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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.
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.
However, several studies have forced us to re-evaluate this old paradigm, including increasing concern for the infectious and noninfectious complications associated with blood transfusions and the need for cost containment (see Table 1).1,2,4 Due to improved blood screening, infectious complications from transfusions have been greatly reduced; noninfectious complications are 1,000 times more likely than infectious ones.
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Table 1. Transfusion reactions
Review of Data
Although a number of studies have been performed on the indications for blood transfusions, many of the trials conducted in the past were too small to substantiate a certain practice. However, three trials with a large number of participants have allowed for a more evidence-based approach to blood transfusions. The studies address different patient populations to help broaden the restrictive transfusion approach to a larger range of patients.