ZOLL Propaq MD

ECG Lead-Off, Artifact, or No Waveform

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Asset Type

Defibrillator

Manufacturer

ZOLL

Model

Propaq MD

What This Guide Helps With

ECG leads appear disconnected, the waveform is absent, or excessive artifact occurs because of electrodes, cables, connections, placement, settings, or environment.

Step-by-Step Troubleshooting

1. Protect the Patient and Maintain Monitoring

If reliable ECG monitoring is clinically required, move the patient to another verified monitoring method before troubleshooting an unreliable ECG channel.

Do not troubleshoot intermittent or absent ECG monitoring while the patient depends solely on the affected signal.

Expected outcome: Continuous patient monitoring is maintained independently of the affected ECG function.

2. Confirm the Exact ECG Complaint

Determine whether staff reported:

Reproduce the condition using an ECG simulator when appropriate.

Expected outcome: The failure is narrowed to a specific signal condition rather than treated as a general ECG failure.

3. Verify ECG Monitoring Is Selected and Configured Appropriately

Check that the intended ECG source and lead selection are active and that the display has not simply been switched to another monitoring source.

Review visible settings without making unauthorized configuration changes.

Expected outcome: The intended ECG lead is selected and expected to appear on the display. If correcting the lead selection restores a stable waveform, troubleshooting can stop after verification.

4. Inspect Electrodes and Patient-Side Connections

When evaluating a clinical setup, inspect for:

Replace questionable disposable electrodes as appropriate.

Expected outcome: All electrodes have secure electrical and mechanical contact. If the waveform becomes stable, verify all required leads and stop troubleshooting.

5. Inspect the ECG Cable and Lead Wires

Examine the patient cable and individual lead wires for:

Do not continue using visibly damaged patient cables.

Expected outcome: The cable assembly is intact and connections remain stable during normal handling.

6. Reseat All Accessible ECG Connections

Disconnect and firmly reconnect the ECG patient cable and lead-wire connections.

Check for contamination or foreign material before reconnecting.

Expected outcome: Connections seat securely without intermittent lead-off indications. If reseating resolves the problem, complete simulator or patient-equivalent verification and stop troubleshooting.

7. Substitute Known-Good ECG Accessories

Use a known-good compatible patient cable, lead set, and test electrodes or ECG simulator connection as appropriate.

Change one component at a time when practical.

Expected outcome: A defective external accessory is isolated. If known-good accessories restore stable ECG monitoring, replace the faulty accessory and complete final verification.

8. Evaluate Artifact Sources

If a waveform is present but noisy, check for:

Use an ECG simulator to separate device-related artifact from patient or environmental artifact.

Expected outcome: The simulator produces a stable waveform. If artifact occurs only in the clinical setup, correct the external source rather than assuming an internal monitor failure.

9. Perform Final Functional Verification

Using appropriate test equipment:

Expected outcome: ECG monitoring is stable, repeatable, and free of abnormal artifact. Troubleshooting can stop.

10. Escalate Persistent ECG Failure

If a no-waveform, lead-off, or artifact condition persists with a verified simulator and known-good compatible cables, remove the unit from service.

Expected outcome: A device-side ECG acquisition problem is referred for qualified service evaluation.

If the Problem Persists

After electrodes, patient preparation, lead placement, settings, cables, connections, known-good substitutions, simulator testing, and environmental factors are ruled out, the remaining cause may involve the ECG acquisition path, connector interface, configuration, or another internal service-level issue.

The device should be:

Perform applicable ECG, alarm, monitoring, defibrillator, and electrical safety verification before returning the unit to clinical service.

Knowing when to stop external troubleshooting is proper troubleshooting.

Clinical Use Tip

Confirm the complete ECG signal path from electrode to displayed waveform before returning the unit to patient monitoring.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"Clinical staff reported persistent ECG lead-off messages and an intermittent waveform during monitoring."

Cause

What was observed during troubleshooting.

Example:
"Clinical Engineering found an intermittent ECG patient cable that reproduced the lead-off condition during controlled testing."

Resolution

What action was taken.

Example:
"The defective ECG cable was replaced and the Propaq MD passed simulator testing with stable waveforms and proper lead-off detection."

Helpful Details to Include (If Known)

Final Thought

Maintain reliable patient monitoring, work from electrodes and cables inward, verify the signal with controlled test equipment before suspecting internal acquisition failure, escalate unresolved problems, and document the complete troubleshooting path.

That is successful troubleshooting.

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