Blood transfusion therapy involves transfusing whole blood or blood components (specific portion or fraction of blood lacking in patient). One unit of whole blood consists of 450 mL of blood collected into 60 to 70 mL of preservative or anticoagulant. Whole blood stored for more than 6 hours does not provide therapeutic platelet transfusion, nor does it contain therapeutic amounts of labile coagulation factors (factors V and VIII).
Blood components include:
1. Packed RBCs (100% of erythrocyte, 100% of leukocytes, and 20% of plasma originally present in one unit of whole blood), indicated to increase the oxygen-carrying capacity of blood with minimal expansion of blood.
2. Leukocyte-poor packed RBCs, indicated for patients who have experience previous febrile no hemolytic reactions.
3. Platelets, either HLA (human leukocyte antigen) matched or unmatched.
4. Granulocytes ( basophils, eosinophils, and neutrophils )
5. Fresh frozen plasma, containing all coagulation factors, including factors V and VIII (the labile factors).
6. Single donor plasma, containing all stable coagulation factors but reduced levels of factors V and VIII; the preferred product for reversal of Coumadin-induced anticoagulation.
7. Albumin, a plasma protein.
8. Cryoprecipitate, a plasma derivative rich in factor VIII, fibrinogen, factor XIII, and fibronectin.
9. Factor IX concentrate, a concentrated form of factor IX prepared by pooling, fractionating, and freeze-drying large volumes of plasma.
10. Factor VIII concentrate, a concentrated form of factor IX prepared by pooling, fractionating, and freeze-drying large volumes of plasma.
11. Prothrombin complex, containing prothrombin and factors VII, IX, X, and some factor XI.
Advantages of blood component therapy
1. Avoids the risk of sensitizing the patients to other blood components.
2. Provides optimal therapeutic benefit while reducing risk of volume overload.
3. Increases availability of needed blood products to larger population.
Principles of blood transfusion therapy
1. Whole blood transfusion
Ø Generally indicated only for patients who need both increased oxygen-carrying capacity and restoration of blood volume when there is no time to prepare or obtain the specific blood components needed.
2. Packed RBCs
Ø Should be transfused over 2 to 3 hours; if patient cannot tolerate volume over a maximum of 4 hours, it may be necessary for the blood bank to divide a unit into smaller volumes, providing proper refrigeration of remaining blood until needed. One unit of packed red cells should raise hemoglobin approximately 1%, hemactocrit 3%.
3. Platelets
Ø Administer as rapidly as tolerated (usually 4 units every 30 to 60 minutes). Each unit of platelets should raise the recipient’s platelet count by 6000 to 10,000/mm3: however, poor incremental increases occur with alloimmunization from previous transfusions, bleeding, fever, infection, autoimmune destruction, and hypertension.
4. Granulocytes
Ø May be beneficial in selected population of infected, severely granulocytopenic patients (less than 500/mm3) not responding to antibiotic therapy and who are expected to experienced prolonged suppressed granulocyte production.
