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What This Guide Helps With
Troubleshoot air detection and venous clamp problems caused by tubing placement, air, disposable setup, obstruction, contamination, or clamp-area issues.
Step-by-Step Troubleshooting
1. Protect the Patient
An air detector alarm or unreliable venous clamp is a patient-safety issue. Do not troubleshoot the detector or clamp while the patient relies on the machine's blood-return safety functions.
If the issue occurs during treatment, clinical staff must manage the blood circuit and patient according to facility procedure before technical troubleshooting.
Expected outcome: Patient safety is maintained and the device is removed from active treatment before technical evaluation.
2. Confirm the Exact Condition
Determine whether the machine has:
- Detected air
- Failed an air detector check
- Failed to recognize tubing
- Closed the venous clamp unexpectedly
- Failed to close or release the clamp
- Produced an intermittent alarm
Record the exact message and whether the problem occurs during setup or treatment.
Expected outcome: The complaint is clearly defined and reproducible.
3. Inspect the Blood Tubing and Disposable Setup
With the machine off patient, inspect the relevant blood tubing for:
- Air
- Loose connections
- Incorrect routing
- Kinks
- Flattening
- Damage
- Incorrect installation in the detector or clamp
Do not bypass the air detector or clamp.
Expected outcome: Tubing is properly routed and seated with no obvious air or physical defect. If correcting tubing placement resolves the issue, troubleshooting can stop after verification.
4. Inspect the Air Detector Area
Check the accessible detector surface and tubing channel for moisture, residue, contamination, or obstruction.
Clean only with the approved method and ensure the area is dry before retesting.
Expected outcome: The detector area is clean and the tubing is positioned correctly.
5. Inspect the Venous Clamp Area
With no patient connected, visually inspect the accessible clamp mechanism for:
- Tubing incorrectly placed
- Obstruction
- Dried residue
- Visible damage
- Foreign material preventing movement
Do not force the clamp open or closed.
Expected outcome: The clamp pathway is unobstructed and the tubing can be installed normally.
6. Replace Questionable Tubing or Disposable Components
If the tubing is stretched, damaged, deformed, contaminated, or otherwise suspect, install a new approved disposable set according to normal setup procedure.
Expected outcome: The air detector and clamp operate normally with the known-good disposable if the original setup was responsible.
7. Repeat the Normal Setup Check
Run the machine's normal user-accessible setup sequence and observe air detector and clamp behavior.
Do not enter service menus or bypass the safety test.
Expected outcome: The air detector passes its normal check and the venous clamp actuates as expected without recurring alarms.
8. Check for Intermittent Mechanical Behavior
Observe the clamp through several normal machine-controlled operations during the permitted setup process. Do not manually manipulate it beyond normal external interaction.
Expected outcome: Clamp movement is consistent, complete, and repeatable.
9. Perform Final Functional Verification
Verify that normal pre-treatment checks complete successfully and that no air detector or venous clamp fault remains.
Expected outcome: Both safety functions operate normally through setup. Troubleshooting can stop and the machine may be returned to service according to facility policy.
10. Escalate Persistent Safety-System Failure
If correct tubing placement, a clean detector/clamp area, and a known-good disposable do not resolve the problem, remove the machine from service.
Expected outcome: Internal detector, clamp actuator, sensing, control, or calibration problems are referred for qualified service.
If the Problem Persists
Common external tubing, positioning, contamination, disposable, and obstruction causes have been ruled out. A persistent condition may involve detector sensing, clamp actuation, internal control, alignment, or calibration.
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
Air detection and venous clamp safety performance must be verified before return to clinical use. Knowing when to stop external troubleshooting is proper troubleshooting.
Clinical Use Tip
Do not return a dialysis machine to service if either the air detector or venous clamp behaves intermittently, even if the fault temporarily clears.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Staff reported the Tablo failed its air detection check and the venous line clamp remained engaged during setup."
Cause
What was observed during troubleshooting.
Example:
"Clinical Engineering found the venous tubing was not fully seated in the designated detector and clamp pathway."
Resolution
What action was taken.
Example:
"Corrected tubing placement, repeated setup successfully, verified normal air detection and clamp operation, and returned the machine to service."
Helpful Details to Include (If Known)
- Exact alarm or message
- Setup or treatment occurrence
- Presence of visible air
- Tubing routing and condition
- Detector cleanliness
- Clamp-area condition
- Known-good disposable used
- Clamp response observed
- Setup result after correction
- Final device status
Final Thought
Air detection and venous clamp functions are critical dialysis safety systems. Rule out tubing placement, disposable, contamination, and obstruction problems first, but stop when the safety function remains unreliable. Verify normal operation before release and document the corrective action completely.
That is successful troubleshooting.