The American Association of Blood Blanks (AABB) announced upcoming new guidelines in the March online Annals of Internal Medicine, recommending against transfusion for adults and children with stable illness and hemoglobin levels above 7-8 g/dL. They made it a 1A recommendation (strong recommendation with high quality evidence).
Jeffrey Carson et al reviewed literature from 1950 to 2011 and the apparent effects of restrictive transfusion strategies on mortality, myocardial infarction, other cardiac events, strokes, renal failure, pulmonary embolism, bleeding, and recovery and length of hospital stays.
There is a surprising near-total lack of randomized controlled trials in this area, with the famous practice-changing TRICC trial -- still the largest and best study -- demonstrating a restrictive transfusion strategy (transfusing when hemoglobin falls below 7 g/dL in patients who are not bleeding or in shock) is at least as good and probably superior to traditional, more liberal transfusion strategies. Outside of TRICC, the reviewers' conclusions are based largely on observational data.
The AABB's recommendations are:
- Pursue a restrictive transfusion strategy (transfusing to 7 - 8 g/dL hemoglobin) in stable hospitalized patients (Strong recommendation; high-quality evidence).
- They suggest the restrictive strategy be used for hospitalized patients with known coronary artery disease or other cardiovascular disease, with a transfusion threshold of 8 g/dL. (Weak recommendation; moderate-quality evidence).
- No recommendation for patients with acute coronary syndrome, due to lack of quality evidence.
- Consider symptoms as well as the hemoglobin level when making transfusion decisions. (Weak recommendation; low-quality evidence).
If you haven't yet, check out Tim Hannon's blog The Bloody Truth for a fresh take on the most current news in blood transfusions and blood banking.
Carson JL et al. Red Blood Cell Transfusion: A Clinical Practice Guideline From the AABB. Ann Intern Med 2012;ePub ahead of print March 26 2012.