Some Transfusions May Do More Harm Than Good

The resulting overuse of blood is problematic because blood is a scarce and expensive resource and because recent studies have shown that surgical patients do no better, and may do worse, if given transfusions prematurely or unnecessarily.

Scientists at Johns Hopkins University School of Medicine (Baltimore, MD, USA) examined the electronic anesthesia records of more than 48,000 surgical patients at the adjacent Johns Hopkins Hospital over the 18 months from February 2010 to August 2011. Overall, 2,981 patients (6.2%) were given blood transfusions during surgery. The study found wide variation among surgeons and among anesthesiologists, compared to their peers, and how quickly they order blood.

In a healthy adult, a normal hemoglobin level, the quantity of red blood cells carrying oxygen through the body, is approximately 14 g/dL. The guidelines state that when a patient's hemoglobin level falls below 6 or 7 g/dL, a patient will benefit from a transfusion and that if the levels are above 10, a patient does not need a transfusion. But when blood levels are in-between, there has been little consensus about what to do. The study found that the use of erythrocyte salvage, fresh frozen plasma, and platelets varied threefold to fourfold among individual surgeons compared with their peers performing the same surgical procedure.

Blood transfusion, which introduces foreign substances into the body, initiates a series of complex immune reactions. Patients often develop antibodies to transfused red blood cells making it more difficult to find a match if future transfusions are needed. Transfused blood also has a suppressive effect on the immune system, which increases the risk of infections, including pneumonia and sepsis.

Blood is in short supply and expensive. In the USA it costs USD 278 to buy a unit of blood from the American Red Cross (Washington DC, USA) for example, and as much as USD 1,100 for the nonprofit to acquire, test, store and transport. The US national social insurance program, Medicare pays just USD 180 for that unit of blood.

Steven M. Frank, MD, leader of the study, said, "Transfusion is not as safe as people think. Over the past five years, studies have supported giving less blood than we used to, and our study shows that practitioners have not caught up. Blood conservation is one of the few areas in medicine where outcomes can be improved, risk reduced, and costs saved all at the same time. Nothing says it's better to give a patient more blood than is needed.” The study was published on April 23, 2012, in the journal Anesthesiology.

Related Links:
Johns Hopkins University School of Medicine
American Red Cross