exam 2!

📚 CHAPTER 9: Coagulation Disorders

🩸 OVERVIEW OF HEMOSTASIS

• Hemostasis = stopping blood loss through clot formation

• 3 stages:
  

  1. Vessel spasm (vasoconstriction)

  2. Platelet plug formation

  3. Fibrin clot formation via clotting cascade

🧪 LABS TO MONITOR

🧨 ANTICOAGULANTS

1.Heparin

• Action: Inhibits thrombin + factor Xa → prevents clot formation

• Route: IV or subQ

• Use: DVT, PE, MI, open heart surgery, catheter flushes

• Antidote: Protamine sulfate

• BBW: Spinal/epidural hematoma risk with neuraxial anesthesia

• Monitor: aPTT, platelets (HIT)

• Safe in pregnancy

🔴 Special Condition: Heparin-Induced Thrombocytopenia (HIT)

• Sudden drop in platelets > 50%

• Stop heparin, switch to argatroban or fondaparinux

2.Low-Molecular-Weight Heparins (LMWHs) – Enoxaparin

• Action: Inhibits factor Xa more than thrombin

• Route: subQ (abdomen), longer half-life than heparin

• Use: DVT prophylaxis, post-op, immobile patients

• Do NOT expel air bubble, rotate injection sites

• Antidote: Protamine sulfate (partial reversal)

• BBW: Same as heparin

3.Vitamin K Antagonist – Warfarin

• Action: Inhibits synthesis of vitamin K–dependent factors (II, VII, IX, X)

• Route: PO only

• Use: Afib, valve replacement, DVT/PE prevention

• Antidote: Vitamin K (phytonadione)

• BBW: Risk of major/fatal bleeding

• Pregnancy: Category X

• Monitor: INR (goal 2–3)

• Teach: Avoid sudden increase in leafy greens

🔴 Warfarin Interactions:

• ↑ Effect: antibiotics, NSAIDs, amiodarone

• ↓ Effect: leafy greens, vitamin K, carbamazepine

• Many drug-food and drug-drug interactions

4.Direct Thrombin Inhibitor – Dabigatran

• Use: Stroke prevention in Afib, DVT/PE

• No routine labs

• BBW: Spinal hematoma, risk with abrupt stop = thrombotic events

• Antidote: Idarucizumab

• Swallow whole, don’t crush or chew

5.Factor Xa Inhibitors – Rivaroxaban, Apixaban

• Use: Stroke prevention in Afib, post-op DVT/PE

• BBW: Risk of spinal hematoma + abrupt stop = thrombotic events

• No antidote for rivaroxaban (Andexanet alfa is emerging)

• No monitoring required

• Avoid in severe renal impairment

🩹 ANTIPLATELET AGENTS

6.ADP Receptor Blocker – Clopidogrel

• Action: Prevents platelet aggregation

• Use: Prevents MI, stroke, post-PCI (stent)

• BBW: Poor metabolizers = ↓ drug effect → ↑ clot risk

• Hold 5–7 days before surgery

• No antidote

Other ADP blockers:

• Prasugrel: ↑ bleeding risk, avoid if hx of stroke/TIA

• Ticagrelor: Reversible; do not exceed aspirin 100mg daily

7.Thromboxane A2 Inhibitor – Aspirin

• Use: MI, stroke prevention

• Irreversibly inhibits platelet aggregation

• Side effects: GI upset, bleeding

• Stop 7 days before surgery

8.Glycoprotein IIb/IIIa Inhibitors – abciximab, eptifibatide, tirofiban

• IV use in cath lab

• Most potent platelet inhibitors

• Used for high-risk PCI

💥 THROMBOLYTICS (Fibrinolytics)

9.tPA – Alteplase

• Use: Acute MI, ischemic stroke (within 3–4.5 hours), massive PE

• Action: Breaks up clots by converting plasminogen → plasmin

• BBW: Severe bleeding

• Contraindications:
  

  • Any history of hemorrhagic stroke

  • Recent surgery or trauma

  • Uncontrolled HTN

• Pregnancy or lactation, as well as severe hepatic or renal impairment, should also be considered before administering the treatment.

⛔ DRUGS TO CONTROL BLEEDING (Reversal Agents)

🧠 PATIENT TEACHING / NURSING PRIORITIES

⚠ ALL ANTICOAGULANTS & ANTIPLATELETS:

• Report: unusual bleeding, bruising, black/tarry stools, pink urine

• Avoid: contact sports, hard toothbrushes, razors

• Do not take with NSAIDs or herbal supplements (ginkgo, garlic, ginseng = ↑ bleeding)

• Monitor labs, hold before surgery if required

• Safety: fall risk, protect from injury

• Wear med alert bracelet

📝 NCLEX FAVORITES

• Patient on warfarin has INR of 5.5 = HOLD & give vitamin K

• Heparin is IV, warfarin is oral = can overlap when transitioning

• HIT → STOP heparin immediately, switch to direct thrombin inhibitor

• tPA window for stroke = 3–4.5 hours