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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting Puritan Bennett 840 ventilators that fail pre-use checks. Pre-use check failures can prevent the ventilator from entering clinical service, trigger alarms, or indicate potential safety risks. Most failures are caused by easily verifiable external factors such as improper setup, disconnections, sensor contamination, or environmental conditions. This guide focuses on systematic, external checks before assuming internal failure.
Step-by-Step Troubleshooting
Ensure Safe Environment
- Confirm ventilator is powered off and not connected to a patient.
- Remove any circuit, tubing, or accessories that could interfere with testing.
- Why: Pre-use checks must be performed without patient attachment to ensure safety.
Check AC Power and Battery
- Verify AC power is connected and outlet is functional.
- Confirm the internal battery has sufficient charge for a pre-use check.
- Swap outlet or use a verified power strip if unsure.
- Why: Power instability can cause pre-use check errors.
Inspect Circuit and Connectors
- Remove and reattach all patient circuits, sensors, and tubing.
- Check for visible cracks, kinks, moisture, or contamination in circuits.
- Ensure sensors (O₂, flow, pressure) are properly seated.
- Why: Loose or damaged circuits often cause pre-use check failures.
Check the Exhalation Module
- Ensure module is properly installed and free from obstructions.
- Look for dust, moisture, or buildup that could prevent proper calibration.
- Why: A misaligned or contaminated exhalation module can prevent successful pre-use checks.
Run Environmental and Sensor Verification
- Ensure the ventilator is in a room with ambient temperature and humidity within spec.
- Remove unnecessary magnetic or electrical interference nearby.
- Why: Extreme environmental conditions can trigger sensor errors during self-test.
Power Cycle and Retry Pre-Use Check
- Power off, wait 30 seconds, and power on.
- Run the pre-use check following standard prompts.
- Observe the exact error message and which step fails.
- Why: Power cycling often clears minor electronic faults.
If the Problem Persists
Common external causes have been ruled out. The failure is likely internal, involving flow sensors, pressure transducers, or the ventilator’s electronics.
- Remove the ventilator from service.
- Label it Out of Service.
- Send for repair or bench evaluation by qualified personnel.
Knowing when to escalate prevents unnecessary risk and preserves patient safety.
Clinical Use Tip
Never perform a pre-use check on an active patient. Move the patient to a backup ventilator before attempting troubleshooting. Document each step clearly for continuity of care.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Ventilator fails pre-use check; unable to start ventilation.”
Cause
What was observed during troubleshooting.
Example:
“Pre-use check failed due to exhalation module misalignment and sensor connection issues.”
Resolution
What action was taken.
Example:
“Verified power, reconnected circuits, reseated exhalation module, re-ran pre-use check successfully; ventilator cleared for service.”
Helpful Details to Include
- AC outlet tested and confirmed
- Battery charge verified
- Sensor and circuit connections checked
- Error messages and failed pre-use check steps noted
- Final device status (ready or out of service)
Final Thought
Systematic, logic-based troubleshooting ensures patient safety, prevents unnecessary internal disassembly, and emphasizes proper escalation when external checks fail. Clear CCR documentation supports accountability and quick resolution.
That is successful troubleshooting.