Heparin

Definition

Heparin is an anticoagulant that activates antithrombin III, inactivating thrombin and factor Xa. It is used for DVT/PE treatment, ACS, hemodialysis, surgery, and line patency.

Types

• Unfractionated heparin (UFH): IV or SubQ. Monitor aPTT. Rapid onset.
• Low-molecular-weight heparin (LMWH): Enoxaparin (Lovenox), dalteparin. SubQ. More predictable; usually no monitoring needed. Cannot reverse as easily.

Monitoring

• Test: aPTT (activated partial thromboplastin time)
• Therapeutic aPTT: 1.5 to 2.5 times the control value
• Also monitor: Platelet count (HIT risk)

Antidote

Protamine sulfate. Dose: 1 mg per 100 units of heparin received.

Heparin-Induced Thrombocytopenia (HIT)

Immune reaction causing paradoxical clotting. Platelets drop greater than 50% from baseline, typically 5 to 14 days after heparin. STOP heparin (and LMWH) immediately; switch to a direct thrombin inhibitor (argatroban, bivalirudin). Do NOT transfuse platelets.

Nursing Considerations

• Administer SubQ at 90-degree angle in abdomen.
• Do NOT aspirate or rub site (causes bruising).
• Rotate injection sites.
• Monitor aPTT (UFH) and platelets.
• Teach bleeding precautions.
• NOT teratogenic; safe in pregnancy (unlike warfarin).

NCLEX Relevance

Protamine antidote, HIT, and SubQ technique are top test points.