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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting flow imbalance or dialysate preparation faults on an NxStage System One HD machine. These alarms indicate that the machine has detected irregular dialysate flow, improper mixing, or other preparation issues. Most commonly, these are caused by external factors such as kinks in tubing, improper cartridge installation, or blocked filters rather than internal electronic failures.
Step-by-Step Troubleshooting
Verify Machine Power and Startup
- Confirm the machine is plugged into a verified, functional outlet.
- Ensure the machine completes its self-test during startup.
Why: Unstable power or incomplete initialization can trigger false flow or dialysate alarms.
Inspect Dialysate Cartridge
- Remove and reseat the dialysate cartridge according to manufacturer guidelines.
- Check for visible damage, dirt, or misalignment.
Why: Improper cartridge installation can impede fluid flow and mixing.
Examine Tubing and Connections
- Inspect all tubing for kinks, bends, or obstructions.
- Confirm all connections are tight and correctly positioned.
Why: Flow imbalances often result from restricted or misconnected tubing.
Check Dialysate Concentrate and Filters
- Verify the correct dialysate solution is used.
- Inspect inline filters and connectors for blockage or debris.
Why: Contaminated or misconnected filters can reduce flow or cause preparation faults.
Prime the System and Observe Flow
- Run the machine’s priming sequence.
- Monitor dialysate flow rates and sensor readings for abnormalities.
Why: Priming helps confirm whether flow issues persist after initial setup.
Review Alarm History and Machine Logs
- Access the machine’s event log for repeated flow or preparation errors.
- Document any patterns that may indicate consistent external issues.
If the Problem Persists
External causes have been largely ruled out.
Device should be:
- Removed from service
- Labeled Out of Service
- Sent for bench evaluation or repair by manufacturer-authorized service
Reminder: Escalating before attempting internal repair ensures patient safety and preserves warranty.
Clinical Use Tip
Never troubleshoot flow or dialysate faults while the machine is connected to a patient.
Move the patient to a backup dialysis machine before performing troubleshooting steps.
Ensure all safety alarms are acknowledged and that the treatment environment remains safe.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Flow imbalance” or “Dialysate preparation fault” during patient treatment.
Cause
What was observed during troubleshooting.
Example:
Observed kinked dialysate tubing and loosely seated cartridge; dialysate filters inspected and clear.
Resolution
What action was taken.
Example:
Corrected cartridge seating, straightened tubing, and verified proper priming. Flow readings normalized. Machine returned to service.
Helpful Details to Include
- Outlet tested and verified
- Tubing checked for kinks or leaks
- Cartridge properly seated
- Inline filters inspected
- Flow rate and dialysate sensor readings during priming
- Alarm log captured
Final Thought
Patient safety is paramount. Start troubleshooting with external, easily verifiable issues and avoid internal disassembly unless directed by the manufacturer. Proper documentation and timely escalation preserve both safety and machine integrity.
That is successful troubleshooting.