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What This Guide Helps With
Troubleshooting weak, excessive, or restricted anesthetic-gas evacuation caused by hose routing, connections, AGSS terminal suction, accessories, or receiving-system faults.
Step-by-Step Troubleshooting
1. Ensure Patient Safety First
Do not perform extended scavenging troubleshooting while the Perseus is supporting an active patient.
If evacuation is inadequate, anesthetic odor is present, or the scavenging flow indicator is outside its acceptable range:
- Notify the anesthesia provider immediately.
- Transfer ventilation and anesthesia delivery to another verified anesthesia machine when clinically appropriate.
- Follow facility procedures for minimizing staff exposure to waste anesthetic gas.
Expected: Patient care continues on functioning equipment, and personnel are not unnecessarily exposed to anesthetic gas.
If another device is placed into service, continue troubleshooting only in a controlled Clinical Engineering setting.
2. Confirm the Exact Failure Condition
Determine what was reported or observed:
- Flow indicator below the restricted range
- Flow indicator within the restricted range but not normal
- Flow indicator above the normal range
- No visible flow-indicator movement
- Anesthetic odor near the machine
- Failed pre-use or system-test scavenging check
- Weak suction reported at the AGSS terminal
- Scavenging hose repeatedly disconnecting
Record whether the problem is constant or occurs only when the machine is moved.
Expected: The complaint is clearly identified before components are replaced.
3. Verify the AGS and Wall-Terminal Connections
Confirm that:
- The scavenging hose is fully connected to the Perseus anesthetic gas receiving system.
- The opposite end is completely inserted into the correct AGSS terminal.
- The terminal indicates that the connector is properly engaged, when applicable.
- The hose is secured by the machine’s strain relief.
- No connection is loose, partially inserted, or attached to an incorrect outlet.
An incorrectly connected disposal system can allow anesthetic gas to enter the surrounding area.
Expected: Both ends remain securely connected and evacuation flow is restored.
If the indicator returns to its normal range, complete the system checkout and stop troubleshooting.
4. Inspect the Scavenging Hose and Routing
Examine the complete hose for:
- Kinks or sharp bends
- Compression beneath the machine or caster
- Damage, cracks, or soft collapsed sections
- Liquid or visible contamination
- Obstruction at either connector
- Excessive tension caused by moving the machine
- Unauthorized adapters or extensions
Reposition the machine and route the hose without restricting its diameter.
Expected: The hose remains open and unrestricted throughout its entire length.
If correcting the routing restores normal flow, secure the hose properly and stop.
5. Test With a Known-Good Approved Hose
When available, substitute a compatible, known-good scavenging hose.
Do not use tubing or adapters that have not been approved for the machine and facility AGSS configuration.
Expected:
- If normal evacuation returns, replace the original hose.
- If the condition remains unchanged, continue isolating the wall terminal and machine-side receiving system.
6. Observe the Perseus AGS Flow Indicator
Activate the facility scavenging system according to the approved checkout process and observe the AGS flow indicator.
During normal operation and system testing, the indicator should remain within the marked normal range.
Interpret abnormal positions as follows:
- Below the restricted range: Insufficient AGSS terminal suction, a restricted hose, or a contaminated or blocked AGS filter may be present.
- Above the normal range: AGSS terminal suction may be excessive, or the receiving-system filter may be missing or incorrectly installed.
Expected: The flow indicator remains stable within the normal marked range.
Do not adjust a medical-gas pipeline terminal or ejector unless authorized and qualified to service that system.
7. Isolate the Facility AGSS Terminal
Test the wall or ceiling AGSS terminal according to facility policy.
Possible isolation methods include:
- Connecting the machine to another verified AGSS terminal
- Testing the original terminal with an approved flow-testing device
- Comparing its performance with a nearby functioning anesthesia workstation
- Requesting evaluation by Facilities or the medical-gas pipeline service provider
Expected:
- If the fault follows the terminal, remove that terminal or room from use and notify the responsible department.
- If the machine remains abnormal on a verified terminal, continue machine-side evaluation.
Do not return the machine to the original location merely because it operates normally at another outlet. The defective terminal must also be documented and corrected.
8. Inspect the External AGS Assembly
Visually inspect the receiving-system assembly for:
- Cracks or physical damage
- Loose mounting
- Evidence of fluid intrusion
- Missing external components
- Improper seating after cleaning or reprocessing
- Signs that the filter or AGS assembly was recently disturbed
Do not perform internal disassembly or attempt to clean an inaccessible restriction unless permitted by approved service procedures.
Expected: The AGS assembly is complete, secure, clean, and undamaged.
A suspected blocked or missing internal filter requires replacement of the appropriate AGS component or evaluation by qualified service personnel.
9. Perform the Approved System Checkout
After correcting the suspected cause:
- Reconnect the approved scavenging hose.
- Confirm that the AGSS terminal is active.
- Verify that the flow indicator remains in the normal range.
- Run the Perseus system test or approved pre-use checkout.
- Check for unusual noise, hose collapse, disconnection, or anesthetic odor.
- Confirm that moving the machine does not recreate the restriction.
Expected: The machine completes its checkout with stable scavenging flow and no evidence of waste-gas leakage.
If all testing passes, return the device to service according to department policy.
If the Problem Persists
If the hose, connections, routing, accessories, and facility AGSS terminal have been verified, the fault may involve the integrated receiving system, filter, mounting assembly, or another internal scavenging component.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for bench evaluation or qualified repair
- Evaluated using the applicable Drager service documentation and test equipment
A machine must not be returned to clinical use with an unstable flow indicator, persistent anesthetic odor, failed system test, or unresolved evacuation concern.
Knowing when to stop external troubleshooting and escalate the equipment is proper Clinical Engineering practice.
Clinical Use Tip
Never troubleshoot an unresolved scavenging problem during active anesthesia unless directed by the anesthesia provider as part of an immediate patient-safety response. Move the patient to another verified anesthesia system before extended testing.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Anesthesia staff reported weak scavenging, and the Perseus AGS flow indicator remained below the restricted range."
Cause
What was observed during troubleshooting.
Example:
"The AGSS suction hose was compressed behind the rear caster, restricting waste-anesthetic-gas evacuation."
Resolution
What action was taken.
Example:
"Rerouted and secured the hose, verified the flow indicator remained in the normal range, completed the system checkout, and returned the machine to service."
Helpful Details to Include (If Known)
- AGS flow-indicator position
- Anesthetic odor reported or observed
- Machine-side hose connection checked
- AGSS terminal connection checked
- Hose inspected for kinks or collapse
- Known-good hose tested
- Alternate AGSS terminal tested
- Facilities or medical-gas service notified
- System-test result
- Unusual sounds or excessive suction
- Final device and room-terminal status
Final Thought
Scavenging problems can expose personnel to waste anesthetic gas and may originate from either the machine or the facility AGSS. Logical isolation, safe patient transfer, appropriate escalation, and complete CCR documentation protect both patients and staff.
That is successful troubleshooting.