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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting uterine contraction (TOCO) sensor misalignment, inaccurate readings, or error messages on the Avalon FM30. These issues are commonly caused by external factors such as improper placement, loose connections, or accessory issues rather than internal device failure.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Ensure the monitor is not actively being relied on for patient care before troubleshooting.
- Move patient monitoring to another device if needed.
Inspect TOCO Transducer Placement
- Confirm the TOCO sensor is positioned correctly on the uterine fundus.
- Misalignment is the most common cause of inaccurate contraction readings.
- Reposition and secure with the belt to ensure firm but comfortable contact.
Check Belt and Sensor Stability
- Ensure the belt is not too loose or overly tight.
- Loose sensors can cause drifting or absent readings.
- Tight belts may distort readings or cause patient discomfort.
Inspect Cable and Connector
- Check the TOCO cable for visible damage, kinks, or fraying.
- Ensure the connector is fully seated in the correct port on the monitor.
- Partially connected cables can cause intermittent errors.
Swap with Known Good TOCO Transducer
- Replace the sensor with a known working unit.
- This helps quickly determine if the issue is accessory-related.
Check Monitor Recognition
- Confirm the monitor detects the TOCO transducer when connected.
- Look for error messages such as “Transducer Not Detected” or abnormal baseline readings.
Zero / Reset TOCO Sensor (if applicable)
- Ensure the TOCO baseline is properly zeroed per clinical workflow.
- An incorrect baseline can mimic misalignment or inaccurate readings.
Inspect for Environmental or Patient Factors
- Excessive patient movement, repositioning, or obesity can affect readings.
- Ensure consistent placement and minimize movement during testing.
Restart the Monitor
- Power cycle the unit to clear temporary software or detection issues.
Test with Simulator (if available)
- Use a fetal/maternal simulator to verify proper TOCO response.
- Confirms whether the issue is patient/setup-related versus device-related.
If the Problem Persists
If all external factors (placement, cable, transducer, and setup) have been ruled out, the issue is likely internal to the monitor (TOCO module or input circuitry).
- Remove the device from service
- Label as Out of Service
- Send for repair or bench evaluation
Knowing when to stop and escalate is an essential part of proper troubleshooting.
Clinical Use Tip
Do not attempt to troubleshoot TOCO accuracy while the device is actively monitoring a patient in labor. Always transition the patient to a functioning monitor first to ensure continuous and reliable contraction monitoring.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Nursing reported uterine contractions not displaying or inconsistent on Avalon FM30.”
Cause
What was observed during troubleshooting.
Example:
“TOCO transducer found loosely positioned and intermittently losing contact; belt not secured properly.”
Resolution
What action was taken.
Example:
“Repositioned TOCO sensor on uterine fundus, secured belt, and verified stable readings. Tested with known good transducer to confirm proper function.”
Helpful Details to Include
- TOCO placement verified
- Belt condition checked
- Cable condition inspected
- Transducer swapped
- Monitor detection confirmed
- Baseline/zeroing performed
- Simulator test results (if applicable)
- Final device status (in service or sent for repair)
Final Thought
Uterine contraction monitoring issues are most often caused by positioning or accessory problems rather than device failure. A structured approach—starting with simple external checks—ensures patient safety, minimizes downtime, and prevents unnecessary repairs. Strong documentation supports both clinical staff and future troubleshooting efforts.
That is successful troubleshooting.