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What This Guide Helps With
Troubleshoots unstable scavenging pressure or reservoir bag behavior caused by tubing, connections, obstruction, suction, setup, or external scavenging-system problems.
Step-by-Step Troubleshooting
1. Protect the Patient and Maintain Anesthesia Support
If the scavenging problem is occurring during a case and could affect ventilation, breathing-system pressure, or safe removal of waste anesthetic gas, transfer support to an alternate verified method or anesthesia machine before troubleshooting.
Do not disconnect or manipulate the active breathing system while the patient depends on the machine.
Expected outcome: Patient care remains uninterrupted and troubleshooting can be performed without affecting ventilation or anesthesia delivery.
2. Confirm the Exact Scavenging Complaint
Determine whether the reported problem is:
- Excessive scavenging suction
- Insufficient scavenging suction
- A reservoir bag that remains collapsed
- A reservoir bag that stays excessively inflated
- A bag that repeatedly expands and collapses abnormally
- A condition that appears only when the central scavenging connection is attached
Observe the system under controlled non-patient conditions.
Expected outcome: The specific abnormal behavior is reproduced or the system operates normally. If normal operation is verified and the original condition cannot be reproduced, document the findings and stop troubleshooting.
3. Inspect the Scavenging Tubing and Connections
Inspect the external scavenging pathway from the anesthesia machine to the facility connection.
Look for:
- Disconnected tubing
- Loose fittings
- Kinks or compression
- Collapsed tubing
- Obvious blockage
- Damaged connectors
- Tubing routed incorrectly
- A connection accidentally made to an incorrect wall outlet or hose
Correct any obvious external problem.
Expected outcome: Tubing is intact, unobstructed, properly routed, and securely connected. If correcting the connection restores stable scavenging operation, troubleshooting can stop after functional verification.
4. Inspect the Scavenging Reservoir Bag
Check that the reservoir bag is properly installed and not:
- Torn
- Punctured
- Stiff or deteriorated
- Twisted
- Improperly seated
- Restricted by nearby equipment
Substitute a compatible known-good bag when appropriate.
Expected outcome: The reservoir bag can expand and collapse normally without leakage or mechanical restriction. If a known-good bag restores normal behavior, replace the defective accessory and stop troubleshooting after verification.
5. Isolate the Machine From the Facility Scavenging Source
Under safe non-patient conditions, compare scavenging behavior with and without the external facility scavenging connection when permitted by the equipment configuration and facility procedure.
If the abnormal behavior appears only when connected to the building scavenging system, investigate the external suction source, wall connection, or infrastructure rather than assuming an anesthesia-machine failure.
Expected outcome: The comparison identifies whether the problem follows the machine or the facility scavenging connection.
6. Verify the External Scavenging Source
Confirm that the connected scavenging outlet or suction source is available and functioning normally.
Compare with:
- Another known-good scavenging outlet
- Another anesthesia machine connected to the same infrastructure
- A verified alternate room connection when practical
Do not alter facility regulators or infrastructure settings without authorization.
Expected outcome: The external scavenging source provides normal operation. If the problem is isolated to the facility system, remove the affected outlet from use as appropriate and escalate to Facilities or the responsible infrastructure team.
7. Inspect Accessible Scavenging Controls and Interfaces
Inspect externally accessible scavenging controls, indicators, adjustment mechanisms, and connections for:
- Incorrect positioning
- Physical damage
- Binding
- Contamination
- Loose external components
Return user-adjustable controls to the approved operating configuration using manufacturer documentation.
Expected outcome: External scavenging controls move normally and are correctly configured. If correction restores stable operation, troubleshooting can stop after verification.
8. Verify Breathing-System Conditions Are Not Mimicking a Scavenging Fault
Confirm that the breathing circuit, bag, APL valve position, gas flows, and other externally accessible breathing-system components are appropriately configured for the test.
An unrelated breathing-system leak or pressure condition can be mistaken for a scavenging problem.
Expected outcome: The breathing system is correctly assembled and the scavenging abnormality can be evaluated independently.
9. Perform Final Functional Verification
Reconnect the machine in its normal approved configuration and perform the applicable pre-use or functional checks specified by the manufacturer.
Verify:
- Stable scavenging behavior
- Normal reservoir bag response
- No abnormal breathing-system pressure effects
- No unintended leaks
- No persistent alarms or abnormal indications
Expected outcome: Scavenging operates normally throughout the functional check. If all checks pass, troubleshooting is complete.
10. Remove From Service if the Problem Remains
If scavenging pressure remains abnormal, the bag cannot stabilize, or safe scavenging operation cannot be verified, stop external troubleshooting.
Expected outcome: The machine is removed from clinical availability rather than returned to service with an unresolved scavenging problem.
If the Problem Persists
Common external causes such as tubing, reservoir bag condition, connections, setup, room scavenging source, and accessible controls have been ruled out.
The remaining problem may involve an internal scavenging component, pressure-regulating mechanism, internal obstruction, configuration issue, or facility infrastructure condition that requires service-level evaluation.
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
Complete the appropriate anesthesia-machine performance and return-to-service testing before clinical use.
Knowing when to stop external troubleshooting and escalate is proper troubleshooting.
Clinical Use Tip
Do not troubleshoot unstable scavenging on an anesthesia machine while a patient depends on it; maintain ventilation and anesthesia using a verified alternative first.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Anesthesia staff reported that the Aespire scavenging reservoir bag remained collapsed and would not stabilize during setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the external scavenging hose kinked behind the machine, restricting the scavenging pathway."
Resolution
What action was taken.
Example:
"Repositioned the hose, verified secure connections and normal reservoir bag movement, and completed functional testing with normal scavenging operation."
Helpful Details to Include (If Known)
- Reservoir bag behavior
- Whether the problem was high or low scavenging pressure
- Room and scavenging outlet used
- Condition of scavenging tubing
- Connection status
- Known-good outlet comparison
- Known-good reservoir bag substitution
- Behavior with external scavenging connected and disconnected
- Breathing-system configuration
- Final functional-test result
- Final device status
Final Thought
Protect the patient first, then work from the external scavenging pathway toward the machine. Verify tubing, connections, accessories, infrastructure, and configuration before suspecting an internal fault, and document both the cause and final verification clearly.
That is successful troubleshooting.