15-01-2013, 11:26 AM
CLINICAL TEACHING ON Preparation of patient for blood transfusion
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INTRODUCTION
Blood transfusions are done to replace blood lost during surgery or due to a serious injury. A transfusion also may be done if the body cannot make blood properly because of an illness.
During a blood transfusion, a small needle is used to insert an IV line into one of the blood vessels. Through this line, body receive healthy blood. The procedure usually takes 1 to 4 hours, depending on how much blood the body need.
Blood transfusions are very common. Each year, almost 5 million Americans need a blood transfusion. Most blood transfusions go well. Mild complications can occur. Very rarely, serious problems develop.
DEFINITION
“A blood transfusion is the transfer of whole blood or blood products such as blood cells and plasma from one person (donor) to another person's bloodstream (recipient).”
This involves two procedure- the collection of blood from the donor and the administration of blood to the recipient.
IMPORTANT INFORMATION ABOUT BLOOD
The heart pumps blood through a network of arteries and veins throughout the body. Blood has many vital jobs. It carries oxygen and other nutrients to your body's organs and tissues. Having a healthy supply of blood is important to your overall health.
Blood is transfused either as whole blood (with all its parts) or, more often, as individual parts.
Blood is 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.
Blood consists of several types of cells floating around in a fluid called plasma.
1. 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.
2. The white blood cells fight infection.
3. The platelets help the blood to clot, if you get a wound for example.
4. The plasma contains salts and various kinds of proteins.
ALTERNATIVES TO BLOOD TRANSFUSIONS
Researchers are trying to find ways to make blood. There's currently no man-made alternative to human blood.
However, researchers have developed medicines that may help do the job of some blood parts.
For example, some people who have kidney problems can now take a medicine called erythropoietin that helps their bodies make more red blood cells.
This means they may need fewer blood transfusions.
Surgeons try to reduce the amount of blood lost during surgery so that fewer patients need blood transfusions. Sometimes they can collect and reuse the blood for the patient.
PURPOSES OF BLOOD TRANSFUSION
1. To restore the blood volume when there is sudden loss of blood due to haemorrhage, trauma or burns.
2. To raise the haemoglobin level in cases of severe anaemia which are not corrected by the administration of vitamins and iron therapy.
3. To treat deficiencies of plasma proteins, clotting factors and haemophilic globulin, etc.
4. To provide plasma clotting factors, to help in controlling bleeding.
5. To provide antibodies to those persons who are sick and having lowered immunity by giving blood or plasma.
6. To replace the blood with haemolytic agents with fresh blood as in cases of erythroblastosis foetalis, haemolytic anaemia, etc.
7. To improve the leucocyte count of blood as in agranulocytosis.
8. To combat infection in patients with leucopenia
TYPES OF BLOOD TRANSFUSION
Blood can be provided from two sources: autologous blood (using your own blood) or donor blood (using someone else's blood).
Blood is transfused either as whole blood (with all its parts) or, more often, as individual parts. The type of blood transfusion the body need depends on situation.
For example, if the body have an illness that stops the body from properly making a part of blood, the body may need only that part to treat the illness.
RED BLOOD CELL TRANSFUSIONS
Red blood cells are the most commonly transfused part of the blood. These cells carry oxygen from the lungs to the body's organs and tissues. They also help the body get rid of carbon dioxide and other waste products.
The body may need a transfusion of red blood cells if there is lost blood due to an injury or surgery. The body also may need this type of transfusion if the body have severe anaemia due to disease or blood loss.
Anaemia is a condition in which your blood has a lower than normal number of red blood cells. Anaemia also can occur if your red blood cells don't have enough haemoglobin.
Haemoglobin is an iron-rich protein that gives blood its red colour. This protein carries oxygen from the lungs to the rest of the body.
PLATELETS AND CLOTTING FACTOR TRANSFUSIONS
Platelets and clotting factors help stop bleeding, including internal bleeding that we can't see. Some illnesses may cause body to not make enough platelets or clotting factors. The body may need regular transfusions of these parts of the blood to stay healthy.
For example, if a person having haemophilia, he may need a special clotting factor to replace the clotting factor you're lacking. Haemophilia is a rare, inherited bleeding disorder in which your blood doesn't clot normally.
In haemophilia, a person bleeds for a longer time than others after an injury or accident. He may bleed internally, especially in the joints (knees, ankles, and elbows).
PLASMA TRANSFUSIONS
Plasma is the liquid part of blood. It's mainly water, but also contains proteins, clotting factors, hormones, vitamins, cholesterol, sugar, sodium, potassium, calcium, and more.
If the body have been badly burned or have liver failure or a severe infection, it may need a plasma transfusion.
GROPING AND CROSS MATCHING
The individual from whom the blood is transferred is called the donor. The individual to whom the blood is transferred is called the recipient. Indiscriminate transfusion may lead to serious conditions and even death. This consequence is due to the process of agglutination or haemolysis. Agglutination is due to the interaction between substances in red blood corpuscles known as agglutinogens and those in the plasma called agglutinins. Types of blood which get agglutinated in the transfusion is called to be incompatible.
ABO GROUPING
The differences in human blood are due to the presence or absence of certain protein molecules called antigens and antibodies. The antigens are located on the surface of the red blood cells and the antibodies are in the blood plasma. Individuals have different types and combinations of these molecules. The blood group you belong to depends on what you have inherited from your parents.
There are more than 20 genetically determined blood group systems known today, but the AB0 and Rh systems are the most important ones used for blood transfusions. Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals.
Nobel Laureate Karl Landsteiner was involved in the discovery of both the AB0 and Rh blood groups.