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Blood transfusions are a relatively common medical procedure, and while typically safe, there are multiple complications that practitioners need to be able to recognize and treat. This activity reviews the indications for blood transfusion, including for special patient populations, the pre-transfusion preparation, and the potential complications of blood transfusions. In addition, this activity highlights the role of the interprofessional team in caring for patients undergoing blood transfusions. Objectives: Identify the indications for blood transfusions. Describe the management of blood transfusion complications. Explain the importance of proper pre-transfusion preparation of donor blood to reduce the risk of complications. Review a structured interprofessional team approach to provide effective care to and appropriate surveillance of patients undergoing blood transfusion. Access free multiple choice questions on this topic.

Medicine has made significant progress in understanding circulation in the past few hundred years. For millennia medicine believed in the "four humors" and used bloodletting as a treatment. In the 1600s, William Harvey demonstrated how the circulatory system functioned. Shortly after that, scientists became interested in transfusion, initially transfusing animal blood into humans. Dr. Philip Syng Physick carried out the first human blood transfusion in 1795, and the first transfusion of human blood for treating hemorrhage happened in England in 1818 by Dr. James Blundell.[1] Rapid strides have been made in understanding blood typing, blood components, and storage since the early 1900s. This has developed into the field of transfusion medicine. Transfusion medicine involves laboratory and clinical medicine, and physicians from multiple specialties, such as pathology, hematology, anesthesia, and pediatrics, contribute to the field. Charles R. Drew was an American surgeon who was one of the pioneers in blood banking early in World War II. Transfusion of red blood cells has become a relatively common procedure. In the United States, around 15 million units are transfused annually, while about 85 million units are transfused worldwide.[2][3][4] Blood is typically stored in components. Fresh whole blood has always been thought of as the standard for transfusion; however, medical advancement has allowed the efficient use of the different components, such as packed red blood cells (PRBCs), individual factor concentrates, fresh frozen plasma (FFP), platelet concentrates, and cryoprecipitate. Consequently, current indications for whole blood transfusion are generally very few. The US military buddy transfusion system is the most widespread system of whole blood transfusion.[5] Additionally, whole blood transfusion in civilian pre-hospital settings and the trauma bay is seeing a resurgence in some regions. The hemoglobin in red blood cells binds oxygen and is the body's main source of oxygen delivery. A single unit of packed red blood cells is roughly 350 mL and contains about 250 mg of iron.

There are multiple complications of blood transfusions, including infections, hemolytic reactions, allergic reactions, transfusion-related lung injury (TRALI), transfusion-associated circulatory overload, and electrolyte imbalance.[23][24][25] According to the American Association of Blood Banks (AABB), febrile reactions are the most common, followed by transfusion-associated circulatory overload, allergic reaction, TRALI, hepatitis C viral infection, hepatitis B viral infection, human immunodeficiency virus (HIV) infection, and fatal hemolysis which is extremely rare, only occurring almost 1 in 2 million transfused units of RBC. For comparison, the lifetime odds of dying from a lightning strike are about 1 in 161,000. A list of approximate risk per unit transfusion of RBC (adapted from AABB clinical guidelines published JAMA November 15, 2016) will be discussed here.[6] Adverse Event and Approximate Risk Per Unit Transfusion of RBC Febrile reaction: 1:60 Transfusion-associated circulatory overload: 1:100 Allergic reaction: 1:250 TRALI: 1:12,000 Hepatitis C infection: 1:1,149,000 Human immunodeficiency virus infection: 1:1,467,000 Fatal hemolysis: 1:1,972,000 Febrile Reactions [26] Transfusing with leukocyte-reduced blood products, which most blood products in the United States are, may help reduce febrile reactions. If this occurs, the transfusion should be halted, and the patient evaluated, as a hemolytic reaction can initially appear similar and consider performing a hemolytic or infectious workup. The treatment is with acetaminophen and, if needed, diphenhydramine for symptomatic control. After treatment and exclusion of other causes, the transfusion can be resumed at a slower rate. Transfusion-associated Circulatory Overload [27] It is characterized by respiratory distress secondary to cardiogenic pulmonary edema. This reaction is most common in patients already in a fluid-overloaded state, such as congestive heart failure or acute renal failure. Diagnosis is based on symptom onset within 6 to 12 hours of receiving a transfusion, clinical evidence of fluid overload, pulmonary edema, elevated brain natriuretic peptide, and response to diuretics. Preventive efforts and treatment include limiting the number of transfusions to the lowest amount necessary, transfusing over the slowest possible time, and administering diuretics before or between transfusions. Allergic Reaction [28]

