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What This Guide Helps With
Troubleshoot inaccurate or unstable blood-circuit pressure readings caused by tubing, pressure lines, transducer protectors, connections, setup, or service-level problems.
Step-by-Step Troubleshooting
1. Protect the Patient and Preserve Reliable Monitoring
Do not continue dialysis when arterial or venous pressure monitoring is unreliable. Follow clinical procedure and move treatment to another verified machine if accurate pressure monitoring cannot be assured.
Expected outcome: The patient is no longer dependent on questionable pressure monitoring while technical evaluation proceeds.
2. Confirm the Exact Pressure Complaint
Determine whether the arterial or venous reading is unexpectedly high, low, fluctuating, frozen, slow to respond, or inconsistent with the known test condition.
Identify whether the problem affects one pressure channel or both.
Expected outcome: The affected channel and behavior are clearly documented.
3. Inspect Bloodline and Pressure-Line Routing
With no patient connected, inspect the relevant bloodline and pressure-monitoring line for kinks, compression, twists, closed clamps, poor routing, fluid columns, or incorrect connection.
Expected outcome: The tubing and pressure line are correctly routed and unobstructed. If correcting the line restores stable readings, troubleshooting may stop after verification.
4. Inspect the Transducer Protector
Check the applicable external transducer protector for moisture, blood contamination, blockage, incorrect orientation, loose connection, or visible damage.
Replace a compromised disposable according to approved practice. If blood or fluid has crossed into the machine-side pressure connection, remove the device from service for further evaluation.
Expected outcome: A clean, dry, correctly installed protector separates the blood circuit from the machine pressure connection.
5. Check Pressure Connection Security
Verify the pressure monitoring line is fully connected to the correct arterial or venous pressure port and has not been cross-connected or left loose.
Inspect accessible connectors for cracks, damaged threads, or poor fit.
Expected outcome: Pressure connections are secure and correctly identified.
6. Substitute a Known-Good Approved Bloodline Setup
If the complaint may follow the disposable set, repeat the test using a known-good compatible bloodline and transducer-protector setup.
Expected outcome: If pressure stability returns with known-good disposables, replace the affected disposable components and complete verification.
7. Compare Pressure Response With Approved Test Equipment
Using appropriate dialysis analyzer or pressure test equipment and applicable service procedure, verify the machine pressure indication if within Clinical Engineering scope.
Do not adjust pressure calibration without approved manufacturer documentation.
Expected outcome: The displayed reading responds appropriately and agrees with the approved reference within applicable manufacturer requirements.
8. Check for Intermittent Response
Apply a controlled approved test condition and observe whether the value is stable or drops out with minor external movement of the connector or tubing.
Do not manipulate internal wiring or pressure assemblies.
Expected outcome: Pressure indication remains stable throughout the functional test.
9. Escalate Persistent Pressure-Monitoring Failure
If bloodline routing, pressure lines, transducer protectors, connections, and known-good disposables are satisfactory but the reading remains incorrect, remove the machine from service.
Expected outcome: Possible internal pressure sensor, pneumatic path, calibration, or electronic problems are referred for service evaluation.
If the Problem Persists
Common external causes have been ruled out. Remaining causes may involve internal pressure sensing, pneumatic pathways, calibration, connectors, electronic processing, or another service-level condition.
The device should be:
- Removed from service.
- Labeled Out of Service.
- Sent for repair or bench evaluation.
- Evaluated using appropriate B. Braun documentation and approved pressure test equipment.
- Repaired or calibrated only by qualified personnel.
Complete all required pressure-monitoring, alarm, dialysis, and safety verification before return to service.
Knowing when to stop before opening or calibrating an unresolved pressure system without approved procedure is proper troubleshooting.
Clinical Use Tip
A believable pressure number is not enough; confirm that the reading changes appropriately when the test pressure changes.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Dialysis staff reported an unstable venous pressure reading during machine setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the venous transducer protector was partially occluded with moisture."
Resolution
What action was taken.
Example:
"The disposable protector was replaced, pressure response was verified with approved test equipment, and the machine passed functional testing before return to service."
Helpful Details to Include (If Known)
- Arterial or venous channel affected
- High, low, unstable, or frozen reading
- Pressure-line routing
- Transducer protector condition
- Connector condition
- Known-good disposable substitution
- Independent pressure test result
- Intermittent behavior
- Results before and after correction
- Final device status
Final Thought
Maintain reliable patient monitoring, inspect disposable pressure components before assuming sensor failure, verify readings with approved test equipment, escalate unresolved errors, and document the verified correction.
That is successful troubleshooting.