Blood Part 3: PDF

Blood part 3  RBC Cell membrane  contains agglutinogens (antigens)  Blood plasma  contains substance called agglutinins (antibody)  Classification of blood groups ( according to agglutinogens) : 1. ABO system 2. Rh system Importance...

Blood part 3  RBC Cell membrane  contains agglutinogens (antigens)  Blood plasma  contains substance called agglutinins (antibody)  Classification of blood groups ( according to agglutinogens) : 1. ABO system 2. Rh system Importance for blood transfusion ABO system  According to presence or absence of two antigens: 1. Type A antigen 2. Type B antigen 1 Blood part 3 The inheritance of A and B antigens The blood group of a person is genetically determined by the two genes he/she receives : one from each parent. The genotype of persons with different blood groups may be as follows: Blood group Genotype A AA; AO B BB,BO AB AB O OO 2 Blood part 3 DETERMINATION OF BLOOD GROUP The blood group of a person can be determined by: 1. Take two different glass slide and add one drop of blood in each slide. 2. Now Add a drop of each α and β agglutinin separately. 3. 3.The blood group will be shown by the presence of agglutination with one, both or none of the agglutinins. 3 Blood part 3 Incidence :  O+ 37%  O- 6%  A+ 34%  A- 6%  B+ 10%  B- 2%  AB+ 4%  AB- 1 Type O blood is the most common blood type, followed by type A, type B, and, the least common blood type, AB. 4 Blood part 3 Rh - System (Rhesus system)  There is an antigen in the red blood cells, called Rh-factor.  It was first discovered in the blood of Rhesus monkeys  In the Rh system persons are divided into two groups depends on presence of antigen: a) Rh-positive b) Rh-negative.  There are 3 types of Rh antigens : C,D and E  But D has the most antigenic component, therefore Rh-positive= D-positive and Rh- negative =D-negative. Importance of Rh blood group 1- Repeated transfusion  an Rh-negative person has never before been exposed to Rh- positive blood, transfusion of Rh- positive blood into that person will likely cause no immediate reaction. However, anti-Rh antibodies can develop in sufficient quantities during the next 2 to 4 weeks to cause agglutination of those transfused cells that are still circulating in the blood. (Mild &dalyed transfusion reaction )  On subsequent transfusion of Rh-positive blood into the same person against the Rh factor, the transfusion reaction is greatly enhanced and can be immediate and severe. 5 Blood part 3 Hemolytic Disease Of The Newborn Erythroblastosis Fetalis  Erythroblastosis fetalis is a disease of the fetus and newborn child characterized by agglutination and phagocytosis of the fetus's red blood cells.  – Rh+ antibodies of a sensitized Rh– mother cross the placenta and attack and destroy the RBCs of an Rh+ baby  In most instances of erythroblastosis fetalis, the mother is Rh negative and the father Rh positive.  The baby has inherited the Rh-positive antigen from the father, and the mother develops anti-Rh agglutinins from exposure to the fetus's Rh antigen. 6 Blood part 3 Incidence :  Mainly first baby  not affected  second baby  about 3 % develops the disease  third baby  about 10 % of exhibit the disease  the incidence rises progressively with subsequent pregnancies. Pathogenesis :  After anti-Rh antibodies have formed in the mother, they diffuse slowly through the placental membrane into the fetus's blood. There they cause agglutination of the fetus's blood.  The agglutinated red blood cells subsequently hemolyze, releasing hemoglobin into the blood.  The fetus's macrophages then convert the hemoglobin into bilirubin, which causes the baby's skin to become yellow (jaundiced).  The antibodies can also attack and damage other cells of the body. Treatment :  is to replace the neonate's blood with Rh-negative blood.  About 400 milliliters of Rh-negative blood is infused over a period of 1.5 or more hours while the neonate's own Rh-positive blood is being removed. (Exchange transfusion) 7 Blood part 3 Prevention :  anti-D antibody that is administered to the expectant mother starting at 28 to 30 weeks of gestation.  This treatment inactivates the fetal Rh antigens and prevents sensitization of the mother. However, if sensitization of the mother has already occurred, the treatment is ineffective. 8 Blood part 3 Indications : 1. to restore the whole blood (loss>20%) 2. to restore one element of the blood :  RBCs (in sever anemia )  WBCs (in leukemia & leukopenia)  Platelets (in thrombocytopenia)  Plasma proteins (in burn )  Clotting factors (in hemophilia ) 3. to restore baby's blood in erythroblastosis fetalis (exchange transfusion) precautions : (taken before blood transfusion): 1. The recipient`s &donor`s blood should be compatiable. 2. Cross matching test should be done before transfusion 3. Rh- negative female should NEVER receive Rh - positive blood 4. Transfused blood should be :  not anemic (has a high content of Hb)  free from infectious disaease (hepatitis & AIDS)  Fresh & worm. 9 Blood part 3 Blood Transfusion & cross matching  Donor red blood cells are mixed with recipient plasma, while recipient cells are mixed with donor plasma ; there should be no agglutination in either case. This is referred to as cross matching.  universal donor (blood group O, Rh negative)  its RBCs carry no antigens and so cannot be agglutinated  universal recipient (blood group AB, Rh positive) plasma of the universal recipient contains no antibodies and could not agglutinate donor cells, Blood transfusion complication 1. transmission of infectious disease e.g hepatitis ,AIDS & malaria. 2. Massive transfusion of blood (more than 1 liter ) may cause death (Circulatory overload ) 3. Allergy may result due to the some antigens present in WBCs & platelets of the donor`s blood 4. Transfusion reaction : occur when mismatched blood is infused  Donor’s cells are attacked by the recipient’s plasma agglutinins causing: CLUMPING AND HEMOLYSIS 10 Blood part 3 QUIZ  For the ABO blood group, the antigens are found __________ , and the antibodies are found ___________. a) On the erythrocytes, on the leukocytes b) On the erythrocytes, in the plasma c) On the leukocytes, in the plasma d) In the plasma, on the erythrocytes  person with type A blood a) has anti-A antibodies. b) has type B antigens. c) will have a transfusion reaction if given type B blood. d) all of the above.  24. Rh-negative mothers who receive a Rho.GAM injection are given that injection to a) initiate the synthesis of anti-Rh antibodies in the mother. b) initiate anti-Rh antibody production in the baby c) prevent the mother from producing anti-Rh antibodies. d) prevent the baby from producing anti-Rh antibodies. 11 Blood part 3 Blood lab 1. PACKED CELL VOLUME (PCV) OR HEMATOCRIT(HCT)  The ratio of packed blood cells volume to plasma Causes of High hematocrit : 1. Dehydration 2. Burns 3. Diarrhea 4. Polycythemia vera. 5. Low oxygen tension (smoking, congenital heart disease, living at high altitudes). 12 Blood part 3 Causes of Low hematocrit : 1. Anemia 2. Blood loss (hemorrhage). 3. Bone marrow failure (for example, due to radiation, toxin, fibrosis, tumor). 4. Hemolysis (RBC destruction) related to transfusion reaction. 5. Leukemia 13 Blood part 3 14