Rising TMP and a Dark, Streaked Dialyzer

Interpretation:

• TMP rising from 85 to 240 mmHg is the key finding. TMP reflects the pressure gradient across the membrane; a rising TMP at stable settings usually means the membrane is losing permeability - clot or protein/fibrin deposition in the fibers.
• Arterial pressure becoming more negative (-120 to -180) indicates increased resistance on the pull side, consistent with a partially obstructed dialyzer or access.
• Venous pressure rising (165 to 285) indicates increased resistance on the return side, consistent with clot in the dialyzer or venous chamber.
• Visible dark, streaked fibers and clot in the venous chamber make dialyzer clotting the most likely explanation.

Alternatives to rule out:

• Catheter malfunction: would typically make arterial pressure more negative but not drive TMP up this far; the brisk arterial aspiration argues against it.
• Venous needle or line problem, kink, or stenosis: would raise venous pressure but not explain the TMP trend.
• Hypotension or low flow: can alter pressures but not produce visible clot.
• Air or foam in the chamber: check, but does not explain TMP.

The combination of all three pressure changes plus visible clot is not a single-line problem.

Actions in order:

1. Assess the patient first - vital signs, symptoms, access site, and whether there is any sign of hemolysis (chest pain, back pain, dark urine).
2. Check for simple causes - kinks, closed clamps, a line trapped under the arm, chamber level, and catheter position.
3. Reduce blood flow and stop UF temporarily to lower TMP while you assess.
4. Inspect the dialyzer and chamber with a light; note the extent of clotting.
5. Call the nephrologist for orders on anticoagulation.

What I would not do:

• Do not simply increase the heparin bolus without an order.
• Do not keep running at a TMP far above baseline just to finish the prescription. A high TMP can damage fibers, cause leaks, and contribute to hemolysis.
• Do not return clotted blood to the patient.

Criteria for terminating:

• TMP continues to rise despite reduced flow and UF off.
• Clot extends through the dialyzer or the venous chamber.
• Pressure limits are repeatedly reached.
• Any sign of hemolysis or fiber leak.

If terminating, do not return the clotted blood; document the lost volume, notify the physician, and plan makeup dialysis if needed.

Anticoagulation: the current regimen - a 1,000-unit bolus with no maintenance - is a likely contributor. Discuss with the nephrologist whether maintenance heparin, a higher bolus, or an alternative anticoagulation strategy is appropriate, and check baseline coagulation status.

Access: a tunneled catheter can contribute to poor flow and clotting. Review catheter function, history of previous clotting, and whether lock solution or catheter position needs attention.

Prescription and circuit:

• Consider whether the blood flow and dialyzer are appropriate for this patient.
• Ensure adequate pre-dilution or rinse according to unit protocol.
• Confirm the heparin was actually delivered and timed correctly.

Monitoring plan: record baseline and hourly pressures and TMP so a trend is visible early. Teach the patient to report chest or back pain, chills, or dark urine.

Documentation: report the event, the lost blood volume, the interventions, and the physician communication, and flag the chart so the next nurse knows the circuit clotted.