While blood transfusions can be life-saving, they are not without risks. Complications from blood transfusions range from mild allergic reactions to severe, life-threatening conditions. Anesthesia providers must be vigilant in identifying and managing these complications to ensure patient safety.
Transfusion Reactions
Acute transfusion reactions occur during or within 24 hours of a transfusion. The most common is the febrile non-hemolytic reaction (fever and chills from recipient antibodies against donor leukocytes or from accumulated cytokines), followed by allergic urticaria; anaphylaxis is rare and classically occurs in IgA-deficient recipients. Acute hemolytic transfusion reactions from ABO incompatibility, almost always a clerical or identification error, cause rapid intravascular hemolysis with fever, flank pain, hemoglobinuria, hypotension, and DIC. Under general anesthesia the patient cannot report symptoms, so the first signs are often unexplained hypotension, hemoglobinuria, diffuse oozing in the surgical field, or a rising temperature. Management is to stop the transfusion at once, keep the line open with normal saline, recheck the unit and patient identification, send the bag and fresh blood and urine samples to the blood bank, support the blood pressure, and maintain urine output of at least 1 mL/kg/h. Antihistamines treat allergic reactions only; they have no role in a hemolytic reaction. Delayed hemolytic reactions appear 3 to 14 days later as an unexplained fall in hemoglobin, jaundice, and a positive direct antiglobulin test.
Clinical Example: A patient receiving a transfusion during surgery develops chills, fever, and hypotension. The transfusion is immediately stopped, the unit and patient identification are rechecked, the bag and fresh blood and urine samples go to the blood bank, and the patient is supported with IV fluids and vasopressors while the urine is watched for hemoglobinuria.
Transfusion-Related Acute Lung Injury (TRALI)
TRALI is a severe, often life-threatening complication of blood transfusion that presents with acute respiratory distress, hypoxemia, and non-cardiogenic pulmonary edema. It begins within 6 hours of transfusion and is believed to result from donor anti-HLA or anti-neutrophil antibodies, most often in plasma-rich products from previously pregnant donors, activating primed recipient neutrophils in the pulmonary capillaries and causing capillary leak. Fever and hypotension are common, and diuretics do not help because the edema is not hydrostatic. TRALI was the leading cause of transfusion-related death in the United States until male-predominant plasma policies reduced its incidence. Management of TRALI involves supportive care, including oxygen therapy and, in severe cases, mechanical ventilation.
Clinical Example: A patient develops sudden shortness of breath and hypoxemia during a perioperative blood transfusion. The anesthesia provider suspects TRALI, discontinues the transfusion, and provides oxygen therapy, stabilizing the patient’s respiratory status.
Transfusion-Associated Circulatory Overload (TACO)
TACO occurs when blood is transfused too rapidly or in excessive volume, leading to fluid overload, pulmonary edema, and heart failure. This is more common in elderly patients, those with pre-existing heart conditions, or those receiving large-volume transfusions. Unlike TRALI, TACO typically produces hypertension, jugular venous distension, and an elevated BNP, and it responds to diuretics. Careful monitoring of fluid status, transfusing one unit at a time, and administering blood products at a slower rate are essential to prevent TACO, which is now the leading cause of transfusion-related death reported to the FDA.
Clinical Example: In a patient with congestive heart failure undergoing surgery, the anesthesia provider administers blood products slowly and monitors the patient’s fluid status to avoid TACO. Diuretics may also be given to manage fluid overload if it occurs.
Infectious Risks
Although rare, the risk of transmitting infections such as HIV, hepatitis B, and hepatitis C through blood transfusions still exists; with nucleic acid testing the residual risk per unit is roughly 1 in 1.5 to 2 million for HIV and hepatitis C and about 1 in 1 million for hepatitis B. Blood donors undergo rigorous screening, and advanced testing methods have greatly reduced the risk of transfusion-transmitted infections (TTIs). However, bacterial contamination of blood products, particularly platelets because they are stored at room temperature, remains the most common transfusion-transmitted infection. Proper storage and handling of blood products and pathogen-reduction techniques minimize this risk.
Clinical Example: A patient undergoing surgery receives a platelet transfusion and subsequently develops signs of sepsis. The platelet unit is tested, and bacterial contamination is identified. Immediate administration of broad-spectrum antibiotics is initiated to manage the infection.
Hypocalcemia and Citrate Toxicity
During large-volume transfusions, citrate used as an anticoagulant in blood products can bind to calcium, leading to hypocalcemia. Ionized hypocalcemia causes paresthesias and muscle spasm in the awake patient and, under anesthesia, hypotension from reduced contractility and vascular tone, a prolonged QT interval, arrhythmias, and impaired coagulation (calcium is factor IV). Citrate is cleared by the liver, so hypothermia, liver disease, and shock all increase the risk. Ionized calcium is checked after every few units and kept above 1.1-1.2 mmol/L with calcium chloride or gluconate. Stored blood also carries extracellular potassium (hyperkalemia with rapid infusion of older units, especially in children and renal failure) and is cold, so a fluid warmer is used for any rapid transfusion.
Clinical Example: In a patient undergoing a massive transfusion, the anesthesia provider monitors ionized calcium levels and administers calcium gluconate to prevent the development of citrate toxicity.
