Blood Transfusion

Blood Products:

• pRBCs:
  • Transfusion goal of Hgb >7 for most pts
  • Sickle Cell Anemia transfuse to Hgb >10 preop
• Platelets:
  • Transfusion threshold:
    • 100k for neurosurgery
    • 50k for general surgery
    • 20k if febrile
    • 10k for any patient
    • Procedures:
      • Central line: 20k
      • Lumbar puncture: 20k in patients with hematologic malignancies; 50k in patients without hematologic malignancies
• Plasma:
  • Indicated for: multiple acquired factor deficiencies, or factor deficiencies where specific factor concentrates are unavailable
• Cryoprecipitate:
  • Fraction of plasma that precipitates when fresh frozen plasma is thawed at 1.0 to 4.0 °C (33.8-39.2 °F)
  • Contains: fibrinogen, von Willebrand factor, and factor VIII
  • Used to treat: hypofibrinogenemia and disseminated intravascular coagulation (DIC). Cryoprecipitate is also used empirically in uremic bleeding.
• Four-factor PCC:
  • Contains factors II, VII, IX and X
  • Preferred product for patients experiencing life-threatening bleeding while taking warfarin
• Mass transfusion (MTP): Products are usually administered 1:1:1 (pRBC/Plt/FFP)

Product modifications:

• Leukoreduction:

  • More than 80% of blood banks in the United States adhere to universal leukoreduction.
  • Indicated for:
    • chronic transfusion dependence,
    • history of febrile hemolytic transfusion rxn
    • candidates/recipients of a solid-organ or hematopoietic stem cell transplant
    • immunocompromised recipients who are CMV seronegative.

• Irradiation: kills lymphocytes and circulating stem cells in product. Indicated in patients with severe immunodeficiency, whether inherited or acquired (eg: chemotherapy).

• Washing: Used in patients with a history of severe/recurrent allergic reactions, IgA Deficiency (when IgA-deficient donors are unavailable).

Transfusion Reactions:

• Hemolytic Reactions:

  • Acute Hemolytic Transfusion Reactions
    • Typically result from clerical/lab error
    • Presents with fever and flank pain. More severe cases w/ hypotension, DIC, hemoglobinuria, and death
    • Volume expansion and supportive care for associated complications (DIC, acute kidney injury) are required
    • Should trigger an investigation into systems errors that led to incorrect blood transfusion
  • Delayed Hemolytic Transfusion Reaction
    • Typically presents 7-14 days post-transfuse w/ hemolysis
    • Typically results from remote immunity/exposure, now w/ low-level Ab titer against the blood product which simply cannot be detected. Once exposed, induces an anamnestic response.
    • Criteria:
      • Positive DAT 24h-28d post-transfuse
      • Identification of RBC antigen
      • Evidence of hemolysis: low haptoglobin, spherocytes on smear

• Non-hemolytic Reactions

  • Transfusion-Associated Circulatory Overload (TACO):

    • Most common serious complication of blood transfusion, affecting 1% to 8% of transfusion recipients
    • Presents w/ respiratory distress within 6 hours of transfusion, positive fluid balance, elevated CVP/BNP, and radiographic pulmonary edema
    • Treat w/ diuresis, decreased transfusion speed

  • Transfusion-Related Acute Lung Injury (TRALI)

    • Presents w/ noncardiogenic pulmonary edema that occurs within 6 hours of transfusion
    • Most cases occur because of HLA or neutrophil-specific antibodies in donors that bind to and activate recipient leukocytes in the pulmonary vasculature
    • Unlikely to recur in subsequent transfusions

  • Febrile Nonhemolytic Transfusion Reaction

    • Mediated by proinflammatory cytokines produced by donor leukocytes during storage
    • DAT negative
    • Treat w/ antipyretics
    • Leukoreduction reduces incidence rates

  • Transfusion-Associated Graft-versus-Host Disease

    • Donor lymphocytes in a cellular blood product (erythrocytes or platelets) engraft in an immunocompromised recipient and cause toxic effects in the bone marrow, skin, liver, and gastrointestinal tract.
    • Occurs in pts receiving chemotherapy for autoimmune disorders or malignancy, patients with aplastic anemia or other forms of immunodeficiency, patients who have undergone stem cell or other transplantation, recipients of blood components from first-degree relatives, and premature infants
    • Prevented with irradiation

• Misc:

  • Patients with warm autoimmune hemolytic anemia have autoantibodies that may make crossmatch-compatible units impossible to find; these patients should be transfused with ABO and Rh typed (but inevitably crossmatch-incompatible) blood.

References:

• MKSAP