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What This Guide Helps With
Troubleshooting absent maternal SpO2 caused by sensor, cable, connector, placement, perfusion, motion, compatibility, or monitor-channel problems.
Step-by-Step Troubleshooting
1. Ensure Patient Safety and Obtain Alternate Oxygenation Monitoring
Do not rely on an SpO2 channel that is missing, intermittent, or producing questionable readings.
Notify clinical staff and use another verified pulse oximeter or approved clinical assessment method. Escalate immediately if the patient’s condition requires continuous oxygenation monitoring.
Expected outcome: Maternal oxygenation is monitored by a reliable alternate method.
2. Confirm the Exact Reported Condition
Determine whether:
- The sensor is not detected.
- The sensor is detected but no waveform or value appears.
- The value appears intermittently.
- The reading is implausible.
- The failure occurs with one sensor or all sensors.
- The problem began after accessory exchange, cleaning, or patient repositioning.
- A status or alarm message is displayed.
Distinguish sensor recognition from poor physiological signal.
Expected outcome: The problem is categorized as accessory recognition, poor signal acquisition, intermittent connection, or monitor-channel failure.
3. Verify Basic Monitor Operation
Confirm the Philips Avalon FM30 completes startup and responds normally. Verify that other measurement channels function and that the SpO2 function is present in the installed configuration.
Expected outcome: The monitor is operational and the failure is limited to the SpO2 channel or accessory.
4. Inspect the SpO2 Sensor
Check the sensor for:
- Cracked housing.
- Damaged emitter or detector surfaces.
- Torn adhesive or worn reusable attachment.
- Contamination.
- Fluid intrusion.
- Pinched, cut, or stretched cable.
- Damaged strain relief.
- Bent or recessed connector contacts.
Remove damaged sensors from service.
Expected outcome: The sensor is physically intact and appropriate for use. If damaged, replace it and retest.
5. Verify Sensor Compatibility
Confirm the sensor and any extension or adapter cable are compatible with the monitor’s installed SpO2 technology.
Do not assume that a physically fitting connector is electrically or functionally compatible. Do not use unapproved adapters.
Expected outcome: The correct approved sensor and cable combination is connected.
6. Inspect and Reseat Connections
Disconnect and reconnect the sensor, extension cable, and monitor connection as applicable.
Inspect each connection for contamination, moisture, loose fit, bent contacts, or mechanical damage. Ensure connectors are fully seated without forcing them.
Expected outcome: The sensor is detected and remains connected. If recognition returns, continue to signal verification and stop troubleshooting after successful final checks.
7. Verify Sensor Placement
Confirm the sensor is applied correctly to an appropriate site. Check for:
- Misalignment of emitter and detector.
- Excessive ambient light.
- Nail coverings when relevant to the sensor site.
- Tight application that may impair circulation.
- Loose application.
- Patient movement.
- Edema or poor local perfusion.
- Placement on a limb affected by NIBP cycling.
Expected outcome: A stable plethysmographic signal and plausible saturation value appear. If corrected placement resolves the issue, compare the reading with the clinical condition and stop troubleshooting.
8. Evaluate Signal Conditions
Observe the waveform or signal-quality indication while minimizing motion and supporting the measurement site.
Warm or reposition the site only when clinically appropriate and directed by staff. Do not treat a patient condition as an equipment defect.
Expected outcome: Signal quality improves with stable positioning and adequate perfusion. Persistent no-signal with a properly applied known-good sensor requires further testing.
9. Substitute a Known-Good Compatible Sensor and Cable
Use a verified sensor and extension cable known to work correctly.
Test one external component at a time when practical, or replace the full accessory chain if rapid isolation is required.
Expected outcome: Normal operation with known-good accessories confirms failure of the original sensor, cable, or adapter.
10. Test the Original Sensor on Another Verified Compatible Monitor
When available, test the original sensor on another compatible device that has passed functional checks.
Expected outcome: Failure on another monitor confirms an accessory problem. Normal operation points toward the original monitor input or configuration.
11. Test with an Approved SpO2 Simulator
Remove the monitor from patient use. Connect an approved compatible SpO2 simulator and verify detection, displayed saturation, pulse rate, waveform, and alarm response using authorized procedures.
Expected outcome: The SpO2 channel responds correctly to the approved simulator and meets applicable verification requirements.
12. Perform Final Functional Verification
After correction:
- Confirm the sensor is detected.
- Verify a stable waveform or signal-quality indicator.
- Confirm plausible SpO2 and pulse-rate values using an approved test method.
- Gently move accessible cable sections and confirm no intermittent dropout.
- Verify alarm limits, alarm annunciation, and recovery from sensor disconnection.
- Complete applicable safety and performance checks.
Expected outcome: The SpO2 channel remains stable and passes required verification. Troubleshooting can stop.
13. Stop and Escalate When the SpO2 Channel Remains Unreliable
Remove the device from service when:
- Multiple known-good sensors are not detected.
- The monitor fails an approved simulator test.
- The input connector is damaged or intermittent.
- The reading drops out when the connector is touched.
- Values remain unstable or implausible under controlled testing.
- The monitor freezes or resets when the sensor is connected.
- The installed SpO2 configuration cannot be verified.
Expected outcome: The monitor is not used for maternal oxygenation monitoring until evaluated.
If the Problem Persists
Common external causes such as incompatible sensors, damaged cables, loose connections, incorrect placement, motion, poor perfusion, and ambient interference have been ruled out. The remaining cause may involve the monitor input, SpO2 module, internal connection, configuration, or software.
Remove the Philips Avalon FM30 from service, label it Out of Service, and send it for bench evaluation using approved Philips documentation and compatible SpO2 test equipment. Repair or configuration changes should be completed only by qualified personnel.
Return the device to service only after sensor recognition, simulated values, waveform, pulse rate, alarms, and applicable safety checks pass. Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Confirm maternal oxygenation with another verified device whenever the fetal monitor’s SpO2 signal is absent or questionable.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported that the Philips Avalon FM30 displayed no maternal oxygen saturation and did not consistently detect the SpO2 sensor."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found a damaged extension cable that caused intermittent sensor recognition; the sensor and monitor passed testing with a known-good cable."
Resolution
What action was taken.
Example:
"The extension cable was replaced, and sensor detection, simulated saturation, pulse rate, waveform, disconnect response, and alarms were verified."
Helpful Details to Include (If Known)
- Sensor type and compatibility.
- Whether the sensor was detected.
- Waveform or signal-quality status.
- Sensor site and placement.
- Patient motion or perfusion concerns.
- Condition of sensor, cable, and connectors.
- Known-good sensor and cable results.
- Results on another monitor.
- Simulator test results.
- Alarm and disconnect verification.
- Final monitor status.
Final Thought
Maintain alternate oxygenation monitoring, separate poor physiological signal from accessory recognition, verify the entire external sensor path before assuming an internal failure, and document the final test clearly.
That is successful troubleshooting.