Anticoagulation in Hemodialysis Flashcards

Why is anticoagulation necessary during hemodialysis?

Answer: Blood contact with the extracorporeal circuit activates the coagulation cascade, which would clot the dialyzer and tubing

The extracorporeal circuit (tubing, dialyzer) is a foreign surface that activates platelets and clotting factors. Without anticoagulation, the system would clot within minutes, terminating treatment and potentially causing blood loss.

What is the most commonly used anticoagulant in hemodialysis?

Answer: Unfractionated heparin (UFH)

Unfractionated heparin is the standard anticoagulant for hemodialysis. It acts rapidly, has a short half-life (1–2 hours), is reversible with protamine sulfate, and is cost-effective. It is administered as a bolus at initiation and continuous infusion during treatment.

For a patient at high bleeding risk (e.g., post-surgery or active GI bleed), which hemodialysis anticoagulation approach is preferred?

Answer: No-heparin (heparin-free) dialysis with frequent saline flushes to maintain circuit patency

For high-bleeding-risk patients, heparin-free dialysis uses saline flushes (50–100 mL every 15–30 minutes) to rinse the circuit and prevent clotting without systemic anticoagulation. High blood flow rates also reduce clotting tendency.

What does ACT (Activated Clotting Time) measure in the context of hemodialysis anticoagulation monitoring?

Answer: The time for whole blood to clot, used to assess the adequacy of heparin anticoagulation

ACT measures the time for whole blood to clot in the presence of an activating agent. Normal ACT is 90–130 seconds; therapeutic range during hemodialysis is typically 150–200 seconds. It guides heparin dose adjustments.

A patient on hemodialysis is known to have heparin-induced thrombocytopenia (HIT). Which anticoagulant is safe to use as an alternative?

Answer: Argatroban or lepirudin (direct thrombin inhibitors)

HIT is caused by antibodies against heparin-platelet factor 4 complexes. ALL heparin products (including LMWH) are contraindicated. Direct thrombin inhibitors like argatroban do not cross-react with HIT antibodies and are the safe alternative.

What is the role of the priming step in anticoagulation preparation before connecting a patient to the hemodialysis circuit?

Answer: Priming with heparinized saline coats the circuit surfaces, reducing thrombogenic activation when blood contacts the lines

Priming the extracorporeal circuit with heparinized saline pre-coats the tubing and dialyzer with heparin, reducing the thrombogenic surface. It also removes manufacturing residuals and trapped air from the circuit.