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Continuous Renal Replacement Therapy (CRRT)
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Model
What This Guide Helps With
This guide helps troubleshoot a Baxter PrismaFlex Alarm: Set Disconnection condition. This alarm may be caused by low filter pressure, possible set or pressure pod disconnection, tubing obstruction, access flow instability, set loading issue, or pressure sensing failure.
A Set Disconnection alarm should be treated as a potential blood path or pressure monitoring safety event because it may indicate abnormal filter pressure behavior or a possible interruption in the extracorporeal circuit.
Step-by-Step Troubleshooting
Ensure Patient Safety First
- Remove the PrismaFlex from active patient use if the alarm cannot be quickly verified and corrected.
- Confirm the patient is clinically stable and involve the bedside clinical team immediately.
- Verify alternate therapy, monitoring, or a backup CRRT device is available if treatment must continue.
- Follow facility procedure for CRRT interruption, blood return decisions, anticoagulation concerns, and circuit management.
Expected: The patient is protected from unsafe therapy interruption, blood flow issues, or unresolved pressure monitoring faults.
Why it matters: A Set Disconnection alarm may indicate an actual blood path disconnection or a pressure monitoring problem that could affect treatment safety.
Verify the Reported Alarm and Behavior
- Confirm the screen displays Alarm: Set Disconnection.
- Observe whether the alarm occurs during startup, priming, shortly after treatment begins, during active therapy, during patient movement, after flow changes, or after a set change.
- Document whether filter pressure is below +10 mmHg or previously had an operating point above +10 mmHg.
- Look for blood pump stoppage, therapy interruption, visible loose tubing, loose pressure pod connection, abnormal pressure readings, or repeated alarms after reset.
Expected: The alarm is clearly observed and reproducible, or the event history supports the reported condition.
Why it matters: This confirms a true system-reported low filter pressure condition instead of a user misunderstanding or unrelated therapy interruption.
Check the Filter Pressure Pod Installation
- Inspect the filter pressure pod for proper seating in the pressure sensor housing.
- Confirm the pod is fully seated, aligned, and not loose.
- If permitted by facility procedure, remove and reinstall the pod to ensure proper contact.
- Do not force the pod or modify the pressure sensor area.
Expected: The pod sits securely in the sensor housing and the alarm clears after correction.
Why it matters: If the pod is not installed correctly, the PrismaFlex may read filter pressure incorrectly and interpret the condition as a set disconnection.
Inspect the Sensor Housing for Debris or Contamination
- Check the filter pressure sensor housing for debris, dried fluid, residue, or anything preventing proper pod contact.
- Clean or remove visible external debris according to facility-approved cleaning procedures.
- Do not force tools into the sensor area.
- Do not perform internal disassembly during clinical troubleshooting.
Expected: The sensor housing is clean, unobstructed, and able to properly contact the pressure pod.
Why it matters: Debris in the pressure sensor housing can interfere with pressure transmission and create a false low-pressure condition.
Check the Line Between the Blood Pump and Filter
- Trace the blood flowpath from the blood pump to the filter.
- Confirm the tubing is fully connected and properly routed.
- Look for tubing that is separated, stretched, pulled loose, or incorrectly loaded.
- Correct any visible external connection problem according to facility procedure.
Expected: The line between the blood pump and filter is securely connected with no visible disconnection.
Why it matters: A real disconnection between the blood pump and filter can cause filter pressure to fall below the alarm threshold.
Check for Upstream Obstruction
- Inspect the blood flowpath before the filter for closed clamps.
- Check for kinked tubing, compressed lines, improper set routing, obstruction near the blood pump, or restricted access flow.
- Correct any external obstruction found.
- Confirm tubing is open and routed correctly before attempting to continue treatment.
Expected: Tubing is open, correctly routed, and free of restrictions.
Why it matters: An upstream restriction can prevent normal blood flow into the filter and cause an abnormal filter pressure drop.
Verify Blood Flow Is Appropriate for the Access Device
- Review the prescribed blood flow rate with clinical staff.
- Confirm the selected blood flow is appropriate for the patient’s access device.
- If the access device cannot support the selected flow, coordinate with clinical staff before any flow adjustment.
- Do not independently change therapy settings outside facility policy or clinical direction.
Expected: Blood flow is within a range the access device can support without causing abnormal pressure behavior.
