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What This Guide Helps With
Gas-channel calibration fails because of sampling obstruction, contamination, unstable gas conditions, consumables, environment, or analyzer service problems.
Step-by-Step Troubleshooting
1. Protect the Patient and Remove Dependence on Unreliable Gas Monitoring
Do not continue clinical use when required CO2, oxygen, or anesthetic-agent monitoring cannot be verified.
Provide alternate monitoring or exchange the anesthesia machine before troubleshooting.
Expected outcome: Patient care does not depend on the affected analyzer.
2. Identify the Failed Measurement Channel
Confirm whether calibration fails for CO2, oxygen, agent measurement, or multiple channels.
Record the exact failure indication and whether the problem occurs immediately or after calibration begins.
Expected outcome: The affected channel or channels are clearly identified.
3. Allow Proper Startup and Stabilization
Verify the machine has completed normal startup and any required analyzer preparation before repeating calibration.
Do not repeatedly cycle or interrupt calibration unnecessarily.
Expected outcome: Calibration is attempted under stable operating conditions.
4. Inspect the Water Trap and Sampling Line
Check for a full or blocked water trap, kinked sampling line, condensation, loose fittings, contamination, or incorrect installation.
Replace questionable consumables with approved compatible components.
Expected outcome: The sampling path is open, dry, and stable. If calibration succeeds afterward, proceed to checkout.
5. Check the Test Environment
Ensure the machine is not sampling contaminated ambient air or residual anesthetic agent from a recently used breathing circuit when the calibration procedure requires a clean or stable reference environment.
Expected outcome: Calibration is performed under appropriate environmental conditions.
6. Verify Breathing-System and Sampling Connections
Inspect the patient cassette, breathing circuit, sample adapter, filters, and analyzer connections for leaks or incorrect assembly.
Expected outcome: Sampling gas reaches the analyzer without leakage or dilution from an external assembly problem.
7. Replace Suspect External Consumables
Substitute known-good water traps, sampling lines, adapters, or other approved analyzer consumables one at a time.
Expected outcome: If calibration succeeds after a specific substitution, the defective consumable is isolated and removed from use.
8. Compare Analyzer Response With Approved Test Gas or Equipment
When applicable under approved manufacturer procedures, verify analyzer response using appropriate reference gas or independent gas-analysis equipment.
Do not create improvised calibration mixtures.
Expected outcome: The analyzer responds predictably to known conditions. A persistent disagreement or inability to calibrate requires service-level evaluation.
9. Repeat the Complete Checkout
After successful calibration, perform the relevant gas-analysis and full anesthesia-machine checkout procedures.
Expected outcome: CO2, oxygen, and agent measurements required for the installed configuration operate normally and remain stable.
10. Escalate Repeated Calibration Failure
If the affected channel will not calibrate after external sampling components, environment, and test setup are verified, stop troubleshooting.
Expected outcome: The machine remains removed from service until qualified service personnel evaluate the analyzer.
If the Problem Persists
Common external sampling, moisture, consumable, setup, and environmental causes have been ruled out. Remaining possibilities include analyzer sensor degradation, internal sampling problems, calibration data, internal pneumatic faults, electronics, or service-level configuration.
The Flow-e should be:
- Removed from service.
- Labeled Out of Service.
- Sent for repair or bench evaluation.
- Evaluated using approved Getinge service documentation, reference materials, and test equipment.
- Calibrated or repaired only by qualified personnel.
Do not manipulate protected calibration values solely to force a passing result.
Return to service only after successful calibration, gas-measurement verification, alarms, and complete machine checkout.
Clinical Use Tip
A gas value that cannot be calibrated should be considered unreliable even if the displayed number appears clinically reasonable.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Anesthesia staff reported that the Flow-e oxygen measurement would not complete calibration during checkout."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found moisture and partial obstruction in the analyzer sampling line."
Resolution
What action was taken.
Example:
"Replaced the affected sampling components, successfully completed gas calibration and full checkout, and verified stable oxygen measurement before return to service."
Helpful Details to Include (If Known)
- Failed gas channel
- Exact calibration indication
- Water-trap condition
- Sampling-line condition
- Environmental conditions
- Known-good consumables tested
- Independent analyzer comparison
- Calibration result
- Checkout result
- Final device status
Final Thought
Verify the sampling system and calibration conditions before suspecting the analyzer itself, never accept an uncalibrated gas measurement for clinical use, and escalate when reliable calibration cannot be demonstrated.
That is successful troubleshooting.