Blood transfusion. Dr. J. Potgieter Dept. of Haematology NHLS - TAD

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1 Blood transfusion Dr. J. Potgieter Dept. of Haematology NHLS - TAD

2 General Blood is collected from volunteer donors >90% is separated into individual components and plasma Donors should be: healthy, have had no serious previous illnesses, a low risk for transmitting infectious agents Donors are screened for anaemia and donate up to 4 times a year

3 General Donated blood is routinely tested: Hepatitis B & C, HIV 1 & 2, T Pallidum Serologically to determine blood grouping (ABO & Rh) Cytomegalovirus (CMV) antibody screening is done selectively

4 Blood grouping & compatibility testing Red cells have surface antigens Individuals lacking red cell antigens may make antibodies if exposed to the antigen (transfusion or feto-maternal transfer) Antibodies to ABO antigens occur naturally, are IgM and complete (detectable by incubation of Ag & room temperature) Ab s to other red cell antigens are IgG and incomplete (detectable by special techniques). Appear only after sensitization

5 Blood grouping & compatibility testing - 2 Antibodies may cause: Intravascular or extravascular haemolysis of donor red cells in the recipient Haemolytic disease of the fetus/newborn because of trans placental passage Blood grouping Red cell group is determined by suspending washed red cells with diluted anti-a, anti-b, anti A+B and anti Rh (D). Agglutination indicates a positive result. Serum is simultaneously incubated with group A, B and O cells to confirm the presence of the expected naturally occurring ABO ab s Recipient serum is also incubated against a pool of group O cells which together express most common Ag s against which Ab s occur. If such an Ab is found, it is characterised if clinically significant donor blood negative for the corresponding antigen is used for transfusion. Compatibility testing Cross-matching entails suspension of donor red cells with recipient serum, incubation to allow a reaction to occur, and examination for agglutination, including indirect antiglobulin test.

6 Red cell transfusion Indications Haemorrhage severe anaemia (refractory or requiring rapid correction) Types of red cells Whole blood acute haemorrhage with hypovolaemia. Preferable for neonates. Packed red cells (shelf life days) Leucocyte depleted red cells (passed through a filter at bedside or laboratory)

7 Red cell transfusion - 2 Leucocyte depleted red cells are given: To reduce reactions to leucocytes in patients sentisized to HLA antigens To reduce incidence of sensitization In patients requiring cytomegalovirus (CMV) negative components To reduce the risk of transmission of variant Creutzfeldt-Jacob disease Autologous donation Patients donate their own red cells preoperatively on several occasions and receive iron. These units are screened for infective agents in the usual way and stored at 4 o C.

8 Platelet transfusion Single donor unit is prepared from a unit of whole blood by centrifugation within hours. It contains ~5 X platelets in ml plasma. Shelf life of 4-6 days. Standard adult dose is 5 pooled units and group ABO and Rh compatible, but not crossmatched Patients with HLA ab s may require platelets from HLA-compatible donors who donate platelets by platelet pheresis

9 Platelet transfusion - 2 Indications Thrombocytopenia <50 X 10 9 /l in the presence of significant bleeding or prior to an invasive procedure Thrombocytopenia <10 X 10 9 /l prophylactic transfusion (post chemotherapy, stem cell transplant or failure of marrow production) Platelet function defects (actively bleeding or prior to surgery), DIC and dilutional thrombocytopenia following massive transfusion

10 Fresh frozen plasma (FFP) A source of all coagulation and other plasma proteins. Compatibility testing is not required, but blood group compatible units are used FFP from group AB donors may be used if the recipient blood group is unknown FFP is not heat sterilized and may transmit infection

11 Fresh frozen plasma (FFP) - 2 Indications Coagulation factor replacement. Perform coagulation studies and platelet counts before use. Patients with DIC or massive transfusion may benefit. Single factor deficiencies are best treated with a specific factor concentate Liver disease if bleeding or prior to invasive procedures e.g. liver biopsy Thrombotic Thrombocytopenic purpura (TTP) often with plasma exchange. Reversal of oral anticoagulation o thrombolytic therapy

12 Cryoprecipitate Cryoprecipitate is produced from the precipitate formed from FFP during controlled thawing, resuspended in 20 ml plasma It is rich in fibrinogen, fibronectin and factor VIII Group compatible units are used It may be useful in patients with DIC, liver disease, following massive transfusion and rarely, in von Willebrand s disease

13 Coagulation factor concentrates Are available as freeze-dried powder of high purity Factor VIII concentrate is used for the treatment of haemophilia A and von Willebrand s disease. Recombinant factor VIII is available Factor IX concentrate is used for haemophilia B. Factor IX complex also contain factors II, VII and X. Also of value in patients with specific disorders of factors II or X, oral anticoagulant overdose, in severe liver failure and to overcome inhibitors to factor VIII. Its use carries a risk of thrombosis and DIC.

14 Other blood products Albumin solution 5%, 20%, 20% salt-poor formulations. Contains no coagulation factors. Used in the treatment of hypovolaemia Immunoglobulins (Igs) Prepared from pooled donor plasma by fractionation and sterile filtration. Specific Igs include hepatitis B and herpes zoster which provide passive immune protection

15 Immunoglobulins (Igs) cont. Standard human Igs for IM injection is used for prophylaxis against hepatitis A, rubella and measles Hyperimmune globulin is prepared from donors with high titres of the relevant antibodies for prophylaxis of tetanus, hepatitis A, diphtheria, rabies, mumps, measles, rubella, CMV and Pseudomonas infection IV Igs may be used in congenital or acquired immune deficiency and some auto-immune disorders, e.g. ITP

16 Complications of transfusions Administrative and clerical errors most prevalent Circulatory overload e.g. congestive heart failure Immunological reactions e.g. haemolytic transfusion reactions such as ABO incompatibility Hypersensitivity reactions e.g. non-hemolytic transfusion reactions such as pyrexial reactions

17 Complications of transfusions - 2 Transmission of infection. Bacterial infection can occur through failure of sterile technique at the time of collection or bacteraemia in the donor. Protozoal infection e.g. malaria. Viral infection or prion diseases. Iron overload Complications of massive transfusion. Hypothermia, DIC, thrombocytopenia, electrolyte disturbance, transfusion associated lung injury (TRALI) Other complications. Immune deficiency, graft vs. host disease