Why it matters: If blood flow is unstable or not supported by the access condition, the system may not maintain expected pressure values.
Check for Access or Set-Related Causes
- Work with clinical staff to confirm there are no access problems contributing to unstable flow.
- Check for poor catheter flow, line reversal issues, patient movement affecting access flow, clotted or malpositioned access catheter, improper set loading, or recent set manipulation.
- Confirm the set is loaded correctly and has not been disturbed.
- Document whether the alarm follows patient movement, access changes, or set manipulation.
Expected: Access and set conditions are stable, and the alarm is not caused by an external flow issue.
Why it matters: Filter pressure problems may originate from access or set conditions before assuming a device fault.
Perform the System Tools Self-Test
- If external tubing, pod, and access checks do not resolve the alarm, perform the appropriate self-test through SYSTEM TOOLS if allowed by facility procedure.
- Use the self-test to help reposition the pod membrane and verify pressure response.
- Follow on-screen prompts and facility procedure.
- Do not continue use if the self-test fails or pressure readings remain abnormal.
Expected: The self-test completes successfully and pressure readings normalize.
Why it matters: The pod membrane may not be positioned correctly for accurate pressure measurement, even when the pod appears installed.
Replace the Set if the Alarm Remains Set-Related
- If the pod, tubing, and flowpath appear correct but the alarm continues, change the set according to PrismaFlex and facility procedure.
- Load and prime the new set correctly.
- Confirm all pods, tubing segments, clamps, and connections are properly installed.
- Monitor whether the alarm returns with the new set.
Expected: The alarm clears with a properly loaded and primed new set.
Why it matters: A defective, contaminated, or improperly functioning set may cause repeated filter pressure measurement issues.
Recheck Operation After Corrective Action
- Confirm the alarm clears.
- Verify filter pressure displays appropriately.
- Confirm no tubing disconnection is present.
- Confirm treatment can run without recurring Set Disconnection alarms.
- Watch for new access, return, filter, or pressure alarms.
Expected: The PrismaFlex operates normally without recurring alarm conditions.
Why it matters: Rechecking operation confirms whether the issue was corrected or whether the device needs escalation.
If the Problem Persists
If the Set Disconnection alarm continues after the pressure pod, tubing, sensor housing, access flow, self-test, and set replacement have been checked, external and common causes have been ruled out.
Persistent Set Disconnection alarms may indicate filter pressure measurement failure, filter pressure sensor failure, ARPS circuit leakage or malfunction, internal pressure sensing fault, or another device-side hardware issue.
Remove the device from service, label it Out of Service, and send it for repair or bench evaluation.
Clinical Engineering should evaluate pressure sensing performance, inspect for ARPS circuit leakage, perform pressure sensor calibration if applicable, and replace the filter pressure sensor if deviation remains.
Knowing when to stop is proper troubleshooting. Continued use with unresolved pressure sensing alarms is not appropriate.
Clinical Use Tip
Never troubleshoot on an active patient longer than necessary. Move the patient to a backup device first if therapy must continue, and avoid relying on a CRRT device with unresolved pressure monitoring faults.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"PrismaFlex reported Alarm: Set Disconnection during CRRT. Filter pressure dropped below +10 mmHg after previously operating above +10 mmHg, causing therapy interruption."
Cause
What was observed during troubleshooting.
Example:
"Filter pressure pod and blood flowpath inspected. No external tubing disconnection or obstruction found. Alarm persisted after pod reseating and set replacement, indicating likely filter pressure sensing or ARPS-related failure."
Resolution
What action was taken.
Example:
"Removed device from service and labeled Out of Service. Sent for bench evaluation of filter pressure sensor, ARPS circuit leakage, and pressure sensor calibration. Device not returned to service pending repair verification."
Helpful Details to Include (If Known)
- Alarm behavior
- Accessories swapped
- Power behavior
- Environmental factors
- Indicator lights
- Final device status
Final Thought
Set Disconnection alarms should always be treated as potential blood path or pressure monitoring safety events. Start with the obvious external causes, confirm the pod and tubing are correctly installed, then isolate whether the issue follows the set, the access condition, or the device. If the alarm persists after a new set and basic checks, escalation is appropriate. Clear documentation helps distinguish a corrected setup issue from a true pressure sensing failure.
That is successful troubleshooting.