What Are the Indications for a Blood Transfusion?

Close-up of a bag of blood being used to administer a blood transfusion to a 94-year-old patient with chronic lung disease (fibrosing alveolitis) in his home.

Key Points

  • The general consensus of major trials and meta-analyses favors a restrictive blood-transfusion strategy.
  • For most patients, a transfusion trigger of Hb 7-8 g/dL results in a significant decrease in RBC transfusions without negatively affecting outcomes.
  • No guidelines or data can replace clinical judgment when determining the need to transfuse.

Additional Reading

  • Carson JL, Grossman BJ, Kleinman S, et al. Red blood cell transfusion: a clinical practice guideline from the AABB. Ann Intern Med. 2012;157:49-58.
  • Hébert PC, Wells G, Blajchman MA, et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. N Engl J Med. 1999;340:409-417.
  • Carson JL, Terrin ML, Noveck H, et al. Liberal or restrictive transfusion in high-risk patients after hip surgery. N Engl J Med. 2011;365:2453-2462.
  • Hajjar LA, Vincent JL, Galas FR, et al. Transfusion requirements after cardiac surgery: the TRACS randomized controlled trial. JAMA. 2010;304:1559-1567.

Case

A 65-year-old man with a history of coronary artery disease (CAD) presents to the ED after a mechanical fall. He was found to have a hip fracture, admitted to orthopedic service, and underwent an uneventful hip repair. His post-operative course was uncomplicated, except for his hemoglobin level of 7.5 g/dL, which had decreased from his pre-operative hemoglobin of 11.2 g/dL. The patient was without cardiac symptoms, was ambulating with assistance, had normal vital signs, and was otherwise having an unremarkable recovery. The orthopedic surgeon, who recently heard that you do not have to transfuse patients unless their hemoglobin is less than 7 g/dL, consulted the hospitalist to help make the decision. What would your recommendation be?

Overview

Blood transfusions are a common medical procedure routinely given in the hospital.1 An estimated 15 million red blood cell (RBC) units are transfused each year in the United States.2 Despite its common use, the clinical indications for transfusion continue to be the subject of considerable debate. Most clinicians would agree that treating a patient with a low hemoglobin level and symptoms of anemia is reasonable.1,3 However, in the absence of overt symptoms, there is debate about when transfusions are appropriate.2,3

Because tissue oxygen delivery is dependent on hemoglobin and cardiac output, past medical practice has supported the use of the “golden 10/30 rule,” by which patients are transfused to a hemoglobin concentration of 10 g/dL or a hematocrit of 30%, regardless of symptoms. The rationale for this approach is based on physiologic evidence that cardiac output increases when hemoglobin falls below 7 g/dl. In patients with cardiac disease, the ability to increase cardiac output is compromised. Therefore, in order to reduce strain on the heart, hemoglobin levels historically have been kept higher than this threshold.

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