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What This Guide Helps With
Troubleshoot CO2 detection or zeroing failures caused by sensor condition, contamination, cables, adapters, connections, environment, or service-level module faults.
Step-by-Step Troubleshooting
1. Protect the Patient and Provide Alternate CO2 Monitoring
If CO2 monitoring is clinically required and the Evita XL cannot provide reliable values, use another verified CO2 monitoring method before troubleshooting.
Do not allow an unreliable CO2 display to guide clinical decisions.
Expected outcome: Required patient CO2 monitoring continues through a verified alternate method.
2. Confirm the Exact CO2 Problem
Determine whether the CO2 module is absent from the display, intermittently detected, unable to zero, producing unstable values, or generating a sensor-related message.
Reproduce the condition without patient dependence.
Expected outcome: The exact failure mode is identified and documented.
3. Inspect the CO2 Sensor and Cable
Inspect the external CO2 sensor, cable, connectors, and any airway adapter for damage, contamination, moisture, loose connections, or mechanical strain.
Do not open or repair the sensor or module.
Expected outcome: All accessible components are clean, dry, intact, and securely connected. If correcting a connection restores detection, continue with zeroing and functional verification.
4. Inspect the Airway Adapter or Sampling Interface
Check the applicable CO2 airway interface for contamination, condensation, secretions, cracked surfaces, or incorrect installation.
Replace contaminated or damaged disposable accessories as appropriate.
Expected outcome: The CO2 measurement path is clean and correctly installed. If the sensor now zeros and reads normally, troubleshooting can stop after verification.
5. Provide Appropriate Zeroing Conditions
Follow the approved normal procedure for zeroing the connected CO2 system. Ensure the sensor or measurement interface is in the proper environment for the zero procedure and is not exposed to an unintended gas source.
Do not improvise calibration gases or service procedures.
Expected outcome: Zeroing completes successfully. If it does and readings remain stable, continue to functional verification.
6. Substitute Known-Good External Components
When available, test with a known-good compatible CO2 sensor, cable, and adapter one component at a time.
Expected outcome: Successful detection and zeroing with a known-good component identifies the defective external accessory. Replace it and stop troubleshooting after verification.
7. Confirm CO2 Response
After successful zeroing, use an appropriate approved simulator or test method to confirm that the CO2 channel responds and displays plausibly.
Avoid relying solely on the absence of an error message.
Expected outcome: The CO2 channel responds consistently during verification. If successful, troubleshooting can stop.
8. Check for Intermittent Connection Problems
Gently inspect normal cable movement and connector strain during testing to determine whether detection is lost intermittently.
Expected outcome: The CO2 module remains continuously detected during normal handling. An intermittent sensor or cable should be replaced rather than returned to use.
9. Escalate Persistent CO2 Detection or Zeroing Failure
If known-good external sensors, cables, adapters, connections, and appropriate zeroing conditions do not resolve the problem, stop external troubleshooting.
The fault may involve the internal module interface, power, communications, or measurement electronics.
Expected outcome: The ventilator is removed from service when CO2 functionality is required and routed for qualified evaluation.
If the Problem Persists
External sensor condition, cable integrity, airway interface, zeroing environment, and known-good substitutions have been ruled out.
Remove the Evita XL from service if the CO2 function is required for its intended use, label it Out of Service, and send it for repair or bench evaluation. Use appropriate Drager documentation and approved test equipment. Internal CO2 interface or module repairs should be performed only by qualified personnel.
After repair, verify module detection, zeroing, measurement response, alarms where applicable, and all required return-to-service testing.
Clinical Use Tip
When ventilator-integrated CO2 monitoring is unavailable, establish another verified monitoring method before the patient depends on the affected ventilator.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Respiratory Therapy reported that the Evita XL recognized the CO2 sensor but repeatedly failed the zero procedure."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found condensation and contamination on the external CO2 airway adapter."
Resolution
What action was taken.
Example:
"The adapter was replaced, the CO2 system zeroed normally, measurement response was verified, and the ventilator was returned to service."
Helpful Details to Include (If Known)
- Exact CO2 message
- Sensor detection status
- Sensor and cable condition
- Airway adapter condition
- Presence of moisture or contamination
- Zeroing conditions
- Known-good component substitutions
- CO2 response after correction
- Final device status
Final Thought
Maintain alternate monitoring when CO2 reliability is uncertain, inspect the external sensor pathway carefully, verify successful zeroing and response before assuming an internal failure, and escalate unresolved module problems appropriately.
That is successful troubleshooting.