GE Healthcare B105 / B125 / B155 Series

ECG Lead-Off, Artifact, or No Waveform

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Asset Type

Patient Monitor

Manufacturer

GE Healthcare

Model

B105 / B125 / B155 Series

What This Guide Helps With

Troubleshoots ECG lead-off messages, noisy traces, intermittent signals, missing waveforms, patient cable problems, electrodes, placement, and external interference.

Step-by-Step Troubleshooting

1. Protect the Patient and Confirm an Alternate Assessment Method

If reliable ECG monitoring is clinically required and the monitor is not producing dependable ECG information, ensure the patient is monitored by another verified device or appropriate clinical method before technical troubleshooting.

Do not troubleshoot unreliable monitoring while a patient depends on it.

Expected outcome: The patient has reliable monitoring while the affected ECG path is evaluated.

2. Confirm the Exact ECG Complaint

Determine whether the reported problem is:

Observe which leads or channels are affected.

Expected outcome: The exact ECG failure pattern is identified.

3. Inspect the ECG Patient Cable and Lead Wires

Inspect the ECG trunk cable, lead wires, connectors, strain reliefs, and accessible contacts for:

Reseat all external ECG connections.

Expected outcome: ECG cables and lead wires are intact and securely connected.

If reseating a loose connection restores a stable waveform, complete final verification and troubleshooting can stop.

4. Check Electrodes and Patient Connections

Coordinate with clinical staff to verify that:

Clinical staff should manage patient skin preparation and electrode placement as appropriate.

Expected outcome: Each required lead has a secure conductive patient connection.

If replacing a loose or degraded electrode corrects the waveform, verify all displayed leads and troubleshooting can stop.

5. Verify the Selected ECG Configuration

Confirm that the monitor is configured for the ECG lead set and monitoring arrangement actually connected.

Do not alter clinical settings unnecessarily. Record existing settings before making any authorized correction.

Expected outcome: The monitor configuration corresponds with the connected ECG cable and intended clinical monitoring setup.

If an incorrect external configuration caused the issue, restore the correct setting and verify normal operation.

6. Check for Motion and Environmental Artifact

Determine whether artifact occurs primarily during:

Route cables to reduce tension and unnecessary movement.

Expected outcome: The ECG waveform remains stable under normal conditions without avoidable external interference.

If correcting cable routing or an environmental source resolves the artifact, troubleshooting can stop after verification.

7. Substitute Known-Good ECG Accessories

When available, substitute compatible known-good components systematically:

Change one item at a time so the cause can be identified.

Expected outcome: A known-good accessory produces a stable ECG waveform.

If the problem follows an ECG cable or lead-wire set, replace that accessory and proceed to final verification.

8. Test With an ECG Simulator Off-Patient

Connect an approved patient simulator using known-good ECG accessories.

Verify that the monitor displays a stable ECG waveform and heart-rate value without lead-off indications.

Do not use simulator testing as a substitute for checking the patient-side electrode and cable path when the original problem occurred clinically.

Expected outcome: The monitor correctly detects and displays the simulated ECG signal.

If simulator performance is normal, the monitor is likely functioning and attention should return to patient electrodes, cables, environment, or application conditions.

9. Check the Monitor ECG Input Externally

Inspect the accessible monitor ECG connection for debris, contamination, physical damage, or looseness.

Do not probe, disassemble, or attempt internal connector repair without approved service procedures.

Expected outcome: The ECG input is clean, intact, and securely retains the appropriate connector.

10. Perform Final Functional Verification

After correction, verify:

Expected outcome: ECG monitoring and associated alarms function reliably.

If all checks pass, document the cause and return the monitor to service.

11. Escalate Persistent ECG Failure

If a known-good ECG cable and simulator do not produce reliable ECG monitoring, or the input connector is damaged, stop external troubleshooting.

Expected outcome: A monitor with unresolved ECG failure is removed from clinical availability and sent for service.

If the Problem Persists

Electrodes, cables, lead wires, configuration, environmental factors, and known-good simulated inputs have been evaluated. Remaining possibilities may include the monitor's ECG acquisition circuitry, input interface, configuration, or another internal service-level issue.

The monitor should be:

Following repair, verify ECG acquisition, lead detection, heart-rate processing, applicable alarms, and other required return-to-service functions.

Knowing when an ECG problem has moved beyond accessories and external connections is proper troubleshooting.

Clinical Use Tip

A displayed heart rate does not prove the ECG waveform is clinically reliable; verify the waveform quality and complete ECG signal path after any repair.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
"Nursing reported intermittent ECG lead-off indications and excessive artifact on the B105 monitor."

Cause

What was observed during troubleshooting.

Example:
"Clinical Engineering found an intermittent ECG lead-wire set that produced artifact when the cable was moved."

Resolution

What action was taken.

Example:
"Replaced the defective lead-wire set, verified a stable simulated ECG waveform and heart-rate display, tested ECG alarms, and returned the monitor to service."

Helpful Details to Include (If Known)

Final Thought

Protect the patient, follow the ECG signal path from electrodes to monitor, eliminate cable and environmental causes before suspecting internal acquisition hardware, and verify both waveform and alarm performance before returning the device to use.

That is successful troubleshooting.

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