remove the suspect CR2 from service after the event
Clinical Engineering testing should be performed off patient using approved simulation equipment.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported the LIFEPAK CR2 powered on and delivered voice prompts but would not complete ECG rhythm analysis during use."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering reproduced intermittent analysis failure with the original electrode assembly; analysis completed normally after installation of a known-good compatible electrode set."
Resolution
What action was taken.
Example:
"Replaced the suspect electrode assembly, verified repeated analysis sequences using an approved AED simulator, confirmed ready status, and returned the device to service."
Helpful Details to Include (If Known)
- Exact voice prompt documented
- Readiness indicator status recorded
- Electrode expiration checked
- Electrode package inspected
- Electrode assembly reseated or replaced
- Known-good compatible electrodes tested
- Battery condition checked
- Unexpected restart or shutdown observed
- Motion sensitivity evaluated
- Alternate test location used
- EMI/RFI sources considered
- Approved AED simulator used
- Shock/no-shock test behavior recorded
- Intermittent failure reproduced
- External damage checked
- Unusual heat or smell noted
- Final device status documented
Final Thought
ECG analysis failure on an AED demands disciplined troubleshooting: protect the patient first, verify electrodes and signal conditions, eliminate external causes, test with approved equipment, and escalate when reliability remains uncertain. Clear CCR documentation preserves what failed, what was proven, and why the final disposition was appropriate.
That is successful troubleshooting.