Stryker LIFEPAK 35

ECG Artifact / Poor Signal

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Asset Type

Defibrillator

Manufacturer

Stryker

Model

LIFEPAK 35

What This Guide Helps With

Troubleshooting noisy, unstable, intermittent, or poor-quality ECG waveforms caused by electrodes, skin contact, cables, lead selection, motion, or external interference.

Step-by-Step Troubleshooting

1. Ensure Patient Safety First

Do not troubleshoot persistent ECG artifact or questionable signal quality while the LIFEPAK 35 is being relied upon for active patient monitoring or therapy decisions.

If ECG reliability is uncertain, move the patient to another verified monitor/defibrillator before continuing.

Expected: Patient care continues with a known-good device while the affected LIFEPAK 35 is evaluated.

Why it matters: An unreliable ECG signal can interfere with rhythm interpretation and confidence in monitoring or synchronized therapy functions.

2. Verify the Reported Symptom

Confirm exactly what staff observed:

Observe whether the issue is reproducible during a controlled, non-patient evaluation.

Expected: The symptom is clearly characterized before parts are replaced.

If the ECG appears normal and the issue cannot be reproduced, document the reported condition and continue checking likely intermittent external causes.

3. Check the Selected ECG Source and Lead

Verify that the displayed ECG source and selected lead are appropriate for the test being performed.

Change to another available ECG lead and compare waveform quality.

Expected: A stable waveform appears when a usable lead vector is selected.

If changing leads resolves the issue, investigate the electrodes or lead wires associated with the affected vector and stop once reliable operation is confirmed.

4. Inspect Electrode Placement and Skin Contact

For a controlled patient-side evaluation performed only when clinically safe, verify:

Replace questionable electrodes with known-good compatible electrodes.

Expected: ECG signal quality improves and the waveform becomes stable.

Why it matters: Poor electrode-to-skin contact is a common external cause of ECG artifact. Stryker troubleshooting information for the LIFEPAK family identifies poor electrode contact, cable tension, skin preparation, and degraded electrodes as causes of poor ECG signal quality.**

If new electrodes restore a stable waveform, the issue is resolved. Stop troubleshooting.

5. Reduce Motion and Cable Tension

Check for:

Support and reposition the cable so its weight does not pull on electrode sites.

Expected: Motion-related artifact decreases or disappears.

If stabilizing the patient cable or lead wires resolves the issue, stop troubleshooting.

6. Inspect the ECG Cable and Lead Wires Externally

Remove the device from patient use before detailed accessory inspection.

Inspect the ECG patient cable and individual lead wires for:

Do not aggressively flex or manipulate damaged wiring.

Expected: Cable assembly is intact with no obvious mechanical damage or intermittent connection.

If visible damage is found, remove the accessory from service and replace it with an approved compatible cable assembly.

7. Reseat All Accessible ECG Connections

Disconnect and reconnect the ECG cable using normal operator-accessible connections.

Verify each connector is:

Expected: Connections remain secure and the ECG waveform is stable.

If reseating resolves the issue, perform a complete functional verification before returning the device to service.

8. Test With a Known-Good Compatible ECG Cable

When available, substitute a known-good compatible ECG cable and lead-wire set.

Use a controlled ECG simulator or approved test setup according to departmental procedures.

Expected: A clean, stable simulated ECG waveform is displayed.

Interpretation:

If replacing the defective accessory resolves the issue and all required testing passes, stop troubleshooting.

9. Verify Performance With an ECG Simulator

Connect an appropriate ECG simulator using an approved test configuration.

Verify:

Expected: The LIFEPAK 35 displays a stable ECG signal consistent with the simulator input.

Why it matters: Stryker publishes LIFEPAK 35 ECG monitoring performance-evaluation resources, making controlled functional evaluation appropriate before declaring an internal device fault.

If simulator performance is normal, the original problem is more likely related to patient preparation, electrodes, accessories, movement, or the clinical environment.

10. Check for Environmental Electrical Interference

If artifact remains, move the device to a controlled bench location and repeat the simulator test.

Temporarily separate the test setup from likely interference sources such as:

Do not defeat protective grounding or bypass electrical safety features.

Expected: ECG waveform remains stable in a controlled environment.

If artifact disappears after relocation, investigate the clinical environment or nearby equipment rather than assuming LIFEPAK 35 internal failure.

11. Compare Battery and External-Power Operation

When safe and consistent with departmental procedures, repeat the controlled simulator test under available normal power configurations.

Observe whether artifact occurs:

Expected: ECG quality remains stable regardless of normal power source.

If artifact is isolated to one power condition, remove the device from service for further bench evaluation rather than continuing clinical use.

12. Review Device Status and Associated Symptoms

Check for additional abnormalities such as:

Expected: No additional fault indicators are present.

If ECG artifact occurs with other device abnormalities, treat the issue as a broader reliability concern and escalate.

13. Perform Required Clinical Engineering Verification

After correcting an electrode, cable, connection, or environmental cause, complete the applicable facility-approved functional verification before return to service.

At minimum, confirm as appropriate:

Stryker provides dedicated LIFEPAK 35 service and performance-inspection documentation; use the current authorized procedure available to your organization when formal verification is required.

Expected: Device demonstrates repeatable, reliable ECG monitoring performance.

If verification passes, return the device to service according to departmental policy and document the findings.

If the Problem Persists

If known-good electrodes, proper connections, a known-good compatible ECG cable, controlled simulator input, appropriate lead selection, and environmental factors have been ruled out, the problem is likely beyond routine external troubleshooting.

The device should be:

Possible internal fault areas should be evaluated only through authorized service procedures. Do not proceed into unnecessary internal disassembly or board-level troubleshooting based solely on waveform artifact.

Knowing when to stop is proper troubleshooting. A defibrillator with unresolved ECG signal instability should not be returned to clinical use simply because the problem is intermittent.

Clinical Use Tip

Do not troubleshoot persistent ECG artifact on an active patient when monitoring reliability is questionable. Transfer monitoring to another verified device first, then evaluate the LIFEPAK 35 under controlled conditions.

For synchronized cardioversion or other functions dependent on reliable ECG detection, unexplained waveform instability requires especially cautious escalation.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"Clinical staff reported intermittent ECG artifact and an unstable waveform during monitoring on the LIFEPAK 35."

Cause

What was observed during troubleshooting.

Example:
"Testing found an intermittent ECG patient cable that reproduced waveform noise during controlled simulator evaluation."

Resolution

What action was taken.

Example:
"Replaced the defective ECG cable with a known-good compatible assembly, verified stable waveforms across multiple leads, completed functional testing, and returned the device to service."

Helpful Details to Include (If Known)

Final Thought

ECG artifact should be approached logically: protect the patient first, verify the symptom, check electrodes and connections, substitute known-good accessories, test with a simulator, and evaluate environmental causes before suspecting internal failure. Appropriate escalation and precise CCR documentation are essential when a defibrillator’s ECG reliability remains uncertain.

That is successful troubleshooting.

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