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What This Guide Helps With
Troubleshooting unavailable respiratory-gas measurements caused by module seating, sampling components, moisture, blockage, configuration, power, or communication problems.
Step-by-Step Troubleshooting
1. Ensure Patient Safety First
Do not remove, exchange, or troubleshoot the gas module while the Carestation 600 Series is actively supporting a patient unless an approved alternate monitoring plan is established.
If inspired or expired O2, CO2, N2O, or anesthetic-agent measurements are unavailable during a procedure:
- Notify the anesthesia provider immediately.
- Establish approved independent oxygen, capnography, and anesthetic-agent monitoring as applicable.
- Move the patient to another verified anesthesia machine when reliable gas monitoring cannot be maintained.
- Do not rely on estimated gas concentrations.
Expected: Patient care continues with verified ventilation and independent respiratory-gas monitoring.
The airway module measures and monitors gases delivered to and exhaled by the patient, so loss of these measurements is clinically significant.
Once the machine is removed from patient use, continue troubleshooting in a controlled Clinical Engineering environment.
2. Confirm the Exact Failure Condition
Record the complete displayed message and determine whether:
- The gas module is not recognized.
- All gas measurements are unavailable.
- Only CO2, O2, N2O, or anesthetic-agent values are missing.
- Values appear briefly and then disappear.
- Measurements are delayed, unstable, or implausible.
- The problem occurs with one specific module.
- The issue began after cleaning, transport, module replacement, or water-trap replacement.
Expected: The failure is defined as a recognition, sampling, accessory, or measurement problem.
3. Inspect the Gas Module Installation
With the machine out of service:
- Confirm that the airway gas module is fully inserted into the correct module bay.
- Remove and reinstall the module using normal external handling procedures.
- Check that it seats evenly and locks into position.
- Inspect the module housing and bay for bent, cracked, loose, or contaminated external components.
- Do not force the module into place.
Expected: The module is fully seated and is recognized by the Carestation.
If recognition returns and measurements remain stable, complete a full system checkout and stop troubleshooting.
4. Check Module Compatibility
Verify that:
- The installed module is approved for use with the Carestation 600 Series.
- The module provides the gas parameters expected by the clinical department.
- The module is not labeled for another unsupported host or configuration.
- The correct sampling accessories are installed.
Available measurement options can vary by module and host-device configuration.
Expected: A compatible airway module and approved accessories are installed.
5. Inspect the D-Fend Water Trap
Check the water trap for:
- Incorrect installation
- A loose connection
- Cracks or physical damage
- Excessive moisture
- Visible contamination
- An expired or heavily used trap
- A missing internal membrane or damaged sealing surface
Remove and reinstall the water trap. Replace it with a known-good approved water trap when contamination, moisture, age, or damage is suspected.
The water trap protects the respiratory module from water and contaminants. GE guidance also recommends replacement when prompted by the host device.
Expected: The water trap is clean, intact, correctly seated, and the related message clears.
If gas values return and remain accurate, perform checkout and stop.
6. Inspect the Sample Line
Trace the sample line from the airway connection to the water trap.
Check for:
- Kinks
- Crushing
- Disconnection
- Loose fittings
- Moisture
- Secretions or contamination
- Occlusion
- Incorrect tubing
- Damage near either connector
Replace the sample line with a known-good approved line rather than attempting to clear contaminated disposable tubing.
Expected: The sample line is open, dry, correctly connected, and gas measurements appear after the normal sampling delay.
7. Check the Sampling Connection at the Breathing Circuit
Confirm that:
- The sample line is connected to the intended airway sampling port.
- The sampling adapter is not blocked by secretions or condensation.
- The adapter is oriented and assembled correctly.
- Unused sampling ports are capped as required.
- The line is not connected to an inappropriate pressure-monitoring or accessory port.
Expected: The module receives a representative respiratory-gas sample from the breathing circuit.
8. Check the Sample-Gas Return Connection
Inspect the sample-gas return tubing and port, when equipped.
Confirm that:
- The return tubing is connected to the designated return port.
- Tubing is not kinked, blocked, loose, or incorrectly routed.
- The return connection is not confused with the patient sampling connection.
- External tubing does not interfere with module seating.
Expected: Sample gas can return through the intended pathway without restriction.
9. Allow the Module to Initialize
After reseating or replacing the module:
- Power the Carestation normally.
- Allow the module sufficient time to initialize and warm up.
- Observe for recognition, warming, calibration, blocked-line, or water-trap messages.
