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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting uterine contraction (TOCO) sensor errors on the Avalon FM20 fetal monitor. These errors can prevent accurate monitoring of maternal contractions during labor. Most causes are external or setup-related, such as sensor misplacement, loose cables, or patient positioning issues, rather than internal device failure.
Step-by-Step Troubleshooting
Check Sensor Connection
- Ensure the TOCO sensor cable is securely connected to the monitor.
- Loose or intermittent connections are a common cause of signal errors.
Inspect Sensor Placement
- Confirm the TOCO sensor is positioned correctly on the patient’s abdomen, over the uterine fundus.
- Incorrect placement can cause weak or erratic readings.
Verify Sensor Strap Tension
- The elastic strap should be snug but not overly tight.
- Too loose → poor signal; too tight → patient discomfort and inaccurate readings.
Check for Interference or Motion
- Patient movement, coughing, or talking can temporarily disrupt the TOCO signal.
- Ask the patient to remain still for a moment and observe signal stabilization.
Swap Cables or Sensor (if available)
- Use a known-good TOCO sensor and/or cable to rule out a faulty component.
Inspect Monitor Settings
- Confirm the monitor is set to detect TOCO signals and that alarm thresholds are appropriate.
Check Power Source
- Ensure the monitor is on a stable power source or fully charged battery.
- Voltage fluctuations can sometimes affect sensor readings.
If the Problem Persists
Common external causes have been ruled out.
The TOCO sensor or internal monitor circuitry may be faulty.
- Remove the monitor from service.
- Label it Out of Service.
- Send it to Biomedical Engineering for bench evaluation or manufacturer repair.
Knowing when to escalate avoids unnecessary patient risk and wasted troubleshooting time.
Clinical Use Tip
- Never rely solely on a faulty TOCO reading for clinical decisions.
- Move the patient to another monitor if available while troubleshooting.
- Always ensure patient safety before adjusting or testing sensors.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
TOCO sensor error alarm reported; no reliable uterine contraction tracing.
Cause
What was observed during troubleshooting.
Example:
Sensor cable loosely connected; patient movement detected; TOCO sensor misaligned.
Resolution
What action was taken.
Example:
Repositioned TOCO sensor over uterine fundus, adjusted strap tension, and replaced cable with a known-good spare. Signal verified; tracing stable.
Helpful Details to Include
- Outlet tested and verified stable
- TOCO cable and sensor checked/swapped
- Alarm behavior noted
- Patient movement observed
- Final device status: working OR removed from service
Final Thought
Patient safety is paramount. Logical troubleshooting, starting with external checks, ensures accurate monitoring while minimizing risk. Proper documentation and escalation protect both staff and patients and provide a clear record for future reference.
That is successful troubleshooting.