hematology and oncology
Complications of Transfusion
Acute hemolytic transfusion reaction (AHTR)
About 20 people die yearly in the US as a result of acute hemolytic transfusion reaction. AHTR usually results from recipient plasma antibodies to donor RBC antigens. ABO incompatibility is the most common cause of acute hemolytic transfusion reaction. Antibodies against blood group antigens other than ABO can also cause AHTR. Mislabeling the recipient’s pretransfusion sample at collection and failing to match the intended recipient with the blood product immediately before transfusion are the usual causes. Hemolysis is intravascular, causing hemoglobinuria with varying degrees of Acute Kidney Injury (AKI) and possibly Degree of incompatibility Amount of blood given Rate of administration Integrity of the kidneys, liver, and heart An acute phase usually develops within 1 hour of initiation of transfusion, but it may occur late during the transfusion or immediately afterward. Onset is usually abrupt. The patient may complain of discomfort and anxiety. Dyspnea, fever, chills, facial flushing, and severe pain may occur, especially in the lumbar area. Shock may develop, causing a rapid, feeble pulse; cold, clammy skin; low blood pressure; and nausea and vomiting. Jaundice may follow acute hemolysis. If AHTR occurs while the patient is under general anesthesia, the only symptom may be hypotension, uncontrollable bleeding from incision sites and mucous membranes caused by an associated DIC, or dark urine that reflects hemoglobinuria. If AHTR is suspected, one of the first steps is to recheck the identification labels on the sample and patient. Diagnosis is confirmed by a positive Direct antiglobulin (direct Coombs) test , measuring urinary hemoglobin, serum lactate dehydrogenase, bilirubin, and haptoglobin. Intravascular hemolysis produces free hemoglobin in the plasma and urine; haptoglobin levels are very low. Hyperbilirubinemia may follow. After the acute phase, the degree of Acute Kidney Injury (AKI) determines the prognosis. Diuresis and a decreasing BUN (blood If AHTR is suspected, the transfusion should be stopped and supportive treatment begun. The goal of initial therapy is to achieve and maintain adequate blood pressure and renal blood flow with IV 0.9% saline andfurosemide. IV saline is given to maintain urine output of 100 mL/hour for 24 hours. The initialfurosemidedose is 40 to 80 mg (1 to 2 mg/kg in children), with later doses adjusted to maintain a urinary flow of>100 mL/hour during the first day. Drug treatment of hypotension must be done cautiously. Pressor drugs that decrease renal blood flow (eg,epinephrine,norepinephrine, high-dosedopamine) are contraindicated. If a pressor drug is necessary,dopamine2 to 5 mcg/kg/minute is usually used. A nephrologist should be consulted as early as possible, particularly if no diuretic response occurs within about 2 to 3 hours after initiating therapy, which may indicate Acute Tubular Necrosis (ATN) . Further fluid and diuretic therapy may be contraindicated, and early dialysis may be helpful. 