GE Healthcare Aisys Anesthesia Machine

Asset Type

Anesthesia Machine

Manufacturer

GE Healthcare

Model

Aisys

What This Guide Helps With

This guide addresses situations where the GE Healthcare Aisys anesthesia machine:

• Displays gas delivery or agent concentration errors
• Fails to deliver expected tidal volume due to gas supply issues
• Shows hypoxic guard, low O₂ pressure, or agent delivery alarms
• Does not reach set anesthetic agent concentration

This guide focuses on logical, external checks first—such as gas supply, vaporizers, circuit setup, and configuration—before assuming internal flow sensor or module failure.

Step-by-Step Troubleshooting

Ensure the Patient Is Safely Supported First

• If the issue occurs during a case, immediately transition the patient to manual ventilation or an alternate anesthesia machine.
• Do not continue troubleshooting while actively delivering anesthesia to a patient.

Check Pipeline Gas Supply Pressures

• Verify wall supply pressures (O₂, Air, N₂O as applicable).
• Confirm hoses are securely connected and not kinked.
• Look for low-pressure pipeline alarms on the display.
• If pipeline pressure is low, connect a known-full E-cylinder and observe whether the alarm clears.

Why this matters: Gas delivery errors are commonly caused by supply pressure issues rather than internal machine faults.

Verify Cylinder Status (If Installed)

• Ensure cylinders are open and contain adequate pressure.
• Confirm no slow leaks at the yoke connections.
• Check that the cylinder is not cross-threaded or misaligned.

Confirm Vaporizers Are Properly Seated and Locked

• Remove and reseat the vaporizer if needed.
• Ensure it is fully locked into position.
• Check that only one vaporizer is turned on (unless system allows otherwise).
• Verify adequate agent level in the vaporizer.

An improperly seated vaporizer can trigger agent delivery or concentration errors.

Check Fresh Gas Flow Settings

• Confirm flow settings match clinical intent.
• Ensure O₂ flow is not set extremely low, which may prevent agent from reaching target concentration.
• Observe flow tubes or digital flow indicators for proper response when adjusting settings.

Inspect the Breathing Circuit

• Perform a full leak test per hospital policy.
• Check for loose connections, cracked hoses, faulty CO₂ absorber canister seating, or improperly installed filters.
• Verify APL valve position during manual mode testing.

A significant circuit leak may appear as a delivery issue.

Run the System Self-Test (If Not in Active Case)

• Power cycle the machine (only when patient is off the unit).
• Perform a full checkout test.
• Note any flow sensor, pressure sensor, or internal module errors.
• Document exact error codes for repair reference.

Check for Recent Service or Configuration Changes

• Verify that recent PM, gas module replacement, or software updates did not precede the issue.
• Ensure calibration procedures were completed properly if recently serviced.

Observe for Physical Signs

• Unusual noises from internal gas modules
• Smell of anesthetic agent inside machine housing
• Inconsistent digital flow readings compared to external analyzer

These may indicate internal valve or sensor failure.

If the Problem Persists

If gas supply, vaporizers, circuit integrity, and configuration have been verified and the machine continues to display gas or agent delivery errors, the issue is likely internal. Possible causes include:

• Faulty flow sensors
• Gas module failure
• Internal proportional valve malfunction
• Software or calibration errors

At this point:

• Remove the machine from service
• Label it Out of Service
• Send for qualified repair or bench evaluation

Knowing when to stop prevents unnecessary risk and protects patient safety.

Clinical Use Tip

Never troubleshoot gas delivery issues while the machine is connected to a patient unless transitioning them safely to manual ventilation or a backup machine. Gas delivery errors directly affect oxygenation and anesthetic depth—patient safety always comes first.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
“OR staff reported the Aisys would not reach set Sevoflurane concentration and displayed low agent delivery alarm during induction.”

Cause

What was observed during troubleshooting.

Example:
Pipeline O₂ pressure was found below normal range due to loose wall hose connection. Machine operating normally once pressure restored.

Resolution

What action was taken.

Example:
Re-secured pipeline hose connection, verified proper supply pressure, completed system checkout test, returned unit to service.

Helpful Details to Include in Documentation

• Pipeline pressures verified
• Cylinders checked
• Vaporizers reseated
• Leak test results
• Error codes displayed
• Final system checkout result
• Final device status

Final Thought

Anesthesia machine gas delivery issues must be approached logically—starting with supply and setup before assuming internal failure. Clear thinking, controlled escalation, and proper documentation protect both patients and providers. The goal is safe function, not unnecessary disassembly.

That is successful troubleshooting.