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What This Guide Helps With
Fresh gas flow does not respond as expected because of gas supply, controls, settings, external connections, configuration, or an internal gas-delivery fault.
Step-by-Step Troubleshooting
1. Protect the Patient and Maintain Anesthetic Delivery
If fresh gas delivery cannot be confirmed, do not continue using the affected machine for a patient. Transition to an appropriate verified anesthesia-delivery method before troubleshooting. Expected outcome: The patient remains safely supported by reliable equipment and the affected machine is available for controlled testing.
2. Confirm the Exact Fresh Gas Flow Problem
Record the selected gas mixture and flow condition, displayed values, actual observed response, and any associated messages or alarms. Determine whether the issue affects one gas, multiple gases, only one operating mode, or the entire fresh-gas control function. Expected outcome: The reported failure is clearly defined. If the machine responds normally under controlled testing, investigate setup or intermittent external causes before release.
3. Verify Pipeline Gas Connections
Confirm each required gas hose is connected to the correct machine inlet and wall or ceiling outlet. Inspect hoses and connectors for kinks, damage, looseness, or incorrect connection. Expected outcome: Required pipeline gases are securely and correctly connected. If restoring a supply connection resolves fresh-gas flow, complete system testing.
4. Check for Gas Supply Alarms
Review current machine indicators and alarms for any air, oxygen, or nitrous oxide supply problem that could prevent the requested fresh-gas mixture or flow. Address external supply availability before investigating machine-side flow control. Expected outcome: Required external gas supplies are available without active supply-related faults. If the issue resolves after restoring supply, troubleshooting can stop after final verification.
5. Verify Controls and Selected Settings
Confirm the fresh-gas controls are responsive and that the selected gas mixture, flow mode, and related user settings correspond to the intended test condition. Look for accidental control changes without altering protected configuration. Expected outcome: The machine is configured for the intended fresh-gas delivery. If correcting a user-level setting restores normal operation, complete the system test.
6. Inspect External Gas Path Components
Check externally accessible supply hoses, connectors, and installed gas-delivery accessories for restriction, damage, or incorrect attachment. Do not open internal gas manifolds or attempt internal pneumatic adjustments. Expected outcome: No external restriction or connection fault is found. If replacing an approved damaged external component restores flow, proceed to verification.
7. Test Fresh Gas Delivery With Approved Equipment
Using appropriate anesthesia-machine test equipment and a controlled non-patient setup, verify fresh-gas output and response to normal control changes. Use independent measurement rather than relying only on the machine display. Expected outcome: Fresh gas responds predictably to control changes and independent measurement confirms appropriate delivery. If verified after an external correction, troubleshooting can stop.
8. Repeat the System Test
Run the applicable startup or system test after correcting any supply, connection, or control issue. Expected outcome: The machine completes the system test without gas-delivery faults.
9. Perform Final Functional Verification
Verify fresh-gas control, ventilation, oxygen concentration, applicable alarms, and other gas-delivery functions required by facility procedure. Expected outcome: Fresh gas delivery is stable, controllable, independently verified, and all required return-to-service tests pass.
10. Escalate Persistent Flow-Control Failure
If fresh-gas output remains absent, unstable, or unresponsive after external supplies and controls are verified, remove the machine from service. Expected outcome: A machine with unreliable gas delivery receives qualified service evaluation rather than clinical use.
If the Problem Persists
Pipeline supply, gas hoses, controls, settings, external restrictions, and independent output measurements have been evaluated. Remaining causes may involve an internal gas-mixing system, control valve, flow sensor, pneumatic regulator, electronics, configuration, or other service-level condition. The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate manufacturer documentation and approved test equipment
- Repaired or configured only by qualified personnel
After repair, independently verify fresh-gas delivery and complete all required system, oxygen, ventilation, alarm, and return-to-service testing. Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Do not rely on displayed fresh-gas settings alone when actual gas delivery is in question; confirm output with appropriate test equipment.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Anesthesia staff reported the Drager Atlan A350 would not produce the expected fresh gas flow during room setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the pipeline air hose incompletely connected to the machine."
Resolution
What action was taken.
Example:
"Clinical Engineering secured the gas connection, verified fresh-gas response with approved test equipment, completed the system checks, and returned the machine to service."
Helpful Details to Include (If Known)
- Gas mixture selected
- Fresh gas setting
- Displayed flow condition
- Pipeline connections
- Gas supply alarms
- Hose condition
- Control response
- Independent flow measurement
- System-test results
- Results before and after correction
- Final device status
- Gas mixture selected
- Fresh gas setting
- Displayed flow condition
- Pipeline connections
- Gas supply alarms
- Hose condition
- Control response
- Independent flow measurement
- System-test results
- Results before and after correction
- Final device status
Final Thought
Fresh-gas delivery must be dependable before an anesthesia machine is used clinically. Verify external supplies and controls first, measure actual performance, and escalate any unresolved delivery problem. That is successful troubleshooting.