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Prepared by : Shurouq Qadous & Samah ishtieh. Blood Transfusion. What is blood made up of?. An adult human has about 4–6 liters of blood circulating in the body. Among other things, blood transports oxygen to various parts of the body.
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Prepared by : Shurouq Qadous & Samah ishtieh Blood Transfusion
An adult human has about 4–6 liters of blood circulating in the body. Among other things, blood transports oxygen to various parts of the body. • Blood consists of several types of cells floating around in a fluid called plasma.
The red blood cells contain hemoglobin, a protein that binds oxygen. Red blood cells transport oxygen to, and remove carbon dioxide from, the body tissues. • The white blood cells fight infection. • The platelets help the blood to clot. • The plasma contains salts and various kinds of proteins.
Blood and Blood Products A blood transfusion is the infusion of whole blood or a blood component such as plasma, red blood cells, or platelets into the patient’s venous circulation. A blood transfusion is given because of red blood cell loss, such as with a major cut or when the body is not adequately producing cells such as platelets. The person receiving the blood is the recipient. The person giving the blood is the donor.
Blood Groups Human blood is commonly classified into four main groups (A, B, AB, and O).The surface of an individual’s red blood cells contains a number of proteins known as antigens that are unique for each person. Many blood antigens have been identified, but the antigens A, B, and RH are the most important in determining blood group or type. Because antigens promote agglutination or clumping of blood cells, they also known as agglutinogens.
The A antigen or agglutinogens is present on the RBCs of people with blood group A , the B antigen is present in people with blood group B, and both A and B antigens are found on the RBC surface in people with group AB blood. Neither antigen is present in people with group O blood .
Preformed antibodies to RBC antigens are present in the plasma; these antibodies are often called agglutinins. People with blood group A have B antibodies (agglutinins ), A antibodies are present in people with blood group B, and people with blood group O have antibodies to both A and B antigens. People with group AB blood do not have antibodies to either A or B antigens.
If a person with type O blood is transfused with blood from a person with either group A or group B blood, there would be destruction of the recipient’s red blood cells because his or her anti-A or anti-B agglutinins would react with the A or B antigens in the donor’s red blood cells.
This example shows why individuals with type AB blood are often called universal recipients (because people in this blood group have no agglutinins for either A or B antigens) and group O people are often called universal donors (because they have neither A nor B antigens).
Rhesus (RH) Factor The Rh factor is an inherited antigen in human blood. Blood that contains the Rh factor is known as Rh positive, when it is not present the blood is said to be Rh – negative. Rh blood does not naturally contain Rh antibodies. If Rh-positive blood is injected into an Rh-negative person, the recipient develops Rh antibodies. Subsequent transfusion with Rh-positive blood may cause serious reactions with clumping and hemolysis of red blood cells.
Typing and Cross Matching Before any blood can be given to a patient, it must be determined that the blood of the donor is compatible with the patient. The laboratory examination to determine a person’s blood group and Rh factor is called Blood Typing.
The process of determining compatibility between blood specimens is cross matching. RBCs from the donor blood are mixed with serum from the recipient, a reagent from (Coombs’ serum) is added, and the mixture is examined for visible agglutination. If no antibodies to the donated RBCS are present in the recipient’s serum, agglutination does not occur and the risk of transfusion reaction is small.
Selection of Blood Donors Blood donors must be selected with care. Not only must the donor’s blood be accurately typed, but it is also important to determine that the donor is free from diseases. The blood will be tested for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and other viruses that can be transmitted to the recipient.
Some patients who know in advance that they will need blood can donate their own blood for transfusion (autologoustransfusion), also called autotransfusion. Autotransfusion eliminates the danger of transmitting cross-infection from donor to recipient and decreases the risk for complications from mismatched blood but requires advance planning (the blood must be donated 5 weeks before the surgery).
Blood and Blood products for transfusion Whole blood is rarely used unless blood loss has been massive. With current technology, whole blood can be easily separated into its components, and patients receive only the blood product they need.
Red blood cells in concentrated form, called packed red blood cells, may be used in the following situations: • Patient with anemia suffering with a low red blood cell count • Patient with cardiovascular failure, with a need to increase blood volume and red blood cells while avoiding cardiovascular overload • Patient with GI bleeding, with a need to maintain adequate hemoglobin levels without increasing blood pressure
In other situations, only plasma is required, such as when plasma protein or the blood’s clotting factor is low. Fresh frozen plasma is particularly useful in emergencies for immediate restoration of fluid because serum transfusion presents no compatibility problems and time need not be lost seeking donors and matching blood.
Platelet infusion is indicated for the treatment or prevention of bleeding associated with deficiencies in the number or function of a patient’s platelets.
Transfusion Reactions Transfusion of ABO – or Rh incompatible blood can result in a hemolytic transfusion reaction with destruction of the transfused RBCs and subsequent risk of kidney damage or failure. SEE THE TABLE IN PAGE 1474