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What This Guide Helps With
Troubleshooting absent or abnormal bellows movement caused by ventilation mode, circuit leaks, breathing-system components, gas supply, setup, or ventilator faults.
Step-by-Step Troubleshooting
1. Ensure Patient Safety First
Do not perform extended bellows or ventilator troubleshooting while the Aisys CS2 is supporting an active patient.
If the bellows stop rising or cycling during clinical use:
- Notify the anesthesia provider immediately.
- Confirm whether ventilation, oxygen delivery, airway pressure, and patient monitoring remain functional.
- Begin ventilation with another verified anesthesia machine or approved backup method.
- Maintain appropriate independent patient monitoring.
- Follow the facility’s anesthesia-equipment failure procedure.
Expected outcome: Patient ventilation no longer depends on equipment with unreliable bellows movement.
Continue troubleshooting only after the machine is removed from active patient use.
2. Confirm the Exact Failure Condition
Determine whether:
- The bellows remain completely collapsed.
- The bellows rise but do not cycle.
- The bellows cycle only partially.
- The bellows gradually lose volume.
- The failure occurs only in mechanical ventilation.
- An alarm such as Unable to drive bellows, low minute volume, apnea, or circuit leak is displayed.
Record the complete alarm message and ventilation mode.
Expected outcome: The reported symptom is clearly identified before components are changed.
3. Verify the Bag/Vent Switch Position
Confirm that the Bag/Vent switch is fully placed in the Vent position for mechanical ventilation.
Move the switch fully to Bag and then back to Vent while the machine is off patient and configured for testing. The Aisys CS2 uses this switch to select manual or mechanical ventilation, and moving it to Vent should activate the ventilator.
Expected outcome: The ventilator starts and the bellows begin cycling.
If normal operation returns, complete the manufacturer checkout before returning the device to service, document the result, and stop troubleshooting.
4. Confirm Ventilator Settings and Start Condition
Verify that:
- An appropriate mechanical ventilation mode is selected.
- The respiratory rate is not set to zero or an unintended value.
- Tidal volume or pressure-control settings are appropriate for the test setup.
- Ventilation is not paused or in standby.
- The system is not waiting for completion of an on-screen instruction.
Use a verified test lung rather than testing on a patient.
Expected outcome: The ventilator delivers regular test breaths and the bellows move with each cycle.
5. Check the Breathing Circuit and Test Lung
Inspect the entire breathing circuit for:
- Disconnected inspiratory or expiratory limbs
- Loose Y-piece connections
- Split, punctured, or stretched tubing
- Missing adapters
- Open sampling or accessory ports
- Poor test-lung connection
- Incorrectly assembled circuit components
Reconnect all components securely. Substitute a known-good breathing circuit and test lung when available.
Expected outcome: A sealed circuit allows the bellows to fill and cycle normally.
If replacing the external circuit corrects the problem, remove the defective accessory from use, complete checkout, document the repair, and stop.
6. Inspect the Bellows Assembly Externally
With the system off patient, visually inspect the bellows and housing.
Check for:
- Bellows folded, twisted, or displaced
- Bellows stuck against the housing
- Visible tears, holes, or deterioration
- An improperly seated bellows assembly
- A loose or damaged housing
- Condensation or contamination affecting movement
- Foreign material obstructing travel
Do not apply lubricants or perform deep disassembly unless specifically authorized by GE service documentation.
Expected outcome: The bellows are intact, correctly positioned, and able to move freely.
A visibly damaged bellows assembly requires removal from service and replacement or evaluation by qualified service personnel.
7. Check the Absorber Canister and Breathing-System Seating
Confirm that:
- The absorber canister is installed correctly.
- The canister release mechanism is fully engaged.
- The breathing-system assembly is fully seated and locked.
- Seals and accessible mating surfaces are clean and undamaged.
- No breathing-system component was left loose after cleaning or reassembly.
An incompletely seated canister or breathing-system assembly may create a significant leak and prevent normal bellows filling.
Expected outcome: The breathing system is fully assembled, sealed, and secure.
If reseating a component resolves the problem, perform the complete checkout before returning the machine to service.
8. Inspect Inspiratory and Expiratory Check Valves
Visually inspect the accessible inspiratory and expiratory check-valve areas for:
- Moisture
- Debris
- Incorrectly seated valve components
- Cracked or visibly distorted valve discs
- Valve movement that appears restricted
The expiratory valve should permit flow during expiration, while the inspiratory valve should permit flow during inspiration.
Clean or exchange user-removable components only according to approved procedures.
Expected outcome: Check valves move freely and are correctly installed.
