Transfusion medicine (Proceedings)
Choosing the Transfusion Type
Common transfusion types include fresh whole blood, stored whole blood, packed red blood cells, fresh frozen plasma, and frozen plasma. Other, less common transfusion products include cryoprecipitate, cryo-poor plasma, platelet-rich plasma, platelet concentrate, lyophilized albumin, and lyophilized platelets. Choosing a transfusion to administer will depend on the specific needs of the patient.
Fresh whole blood (FWB) is blood that is collected from a donor and transfused to a recipient within 8 hours. It contains red blood cells, platelets, plasma proteins, clotting factors, and immunoglobulins. Fresh whole blood becomes stored whole blood (WB) after 8 hours. Stored whole blood contains the same components as fresh whole blood, but the platelets will be inactive. Whole blood is stored at temperatures between 1 and 6°C for up to 35 days.Packed red blood cells (pRBC) are made from whole blood that has been centrifuged at high speed, and most of the plasma component has been removed. The resultant RBC units have a PCV of approximately 80%. RBC's are stored between 1 and 6°C for 20 to 35 days. Indications for use of red blood cell containing products include blood loss anemia, hemolytic anemia, and nonregenerative anemias. The advantages of pRBCs over whole blood are the decreased risk of volume overload and reduced exposure to plasma antigens. Packed RBC transfusions are administered to increase blood oxygen capacity in a patient that does not require albumin, clotting factors, or platelets.
Fresh frozen plasma (FFP) is prepared from whole blood by centrifugation at high speed, and then freezing the plasma supernatant within 6 hours of collection. The FFP units contain all the coagulation proteins, albumin, and immunoglobulins present in the starting whole blood unit. Storage at temperatures below -20°C retains clotting factor activity for up to 1 year. Plasma stored for more than 1 year is referred to as frozen plasma. This product does not contain the labile factors but is a source of other plasma proteins and clotting factors. The indications for plasma transfusion include control of active bleeding or as a pre-operative prophylaxis for patients with hereditary and acquired factor deficiencies. Plasma is used in cases of hemorrhage caused by severe liver disease, vitamin K deficiency, and DIC. FFP or FP can be used in the short-term management of hypoproteinemia or hypoalbuminemia associated with several underlying disorders. The benefit of FFP in these disorders is transient.
Cryoprecipitate is prepared by slowly thawing FFP at a cold temperature, and then centrifuging the partially thawed material to sediment the heavy, cold-insoluble proteins. The resultant cryoprecipitate contains an approximately 50% yield of Factor VIII, von Willebrand Factor, fibrinogen, and fibronectin in a volume approximately 1/10th of plasma. It is stored at temperatures below -20°C for up to 1 year. Major advantages of cryoprecipitate include small volume and ease of administration. Cryoprecipitate is the component of choice for treating Hemophilia A (Factor VIII deficiency), von Willebrand disease, and fibrinogen deficiency or dysfunction.
Cryopoor plasma is the remaining component after the production of cryoprecipitate. It contains all the serine protease clotting factors, anticoagulant and fibrinolytic factors, albumin, and globulin of FFP. It is stored at temperatures below -20°C for a 1 year or longer. Cryopoor plasma can be used for treating hemophilia B, deficiencies of vitamin K dependent factors, hypoproteinemia, or hypoglobulinemia.
Platelet rich plasma (PRP) is prepared by centrifugation of whole blood within 6 hours of collection at low speed. Units prepared from single units of whole blood are expected to contain > 5 × 1010 platelets in approximately 50 to 75 ml of plasma. PRP is maintained at room temperature from the time of collection until transfusion in order to prevent platelet activation and aggregation. PRP can be stored for up to 5 days but is best if used within 48 hours. Platelet concentrate (PC) is generated by the centrifugation of PRP at higher speeds and pooling of several units or from plateletpheresis. Platelet concentrate units contain approximately 3 × 1011 platelets per unit and are available from Animal Blood Resources International, Stockbridge, MI in fresh or frozen forms. Platelet transfusions should only be considered for patients with severe, life-threatening thrombocytopenia or severe platelet dysfunction and active hemorrhage or pre-surgery. PRP and PC are rarely indicated for use in immune-mediated thrombocytopenias, as the half-life of the transfused platelets will be extremely short.