Hemostasis and Blood Transfusion

Hemostasis and Blood Transfusion

Hemostasis and Blood Transfusion

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Hemostasis Essentials - Clotting Crew Call

  • Hemostasis: Physiological process halting blood loss post-injury.
  • Key Stages:
    • Vascular Spasm: Initial vasoconstriction reduces blood flow.
    • Primary Hemostasis (Platelet Plug Formation):
      • Adhesion: Platelets bind exposed collagen via vWF-GpIb.
      • Activation: Shape change; release of ADP, TXA2 (potent vasoconstrictor & platelet activator).
      • Aggregation: GpIIb/IIIa binds fibrinogen, linking platelets.
    • Secondary Hemostasis (Coagulation Cascade): Enzymatic cascade forming fibrin clot.
      • Coagulation Cascade Diagram
    • Fibrinolysis: Clot dissolution by plasmin.
  • Simplified Coagulation Pathways:

⭐ Vitamin K is crucial for factors II, VII, IX, X (📌 Mnemonic: 1972) & anticoagulant proteins C, S.

Bleeding & Clotting Chaos - When Systems Fail

Disorders of hemostasis: excessive bleeding or thrombosis. Key conditions:

DisorderDefectPTaPTTBTPlateletsClinical Features / Notes
Hemophilia AFVIII def.NNNHemarthrosis, deep muscle hematomas; X-linked recessive
Hemophilia BFIX def.NNNLike Hemophilia A; X-linked recessive
vWDvWF def./abnormalityNN/↑NMucocutaneous bleed (epistaxis); AD; 📌 Most common inherited
ITPAnti-platelet Abs (GPIIb/IIIa)NN↓↓↓Isolated ↓platelets; petechiae, purpura; often post-viral
TTPADAMTS13 def./autoAbNN↓↓↓FAT RN: Fever, MAHA, ↓Platelets, Renal, Neuro sx
DICConsumptive coagulopathyBleeding + Thrombosis; ↑D-dimer, ↓Fibrinogen; schistocytes
  • Thrombophilias (Hypercoagulable States):
    • Factor V Leiden: Most common inherited (APC resistance).
    • Antiphospholipid Syndrome (APS): Acquired; arterial/venous thrombosis, recurrent fetal loss.
    • Protein C/S, Antithrombin III deficiencies.

⭐ FFP replaces all clotting factors; Cryoprecipitate: rich in Fibrinogen, FVIII, vWF, FXIII.

Hemostasis Meds & Moves - Drug & Scalpel Fixes

Pharmacological:

  • Anticoagulants:
    DrugMOAMonitorReversal
    UFHPotentiates ATIIIaPTTProtamine (1mg/100U)
    WarfarinVit K antagPT/INR (2-3)Vit K, PCC, FFP
    DOACsDirect Th/Xa inhib(Specific)Idaru (Dabi), Andex (Xa inh)
  • Procoagulants:
    • Tranexamic Acid (TXA): Antifibrinolytic (1g IV).
    • DDAVP: ↑vWF, FVIII.
    • Blood: FFP, Cryo, Plts.

      ⭐ FFP replaces all clotting factors; dose 10-15 mL/kg. Cryoprecipitate: Fibrinogen, FVIII, FXIII, vWF.

Surgical & Topical:

  • Mechanical: Pressure, ligature, tourniquet.
  • Thermal: Cautery, Argon Plasma Coagulation (APC).
  • Topical: Gelfoam, Surgicel, Thrombin. 📌 Surgicel Slowly resorbed.

Anticoagulation Reversal Algorithm:

Blood Transfusion Basics - Life‑Saving Liquids

  • Indications: Symptomatic anemia, Hb < 7 g/dL (or < 8 g/dL if cardiac hx), active bleeding, coagulopathy.

  • Blood Products Table:

    ProductContentKey IndicationVolume/Effect (Typical)Storage Temp
    PRBCRBCs↑O₂ capacity~300mL; 1U ↑Hb 1g/dL2-6°C
    PlateletsPlateletsBleeding, Plt < 10-20k~50mL(RDP); 1U RDP ↑Plt 5-10k20-24°C (agitate)
    FFPAll factorsCoagulopathy (INR > 1.5)~250mL; 10-15mL/kg-18°C
    CryoprecipitateFibrinogen, FVIII, vWFFibrinogen < 100mg/dL~15mL/U; 10U ↑Fib 50-70mg/dL-18°C
  • Massive Transfusion Protocol (MTP): >10 units PRBC/24h. Ratio 1:1:1 (PRBC:FFP:Platelets).

  • Acute Transfusion Reaction Management:

Signs and Symptoms of Transfusion Reactions

⭐ ABO incompatibility (clerical error) is the leading cause of fatal transfusion reactions.

High‑Yield Points - ⚡ Biggest Takeaways

  • Primary hemostasis: Platelet plug formation (adhesion, activation, aggregation).
  • Secondary hemostasis: Coagulation cascade activation leads to a stable fibrin clot.
  • Vitamin K dependent factors include II, VII, IX, X, Protein C & S.
  • FFP replaces all clotting factors; Cryoprecipitate for fibrinogen, Factor VIII, vWF, Factor XIII.
  • Massive transfusion protocol (MTP) aims for 1:1:1 ratio of PRBC:FFP:Platelets.
  • Febrile non-hemolytic is the most common transfusion reaction; monitor for TRALI and TACO.

Practice Questions: Hemostasis and Blood Transfusion

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All are predisposing factors of Deep Vein thrombosis, EXCEPT :

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Flashcards: Hemostasis and Blood Transfusion

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_____ flaps this case the blood supply is isolated, disconnected, and then reconnected using microsurgery at the new site

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_____ flaps this case the blood supply is isolated, disconnected, and then reconnected using microsurgery at the new site

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