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What This Guide Helps With
Helps identify external leaks, circuit problems, settings, accessories, or test conditions that can prevent stable PEEP or cause airway-pressure drift.
Step-by-Step Troubleshooting
1. Protect the Patient
Do not troubleshoot unstable PEEP or airway pressure while a patient relies on the affected ventilator. Move ventilation to an alternate verified source when pressure stability cannot be assured.
Expected outcome: Patient support is maintained and the affected unit is available for bench evaluation.
2. Confirm the Pressure Complaint
Determine whether PEEP falls below the selected value, rises unexpectedly, drifts over time, or differs from an external airway-pressure measurement.
Reproduce the condition using an appropriate test lung and analyzer.
Expected outcome: The pressure abnormality is confirmed under controlled conditions.
3. Verify the Selected Ventilation Settings
Confirm ventilation mode, PEEP setting, pressure settings, rate, and other externally accessible controls are configured as intended.
Check whether the complaint began after a mode or configuration change.
Expected outcome: The machine is operating with the intended settings. If an incorrect setting explains the complaint, correct it and proceed to verification.
4. Inspect the Breathing Circuit for Leaks
Examine the inspiratory and expiratory limbs, Y-piece, bag, filters, adapters, sampling connections, absorber interfaces, and other accessible breathing-system connections.
Expected outcome: No significant external leak is present. If a corrected leak restores stable PEEP, troubleshooting can stop after final testing.
5. Check for Restrictions or Obstructions
Inspect for kinked tubing, occluded filters, blocked expiratory components, water accumulation, or improperly installed accessories that could alter pressure.
Expected outcome: The breathing pathway is unobstructed and pressure is able to rise and fall normally.
6. Verify External Pressure Measurement
Use approved test equipment to compare the machine's indicated airway pressure with an independent measurement at an appropriate test point.
Expected outcome: Pressure indication and measured pressure are consistent with the applicable service evaluation. If the machine is stable and the discrepancy exists only in an external accessory, correct that accessory.
7. Compare With a Known-Good Circuit
When practical, replace the external breathing circuit and disposable accessories with compatible known-good components.
Expected outcome: If PEEP becomes stable, the removed circuit or accessory was contributing to the problem. Replace it and proceed to final verification.
8. Inspect Accessible Breathing-System Assemblies
Verify accessible valves, breathing-system assemblies, absorber components, and external sealing interfaces are correctly seated and undamaged.
Do not perform deep pneumatic disassembly.
Expected outcome: External assemblies are secure and properly installed.
9. Perform Final Functional Testing
Run the appropriate ventilator and breathing-system checks with a test lung. Confirm stable PEEP, expected pressure release, alarm behavior, and consistent ventilation over an adequate observation period.
Expected outcome: PEEP remains stable without unexplained drift. If so, the device may be returned to service after required checks.
10. Remove From Service if Pressure Remains Unstable
Persistent PEEP loss or pressure drift after external causes are eliminated requires escalation.
Expected outcome: The anesthesia machine is removed from service for qualified internal evaluation.
If the Problem Persists
External leaks, settings, restrictions, accessories, and test configuration have been ruled out. Remaining possibilities may involve internal pressure-control, expiratory-valve, pneumatic regulation, pressure-sensing, or calibration-related faults.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate manufacturer documentation and approved test equipment
- Repaired, adjusted, or calibrated only by qualified personnel
Verify ventilation, airway-pressure monitoring, alarms, and breathing-system integrity before return to service.
Clinical Use Tip
Unstable PEEP can compromise ventilation even when other displayed parameters appear normal; move the patient to verified support before investigating the machine.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"OR staff reported that PEEP would not remain stable during pre-case ventilation testing."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found a damaged external circuit connection producing a breathing-system leak."
Resolution
What action was taken.
Example:
"The affected circuit component was replaced and stable PEEP, ventilation, alarms, and leak performance were verified before return to service."
Helpful Details to Include (If Known)
- Selected PEEP
- Observed pressure behavior
- Ventilation mode
- Leak-test result
- Circuit condition
- Filters and accessories
- Independent pressure measurement
- Known-good circuit comparison
- Alarm behavior
- Final device status
- Selected PEEP
- Observed pressure behavior
- Ventilation mode
- Leak-test result
- Circuit condition
- Filters and accessories
- Independent pressure measurement
- Known-good circuit comparison
- Alarm behavior
- Final device status
Final Thought
Pressure instability should be approached as a system problem first. Protect the patient, verify settings, eliminate leaks and restrictions, compare against approved test equipment, and escalate only after external causes are excluded and documented.
That is successful troubleshooting.