Dr. Jeffrey Carson, a Rutgers University medical professor, has finished a massive study on blood transfusion that shows how the medical community can save more blood and more patients.
The study, published in the New England Journal of Medicine in late 2023, tested transfusion strategies in more than 3,500 patients at 144 hospitals worldwide. Results showed that patients given more blood to maintain hemoglobin levels near 10 grams per deciliter fared better than those treated under the current restrictive standard of 7–8 g/dl.
The findings prompted the Association for the Advancement of Blood & Biotherapies to update its recommendations, joining the American College of Cardiology and the American Heart Association. The new guidelines advise doctors to consider more frequent transfusions for anemic patients who have had heart attacks.
The two new guideline papers are the first to break from more restrictive transfusion recommendations urging fewer transfusions that keep hemoglobin at 7-8 grams per deciliter for all anemic patients. Ironically, these recommendations were largely the result of Carson’s earlier transfusion studies.
Each year, about 200,000 Americans who suffer heart attacks also have anemia (low levels of hemoglobin). Adopting a liberal strategy (giving more blood to maintain a higher hemoglobin level) could prevent 4,800 recurrent attacks or deaths and 3,200 deaths annually, Carson’s study found. All this would require an extra 366,000 pints of blood, slightly more than 3% of the 10 million transfused nationwide each year.
Carson remarked on the irony of this revolution, but is proud of the progress.
“Yes, there’s some irony in spending decades demonstrating that liberal transfusions are unnecessary, though certainly not harmful, and then turning around and finding a major exception where liberal transfusions are justified,” he said. “But you go where the evidence leads and embrace the practices that will save lives.”
This work created a natural experiment on the value of using transfusions to maintain normal levels of blood hemoglobin, which delivers oxygen to all the cells in the body. Each patient who declined transfusion faced surgery and its aftermath with whatever hemoglobin their bodies naturally had, so they gave Carson his first evidence of two facts he would spend the next several decades establishing more rigorously:
Most patients fared just as well with hemoglobin levels of 7–8 grams per deciliter, so guidelines calling for enough extra blood to keep it at 10 are likely wasting a lot of blood
However, people with serious heart problems fared better with higher hemoglobin levels, so giving more transfusions might help their care.
Aaron Tobian, the director of transfusion medicine at Johns Hopkins Medicine, praised Carson’s work.
“Jeff has now changed clinical medicine twice in the past 25 years,” he said. “He has had more influence on the way we transfuse these days than anyone else.”
