>> Hemolytic:
Acute Intravascular Hemolytic Reaction
Overview:
Occurs when recipient's antibodies recognize and induce hemolysis of donor's RBCs
Most of the transfused cells are destroyed, which may result in activation of the coagulation system, DIC, and release of anaphylatoxins and other vasoactive amines
Caused by ABO incompatibility; usually the result of technical errors
Risk is 1 to 4 per million units transfused
Serum haptoglobin will be decreased, serum lactate dehydrogenase will be elevated, and direct antigen (Coombs) test usually will be positive
Signs/Symptoms: Fever, chills, low back pain, flushing, dyspnea, tachycardia, shock, hemoglobinuria
Management:
Immediately stop transfusion
IV hydration to maintain diuresis; diuretics may be necessary
Cardiorespiratory support as indicated
Evaluation:
Retype and repeat cross-match
Direct and indirect Coombs test
CBC, creatinine, prothrombin time, activated partial thromboplastin time
Haptoglobin, indirect bilirubin, lactate dehydrogenase, plasma free hemoglobin
Urine for hemoglobin
Delayed Extravascular Hemolytic Reaction
Often have low-grade fever but may be entirely asymptomatic
Usually presents days to weeks after transfusion
More common than intravascular hemolytic reaction; rarely causes clinical instability
Hemolysis most commonly occurs in the spleen and occasionally in liver and bone marrow
Requires hemolytic workup as above to investigate the possibility of intravascular hemolysis
May be identified by a positive Coombs test, elevated unconjugated (indirect) bilirubin level, and less than expected increase in hemoglobin from the transfusion
>> Febrile:
Overview:
Characterized by fever during or within a few hours of a blood transfusion
Quite common => occurs in approximately 1 per 300 units of PRBCs infused
Most common in multiparous women or multiply transfused patients (pts who have been exposed to foreign blood antigens)
For patients with recurrent febrile reactions, use of leukocyte-reduced blood products may be helpful
Signs/Symptoms: Fever, chills
Management:
Stop transfusion
Initially manage as intravascular hemolytic reaction because one cannot reliably distinguish between the two
Can treat fever and chills with Acetaminophen
Consider infectious workup
Evaluation:
Hemolytic workup as above
>> Allergic:
Overview:
Caused by an immune response to transfused plasma proteins
Pts with immunoglobulin A deficiency may experience severe anaphylactic reactions due to presence of immunoglobulin A in donor products
Washing the plasma from the RBCs minimizes this type of reaction
Signs/Symptoms:
Mild: urticaria, pruritus
Severe: anaphylaxis => dyspnea, bronchospasm, hypotension, tachycardia, shock
Management:
Stop transfusion
If mild, reaction can be treated with Diphenhydramine; if symptoms resolve, can resume transfusion
If severe, may require cardiopulmonary support; do not restart transfusion
Evaluation:
For mild symptoms that resolve with Diphenhydramine, no further workup is necessary
For severe reaction, do hemolytic workup because initially may be indistinguishable from a hemolytic reaction
>> Infectious:
HIV-1: 1 per 6 million units transfused
HIV-2: Unknown, but extremely low
Human T-cell Lymphotropic Virus Types 1 and 2: 1 per 640,000 units transfused
Hepatitis B: 1 per 1 million units transfused
Hepatitis C: 1 per 100 million units transfused
Parvovirus B19: 1 per 10,000 units transfused
Note: Blood is not tested routinely for CMV unless recipient is seronegative AND either pregnant, a potential or present transplant candidate, immunocompromised, or a premature infant
Leukocyte-reduced blood components further decrease the risk of CMV transmission to susceptible populations because most of the virus resides in leukocytes
>> Transfusion Related Acute Lung Injury:
Thought to be due to granulocyte recruitment and degranulation within the lung
Usually a complication of fresh frozen plasma or platelet transfusion; rare after PRBC transfusion alone
Presents with respiratory distress and bilateral pulmonary infiltrates due to noncardiogenic pulmonary edema, during or within 6 hours of transfusion
Often self-limiting and resolves spontaneously with supportive care
>> Other:
Hypervolemia
Rapid volume expansion may occur leading to transfusion-associated cardiovascular overload
Pts with limited cardiovascular reserve (infants, severe chronic anemia, elderly) => highest risk
Electrolyte Imbalance
Hypocalcemia, hypokalemia or hyperkalemia rarely occur
The anticoagulant citrate is a component of many blood preservatives and chelates calcium
Pts with normal hepatic function metabolize the citrate to bicarbonate
Rarely, hepatic metabolism is overwhelmed; hypocalcemia can develop and/or the excess bicarbonate generated causes alkalemia, driving potassium into cells and causing hypokalemia
Potassium content in stored blood products increases during storage; uncommonly, pts with renal insufficiency or neonates can develop hyperkalemia