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What This Guide Helps With
This guide assists Clinical Engineering in troubleshooting situations where an NxStage System One HD machine reports pump module or flow controller failures. These alarms typically indicate that the machine cannot maintain proper blood or dialysate flow due to sensor issues, pump malfunctions, or connection faults. External causes should be verified first before assuming internal failure.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Stop the dialysis session if in progress.
- Move the patient to a functioning HD machine.
- Confirm that all tubing clamps are appropriately open/closed.
Why: Avoid patient harm during troubleshooting.
Check Power and Connections
- Verify the machine is powered on and connected to a stable outlet.
- Inspect the power cord for damage.
- Reboot the machine to clear temporary faults.
Why: Some controller errors reset after power cycling.
Inspect Pump Tubing and Lines
- Ensure bloodlines and dialysate lines are installed correctly, without kinks or occlusions.
- Confirm that the cartridge is properly seated and locked.
Why: Improper tubing or cartridge installation can mimic pump/controller failures.
Verify Pump Module Installation
- Confirm that the pump module is fully seated in the system.
- Inspect for any visible damage or debris on the pump drive interface.
Why: Loose or misaligned pump modules can trigger failure alarms.
Check Flow Sensors
- Inspect arterial, venous, and dialysate flow sensors for cleanliness and proper positioning.
- Look for air bubbles, clots, or obstructions in the flow path.
Why: Sensor issues can cause the controller to detect flow faults.
Observe Alarm Patterns and Logs
- Note any error codes displayed.
- Record the frequency and conditions of the alarm.
Why: Helps determine if the failure is intermittent or persistent, guiding repair vs. escalation.
If the Problem Persists
External factors have been ruled out. The pump module or flow controller is likely internally faulty.
- Remove the machine from service.
- Label as "Out of Service."
- Send for vendor repair or internal bench evaluation.
- Avoid further use until cleared by Clinical Engineering.
Clinical Use Tip
- Never attempt troubleshooting on an active patient.
- Always verify blood flow and ultrafiltration safety before returning the machine to service.
- Maintain infection control precautions when handling tubing and pump modules.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Pump module failure alarm displayed during startup.”
Cause
What was observed during troubleshooting.
Example:
“Observed that the pump module was properly seated but the controller repeatedly failed self-test. No external tubing or sensor issues were found.”
Resolution
What action was taken.
Example:
“Machine removed from service, labeled Out of Service, and sent for vendor repair.”
Helpful Details to Include
- Outlet tested and confirmed
- Tubing inspected and reinstalled
- Cartridge seated correctly
- No kinks or obstructions
- Alarm codes recorded
- Final device status: Out of Service
Final Thought
Patient safety is the highest priority. Clinical Engineering troubleshooting should follow a logical, stepwise process starting with external checks. Recognizing when to escalate to repair prevents further risk and ensures reliable dialysis treatment. Proper documentation supports regulatory compliance and future reference.
That is successful troubleshooting.