Transfusion Lecture

 A foundational discussion on evaluation and treatment of acute transfusion reactions. Adapted from a lecture by Dr. Scott.  

Acute Transfusion Reactions

Several factors increase the risk of an acute reaction to blood products. These include ABO incompatibility, pregnancy or prior transfusion, transplants or immunocompromised status, and IgA deficiency. Symptoms include fever,  headache, nausea and vomiting, or anxiety. Pallor may be seen with severe anemia. Pain along the infused extremity is a more specific symptom for acute hemolytic transfusion reaction.

• TRALI: Transfusion-related acute lung injury presents with shortness of breath, hypotension, and onset is usually within 1- 2 hours but can occur up to 6 hours after transfusion. Passive antibodies from donor blood reacting with patient's WBC, causing a non-cardiogenic capillary leak in the pulmonary vasculature.
• TACO: Transfusion-associated circulatory overload is caused by volume overload during transfusion, usually due to rapid infusion of blood products and fluids. Very frequent occurrence. 
• Acute Hemolysis: ABO incompatibility due to inproper blood type being given. Potentially due to mislabling blood from different patients. 
• Allergic response: Occurs in 1/300 transfusions. Usually an allergy to an antigen or donor's IgA. Frequently, patients with an IgA deficiency have an allergic response due to IgA. 
• Febrile reaction to blood products: 1/100 transfusions, due to cytokines in the donor blood, causing an elevated cytokine level and resulting inflammatory reaction. Transient in nature. 
• Sepsis: May potentially be caused by bacteremia in the donor blood. Increased risk with platelets due to pooled supply.

Evaluation of An Acute Reaction

• Stop the blood product & check to ensure the appropriate product was being infused. 
• Assess for airway and complete re-evaluation looking for an allergic reaction, hemodynamic instability, volume status and respiratory status. Blood transfusion allergic reactions are a type 1 response with mast cell release of histamines and cytokines, so recognition of hives and anaphylaxis (true allergic reaction) is important. Monitor vitals and consider a chest X-ray if concerned for TRALI. Your physical evaluation should be adequate to rule out TRALI, TACO and an allergic reaction.
• Do not give Tylenol or Benadryl immediately. Waiting for 30 minutes prior to tylenol to decrease fever will help with your evaluation for simple febrile reaction to blood products (exogenous cytokines) versus sepsis. If fever continues then you should consider sepsis as a possible diagnosis. 
• Order a urine analysis to evaluate for free hemoglobin in the urine. This should be taken 20-30 minutes after the reaction. In addition, a serum free hemoglobin can be ordered for evaluation for overwhelming hemolysis. 
• After the above steps, you will have assessed for every potential cause, and the patient can be considered a simple febrile blood reaction.