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What This Guide Helps With
Displayed flow or volume values are missing, inconsistent, or inaccurate because of circuit, leak, cassette, accessory, moisture, or sensing-related problems.
Step-by-Step Troubleshooting
1. Protect the Patient and Maintain Ventilation
If displayed flow or volume measurements appear unreliable during patient ventilation, move the patient to another verified ventilator or provide appropriate backup ventilation before troubleshooting.
Expected outcome: The patient is no longer dependent on potentially inaccurate monitoring or delivery measurements.
2. Confirm the Measurement Problem
Using an appropriate test lung, reproduce the reported condition and record whether the problem involves:
- No displayed volume
- Unexpected tidal volume
- Unstable measurements
- Large inspired-versus-expired discrepancy
- Flow-related warning
- Pre-use test failure
Expected outcome: The exact measurement problem is confirmed under controlled conditions.
3. Inspect the Patient Circuit for Leaks
Check the entire external breathing circuit for loose connections, cracks, open ports, poorly seated accessories, disconnected sampling components, or other obvious leaks.
Verify the test lung connection is secure.
Expected outcome: The circuit is intact and leak-free externally. If correcting a leak restores stable measurements, troubleshooting can stop after verification.
4. Inspect for Obstruction and Moisture
Inspect the circuit, filters, water traps, humidification components, and accessible expiratory path for excessive condensate, blockage, or kinked tubing.
Correct external obstructions and remove accumulated moisture according to approved practice.
Expected outcome: Gas can flow freely through the external circuit without obstruction or excessive moisture.
5. Verify the Expiratory Cassette
Confirm the expiratory cassette is correctly installed, clean, dry, undamaged, and recognized by the ventilator.
If available, compare operation using a known-good compatible cassette.
Expected outcome: The cassette is not causing the flow or volume measurement problem.
6. Verify Circuit and Accessory Configuration
Confirm installed circuit components and accessories are appropriate for the intended setup and are assembled consistently with the configuration being tested.
Do not change restricted service settings.
Expected outcome: The physical breathing system and accessible configuration correspond correctly.
7. Repeat the Approved Pre-Use Check
Run the complete manufacturer-approved pre-use check after external corrections.
Expected outcome: Circuit integrity and measurement-related checks complete successfully. If the pre-use check passes and displayed measurements are stable, troubleshooting can stop.
8. Compare Against an Approved External Test Device
Using an appropriate ventilator analyzer or other approved test equipment, compare delivered and displayed ventilation under controlled test conditions.
Do not infer an internal sensor failure from bedside observations alone.
Expected outcome: Displayed and externally measured performance are acceptably consistent for return-to-service purposes under the approved test procedure.
9. Perform Final Functional Verification
Verify stable pressure, volume, respiratory rate, alarms, and other applicable displayed parameters using a test lung.
Expected outcome: Flow and volume measurements remain stable and repeatable throughout testing.
10. Escalate Persistent Measurement Errors
If measurements remain missing, unstable, or inconsistent after external causes are ruled out, stop troubleshooting.
Expected outcome: The ventilator remains out of service pending qualified evaluation.
If the Problem Persists
External leaks, circuit obstruction, moisture, accessory setup, cassette seating, and configuration have been evaluated. Remaining causes may involve internal flow sensing, pneumatic pathways, calibration, electronics, or related service-level systems.
The ventilator should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate Getinge documentation and approved test equipment
- Repaired or calibrated only by qualified personnel
Complete applicable performance and safety testing before return to service. Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Do not rely on suspect displayed tidal volume or minute volume values for patient management while investigating a measurement problem.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Respiratory Therapy reported unstable tidal-volume readings on the Servo-c during setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found a loose breathing-circuit connection creating an external leak."
Resolution
What action was taken.
Example:
"The connection was secured, the pre-use check passed, and stable volume measurements were confirmed with a test lung and approved analyzer."
Helpful Details to Include (If Known)
- Reported flow or volume symptom
- Alarm or message displayed
- Circuit leak findings
- Moisture or obstruction
- Expiratory cassette condition
- Accessories installed
- Known-good substitutions
- External analyzer result
- Pre-use check result
- Final device status
Final Thought
Patient safety comes first. Verify the complete external breathing path and cassette before assuming a sensing failure, confirm correction with approved testing, and escalate unresolved measurement errors.
That is successful troubleshooting.