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What This Guide Helps With
Troubleshoots TOCO zeroing difficulty or baseline drift caused by transducer condition, positioning, belt tension, connection, movement, or external setup.
Step-by-Step Troubleshooting
1. Protect the Patient and Maintain Required Monitoring
If uterine activity monitoring is clinically necessary and the TOCO channel is unreliable, provide an alternate verified monitoring method or monitor before technical troubleshooting.
Expected outcome: Required clinical monitoring continues without depending on an unreliable TOCO signal.
2. Confirm the Exact Symptom
Determine whether the TOCO channel will not zero, slowly drifts after zeroing, changes with cable movement, or produces an unstable baseline only when applied to the patient.
Expected outcome: The problem is identified as an equipment issue, application issue, or intermittent condition requiring further isolation.
3. Verify Monitor Stability
Confirm the Avalon FM20 is powered normally and is not freezing, restarting, or displaying broader channel problems.
Expected outcome: The monitor remains stable during TOCO testing.
4. Inspect the TOCO Transducer
Inspect the transducer housing, sensing surface, cable, strain relief, and connector for cracks, contamination, compression damage, liquid intrusion, or other visible defects.
Expected outcome: The transducer is physically intact and clean. Damaged accessories are removed from use.
5. Check the Connection
Reseat the TOCO connector securely and inspect accessible contacts for contamination or damage. Avoid forcing the connector or manipulating it aggressively.
Expected outcome: The TOCO channel remains continuously recognized after reconnection.
6. Eliminate Positioning and Belt-Tension Effects
Verify that the transducer is positioned appropriately and that the securing belt is not excessively loose or tight. Compare operation with the transducer unloaded and then appropriately applied.
Expected outcome: Baseline behavior is stable when external mechanical pressure and positioning are correct.
7. Repeat the Approved Zeroing Process
With the transducer appropriately positioned and free from unnecessary external pressure or movement, perform the normal accessible zeroing function.
Expected outcome: The channel establishes and maintains a usable baseline. If the baseline remains stable, troubleshooting can stop after functional verification.
8. Test With a Known-Good Compatible TOCO Transducer
Substitute a known-good compatible TOCO transducer on the same monitor. When practical, compare the suspect transducer on another compatible verified monitor.
Expected outcome: The fault follows either the transducer or the monitor connection. Replace a confirmed defective accessory.
9. Perform Functional Verification
Verify that the TOCO channel can be zeroed, responds consistently to appropriate test stimulation or approved functional testing, returns toward baseline, and remains stable during normal cable handling.
Expected outcome: The channel operates consistently without unexplained baseline drift.
10. Escalate Persistent Drift or Zeroing Failure
If a known-good transducer also cannot zero or develops unexplained drift, remove the monitor from service for bench evaluation.
Expected outcome: Equipment with unreliable uterine activity monitoring is prevented from returning to clinical use until evaluated.
If the Problem Persists
External causes involving transducer positioning, belt tension, connector seating, and the accessory itself have been ruled out. Remaining possibilities include the monitor input interface, measurement circuitry, configuration, or another service-level problem.
Remove the monitor from service, label it Out of Service, and send it for repair or bench evaluation. Use appropriate Philips documentation and approved test equipment. Calibration, repair, or configuration work should be performed only by qualified personnel.
Complete applicable TOCO performance testing, alarm checks, and full functional verification before returning the monitor to service. Stopping after external causes have been reasonably ruled out is proper troubleshooting.
Clinical Use Tip
Do not interpret an obviously drifting TOCO baseline as reliable uterine activity; restore monitoring with verified equipment before continuing technical evaluation.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Nursing reported that the TOCO channel could be zeroed but the baseline immediately drifted during monitoring."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the TOCO transducer cable was damaged and the problem followed the transducer to another compatible monitor."
Resolution
What action was taken.
Example:
"Replaced the defective TOCO transducer and verified successful zeroing, stable baseline, and normal channel response."
Helpful Details to Include (If Known)
- Whether zeroing failed or drift occurred afterward
- Transducer condition
- Belt and positioning observations
- Connector condition
- Known-good transducer comparison
- Whether drift occurred unloaded or on the patient
- Response after zeroing
- Final functional-test results
- Final device status
Final Thought
Separate application-related TOCO behavior from equipment failure, compare accessories before assuming an internal problem, and verify a stable baseline before returning the device to clinical use.
That is successful troubleshooting.