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 ventilator:

• Is not delivering the set tidal volume
• Displays low exhaled volume
• Shows volume discrepancy alarms
• Appears to cycle without adequate chest rise

This guide focuses on logical, external checks first—especially circuit integrity, gas supply, settings, and user setup—before assuming internal ventilator failure.

Step-by-Step Troubleshooting

Ensure Patient Safety First

• Immediately ensure the patient is being ventilated.
• If volume delivery is questionable, switch to manual bag ventilation using 100% O₂.
• Verify chest rise and adequate airway pressures.
• This ensures patient oxygenation while troubleshooting.

Verify Ventilation Mode and Settings

• Confirm correct mode (e.g., Volume Control vs Pressure Control).
• Verify tidal volume setting is appropriate.
• Confirm respiratory rate and inspiratory time are correctly programmed.
• Incorrect mode or settings can mimic delivery failure.

Check Fresh Gas Flow and Gas Supply

• Confirm pipeline pressures are within normal range (O₂, Air, N₂O as applicable).
• Ensure O₂ supply is not depleted if on cylinder backup.
• Verify no low supply pressure alarms are active.
• Insufficient gas supply can prevent full volume delivery.

Inspect the Patient Circuit for Leaks

• Perform a manual leak check.
• Inspect:
• Circuit tubing connections
• Y-piece
• Elbow connectors
• Humidifier connections
• CO₂ absorber canister seating
• Listen for audible leaks.
• Circuit leaks are one of the most common causes of low delivered volume.

Check the Adjustable Pressure Limiting (APL) Valve (if in Manual Mode)

• Ensure APL valve is appropriately set and not fully open during manual ventilation.
• An open APL can vent volume before reaching the patient.

Inspect the CO₂ Absorber and Breathing System

• Confirm absorber canister is fully seated and locked.
• Check for cracked housing or poor seal.
• Ensure unidirectional valves are not visibly stuck (without disassembly).
• Poor sealing in the breathing system can reduce effective delivered volume.

Verify Airway Integrity

• Confirm endotracheal tube cuff inflation.
• Check for audible leak at the patient airway.
• Suction if obstruction suspected.
• A cuff leak or partial obstruction can alter delivered and measured volume.

Perform System Leak / Compliance Test (if patient safely off circuit)

• Place the machine in standby.
• Perform automated system check.
• Observe compliance and leak test results.
• This helps determine whether the issue is internal to the ventilator or external to the circuit.

Check Bellows or Piston Movement (Visual Observation Only)

• Confirm normal mechanical movement during inspiration and expiration.
• Observe for abnormal hesitation or incomplete stroke.
• Do not open internal compartments.

Power Cycle if Appropriate

• Only if patient is safely supported on alternate ventilation.
• Restart system and allow self-test to complete.
• Software faults can occasionally affect delivery.

If the Problem Persists

If external leaks, setup issues, and gas supply problems have been ruled out and volume delivery remains inconsistent:

• Remove the anesthesia machine from service.
• Label clearly as Out of Service.
• Arrange for further evaluation and repair.

At this point, the issue is likely internal (flow sensors, ventilator drive system, control valves, or internal leak) and requires controlled bench diagnostics.

Knowing when to stop and escalate is proper troubleshooting.

Clinical Use Tip

Never troubleshoot a ventilator volume issue on an active surgical patient.

Always transition the patient to manual ventilation or an alternate anesthesia machine before performing diagnostic checks.

Patient oxygenation and ventilation take priority over equipment evaluation.

Work Order Documentation (CCR Method)

CCR = Complaint, Cause, Resolution

Complaint

What was reported by the clinical staff.

Example:
“OR staff reported anesthesia ventilator not delivering set tidal volume of 500 mL; exhaled volume reading approximately 250 mL with low volume alarm.”

Cause

What was observed during troubleshooting.

Example:
“Found loose connection at CO₂ absorber canister causing circuit leak during positive pressure ventilation.”

Resolution

What action was taken.

Example:
“Reseated and locked absorber canister. Performed leak test—passed. Verified delivered and exhaled volumes matched set tidal volume. Returned to service.”

Helpful Details to Include

• Pipeline pressures verified within range
• O₂ cylinder pressure checked
• Circuit connections tightened
• Leak test results
• Alarm messages displayed
• Bellows/piston movement observed
• Final operational verification performed
• Final device status (Returned to Service or Sent for Repair)

Final Thought

An anesthesia ventilator volume issue is most commonly caused by circuit leaks or setup errors—not internal failure. Logical troubleshooting protects the patient, prevents unnecessary downtime, and avoids premature vendor escalation. Always prioritize patient ventilation, follow a structured process, and document findings clearly.

That is successful troubleshooting.