Blood Groups and Blood Transfusion

1. Blood Groups and Blood Transfusion Dr Stuart Laidlaw Haematology Royal Hallamshire Hospital

2. Red blood cells • Provide intravascular volume and O2 carrying capacity. • Transfusion of red cells can be life-saving in situations of acute intravascular volume loss, e.g. trauma, surgery

3. Red blood cells • Although red cells have a limited life-span, transfusion to another individual is a form of tissue transplantation, with similarities to kidney, heart and bone marrow transplantation • Compatibility between donor and recipient is vital or rejection will occur

4. Red Cells • Carry on the surface of their membrane many different proteins which differ between individuals • These are the red cell antigens • Inherited • Over 400 different systems of red cell antigens • Only 2 very important: ABO and Rhesus

5. ABO blood group system • 4 blood groups: A, B, AB and O • O is recessive, so O = 0,0 • A= AA or AO, B=BB or BO, AB= ABO= 45%, A= 40%,B=12%, AB= 3%

6. ABO blood group system • ABO unusual antigens: carbohydrate, not protein • Naturally occuring antibodies from age 6 months • IgM antibodies in plasma, don’t cross placenta • IgM antibodies fix complement to C9, so transfusion reactions very severe

7. ABO blood group • Can type cells as A, B or AB, using antibodies: anti-A and anti-B.If react with neither =group O • Can type serum as double checkO serum will contain anti-A and anti-BAB serum will not contain any antibodyA will contain anti-B, B will contain anti-A

8. Rhesus blood group system • Complex series of C,D and E antigens • D/d by far most important • D is a null gene, no protein product, so no anti-d possible • D is dominant, so D = DD or Dd • 15% population dd = d = d negative

9. Rhesus blood group system • Women who are rhesus negative (dd) have babies that carry paternal antigens, such as D. • If mother exposed to D red cells will make IgG anti-D • Anti-D crosses placenta and haemolyses babies red cells: can result in in-utero death and need for in-utero blood transfusion

10. Rhesus blood group • It is so vital that women of childbearing age are not exposed to wrong rhesus type blood that everyone receives rhesus, as well as ABO, compatible blood. • All women have rhesus blood type determined at each conception. • Anti-D given to D negative mothers to prevent sensitisation

11. Other blood groups • Many in number • Infrequent problem • Only likely to have been sensitised if had previous blood transfusion (occasionally by pregnancy) • Can cause major problems with finding compatible blood

12. Group and Save • Determine ABO group: cells and serum • Determine Rh D status, using two different reagents • Screen serum for presence of preformed antibodies to any blood group

13. Cross match • Specifically determine compatibility between donor red cells and recipients serum • Very important if known antibodies or multiple previous transfusions • If group and screen neg X 2 may be unnecessary, use electronic cross-match

14. Indications for transfusion • Hypovolaemia due to loss blood • Severe anaemia with symptoms due to inadequate oxygenation of tissues • Anaemia that cannot be corrected by bone marrow function

15. Indications for transfusion • Not indicated for iron deficiency or B12/ folate deficiency. • Not indicated for minor blood loss, especially if fit and healthy(transfusion trigger = 8 g/dl) • Not indicated for asymptomatic anaemia

16. Hazards of transfusion • Blood is tissue from another individual • Transfusion is potentially fatal, although used properly can, and does save lives

17. Early hazards • ABO incompatibility reaction – can be rapidly fatal • Fluid overload, pulmonary oedema • Febrile reactions, urticarial reactions, occasionally life threatening respiratory failure • Bacterial and malerial infection

18. Late hazards • Rh D and other antibody sensitisation • Delayed transfusion reaction • Viral infection: Hepatitis B, C, HIV • ? Prion infection: nvCJD • Iron overload: cardiac, hepatic and endocrine damage

19. Alternatives to transfusion • Treat anaemia pre-op • Use transfusion trigger • Stop anti-platelet and anti-coagulant drugs • Consider intra-operative cell salvage and re-infusion

20. Alternatives to transfusion • Consider pre-and post- operative erythropoietin • Consider individual pre-donation of red cells • Currently no universally available alternatives to blood?O2 carrying solutions, ? Artificial/ recombinant haemoglobin polymers

21. Other components • Blood is not only red cells • Also platelets and plasma • Plasma can be used as it is, or fractionated to produce concentrates of specific components, e.g. factor VIII or IX • White cells only rarely used, as antibiotics so potent!

22. Fresh frozen plasma • Plasma frozen within 6 hours of collection • Contains all the coagulation proteins and inhibitors • Used if massive transfusion and dilutional coagulopathy, in liver disease and DIC

23. Cryoprecipitate • Rich in fibrinogen • Used in DIC and massive transfusion if specific lack of fibrinogen

24. Platelets • Correct bleeding due to thrombocytopenia • Work for lack of production or perippheral consumption • Not useful if deficiency is due to immune anti-platelet antibody

25. Albumin • Useful if oedema due to lack oncotic pressure in liver disease or nephrotic syndrome • Use currently declining rapidly

26. Anti-D globulin • Collected from people deliberately sensitised to D • Used to prevent Rh D disease in Rh d women in pregnancy, after childbirth, miscarriage, abdominal trauma in pregnancy and TOP

27. Intravenous immunoglobulin • Pooled immunoglobulin • Used for immunodeficiency, congenital or acquired • Used in some auto-immune diseases