It is characterized by respiratory distress secondary to cardiogenic pulmonary edema. This reaction is most common in patients already in a fluid-overloaded state, such as congestive heart failure or acute renal failure. Diagnosis is based on symptom onset within 6 to 12 hours of receiving a transfusion, clinical evidence of fluid overload, pulmonary edema, elevated brain natriuretic peptide, and response to diuretics. Preventive efforts and treatment include limiting the number of transfusions to the lowest amount necessary, transfusing over the slowest possible time, and administering diuretics before or between transfusions. Allergic Reaction [28] It often manifests as urticaria and pruritis and occurs in less than 1% of transfusions. More severe symptoms, such as bronchospasm, wheezing, and anaphylaxis, are rare. Allergic reactions may be seen in patients who are IgA deficient, as exposure to IgA in donor products can cause a severe anaphylactoid reaction. This can be avoided by washing the plasma from the cells prior to transfusion. Mild symptoms, such as pruritis and urticaria can be treated with antihistamines. More severe symptoms can be treated with bronchodilators, steroids, and epinephrine. Transfusion-related Lung Injury (TRALI) [29] This is uncommon, occurring in about 1:12,000 transfusions. Patients will develop symptoms within 2 to 4 hours after receiving a transfusion. Patients will develop acute hypoxemic respiratory distress, similar to acute respiratory distress syndrome (ARDS). Patients will have pulmonary edema, normal CVP, without evidence of left heart failure CVP. Diagnosis is made based on a history of recent transfusion, chest x-ray with diffuse patchy infiltrates, and the exclusion of other etiologies. While there is a 10% mortality, the remaining 90% will resolve within 96 hours with supportive care only. Infections These are potential complications. However, the risk of infections has decreased due to the screening of potential donors, so hepatitis C and human immunodeficiency virus risk are less than 1 in a million.[30] Bacterial infection can also occur, but does so rarely, about once in every 250,000 units of red cells transfused. Fatal Hemolysis

These are potential complications. However, the risk of infections has decreased due to the screening of potential donors, so hepatitis C and human immunodeficiency virus risk are less than 1 in a million.[30] Bacterial infection can also occur, but does so rarely, about once in every 250,000 units of red cells transfused. Fatal Hemolysis This is extremely rare, occurring only in 1 out of nearly 2 million transfusions. It results from ABO incompatibility, and the recipient’s antibodies recognize and induce hemolysis in the donor’s transfused cells. Patients will develop an acute onset of fevers and chills, low back pain, flushing, dyspnea as well as becoming tachycardic and going into shock. Treatment is to stop the transfusion, leave the IV in place, intravenous fluids with normal saline, and keep urine output greater than 100 mL/hour, diuretics may also be needed. Cardiorespiratory support may be provided as appropriate. A hemolytic workup should also be performed, including sending the donor blood and tubing and post-transfusion labs (see below for list) from the recipient to the blood bank. Retype and crossmatch Direct and indirect Coombs tests Complete blood count (CBC), creatinine, PT, and PTT (draw from the other arm) Peripheral smear Haptoglobin, indirect bilirubin, LDH, plasma-free hemoglobin Urinalysis for hemoglobin Electrolyte Abnormalities They can also occur, although these are rare and more likely associated with large volume transfusion. Hypocalcemia can result as citrate, an anticoagulant in blood products, binds with calcium.[31] Hyperkalemia can occur from the release of potassium from cells during storage. Higher risk in neonates and patients with renal insufficiency.[32] Hypokalemia can result as a result of alkalinization of the blood as citrate is converted to bicarbonate by the liver in patients with normal hepatic function.

Our understanding of blood transfusion has improved dramatically over the past three decades. Unlike before, empirical blood transfusions are no longer the norm. While blood products do have a benefit, they can also cause harm. Healthcare workers who look after patients needing a blood transfusion should consult with a hematologist if they remain unsure about the indications. Interprofessional team collaboration is crucial in managing patients undergoing blood transfusions and those having adverse reactions to transfusions. The key is to reduce the harm from unnecessary blood transfusions.