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Emergency and Acute Medicine – Transfusion Complications
Transfusion complications are relatively common clinical events associated with blood product administration, ranging from mild allergic reactions to life-threatening conditions. Approximately 5–6% of hospitalized patients receive transfusions, and about 2% of transfused units result in some type of reaction within 24 hours. Although mortality is rare, complications can be severe, especially with acute hemolytic reactions or pulmonary syndromes.
Noninfectious complications are more common than infectious ones. Febrile nonhemolytic reactions occur in approximately 1 in 500 red blood cell transfusions and are characterized by fever and chills due to antigen–antibody reactions involving leukocytes or cytokines. Allergic reactions are relatively frequent and usually mild, presenting with urticaria or pruritus, while anaphylaxis is rare but potentially fatal. Acute hemolytic transfusion reactions, often due to ABO incompatibility, are uncommon but dangerous, occurring in roughly 1 in 38,000 to 70,000 transfusions. Delayed hemolytic reactions occur days later and are typically less severe.
Transfusion-associated circulatory overload (TACO) is relatively common, particularly in elderly or volume-sensitive patients, and presents with signs of fluid overload such as dyspnea and hypertension. Transfusion-related acute lung injury (TRALI) is a serious complication presenting within 6 hours of transfusion with acute respiratory distress, bilateral pulmonary infiltrates, and normal cardiac function. It is a leading cause of transfusion-related mortality and must be distinguished from TACO and Acute Respiratory Distress Syndrome.
Other important complications include electrolyte disturbances such as hypocalcemia (due to citrate binding calcium) and hyperkalemia (from stored blood breakdown), iron overload with repeated transfusions, and rare but fatal graft-versus-host disease. Infectious complications are now rare due to screening but include transmission of viruses such as HIV, Hepatitis B, and Hepatitis C, as well as bacterial contamination (especially in platelet transfusions), which remains the most common infectious cause of mortality.
Acute intravascular hemolytic transfusion reactions are the most severe form and typically occur immediately due to ABO incompatibility, often from clerical or identification errors. Even small volumes (5–20 mL) can trigger symptoms. These reactions result in rapid destruction of transfused red blood cells, triggering a cascade involving cytokine release, activation of the coagulation system, and potential progression to shock, disseminated intravascular coagulation, renal failure, and respiratory failure.
Clinical manifestations of transfusion reactions vary widely but commonly include fever, chills, urticaria, dyspnea, hypotension, chest pain, nausea, and hemoglobinuria. Severe reactions may present with shock, bleeding, renal failure, or respiratory distress. The classic triad of fever, flank pain, and dark urine in hemolytic reactions is uncommon but highly suggestive when present.
Evaluation begins with immediate recognition of symptoms and verification of patient and blood product identity. Laboratory testing includes CBC, electrolytes, renal function, coagulation studies, bilirubin, and a direct Coombs test. Hemolysis may be indicated by hemoglobinemia or hemoglobinuria. Imaging such as chest x-ray is useful when pulmonary complications like TRALI are suspected, typically showing bilateral infiltrates without cardiomegaly.
Management requires immediate cessation of the transfusion as the first and most critical step. Supportive care follows the ABC approach, including oxygen supplementation and hemodynamic stabilization. Intravenous fluids with normal saline are used for hypotension, while avoiding lactated solutions or dextrose-containing fluids. Maintaining adequate urine output is essential to prevent renal failure, often requiring diuretics such as furosemide or osmotic agents like mannitol.
Febrile reactions are treated with antipyretics, while allergic reactions are managed with antihistamines such as diphenhydramine. Severe allergic or anaphylactic reactions require prompt administration of epinephrine and corticosteroids. In cases of electrolyte disturbances, calcium replacement may be necessary. If disseminated intravascular coagulation develops, it must be treated accordingly.
Patients with severe reactions, including hemolysis, anaphylaxis, pulmonary complications, or sepsis, require ICU admission and close monitoring. Mild febrile or allergic reactions may be managed conservatively and discharged with appropriate follow-up.
Key clinical pearls include the importance of strict patient identification and cross-matching procedures to prevent catastrophic hemolytic reactions. Clinicians should always suspect hemolysis when hypotension, dark urine, or unexplained bleeding occurs during transfusion. Additionally, transfusions should be used judiciously, as they carry significant risks despite their lifesaving potential.
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