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What This Guide Helps With
Use this guide when Tablo does not pass ultrafiltration or fluid-balance verification or shows inconsistent measured versus expected fluid movement.
Step-by-Step Troubleshooting
1. Protect the Patient and Stop Clinical Dependence on Questionable Fluid Removal
Do not troubleshoot suspected ultrafiltration or fluid-balance inaccuracy while a patient depends on the affected Tablo.
An unreliable fluid-removal measurement can directly affect patient volume status. If the concern occurs during treatment, clinical personnel should manage the patient and transition therapy according to facility procedure before technical testing begins.
Expected outcome: No patient is exposed to potentially inaccurate fluid removal while the machine is being evaluated. If the system later passes the required verification reliably, troubleshooting can stop.
2. Confirm the Reported Failure
Determine exactly what failed:
- A pre-treatment verification
- A service or performance check
- A repeated fluid-balance warning
- Unexpected difference between programmed and measured fluid removal
- An intermittent rather than consistent result
Record the exact displayed message and the conditions under which the failure occurred.
Expected outcome: The issue is defined clearly enough to reproduce under controlled conditions. If the concern cannot be reproduced and all required verification tests pass, document the results and troubleshooting can stop.
3. Check the Test Setup Before Suspecting the Machine
If the issue was identified during a bench or verification procedure, confirm that the test setup itself is correct.
Inspect for:
- Correct test connections
- Correct containers or measurement devices
- Stable placement
- Tubing routed without kinks
- No external leaks
- No accidental drainage or siphoning
- Correct initial fluid levels or measurement setup
- Appropriate zeroing or preparation of external test equipment when required
Expected outcome: The verification setup is mechanically stable and correctly assembled. If correcting the test setup produces an acceptable verification result, troubleshooting can stop after repeating the test.
4. Inspect the Disposable and External Fluid Path
Check the installed cartridge or disposable fluid path for:
- Incorrect loading
- Kinked tubing
- Partially closed or obstructed tubing
- Loose connections
- External leaks
- Air where it should not be present
- Damaged disposable components
- Improper routing
Do not open or modify sealed fluid-path components.
Expected outcome: The external fluid path is intact, properly loaded, unobstructed, and leak-free. If correcting an external setup problem restores verification, repeat the complete test and troubleshooting can stop.
5. Verify Drain and Supply Conditions
Confirm that required water, drain, and other external fluid connections are correctly established and are not creating an abnormal flow condition.
Inspect accessible hoses and connections for:
- Kinks
- Compression
- Partial disconnection
- Leakage
- Obstruction
- Unusual routing
- Drain positioning that could interfere with expected flow
Expected outcome: External supply and drain conditions are normal and stable. If correcting an external connection or restriction restores fluid-balance verification, troubleshooting can stop after retesting.
6. Eliminate Measurement Error
If a separate measurement device is being used for verification, confirm that it is suitable for the test, functioning correctly, and prepared according to its approved procedure.
Check for:
- Unstable scale placement
- Container contact with surrounding surfaces
- Fluid loss from splashing
- Evaporation during an extended test
- Incorrect tare or zero condition
- Tubing exerting force on a weighing container
Do not adjust the Tablo simply to match questionable test equipment.
Expected outcome: The external measurement method is reliable. If correcting the measurement setup resolves the apparent discrepancy, repeat the verification and troubleshooting can stop.
7. Repeat the Test With a Known-Good Disposable
If permitted by the applicable procedure, install a new known-good compatible disposable and repeat the fluid-balance or ultrafiltration verification.
This helps separate a disposable-related restriction or leak from a machine-related problem.
Expected outcome: The known-good disposable produces a consistent verification result. If the original disposable is identified as the cause, replace it and document the finding.
8. Inspect for Visible Leakage During the Test
Observe all accessible fluid connections and external pathways during controlled operation. Look for any leakage that could alter the measured volume without being immediately obvious.
Stop testing if significant leakage, electrical exposure, or other unsafe conditions develop.
Expected outcome: No external fluid loss is present. If a loose or leaking external connection is corrected and verification then passes, troubleshooting can stop after successful repeat testing.
9. Restart and Repeat the Approved Verification
After external causes have been addressed, perform a normal controlled restart if appropriate and repeat the approved ultrafiltration or fluid-balance verification from the beginning.
Do not alter calibration values, service parameters, or internal adjustment factors merely to make the test pass.
Expected outcome: The verification completes consistently within the applicable manufacturer acceptance criteria. Troubleshooting can stop.
10. Perform Final Functional and Safety Verification
Before return to clinical use, ensure that all required fluid-system, alarm, functional, and safety checks associated with the corrective action have been completed using approved procedures and test equipment.
A single passing test after repeated unexplained failures should be evaluated carefully for intermittency.
Expected outcome: Fluid-balance and ultrafiltration performance are repeatable and meet the applicable manufacturer requirements. The machine can be returned to service only when reliability is established.
If the Problem Persists
If the disposable, test setup, external fluid path, supply and drain conditions, leaks, and independent measurement method have all been verified, common external causes have been ruled out.
The remaining problem may involve an internal flow-measurement system, balancing mechanism, pump performance, valve operation, sensor calibration, internal leak, software calculation, or other service-level fluid-control issue.
Do not attempt to compensate for the discrepancy by changing calibration or hidden service values without authorized manufacturer procedures.
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
- Evaluated using appropriate Outset Medical documentation and approved test equipment
- Repaired or calibrated only by qualified personnel
After repair, the machine must successfully complete all applicable manufacturer fluid-balance, ultrafiltration, alarm, and functional verification before return to clinical use.
Knowing when to stop external troubleshooting and escalate a fluid-accuracy problem is proper troubleshooting.
Clinical Use Tip
Never return a dialysis machine to patient use when fluid-removal accuracy is uncertain, even if the discrepancy appears small or intermittent.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Clinical staff reported that the Tablo failed fluid-balance verification during preparation for clinical use."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found a kink in the externally routed disposable tubing that restricted fluid movement during the verification test."
Resolution
What action was taken.
Example:
"The disposable tubing was correctly rerouted, the verification was repeated successfully, and required fluid-system functional checks passed before return to service."
Helpful Details to Include (If Known)
- Exact verification message or failure
- Whether the issue occurred clinically or during bench testing
- Programmed versus measured fluid behavior when documented
- Disposable condition and routing
- Supply and drain connection condition
- Presence or absence of external leaks
- Measurement equipment used
- Known-good disposable results
- Results before and after correction
- Whether the failure was repeatable
- Final fluid-balance verification result
- Final device status
Final Thought
Fluid-balance and ultrafiltration concerns require a conservative approach because they directly affect patient treatment. Verify the test method, disposable, external fluid path, and connections before suspecting internal failure, then escalate any unresolved or intermittent accuracy problem with complete CCR documentation.
That is successful troubleshooting.