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What This Guide Helps With
Troubleshoot inadequate scavenging or unintended breathing-system pressure by checking hoses, disposal connections, reservoir behavior, obstruction, positioning, and facility suction.
Step-by-Step Troubleshooting
1. Protect the Patient From Abnormal Circuit Pressure
Do not troubleshoot a scavenging problem while a patient remains dependent on an anesthesia system experiencing unexplained pressure rise or unreliable gas disposal.
Move the patient to another verified anesthesia machine or establish the facility-approved alternate ventilation and anesthesia method before continuing.
If excessive pressure, impaired ventilation, or a significant waste-gas leak is suspected, immediately remove the affected machine from clinical use.
Expected outcome: The patient is supported safely and troubleshooting can proceed without exposing the patient to abnormal circuit pressure.
2. Confirm the Exact Scavenging Complaint
Determine whether staff observed:
- Inadequate waste-gas removal
- Scavenging reservoir bag staying excessively full
- Reservoir bag remaining collapsed
- Breathing-system pressure rising unexpectedly
- Scavenging hose repeatedly disconnecting
- Strong anesthetic odor in the room
- Problem only in one room or at one wall connection
Record the conditions under which the problem occurs.
Expected outcome: The failure is reproduced or clearly characterized as inadequate scavenging, excessive suction, obstruction, or a possible infrastructure issue.
3. Inspect the Scavenging Hose Routing
Trace the complete external AGSS/scavenging path from the anesthesia machine to the disposal connection.
Check for:
- Kinks
- Compression by wheels or equipment
- Tight bends
- Collapsed tubing
- Disconnected sections
- Incorrect routing
- Excessively stretched hose
- Foreign material or visible obstruction
Expected outcome: The scavenging pathway is open, properly routed, and securely connected.
If correcting a kink or disconnected hose restores normal scavenging behavior, complete final verification and stop troubleshooting.
4. Verify the Correct Disposal Connection
Confirm the scavenging hose is attached to the appropriate waste-anesthetic-gas disposal connection and not an unrelated vacuum, suction, or gas outlet.
Verify the connection is fully seated and appropriate for the installed scavenging arrangement.
Expected outcome: The A7 is connected to the intended facility scavenging infrastructure.
5. Inspect the External Scavenging Assembly
Inspect accessible scavenging components for:
- Cracked tubing
- Loose fittings
- Damaged reservoir components
- Debris
- Obvious obstruction
- Improperly installed components
- Signs of liquid contamination
Do not disassemble internal valves or regulators beyond approved external inspection.
Expected outcome: External scavenging components are intact, correctly assembled, and free of visible obstruction.
6. Observe Reservoir Behavior
With the machine removed from patient use and set up according to approved test procedures, observe scavenging reservoir behavior.
A reservoir that remains excessively distended may indicate inadequate disposal flow or downstream restriction. A reservoir that remains fully collapsed may suggest excessive suction or an incorrectly configured external scavenging source.
Do not compensate for abnormal scavenging by making unauthorized internal adjustments.
Expected outcome: Reservoir behavior is consistent with stable waste-gas removal and does not contribute to breathing-system pressure abnormalities.
7. Verify Facility Scavenging Availability
Determine whether the facility AGSS or disposal source is functioning correctly at the exact location.
Compare with another verified connection or have the infrastructure checked using the facility-approved process.
If multiple machines exhibit the same problem at one room connection, prioritize infrastructure investigation.
Expected outcome: The facility disposal source is confirmed available and functioning normally at the affected location.
If the infrastructure is deficient, stop troubleshooting the A7 and escalate the room or facility system.
8. Compare With Known-Good External Components
Where appropriate, substitute a known-good compatible scavenging hose or external accessory.
If practical, compare machine behavior on a verified disposal connection.
Change only one variable at a time.
Expected outcome: The problem is isolated to an external accessory, room infrastructure, or the anesthesia machine.
9. Check for Breathing-System Pressure Normalization
After any external correction, verify that breathing-system pressure no longer rises unexpectedly during approved non-patient functional testing.
Confirm:
- Scavenging path remains open
- Reservoir behavior is appropriate
- No abnormal gas buildup occurs
- No persistent scavenging warnings remain
- No obvious waste-gas leakage is present
Expected outcome: Scavenging remains stable without adversely affecting breathing-system pressure.
If these conditions are consistently met and required tests pass, troubleshooting can stop.
10. Perform Final Functional Verification
Complete the applicable manufacturer and facility anesthesia-machine pre-use or return-to-service checks.
Include verification of the breathing system, scavenging function, leak integrity, alarms, and pressure behavior as applicable.
Expected outcome: The A7 passes the required functional checks without abnormal pressure rise or scavenging malfunction.
11. Escalate an Unresolved Scavenging Problem
Remove the machine from service if:
- Facility scavenging has been independently verified
- External hoses and accessories are known good
- Scavenging remains inadequate
- Breathing-system pressure continues to rise
- Reservoir behavior remains abnormal
- Waste-gas leakage persists
Expected outcome: The machine remains unavailable until the gas-disposal and breathing-system interaction can be evaluated safely.
If the Problem Persists
Common external causes involving disconnected or kinked tubing, wrong disposal connections, damaged accessories, obstructed external components, and facility scavenging problems have been ruled out.
The remaining condition may involve internal scavenging control, breathing-system interaction, internal restriction, pressure regulation, or another service-level pneumatic issue. Do not identify a specific internal valve or component without manufacturer-supported testing.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate Mindray documentation and approved test equipment
- Repaired or configured only by qualified personnel
Complete required breathing-system, leak, scavenging, pressure, alarm, and anesthesia-machine functional testing before return to service.
Knowing when to stop external troubleshooting when circuit pressure may be affected is proper troubleshooting.
Clinical Use Tip
Unexpected pressure rise associated with scavenging should be treated as a patient-safety issue; move the patient to verified equipment before investigating the gas-disposal path.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported that the Mindray A7 scavenging reservoir remained full and breathing-system pressure increased during setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the external scavenging hose compressed beneath the anesthesia machine caster."
Resolution
What action was taken.
Example:
"Clinical Engineering rerouted the hose, verified normal reservoir behavior and breathing-system pressure, and completed functional testing successfully."
Helpful Details to Include (If Known)
- Exact scavenging complaint
- Whether breathing-system pressure increased
- Reservoir bag behavior
- Hose routing and condition
- Disposal connection used
- Anesthetic odor or visible leakage
- Facility AGSS verification result
- Known-good hose comparison
- Alternate disposal connection result
- Findings before and after correction
- Final leak and functional-check results
- Final device status
Final Thought
Protect the patient first, inspect the complete external scavenging path before assuming an internal fault, verify the facility disposal source, and remove the machine from service whenever abnormal scavenging can affect breathing-system pressure.
That is successful troubleshooting.