On this page
Asset Type
Manufacturer
Model
What This Guide Helps With
This guide addresses situations where the Perseus anesthesia machine:
- Bellows do not rise or fall as expected
- Ventilator fails to deliver breaths
- Alarms indicate “Ventilator Not Cycling” or “Bellows Stopped”
The focus is on external, easily verifiable causes first—such as power, gas supply, ventilator settings, and patient circuit setup—before assuming internal mechanical or electronic failure.
Step-by-Step Troubleshooting
Confirm Machine Power
- Verify that the anesthesia machine is plugged in and switched on.
- Check that battery backup (if present) is charged and functional.
Reason: Without proper power, bellows cannot cycle.
Verify Gas Supply
- Check that oxygen, air, and nitrous oxide supply pressures are within normal limits.
- Ensure the gas cylinders are open or pipeline supply is active.
Reason: Ventilation is driven by gas flow; low or absent pressure prevents cycling.
Inspect Breathing Circuit Connections
- Ensure the inspiratory and expiratory limbs are correctly connected.
- Confirm that the patient Y-piece is attached properly.
- Look for kinks, disconnections, or leaks.
Reason: Bellows will not rise if the circuit is blocked or has leaks.
Check the Ventilator Mode and Settings
- Verify the ventilator mode is correctly selected (e.g., Volume Control, Pressure Control).
- Confirm tidal volume, respiratory rate, and pressure limits are set appropriately.
Reason: Improper settings can prevent cycling or trigger safety stops.
Assess Bellows Assembly
- Confirm that the bellows are seated correctly on the mount.
- Check that the bellows are not stuck, collapsed, or obstructed.
Reason: Physical misalignment or obstruction can prevent movement.
Examine Safety Valves
- Inspect APL (Adjustable Pressure-Limiting) valve and ventilator relief valves to ensure they are in correct position.
Reason: Incorrect valve positions can prevent proper bellows cycling.
Perform Leak Test / System Check
- Run the anesthesia machine’s automated system check per Drager prompts.
- Observe any alarms or error messages.
Reason: Detects issues in ventilator drive system or circuit integrity.
If the Problem Persists
If all external checks pass but the bellows still do not cycle:
- The internal ventilator drive mechanism or electronics may be faulty.
Action:
- Remove the machine from service.
- Label as “Out of Service.”
- Send for manufacturer-authorized repair or bench evaluation.
Note: Continuing use without cycling bellows poses serious patient safety risk.
Clinical Use Tip
- Do not ventilate a patient using the Perseus machine if bellows are not cycling.
- Switch the patient to a functioning anesthesia machine or manual ventilation using a self-inflating bag before troubleshooting further.
- Always ensure patient oxygenation first—troubleshooting comes second.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Ventilator bellows not cycling during routine use.”
Cause
What was observed during troubleshooting.
Example:
“External power, gas supply, and circuit connections verified; bellows seated properly; ventilator mode and safety valves checked. Issue persists, likely internal ventilator drive failure.”
Resolution
What action was taken.
Example:
“Machine removed from service, labeled Out of Service, and sent for manufacturer-authorized repair.”
Helpful Details to Include
- Power source verified
- Gas supply pressures normal
- Circuit inspected, no kinks or leaks
- Bellows assembly seated and unobstructed
- Ventilator mode/settings confirmed
- Automated system check results noted
- Alarm messages recorded
Final Thought
Patient safety is paramount: never attempt internal repairs on the Perseus ventilator while a patient is attached. Logical troubleshooting, careful escalation, and detailed CCR documentation ensure safe, effective resolution and protect both patients and staff.
That is successful troubleshooting.