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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting Puritan Bennett 840 ventilators that display flow sensor errors or fail calibration. Flow sensor issues can prevent accurate ventilation, trigger alarms, or compromise patient safety. Most causes are external, such as sensor obstruction, improper setup, or environmental conditions. This guide emphasizes safe, step-by-step troubleshooting before assuming internal sensor or board failure.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Move the patient to an alternative ventilator if actively connected.
- Do not perform troubleshooting while a patient is on the ventilator.
Check Power and Connections
- Confirm the ventilator is properly powered and on a stable AC source or fully charged battery.
- Verify all circuit connections, including the flow sensor assembly, are fully seated and free from damage.
Inspect the Flow Sensor
- Remove and visually inspect the flow sensor for moisture, condensation, or debris.
- Check for cracks, loose components, or signs of contamination that could impede airflow measurement.
Verify Circuit Assembly
- Reattach the flow sensor ensuring proper orientation per manufacturer markings.
- Inspect patient circuit tubing for kinks, obstructions, or misaligned components that may trigger false errors.
Perform Calibration
- Initiate the ventilator’s automatic flow sensor calibration procedure.
- Ensure the sensor is at room temperature and dry; environmental extremes can prevent proper calibration.
Check for Software or Settings Issues
- Confirm the ventilator software version is current and matches hospital standards.
- Verify any flow compensation or calibration offsets are correctly configured.
If the Problem Persists
External and setup-related causes have been ruled out. The flow sensor or internal electronics may be defective.
- Remove the ventilator from service.
- Label it “Out of Service.”
- Send for manufacturer repair or in-house bench evaluation.
Remember: knowing when to escalate is proper troubleshooting.
Clinical Use Tip
- Never attempt patient ventilation with a known flow sensor error.
- Always ensure a backup ventilator is available before troubleshooting.
- Avoid contaminating sensors with moisture or cleaning solutions during inspections.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Ventilator displays flow sensor error and fails calibration.”
Cause
What was observed during troubleshooting.
Example:
Observed debris in flow sensor and/or misaligned circuit connections preventing calibration.
Resolution
What action was taken.
Example:
Cleaned or replaced flow sensor, reattached circuits properly, recalibrated ventilator. If errors persisted, removed ventilator from service and sent for repair.
Helpful Details to Include
- Ventilator power source verified (AC/battery).
- Flow sensor inspected for moisture or debris.
- Circuit tubing checked for kinks or disconnections.
- Calibration attempts and environmental conditions recorded.
- Any alarms noted (frequency, type, duration).
Final Thought
Patient safety and logical troubleshooting are paramount. Always start with external checks and simple fixes before assuming internal failure. Proper documentation ensures maintenance history and safe equipment management. Escalating promptly when needed protects both patients and staff.
That is successful troubleshooting.