- Do not judge measurement availability immediately after startup.
Expected: The module completes initialization and begins displaying stable gas values.
10. Review Gas-Monitoring Setup and Display Configuration
Verify that:
- The expected gas waveforms and numeric fields are enabled.
- The correct measurement source is selected.
- Gas monitoring has not been disabled through configuration.
- The module is not being mistaken for an external-monitor measurement source.
- The displayed units and agent identification settings are appropriate.
Expected: Available module measurements are configured to appear on the user interface.
11. Test With Known-Good External Accessories
One component at a time, substitute known-good approved accessories:
- Water trap
- Sample line
- Sampling adapter
- Sample-gas return tubing, when applicable
Do not replace multiple parts simultaneously unless required for contamination control.
Expected: The defective external accessory is isolated.
If replacing one accessory restores normal operation, perform a complete checkout and document the failed component.
12. Test With a Known-Good Compatible Module
If available under facility policy:
- Install a verified compatible airway module.
- Allow it to initialize fully.
- Connect known-good sampling accessories.
- Confirm whether measurements become available.
Interpretation:
- If the known-good module works, the original module likely requires bench evaluation or repair.
- If neither module is recognized, suspect the module bay, host communication, power, or system-level failure.
- If both modules are recognized but cannot sample, continue evaluating the external sampling path and host configuration.
Expected: The failure is isolated to the original module or the Carestation host.
13. Restart the Carestation Safely
With no patient connected:
- Shut down the system using the normal procedure.
- Confirm that the module and accessories are installed correctly.
- Restore power.
- Allow the system and module to complete startup.
- Review all messages and perform the required checkout.
Expected: A temporary communication or initialization fault clears.
If the problem returns, do not repeatedly restart the machine as a substitute for repair.
14. Perform the Approved System Checkout
Run the Carestation’s normal pre-use checkout with:
- The gas module installed
- A clean water trap
- A known-good sample line
- The breathing system assembled correctly
- Appropriate test equipment and gas sources available
Verify:
- Module recognition
- CO2 response
- O2 measurement, when provided by the module
- Agent identification and concentration, when applicable
- Stable waveforms and numeric values
- No blocked-line, water-trap, calibration, or communication messages
Expected: The machine passes checkout and gas measurements are stable and plausible.
Do not return the device to service solely because the message disappeared.
If the Problem Persists
If the module remains unrecognized or gas measurements remain unavailable after checking module seating, compatibility, water trap, sample tubing, airway connections, configuration, startup, and known-good accessories, common external causes have been ruled out.
The issue may involve:
- A failed airway gas module
- Damaged module contacts
- Module-bay power or communication failure
- Internal sampling-pump failure
- Internal contamination
- Calibration failure
- Host-system hardware or software failure
The anesthesia machine should be:
- Removed from service
- Labeled Out of Service
- Sent for qualified repair or bench evaluation
- Evaluated using the applicable GE Healthcare service documentation and approved test equipment
Do not open or internally disassemble the gas module during routine floor troubleshooting.
Knowing when to stop and escalate is proper troubleshooting.
Clinical Use Tip
Never troubleshoot missing gas measurements while the machine is supporting an active patient. Move the patient to verified equipment or establish approved independent gas monitoring before removing modules, changing sampling components, or restarting the system.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Anesthesia staff reported that the Carestation 600 Series did not recognize the airway gas module and displayed no CO2 or anesthetic-agent measurements."
Cause
What was observed during troubleshooting.
Example:
"Inspection found the D-Fend water trap saturated with moisture, preventing normal respiratory-gas sampling."
Resolution
What action was taken.
Example:
"Removed the device from service, replaced the water trap and sample line, verified module recognition and stable gas measurements, and completed the system checkout successfully."
Helpful Details to Include (If Known)
- Exact displayed message
- Gas parameters affected
- Module model or identification
- Module recognized at startup
- Water-trap condition
- Sample line inspected or replaced
- Sampling adapter condition
- Sample-gas return connection checked
- Known-good accessories tested
- Known-good module tested
- Measurement response during checkout
- Calibration or blocked-line messages
- Unusual heat, smell, or sound
- Final device status
Final Thought
Respiratory-gas measurement faults should be approached by protecting the patient first, then checking module seating, water management, sampling accessories, connections, and configuration. Clear documentation and timely escalation prevent an intermittent monitoring problem from returning to clinical use unresolved.
That is successful troubleshooting.