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Haemostasis, coagulation & blood transfusion

Aug 24, 20252 min read

Haemostasis, & blood transfusion

Moneer Almadani

Objectives

  • Introduction
  • Coagulation pathway
  • Blood disorders
  • Surgical haemorrhage
  • Blood transfusion
    • Indication
    • Complications
  • Massive blood transfusion

Introduction

Haemostasis is a complex process that prevents or terminates blood loss from a disrupted intravascular space

Stages:

  • Primary haemostasis:

    1. Vasoconstriction
    2. Platelet plug formation

  • Secondary haemostasis: 3) Blood clotting -coagulation- (fibrin formation) 4) Fibrinolysis

Coagulation pathway

Intrinsic Factor Surface contact XII-IX a = X (VIII, PL< Ca++) ⇒ X a

Intrinsic Factor Tissue Damage TF: VII a ⇒ X = X a

Common Pathway X a + (V, PL, Ca++) + Prothrombin ⇒ Thrombin ⇒ XIII ⇒ XIII a | v Fibronogen ⇒ Fibrin ⇒ XIIa = Stable fibrin clot

  • PT is reported with the international normalized ratio (INR). Extrinsic Pathway monitored by INR - affected by warfarin Intrinsic Pathway monitored by aPTT - affected by Heparin

Blood disorders

Surgical haemorrhage

Primary: At the time of injury or surgery

Intermediate/ Reactionary: Within 24 h of injury or surgery

  • Postop high BP, sneezing, coughing

Secondary: 48-72 h after injury or surgery

  • Infection/ Sepsis

Blood transfusion

  • 1 unit of PRBC has 300 ml, raise Hb around 1 gm
  • PRBC could be stored up to 6 weeks
  • Type and screen Vs type and cross match
  • Thrombocytopenia
  • Stop aspirin to restore Platelets function
  • PLT should be at least 50,000 before surgery, less than 20,000 associated with bleeding

Fresh frozen plasma FFP:

  • Replaces clotting factors
  • No RBC, No PLT

Cryoprecipitate:

  • Replaces fibrinogen
  • VWF
  • Some clotting factors

Studies have shown an association between anemia and increased mortality, It is not clear that correction of anemia will improve mortality. - Clear risk of postoperative death when the Hg fell below 7 g/dL

Indications of blood transfusion

Steps prior to blood transfusion

Complications of blood Tx

  • Acute: fever due to WBC of donor
  • Urticaria: recipient’s preformed-antibodies
  • Hyperkalemia from potassium released from RBCs during blood bank storage
  • Late: hemolytic reaction: Immune sensitization (Rh D antigen)

Risks of infection in blood Tx

Complications of blood Tx

Symptoms of transfusion reaction:

  • Fever
  • Chills
  • Nausea
  • Low BP
  • Lumber pain
  • Chest pain
  • Abnormal bleeding

What to do? MBT

Massive Blood Transfusion MBT

  • Different definitions
  • Replacement of 10 units of PRBC in 24 hours,
  • 3 units over one hour are more sensitive
  • Replacement of 50% of total blood volume (TBV) within 3 h
  • Hemostatic and metabolic complications

Complications of MBT

References

Principles and Practice of Surgery Pg 27-37

Graph View

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