9. Check Flow Sensors and Their Connections
Inspect the inspiratory and expiratory flow sensors for:
- Incorrect installation
- Loose connections
- Moisture or condensation
- Contamination
- Cracks or physical damage
- Sensors installed in the wrong positions
Reseat the sensors or substitute known-good compatible sensors when authorized.
Expected outcome: The machine receives stable flow information and ventilation operates normally.
If the issue follows a sensor, remove that sensor from service and complete the required checkout or calibration.
10. Verify Gas Supply
Confirm that required pipeline gases are connected and within the facility’s normal operating range.
Check:
- Pipeline hoses are fully connected.
- Gas-supply alarms are absent.
- Backup cylinders are available according to facility policy.
- Supply hoses are not kinked or damaged.
- The problem is not isolated to one wall outlet.
Test the pipeline outlet with approved equipment or move the machine to a known-good outlet when appropriate.
Expected outcome: Adequate gas supply is available for normal ventilator operation.
If the issue is traced to the facility gas source, keep the affected outlet out of use and notify the appropriate facilities or medical-gas team.
11. Evaluate the Scavenging Connection
Inspect the AGSS or scavenging system for:
- Kinked or obstructed tubing
- Incorrect connections
- Excessive suction
- A full or collapsed reservoir
- An incorrectly adjusted receiving system
- A restricted wall evacuation connection
Temporarily evaluate the device using an approved test configuration according to facility procedures. Do not release anesthetic gas into the work area.
Expected outcome: The scavenging system does not create excessive positive or negative pressure that interferes with breathing-system operation.
12. Restart the System Off Patient
After confirming that the circuit and breathing system are correctly assembled:
- Turn the system off according to the approved shutdown procedure.
- Wait for the shutdown to complete.
- Restore power.
- Observe the startup sequence.
- Record any alarms, failed checks, or diagnostic messages.
Do not repeatedly power-cycle a system showing unusual heat, odor, smoke, or electrical instability.
Expected outcome: The system completes startup and the ventilator initializes without an alarm.
13. Run the Manufacturer Checkout
Run the complete preoperative or Full Test using the required test equipment and follow all on-screen instructions.
The Aisys CS2 Full Test evaluates ventilation operation and leakage, the Bag/Vent switch, gas-supply pressures, circuit compliance, flow control, electrical power, and other system functions.
Record:
- Which test failed
- The exact failure message
- Whether the bellows moved during testing
- Whether the failure repeated with a known-good circuit
- Any components exchanged during troubleshooting
Expected outcome: All required tests pass and the bellows consistently rise and cycle with a verified test lung.
Do not return the machine to clinical service if any required checkout test fails.
If the Problem Persists
If the Bag/Vent switch, settings, breathing circuit, bellows assembly, absorber canister, breathing-system seating, check valves, flow sensors, gas supply, and scavenging system have been checked, the common external causes have been ruled out.
The problem may involve an internal ventilator drive, control valve, pressure-sensing component, pneumatic pathway, electrical connection, or ventilation-control fault.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for qualified bench evaluation or GE-authorized repair
- Evaluated using the appropriate technical reference documentation and test equipment
Do not continue into internal pneumatic or board-level repair without proper training, authorization, and service documentation. Knowing when to stop is proper troubleshooting.
Clinical Use Tip
Never troubleshoot absent or unreliable bellows movement while depending on the machine to ventilate an active patient. Establish alternate ventilation and monitoring before inspecting, reseating, or exchanging components.
Move the patient to a verified backup device or approved ventilation method first so therapy continuity is maintained.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Anesthesia staff reported that the Aisys CS2 bellows would not rise or cycle when mechanical ventilation was selected."
Cause
What was observed during troubleshooting.
Example:
"Inspection found the absorber canister incompletely seated, creating a breathing-system leak that prevented normal bellows filling."
Resolution
What action was taken.
Example:
"Reseated and secured the absorber canister, tested the system with a verified breathing circuit and test lung, and completed the Full Test successfully before returning the machine to service."
Helpful Details to Include (If Known)
- Exact displayed alarm or advisory
- Alarm behavior
- Bag/Vent switch position
- Ventilation mode and settings
- Bellows position and movement
- Pipeline gas pressures verified
- Breathing circuit swapped
- Test lung swapped
- Accessories swapped
- Absorber canister seating checked
- Flow sensors inspected or exchanged
- Check valves inspected
- Scavenging condition checked
- Power behavior
- Environmental factors
- Indicator lights
- Full Test results
- Unusual sounds
- Unusual heat or smell
- Final device status
Final Thought
Bellows movement depends on a properly configured ventilator, sealed breathing circuit, correctly assembled breathing system, and adequate gas supply. Patient safety comes first, followed by logical external checks, required checkout testing, appropriate escalation, and complete CCR documentation.
That is successful troubleshooting.