Hematology

Hemoglobin Transfusion Guidelines

SUMMARY:

Blood transfusions are a common treatment for anemia and acute bleeding, with more than 14 million units of blood transfused each year in the United States. Despite this, the costs and risks involved can be significant. Over the past few decades a growing body of research has supported using a restrictive hemoglobin-based transfusion threshold, typically aiming for a hemoglobin of 7 to 8 g/dL, and only when benefits outweigh potential risks for the individual patient. The Association for the Advancement of Blood and Biotherapies (AABB) has updated their transfusion guidelines with continued endorsement of a restrictive transfusion threshold after evaluating 45 RTCs studying the difference in outcomes between a restrictive hemoglobin-based transfusion threshold vs. a liberal transfusion threshold of 9 to 10 g/dL.

Recommendations

For hospitalized and hemodynamically stable patients, the AABB recommends a restrictive hemoglobin-based transfusion threshold, aiming for a hemoglobin of 7 g/dL
Clinicians may consider a higher hemoglobin goal in specific patient populations
- Patients undergoing cardiac surgery: 7.5 g/dL
- Patients undergoing orthopedic surgery: 8 g/dL
- Patients with preexisting cardiac conditions: 8 g/dL
The panel choose not to recommend a transfusion threshold for patients with acute myocardial infarction given conflicting and uncertain evidence regarding this patient population
Decision to transfusion should ultimately take into account patient’s personal preference, transfusion history, and co-morbid conditions
Risks and complications of blood transfusion should be discussed as part of the blood consent process prior to administering blood products in hemodynamically stable patients

Risks and Complications

Infectious Complications

Bacterial infections
- Risk is highest with platelet transfusions, less risk with RBC transfusions
- Pathogens include: Strep | Staph | E. coli
Hepatitis B virus: 1:1,100,000 risk per blood transfusion
Hepatitis C virus: 1:1,200,000 risk per blood transfusion
HIV: 1:1,600,000 risk per blood transfusion
Less commonly: HTLV | CMV

Non-Infectious Complications

Febrile reaction: 1:161 risk per blood transfusion
- Febrile non-hemolytic transfusion reaction is characterized by fever within 4 hours of transfusion in the absence of hemolysis
Allergic reaction: 1:345 risk per blood transfusion
- Due to the presence of an allergen in the transfused blood
- Symptoms may be mild (e.g., skin irritation) or progress to anaphylaxis
Transfusion-associated circulatory overload (TACO): 1:125 risk per blood transfusion
- Volume overload due to high rate of blood infusion or inability of patient to process blood transfusion due to co-morbid conditions (e.g., CKD| CHF)
Transfusion-related acute lung injury (TRALI): 1:1250 risk per blood transfusion
- Respiratory distress within 6 hours of blood transfusion in the absence of other cause (e.g., Pneumonia | Trauma)
Anaphylactic reaction: 1:5000 risk per blood transfusion
Hemolytic transfusion reaction: Acute | Delayed (Between 24 hours and 28 days after a transfusion)
Risks with repeated transfusions: Hypocalcemia | Hyperkalemia | Iron overload

KEY POINTS:

For hemodynamically stable patients a restrictive hemoglobin-based transfusion threshold, aiming for a hemoglobin of 7 g/dL, is recommended
Data is still uncertain regarding transfusion goals for patients with acute myocardial infarction
Ultimately, the risks and benefits of transfusion should be considered for each patient based on their preferences and co-morbid conditions