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What This Guide Helps With
Use this guide when the blood pump does not start, stops unexpectedly, or runs inconsistently because of tubing, interlocks, settings, loading, or drive faults.
Step-by-Step Troubleshooting
1. Protect the Patient and Maintain Blood-Circuit Safety
Do not troubleshoot an unreliable blood pump while a patient depends on it for active treatment. Follow the clinical contingency process and move treatment to a verified machine when required.
Prevent unintended blood movement while inspecting the pump area.
Expected outcome: The patient and extracorporeal circuit are safely managed before technical troubleshooting begins.
2. Confirm the Exact Pump Problem
Determine whether the blood pump does not start, starts and stops, runs at the wrong apparent speed, produces abnormal noise, or becomes unstable only at certain times.
Record any displayed message or interlock indication.
Expected outcome: The failure is clearly defined and distinguished from a commanded pump stop.
3. Verify Operating Conditions and Commands
Check that the machine is in a state that permits blood-pump operation and that the requested operator setting has been entered correctly.
Confirm no active safety alarm or interlock is intentionally preventing pump operation.
Expected outcome: The pump is being commanded to run under conditions where operation should be permitted. If clearing a legitimate setup condition restores normal operation, proceed to verification.
4. Inspect Bloodline Loading
With no patient dependent on the circuit, inspect the pump tubing segment for correct loading, seating, orientation, tension, and closure of the accessible pump mechanism.
Look for twisted, stretched, flattened, damaged, or incorrectly sized tubing.
Expected outcome: The tubing segment is correctly installed and can move freely through the pump mechanism.
5. Inspect the Pump Area for Obstruction
Check accessible surfaces for foreign material, dried residue, displaced tubing, or another external obstruction that could interfere with rotation or closure.
Do not disassemble the pump drive or defeat protective covers or interlocks.
Expected outcome: The pump path is clear and accessible mechanical parts move only as intended.
6. Substitute a Known-Good Disposable Set
If tubing condition is questionable, use an approved known-good disposable set for a nonpatient test.
Observe whether the pump starts and maintains commanded operation.
Expected outcome: If the pump operates normally with a known-good disposable, the original tubing or installation was the likely cause and troubleshooting can stop after verification.
7. Observe Pump Operation Without Patient Use
Run the machine under an approved nonpatient test condition and observe for hesitation, speed fluctuation, unusual sound, vibration, or intermittent stopping.
Do not continue operating the pump if abnormal mechanical noise or binding occurs.
Expected outcome: The pump operates smoothly and consistently at the commanded setting.
8. Perform Final Functional Verification
Verify normal blood-pump startup, stop, control response, and stable operation through the applicable checks. Confirm no related alarms recur.
Expected outcome: Pump operation is smooth and consistent and all applicable protective functions remain intact. Troubleshooting can stop.
If the Problem Persists
If operating conditions, interlocks, bloodline loading, disposable condition, and accessible obstructions have been ruled out, the problem may involve the internal motor drive, speed feedback, control electronics, mechanical drive components, or associated sensing.
The device should be:
- Removed from service.
- Labeled Out of Service.
- Sent for repair or bench evaluation.
- Evaluated using Fresenius Medical Care service documentation and approved test equipment.
- Repaired or adjusted only by qualified personnel.
- Functionally verified under nonpatient conditions before return to clinical use.
An intermittent or unstable blood pump should not be accepted simply because it operates normally during one brief test.
Clinical Use Tip
Before investigating a blood-pump complaint, confirm the patient is no longer dependent on the affected extracorporeal circuit.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Dialysis staff reported the blood pump on the 5008S CorDiax would start and then stop during setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the pump tubing segment was twisted and not fully seated in the pump path."
Resolution
What action was taken.
Example:
"The tubing was correctly reloaded, pump operation remained stable through nonpatient functional testing, and the machine was returned to service."
Helpful Details to Include (If Known)
- Pump does not start versus unstable speed.
- Displayed message or active alarm.
- Requested pump setting.
- Bloodline type and condition.
- Tubing position in the pump.
- Abnormal sound or vibration.
- Known-good disposable substitution.
- Results of nonpatient operation.
- Final device status.
Final Thought
Blood-pump troubleshooting should begin with setup, tubing, and interlocks before internal drive problems are considered, with reliable function verified before the machine returns to patient care.
That is successful troubleshooting.