The American Association of Blood Banks published in the Journal of the American Medical Association new clinical practice guidelines for red blood cell (RBC) transfusion thresholds and storage.
Based on a review of 31 randomized clinical trials (comprising 12,587 participants) in which patients were randomized to receive transfusion at either restrictive thresholds (transfusion not indicated until the hemoglobin level of 7-8 g/dL) or liberal thresholds (9-10 g/dL), the guidelines recommend more restrictive transfusion thresholds for adult patients:
- Transfusion is not indicated until the hemoglobin level is 7 g/dL. This is recommended for hospitalized adult patients who are hemodynamically stable, including critically ill patients, rather than when the hemoglobin level is 10 g/dL (strong recommendation, moderate quality evidence).
- A restrictive RBC transfusion threshold of 8 g/dL is recommended for patients undergoing orthopedic surgery, cardiac surgery, and those with preexisting cardiovascular disease (strong recommendation, moderate quality evidence).
These more restrictive thresholds were not associated with higher rates of adverse clinical outcomes, including 30-day mortality, myocardial infarction, cerebrovascular accident, rebleeding, pneumonia, or thromboembolism. However, the authors noted that these recommendations do not apply to patients with acute coronary syndrome, severe thrombocytopenia, and chronic transfusion-dependent anemia.
In a review of 13 randomized controlled trials (comprising 5,515 participants) evaluating clinical outcomes of fresher blood (storage length <10 days) or standard-issue blood (used within the licensed dating period), the guideline authors determined that fresher blood did not improve clinical outcomes.
Based on these data, the guidelines recommend that patients, including neonates, should receive standard-issue RBC units rather than limiting patients to transfusion of only fresh RBC units (strong recommendation, moderate quality evidence).
Source: Carson JL, Guyatt G, Heddle NM. Clinical practice guidelines from the AABB: Red blood cell transfusion thresholds and storage. JAMA. 2016 October 12. [Epub ahead of print]