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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting Corometrics fetal monitors that trigger signal loss or sensor not detected alarms. These alarms typically indicate the monitor is unable to receive a reliable signal from one or more fetal or maternal sensors. Most often, this is caused by external factors such as loose connections, improperly applied electrodes, or faulty sensor cables rather than internal device failure.
Step-by-Step Troubleshooting
Verify Monitor Power and Initialization
- Ensure the monitor is plugged into a known good power source.
- Confirm that the monitor completes its startup self-test without errors.
Why: Power fluctuations can prevent proper sensor detection and generate false alarms.
Check Sensor Connections
- Confirm that all fetal and maternal sensors are correctly connected to their respective ports.
- Inspect connectors for bent pins, corrosion, or debris.
Why: Loose or damaged connectors are the most common cause of “sensor not detected” alarms.
Inspect Sensor Placement and Skin Contact
- Verify that fetal electrodes (TOCO or scalp electrodes) are properly positioned according to manufacturer guidelines.
- Ensure maternal pulse oximetry or other sensors have proper skin contact and adhesive.
Why: Poor contact or incorrect placement can prevent signal acquisition.
Swap Sensors or Cables
- If available, replace the suspect sensor with a known good sensor.
- Swap cables to isolate whether the issue is with the cable or the sensor itself.
Why: This helps differentiate between cable/sensor faults and device port issues.
Review Monitor Settings and Channel Configuration
- Confirm that the correct channel is enabled and assigned to the sensor type in use.
- Check for any channel-specific alarm limits or settings that could prevent detection.
Why: Misconfigured channels can cause false “not detected” alarms.
Observe for Environmental or Patient Factors
- Ensure no excessive movement or interference (electrocautery, other monitors) is affecting the signal.
- Reposition patient or electrode site if necessary.
Why: External interference can mimic sensor failure.
If the Problem Persists
External causes have been ruled out; the problem is likely internal.
- Remove the monitor from service and label it Out of Service.
- Send the unit for manufacturer repair or Clinical Engineering bench evaluation.
Reminder: Stopping troubleshooting when external checks fail is proper Clinical Engineering practice.
Clinical Use Tip
Never troubleshoot sensors or reposition electrodes on an active patient without ensuring patient safety.
If the monitor is unreliable, move the patient to a backup monitor while resolving the issue.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Nurse reports repeated “Sensor Not Detected” alarms on fetal channel.”
Cause
What was observed during troubleshooting.
Example:
“Clinical Engineering observed loose fetal electrode connection; cable tested and swapped, but alarms persisted on the original port.”
Resolution
What action was taken.
Example:
“Replaced fetal electrode and cable; monitor channel confirmed functional. Monitor returned to service.”
Helpful Details to Include
- Outlet tested for stable power.
- Sensor cables and connectors inspected and swapped.
- Channel assignments and alarm limits verified.
- Monitor startup self-test results noted.
- Patient repositioning or electrode placement adjustments recorded.
Final Thought
Signal loss alarms often originate from simple connection, placement, or sensor issues rather than internal monitor failure. Following a methodical, stepwise approach ensures patient safety, minimizes unnecessary device downtime, and supports thorough documentation for traceability. Escalation to repair should only occur after external troubleshooting is exhausted.
That is successful troubleshooting.