Blood Transfusion PDF

Blood Transfusion red cell transfusion The cross-match procedure is used to determine compatibility is ensured between antigens on the donor erythrocytes and antibodies present in the recipient's plasma to avoid acute haemolysis of the donor cells which may be fatal. Red cell antigens and antibodies...

Blood Transfusion red cell transfusion The cross-match procedure is used to determine compatibility is ensured between antigens on the donor erythrocytes and antibodies present in the recipient's plasma to avoid acute haemolysis of the donor cells which may be fatal. Red cell antigens and antibodies : there are about 400 red blood cell antigens, only a minority are clinically important. An individual lacking a particular antigen may develop an antibody after exposure to red cells carrying the antigen. The rhesus blood group system: Allelic genes at closely linked loci code for paired antigens designated C and c, E and e and D. Absence of D is termed d. A set of genes and hence antigens is inherited from each parent and the presence of D determines rhesus 'positivity'. 'immune' antibodies: 'naturally occurring' antibodies to red cell antigens predominantly IgM require no previous red cell antigen exposure occur in the ABO blood group system anti-A and anti-B Induced antibodies to red cell antigens Exposure occurs by transfusion of red cells or by passage of fetal red cells into the maternal circulation during pregnancy, IgG immune antibodies, anti-D antibody The important clinical consequences of the development of an 'immune' antibody: 1. are the development of a hemolytic transfusion reaction on further exposure to red cells carrying the antigen, 2. hemolytic disease of the newborn due to trans placental passage of maternal IgG antibody against fetal red cell antigens Hemolytic transfusion reactions: Immediate reactions Massive intravascular haemolysis :occurs when complement-activating antibodies, such as anti-A and anti-B, interact with the relevant antigen on transfused red cells. Lead to: collapse, hypotension and pain in the lumbar region. Haemoglobin-stained urine oliguric renal failure may ensue. disseminated intravascular coagulation. This clinical scenario can develop after transfusion with only a few millilitres of incompatible red cells. 1. Treatment : immediate interruption of the transfusion, 2. resuscitation with intravenous fluid, immunosuppression with corticosteroid therapy 3. management of the renal failure. Fatalities still occur. The cross-match procedure should prevent exposure to such incompatible blood. causes: 1. clerical error through mislabeling of the crossmatch sample 2. transfusion to the wrong recipient. Because antibodies to the rhesus system are not complement-fixing, cell lysis occurs in the reticulo-endothelial system and reactions are generally milder, although they can still be lifethreatening Delayed reactions: gradual red cell lysis occurs, producing anemia and jaundice; Allergic reactions may also develop in a recipient because of hypersensitivity to a protein present in the donor plasma. Fever, urticaria and oedema may result Virus transmission :hepatitis B and C, HIV, parvovirus , cytomegalovirus, syphilis , malaria & prion Circulatory overload from excessive volume. bank blood is devoid of functioning platelets, transfusion of large volumes can cause thrombocytopenia and hemorrhage Secondary hemosiderosis : Repeated red cell transfusion inevitably leads to tissue iron overload. A unit of blood contains 200 mg of iron, Although, initially, deposition occurs in reticuloendothelial tissues without toxic results, iron later accumulates in skin, liver, myocardium and pancreas. Pigmentation, liver cirrhosis heart failure and diabetes mellitus are the consequences. An iron chelating compound, desferrioxamine, is administered by subcutaneous infusion to minimise iron accumulation in tissues Hemolytic disease of the newborn due to passage across the placenta of maternal IgG antibodies which are reactive against, and cause destruction of, the fetal red cells. This disorder requires the inheritance by the fetus of a red cell antigen from the father which is not present on the maternal red cells, thus provoking antibody development in the mother. Antibodies against the D antigen of the rhesus blood group system are most commonly implicated, increased proportion of cases are due to antibodies to other antigens in the rhesus system, the A antigen of the ABO system or occasionally other antibodies. Passage of fetal red cells into the maternal circulation occurs normally at delivery or as a result of miscarriage or operative intervention during pregnancy and these Dpositive cells sensitize a D-negative mother. Further stimulation of antibody production occurs in subsequent pregnancies with a D-positive fetus. IgG antibody then crosses the placenta from mother to fetus and causes immune destruction of fetal red cells. Thus, the disorder does not manifest in the first pregnancy. however, the fetus may be affected in the first pregnancy in ABO hemolytic disease of the newborn, where IgG antibody to A or B on fetal red cells develops in a group O mother. Management. injection of anti-D into the D negative mother. Management of the affected fetus unsensitised red cells by intra-uterine transfusion removal of bilirubin by exchange blood transfusion postnatally. Mildly affected neonates are treated by phototherapy, in which exposure to light of an appropriate wavelength degrades bilirubin. Indication for blood transfusion: There are three reasons for blood transfusion: Surgery Injury Disease and bleeding disorders Safe transfusion: Right blood Right patient Right time Right place 7 to 8 g/dl is safe level but may be too low in certain conditions. Transfusion is not indicated if Hb is above 10 g/dl What are the blood product? RBC (packed RBC) Platelets Plasma (FFP) Cryoprecipitate (Cryo) Granulocytes Blood components : Nourishment Electrolytes Hormones Vitamins Antibodies Oxygen Immune cells Plasma is aqueous part of blood conataining proteins and salts in which WBC, RBC and Plt are suspended it constitute about 55% of total blood volume. Important elements of plasma include: Albumin Coagulation factors Fibrinolytic proteins Immunoglobulin and other proteins. Cryopreciptate:is prepared from plasma and contain: Fibringene Factor VIII vonWillebrand factor Factor XIII Fibronectin It stored frozen