On this page
Asset Type
Manufacturer
Model
What This Guide Helps With
Addresses missing flow sensing or inaccurate tidal-volume measurement caused by circuit leaks, sensor setup, contamination, connections, configuration, or calibration.
Step-by-Step Troubleshooting
1. Protect the Patient and Confirm the Symptom
Do not continue clinical use if tidal-volume monitoring or delivery cannot be trusted. Transfer the patient to another verified ventilator.
Determine whether the problem is sensor detection, displayed tidal volume, delivered tidal volume, or a failed verification test.
Expected outcome: The patient is protected and the reported measurement problem is clearly defined.
2. Inspect the Breathing Circuit
Check the circuit for loose connections, leaks, incorrectly installed components, water accumulation, damaged tubing, or open sampling ports.
Expected outcome: The breathing circuit is intact and correctly assembled. If correcting a circuit leak restores normal volume readings, the issue is resolved after verification.
3. Inspect the Flow-Sensing Components
Inspect externally accessible flow-sensing components and their connectors for contamination, moisture, physical damage, improper orientation, or incomplete seating.
Do not attempt internal sensor repair.
Expected outcome: The sensor and connections are clean, dry, properly installed, and undamaged.
4. Reseat Sensor Connections
Disconnect and reconnect approved removable sensor connections with the ventilator removed from clinical use. Check for bent contacts, damaged connectors, or poor engagement.
Expected outcome: The ventilator consistently recognizes the sensor. If reseating restores detection and subsequent verification passes, troubleshooting can stop.
5. Substitute a Known-Good Compatible Sensor or Circuit
When available, install a verified compatible sensor or circuit component.
Expected outcome: The known-good component is detected and produces stable measurements. If the fault follows the original accessory, replace it and proceed to final testing.
6. Verify Configuration and Circuit Type
Confirm that the ventilator is configured appropriately for the circuit and accessories installed. Do not enter unauthorized service menus or alter calibration constants.
Expected outcome: External setup and permitted configuration agree with the installed circuit.
7. Perform Approved Flow or Sensor Calibration
With the ventilator off-patient, complete any user-accessible or authorized calibration required for the installed flow-sensing setup.
Expected outcome: Calibration completes successfully. A repeated calibration failure with known-good external components requires escalation.
8. Measure Delivered Tidal Volume Independently
Connect an approved ventilator analyzer and test lung. Compare independently measured tidal volume with the ventilator's delivered and displayed values under controlled conditions.
Expected outcome: Delivered and monitored values meet the applicable manufacturer verification criteria. If they do, the issue is resolved.
9. Check Across Representative Test Conditions
Where permitted by the approved procedure, repeat volume verification using more than one controlled test setting to ensure the problem is not intermittent or condition-dependent.
Expected outcome: Volume measurement remains stable and acceptable throughout testing.
10. Escalate an Unresolved Accuracy Problem
If known-good circuits and sensors, proper setup, and approved calibration do not restore acceptable performance, stop troubleshooting.
Expected outcome: The ventilator is removed from service for further evaluation.
If the Problem Persists
External leaks, sensor installation, connectors, contamination, circuit configuration, and known-good substitutions have been ruled out. Remaining causes may involve internal flow sensing, pressure sensing, pneumatic delivery, signal processing, calibration, or other service-level systems.
Remove the ventilator from service, label it Out of Service, and send it for manufacturer-directed bench evaluation using approved ventilator-analysis equipment. Do not perform board-level repair or unauthorized calibration.
Return the ventilator to service only after flow sensing, tidal-volume accuracy, ventilation performance, and applicable alarms have been verified.
Clinical Use Tip
Do not rely on a ventilator for patient management when measured tidal volume is known to be unreliable, even if the ventilator appears to cycle normally.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Respiratory Therapy reported that the Newport e360 displayed inconsistent tidal volumes during setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found moisture in the externally connected flow-sensing component, causing unstable measurements."
Resolution
What action was taken.
Example:
"The affected component was replaced with a verified compatible sensor, calibration passed, and tidal-volume accuracy was confirmed with a ventilator analyzer."
Helpful Details to Include (If Known)
- Sensor-detection message
- Circuit condition
- Flow-sensor condition
- Moisture or contamination
- Connector condition
- Known-good substitution results
- Calibration result
- Ventilator analyzer measurements
- Results before and after correction
- Final device status
Final Thought
Verify the circuit, flow-sensing components, connections, calibration, and independent delivered volume before assuming an internal fault. Remove inaccurate equipment from service and document objective test results.
That is successful troubleshooting.