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What This Guide Helps With
Breathing-system leak or leak-test failures caused by loose connections, open ports, damaged circuits, accessories, seals, or incorrect assembly.
Step-by-Step Troubleshooting
1. Protect the Patient and Remove the Machine From Active Use
Do not troubleshoot a suspected breathing-system leak while the machine is supporting an anesthetized patient. Transfer care to a verified alternate anesthesia machine or approved backup system first.
Expected outcome: Patient ventilation and anesthesia delivery are maintained independently of the affected machine.
2. Confirm the Leak-Test Failure
Reproduce the leak test under controlled conditions. Note whether the failure is continuous or intermittent and record any displayed message identifying the affected circuit or test stage.
Inspect the setup before disturbing components so an obvious disconnection is not missed.
Expected outcome: The leak condition is confirmed and its general location or test stage is understood.
3. Inspect the Patient Circuit
Check inspiratory and expiratory limbs, Y-piece, reservoir bag, elbows, adapters, filters, and other externally connected circuit components.
Look for loose connections, cracks, splits, punctures, damaged cuffs, missing components, or fittings that are not fully seated.
Expected outcome: The patient circuit is intact and tightly connected. If correcting a circuit problem allows the leak test to pass, troubleshooting can stop after final verification.
4. Check Open Ports and Sampling Connections
Inspect all accessible breathing-system and gas-sampling ports. Verify unused ports are appropriately closed and required sampling lines, water traps, or adapters are correctly connected.
A disconnected sampling line or open fitting can create a leak without an internal machine failure.
Expected outcome: No unintended open connection remains in the breathing system.
5. Inspect the Breathing System Assembly
Verify removable breathing-system components are assembled and installed correctly. Check for components that are partially seated, misaligned, loose, or installed in the wrong orientation.
Inspect accessible seals and mating surfaces for contamination, deformation, or visible damage without deep disassembly.
Expected outcome: The breathing-system assembly is completely and correctly seated.
6. Substitute Known-Good External Components
When appropriate, replace the disposable or removable patient circuit, reservoir bag, filter, sampling line, or other suspect external component with a compatible known-good item.
Change one item at a time when practical to identify the actual cause.
Expected outcome: The leak test passes after the faulty external component is replaced. If so, the issue is resolved.
7. Verify Vaporizers and External Gas Connections
Confirm vaporizers are securely mounted and external gas connections are fully engaged. Inspect accessible connections for anything visibly loose or improperly installed that may affect system integrity.
Expected outcome: External gas-delivery components are correctly mounted and do not contribute to the leak.
8. Repeat the Leak/System Test
Repeat the normal machine leak or system test after correcting external causes. Do not return the machine to service if the test continues to fail.
Expected outcome: The leak test completes successfully and no recurring leak indication is present.
9. Perform Final Functional Verification
Connect an appropriate test lung and verify ventilation, circuit pressure behavior, displayed volume measurements, alarms, and normal machine operation.
Expected outcome: Ventilation and monitoring remain stable with no evidence of an unresolved leak.
10. Escalate if the Leak Persists
If the leak test still fails after the circuit, external accessories, connections, ports, and breathing-system assembly have been verified, stop external troubleshooting.
Expected outcome: The machine is removed from service for qualified bench evaluation.
If the Problem Persists
External leak sources have been ruled out. The remaining condition may involve an internal breathing-system seal, valve, pneumatic pathway, pressure-sensing pathway, or other service-level problem.
Remove the machine from service, label it Out of Service, and send it for repair or bench evaluation. Use appropriate Drager documentation and approved leak/performance test equipment. Internal pneumatic repairs or component replacement should be performed only by qualified personnel.
Complete the applicable system test, leak test, ventilation verification, and alarm checks before return to service.
Knowing when to stop external troubleshooting and escalate is proper troubleshooting.
Clinical Use Tip
Never accept a marginal or intermittently passing leak test when the machine will be relied upon for patient ventilation.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"OR staff reported the Atlan A300 repeatedly failed the breathing-system leak test."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found a cracked disposable breathing-circuit connector causing loss of circuit integrity."
Resolution
What action was taken.
Example:
"Replaced the damaged circuit, repeated the leak and system tests successfully, verified ventilation with a test lung, and returned the machine to service."
Helpful Details to Include (If Known)
- Exact leak-test message
- Test stage where failure occurred
- Circuit type and condition
- Reservoir bag condition
- Filters and adapters installed
- Sampling-line status
- Open or unused ports checked
- Breathing-system seating
- Known-good substitutions
- Results before and after correction
- Final leak-test result
- Final device status
Final Thought
Breathing-system leaks should be approached from the patient circuit inward, correcting visible and easily verified causes first and escalating only after external components have been ruled out.
That is successful troubleshooting.