A blood transfusion is a procedure that transfers donor blood into a patient via intravenous injection. Donated blood products are kept in sterile bags and pumped slowly through an IV into a vein or artery of the person receiving the blood. In the past, blood transfusion recipients received whole blood, but many patients had complications due to incompatibility with some parts of the transfused fluid. Current practices can accommodate the transfusion of specific blood components.
Blood transfusions are done to help replace components of blood lost due to an illness or condition. Diseases of the liver and kidney and certain cancers can cause anemia or prevent the body from creating some components of blood. Also, medications and radiation may cause problems with building and maintaining healthy blood cells.
Before a person can receive a blood transfusion, medical professionals must assess the quality and safety of the donated blood. Donated blood is always whole blood, which is then separated into blood components such as red, white, and platelet cells. An anticoagulant is added to keep the blood in its liquid form. Donated blood is tested and traced to ensure no viruses, bacteria, or other harmful particles are present. The blood is tested for blood type and RH factor so that the donor receives the type that matches their own blood.
Sometimes people who sustain acute blood loss due to injury or complications of surgery require blood transfusions. Certain infections or liver disease stop the body from making healthy amounts of blood in the bone marrow. Illnesses such as anemia, kidney disease, and cancer can destroy healthy blood cells. Also, these conditions may impede the production and maturation of stem cells into healthy blood cells. Lastly, rare conditions such as hemophilia and thrombocytopenia can cause acute, unpredictable blood loss.
Red blood cells are the most common transfused blood product. They contain hemoglobin, which the body needs for oxygen and carbon dioxide transportation. People who have lost blood or who have anemia receive red blood cell transfusions. Platelets and clotting factors help to stop bleeding. People with conditions that reduce the production of these blood cells or cause spontaneous bleeding require platelet transfusions. Blood plasma refers to the liquid component of blood. It contains liquid, clotting factors, proteins, vitamins, and electrolytes. Severe burns, liver failure, and certain infections call for this type of transfusion.
Blood transfusions are usually done in a hospital or clinic setting, and also during surgery. The physician will insert a needle into a vein in the arm. The blood is transfused over one to four hours, depending on the amount and type. Doctors must constantly monitor the patient during the first 15 minutes, to ensure no immediate adverse reactions to the transfusion. Monitoring continues but is less frequent during the rest of the procedure.
After the blood transfusion is complete, the doctor removes the IV, and the patient rests for up to an hour. Vital signs such as blood pressure, temperature, and heart rate are monitored. Adverse reactions are most likely to occur right after the transfusion, which is why patients need vigilant monitoring. Some people experience a tingling or flushing sensation and mild fever, which may be normal and resolve shortly after the procedure. Blood tests can ensure the person's body is handling the transfusion well.
Acute or delayed hemolytic reactions are rare but can be serious due to kidney injury from substances damaged blood cells may release. Hemolysis is a process of red blood cell destruction that happens due to mismatched blood type. Symptoms include fever, nausea, back pain, and dark urine. This reaction is more common in people who have had previous blood transfusions, as the body remembers and targets the foreign cells. Careful monitoring allows doctors to quickly intervene and limit the effects of the reaction.
Blood banks usually screen blood donations carefully, so the risk of infection is low. However, in developing countries where blood screening is limited, the risks are still high. Some bacterial and viral infections can be transferred to the patient, such as HIV, hepatitis, and septicemia. The chances of infection are slightly higher when transfusing more significant amounts of red blood cells.
Anaphylactic allergic reactions are possible, but the risk decreases when transfusing the proper blood type. A buildup of antibodies in lung cells can cause rare injuries. Iron overload may occur after a patient receives copious amounts of blood. Treatment for iron overload involves medications that help draw out iron from the cells. Lastly, graft-versus-host disease occurs when the body rejects the new blood and attacks it. Symptoms include fever, rash, fatigue, and diarrhea. Graft-versus-host can be serious and usually happens in people with weakened immune systems.
The best risk prevention strategy is to ensure proper screening and testing of donations prior to blood transfusions. People with compromised immune systems may need extra medications to prevent reactions and infections. To avoid graft-versus-host disease, practitioners may treat blood products before the procedure. Research confirms risks can be limited by giving the least amount of blood possible. It's best to treat anemia with transfusions before the patient's red blood cell levels get too low.
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