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What This Guide Helps With
Troubleshoots repeated expiratory cassette pre-use check failures caused by cassette installation, contamination, connections, setup, or service-level faults.
Step-by-Step Troubleshooting
1. Protect the Patient and Remove the Ventilator From Clinical Dependency
Do not troubleshoot a ventilator that a patient currently depends on. Transfer ventilation to another verified ventilator or appropriate backup method before beginning technical troubleshooting.
If the expiratory cassette cannot pass the required pre-use verification, do not place the Servo-n into patient service.
Expected outcome: The patient is supported independently and the Servo-n is available for safe troubleshooting.
2. Confirm the Exact Failure
Repeat the approved pre-use check under controlled conditions and identify whether the failure consistently points to the expiratory cassette or expiratory path.
Note when the failure occurs and whether any additional messages appear.
Expected outcome: The reported condition is reproduced and clearly associated with the expiratory cassette portion of the check. If the check now passes normally and remains repeatable, troubleshooting can stop after final verification.
3. Inspect the Expiratory Cassette
Remove the cassette and inspect it externally for:
- Cracks or physical damage
- Liquid or condensate
- Contamination
- Damaged seals or mating surfaces
- Debris around connection points
- Evidence that the cassette was not completely seated
Do not use a visibly damaged or contaminated cassette.
Expected outcome: The cassette is clean, dry as required, undamaged, and suitable for installation.
4. Reinstall the Cassette Correctly
Reinstall the expiratory cassette carefully and verify that it seats fully and locks into position without excessive force.
Inspect the ventilator-side mating area for obvious contamination, damage, or foreign material.
Expected outcome: The cassette installs completely and securely. If the pre-use check passes after reseating, the issue is resolved and troubleshooting can stop after confirming repeatability.
5. Verify the Breathing Circuit and External Connections
Inspect the connected breathing circuit and expiratory pathway for:
- Incorrect assembly
- Occluded tubing
- Kinks
- Open or disconnected ports
- Excessive condensate
- Incorrect accessories
- Loose connections
Use the correct approved circuit configuration for testing.
Expected outcome: The external breathing system is correctly assembled, patent, and free of leaks or obstruction.
6. Test With a Known-Good Compatible Cassette
When available, install a known-good compatible expiratory cassette that is approved for the Servo-n and repeat the pre-use check.
Do not interchange components unless compatibility is established.
Expected outcome: If the known-good cassette passes, the original cassette should be removed from service and processed according to facility and manufacturer requirements. Troubleshooting can stop after successful verification.
7. Check Environmental and Handling Conditions
Confirm the cassette and ventilator have not been exposed to unusual temperature, moisture, cleaning residue, physical impact, or storage conditions that could interfere with the check.
Allow equipment to reach appropriate operating conditions when applicable.
Expected outcome: No environmental or handling condition is interfering with the test.
8. Perform Final Functional Verification
Run the complete required pre-use verification using approved test equipment and the correct circuit configuration.
Do not return the ventilator to service based only on one previously failed test now passing once.
Expected outcome: All required pre-use checks pass consistently and the ventilator is ready for clinical use. Troubleshooting can stop.
If the Problem Persists
Common external causes have been ruled out. A persistent cassette-related pre-use failure may involve the cassette interface, expiratory measurement system, pneumatic pathway, sensor system, or another service-level condition.
The Servo-n should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate Getinge service documentation and approved test equipment
- Repaired or configured only by qualified personnel
Do not bypass the pre-use check or continue into internal pneumatic or electronic repair without appropriate authorization and documentation. After repair, complete all required functional and performance verification before return to service.
Knowing when to stop external troubleshooting and escalate is proper troubleshooting.
Clinical Use Tip
Never place a Servo-n into patient service when the expiratory cassette or required pre-use verification does not pass.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Respiratory Therapy reported that the Servo-n repeatedly failed the pre-use check at the expiratory cassette test."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the expiratory cassette was not fully seated, while the cassette and ventilator interface showed no visible damage."
Resolution
What action was taken.
Example:
"The cassette was removed and correctly reinstalled, the complete pre-use check passed repeatedly, and the ventilator was returned to service."
Helpful Details to Include (If Known)
- Exact pre-use check failure message
- Stage of the check where failure occurred
- Expiratory cassette condition
- Evidence of moisture or contamination
- Circuit configuration
- Result after cassette reseating
- Result with known-good cassette
- Complete pre-use check result
- Final device status
Final Thought
Protect the patient first, verify installation and external conditions before assuming an internal ventilator fault, and escalate when required checks cannot be passed. Document the complaint, confirmed cause, corrective action, and final verification clearly.
That is successful troubleshooting.