Tighter Recommendations Issued for Blood Cell Transfusions
Study found patients do just as well with lower thresholds for red blood cells.
Targeting to cut back on needless red blood cell transfusions, the American Association of Blood Banks has issued new recommendations that raise the bar for when patients should be considered in need of fresh blood.
The guidelines search to clarify the level at which a patient's red blood cell count can be observed as dangerously low, thereby triggering a transfusion.
An individual's red blood cell count level or "hemoglobin threshold" is deemed "healthy" when registering between twelve to fourteen grams per deciliter. That hasn't changed.
Though, until now physicians would sometimes view patients with a hemoglobin threshold of nine or tenas being anemic enough to require a transfusion.
But after an widespread review of the latest study, the association decided that such a "liberal" transfusion policy offered no extra protective health assistance to patients, and that most would do just as well if the threshold for transfusions was limited to a lower level of seven or eight grams per deciliter in hospitalized, stable patients.
"We gauged the medical evidence as to what patients are benefiting from more or less blood, and in what kind of situations and in what kinds of patients," said Dr. Jeffrey Carson, chairman of the recommendations committee. "And the evidence said that we can use less blood in certain settings: patients who are in the exhaustive care unit, patients who undergo most forms of surgery and even in patients who have preexisting heart problems."
Carson also serves as chief of the division of general internal medicine at University of Medicine & Dentistry of New Jersey-Robert Wood Johnson Medical School. The new procedures appear online March 27 in the Annals of Internal Medicine.
At present, red blood cell transfusion can become essential when levels of hemoglobin — which carries oxygen and is the principal ingredient in red blood cells — drop below optimal levels of twelve to fourteen grams per deciliter. This can happen, for example, as a result of blood loss in surgery.
"So the difference today," Carson added, "is that now we really have accumulated enough high quality evidence that we can be more definitive about what is best to do."
The result: Patients who underwent transfusions at higher hemoglobin levels of nine or ten grams per deciliter fared no better than those who underwent them at more restrictive levels of seven or eight.
At issue is the need to balance the potential benefits of transfusions against the potential risks. The association said that while transfusions can prolong a patient's lifespan, increase mobility and shorten hospital stays, there remains a relatively low but even so present risk for infection, for "overloading" the patient with blood, and for allergic reactions or lung injuries.
The professional panel evaluated research published between 1950 and 2011. The team stacked up red cell transfusion cases, the hemoglobin thresholds followed, and the amount of blood used in such transfusions against a range of related medical issues, including death, strokes, heart attacks ,kidney failure, mental confusion ,infection, bleeding, recovery time and hospital stay.
"With transfusions, the risk that we used to be really concerned about was HIV and hepatitis infection," he noted. "But today that risk is very low. Less than one in a million. However, noninfectious risks of transfusion are far more common. Probably ten to one hundred times more common than any viral transfusion risk. So there's still good reason to not expose a patient to the risks of a transfusion without any evidence that they will benefit from it."
Though physicians are encouraged to judge on a case-by-case basis and also consider symptoms of anemia, the recommendations encourage doctors to only consider a transfusion at a hemoglobin level of 7 grams per deciliter for intensive care patients and at eight for most other patients.
Dr. Darrell Triulzi, president of the blood bank association, suggested that the goal has been to find the sweet spot for patient care and public health.
"And if anything," Triulzi said, "the research indicates that some patients might actually fare better without undergoing a transfusion, depending on their circumstance. And at the very least we know with certainty that at these lower thresholds they won't do worse."
"Transfusion decisions need to consider individual patient characteristics, including age and the presence of [coronary artery disease] to estimate a specific patient's likelihood of benefit from transfusion," Vincent wrote. "The decision to transfuse is too complex and important to be based guided by a single number."
At least one professional believes the new guidelines focus too little on the individual patient. Dr. Jean-Louis Vincent, professor of intensive care at Erasme Hospital Free University of Brussels, wrote in an accompanying journal editorial that basing the decision to transfuse on hemoglobin levels alone is insufficient.
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