TUESDAY, Oct. 12 (HealthDay News) -- Patients having heart
surgery who receive fewer blood transfusions do just as well as
those who receive more, new research finds, and yet the rate of
blood transfusions varies widely among U.S. hospitals.
The studies are published in the Oct. 13 issue of the
Journal of the American Medical Association.
In the first study, researchers in Brazil divided 502 cardiac
surgery patients into two groups: one received blood transfusions
when the hemoglobin concentrations in their blood fell to 30
percent. The other group received blood transfusions when their
hemoglobin levels dropped to 24 percent.
Patients who received transfusions at the lower hemoglobin
concentration fared just as well in the 30 days after surgery as
those who received transfusions at the higher hemoglobin level.
Only 47 percent of patients whose surgeons waited until their
blood hemoglobin levels had fallen to 24 percent were given
transfusions compared to 78 percent of those in the 30 percent
hemoglobin concentration group.
Why should this matter to patients?
Hemoglobin concentration is the percentage of the blood made up
of red blood cells. A normal hemoglobin level is about 42 percent,
explained Dr. Timothy Gardner, an American Heart Association
spokesman and a cardiac surgeon at Christiana Care Health System in
Wilmington, Del. Gardner was not involved in the research.
Hemoglobin levels that drop too far can cause severe anemia,
which causes the blood to lose too much of its oxygen-carrying
capacity and raises the risk of death and other complications.
Yet blood transfusion itself carries risks, Gardner said. Prior
research has found an association between transfusions and greater
risk of death and problems including renal failure and
"What this study shows is that in patients that don't have a lot of other problems, you don't need to transfuse them to higher levels," Gardner said. "They will do just as well with a lower level of red blood cell concentration during the operative and early postoperative periods."
After blood loss during heart surgery, hemoglobin concentrations
usually rebound in about a month or two, Gardner explained.
Yet around the nation, the rate of transfusions during cardiac
surgery varies widely, according to a second study in the same
journal by researchers from Duke University in Durham, N.C.
Researchers analyzed data on more than 100,000 patients from
nearly 800 U.S. hospitals who were getting coronary artery bypass
graft surgery for the first time. They found some hospitals
transfused almost no one, while other hospitals transfused nearly
The percentage of patients given red blood cells ranged from 7.8
percent to 92.8 percent; for fresh-frozen plasma, the range was 0
to 97.5 percent, while platelets ranged from 0.4 percent to 90.4
percent, according to the report.
The researchers found no association between post-surgery
patient deaths and the hospital's rate of transfusions.
Patients in academic hospitals, hospitals that performed few
coronary artery bypass graft operations and hospitals in Texas,
Louisiana, Arkansas and Oklahoma were more likely to get
transfusions than those in other hospitals, though taken together,
those differences accounted for only 11 percent of the variation,
the study authors noted.
Patient characteristics, including age and other health
conditions, accounted for another 20 percent, they found.
Differences in surgical techniques that lead to more or less
bleeding or a culture of transfusing patients routinely may help
explain some of the variation, according to the report.
Dr. Lawrence Goodnough, a professor of pathology and medicine at
Stanford University who co-authored an accompanying editorial, said
the findings suggest that transfusion rates should be one factor
taken into account when rating hospital performance.
"Blood transfusions should be a quality indicator that can help track how carefully surgical patients are being handled," Goodnough said.
Taken together, the studies suggest hospitals may need to
rethink their transfusion practices, Gardner said, noting that in
some patients transfusing to the higher hemoglobin level is
"The combination of the two articles is forcing heart surgeons to reconsider their transfusion practices during heart surgery," Gardner said. "The Brazilian study suggests we can safely treat many patients without transfusion. The other study shows that as a community of heart surgeons, there is still a lot of variation in practices. It's a double whammy."
U.S. National Heart, Lung, and Blood Institute has
more on blood transfusions.
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