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What This Guide Helps With
Troubleshoots unavailable CO2 monitoring, module recognition, sampling accessories, blocked or wet sample paths, loose connections, and missing capnograms.
Step-by-Step Troubleshooting
1. Protect the Patient and Maintain Ventilation Monitoring
If capnography is clinically required and unavailable, provide another verified method of ventilation monitoring before troubleshooting.
Do not troubleshoot an unreliable CO2 channel while a patient depends on it.
Expected outcome: Required patient ventilation monitoring continues using reliable equipment.
2. Confirm the Exact CO2 Complaint
Determine whether:
- The CO2 module or parameter is not recognized
- The CO2 value is absent
- No capnogram is displayed
- Sampling does not appear to occur
- The waveform is intermittent
- The problem follows a particular sampling set or module
- A status or alarm message is displayed
Expected outcome: The problem is separated into module recognition, sampling-path, or signal-acquisition categories.
3. Inspect and Reseat External CO2 Connections
Inspect accessible CO2 module and cable connections for:
- Loose seating
- Damaged connectors
- Bent contacts
- Cracks
- Contamination
- Cable strain or damage
Reseat connections according to normal approved operating arrangements.
Expected outcome: The CO2 hardware is securely connected and recognized.
If reseating restores the parameter and normal capnogram, proceed to final verification.
4. Inspect the Sampling Accessories
For sidestream configurations, inspect the external sample line, airway adapter, water-management components, and other disposable sampling accessories as applicable.
Check for:
- Kinks
- Disconnections
- Visible moisture
- Occlusion
- Cracks
- Loose fittings
- Incorrectly assembled accessories
Do not attempt to clear single-use tubing with unapproved methods.
Expected outcome: The external sampling path is dry, open, correctly assembled, and securely connected.
If replacing an obstructed or wet disposable accessory restores the capnogram, proceed to final verification.
5. Confirm Compatible Accessories
Verify that CO2 sampling accessories or sensor components are approved for the installed CO2 monitoring configuration.
Do not assume that visually similar sampling accessories are interchangeable.
Expected outcome: Compatible CO2 accessories are installed.
6. Allow Appropriate Initialization
After reconnecting an appropriate CO2 module or sampling system, allow the parameter to initialize normally.
Observe whether status indicators progress to a usable monitoring condition without repeated disconnection.
Expected outcome: The CO2 parameter becomes available and remains recognized.
If recognition is restored and stable, continue with signal verification.
7. Substitute Known-Good External Components
When available, substitute compatible known-good components such as:
- Sampling line
- Airway adapter or external sensor component
- External module cable
- CO2 module, if it is a user-removable approved module and substitution is within Clinical Engineering scope
Change one item at a time.
Expected outcome: The problem follows a specific replaceable accessory or module, or remains with the monitor.
If a replaceable external item is confirmed faulty, replace it and continue to final verification.
8. Test With Approved CO2 Test Equipment
Off-patient, use approved test equipment or a controlled test method appropriate for the CO2 configuration.
Verify:
- Parameter recognition
- Capnogram presence
- Stable numeric display
- Appropriate response to the test input
- No recurrent loss of recognition
Do not attempt unauthorized calibration or adjustment.
Expected outcome: The monitor produces a stable CO2 waveform and value from a controlled input.
9. Inspect the Accessible Monitor Interface
Inspect the accessible module bay, input connector, or cable interface involved with CO2 monitoring for physical damage, contamination, or looseness.
Do not disassemble the monitor or module to repair internal connectors.
Expected outcome: The monitor-side interface appears intact and mechanically secure.
10. Perform Final Functional Verification
After correction, verify:
- CO2 parameter recognition
- Stable capnogram
- Stable numeric display with approved testing
- Secure sampling connections
- No obstruction or moisture condition
- Appropriate CO2 alarms using an approved test method
Expected outcome: CO2 monitoring is stable and suitable for return to clinical service.
If all checks pass, document and return the monitor to service.
11. Escalate Persistent CO2 Failure
If compatible known-good accessories and approved testing do not restore module recognition or capnogram acquisition, stop external troubleshooting.
Expected outcome: The affected monitor or module is removed from service for qualified evaluation.
If the Problem Persists
Sampling accessories, module seating, external interfaces, compatibility, and known-good test inputs have been evaluated. Remaining possibilities may include internal module failure, monitor-module communication, sampling pump or sensing components, configuration, or another service-level condition.
The affected equipment should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate GE Healthcare documentation and approved test equipment
- Repaired, calibrated, or configured only by qualified personnel
After repair, verify parameter recognition, capnogram acquisition, numeric response, alarms, and required overall monitor functions.
Knowing when the external CO2 path has been ruled out and service-level evaluation is required is proper troubleshooting.
Clinical Use Tip
A numeric EtCO2 value without a dependable capnogram should not be treated as complete verification of the capnography channel.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Respiratory staff reported that the B125 monitor showed no capnogram despite the CO2 parameter being available."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the external CO2 sample line was occluded and confirmed normal operation with a known-good sampling line."
Resolution
What action was taken.
Example:
"Replaced the occluded sample line, verified a stable capnogram and CO2 value with approved testing, confirmed alarm operation, and returned the monitor to service."
Helpful Details to Include (If Known)
- Exact CO2 status or message
- Whether the module was recognized
- Sampling line condition
- Visible moisture or occlusion
- Accessory compatibility
- Module or cable seating
- Known-good substitutions
- Controlled CO2 test result
- Capnogram behavior
- Alarm verification
- Results before and after correction
- Final device status
Final Thought
Maintain required ventilation monitoring, inspect the entire external CO2 sampling and connection path before assuming internal failure, and use compatible known-good components to isolate the cause. Escalate persistent module or acquisition failures and clearly document verification.
That is successful troubleshooting.