The resulting overuse of blood is problematic, the researchers say, 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. "Transfusion is not as safe as people think," says Doctor Steven M. Frank.
"Over the past five years, studies have supported giving less blood than we used to, and our research shows that practitioners have not caught up," says Frank. "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 is better to give a patient more blood than is needed."
General guidelines from three different medical societies govern when a surgical patient should get blood, but they tend to be vague, Frank says. In a healthy adult, a normal haemoglobin level — the quantity of red blood cells carrying oxygen through the body — is roughly 14 grams per decilitre. The guidelines state that when a patient's haemoglobin level falls below six or seven grams per decilitre, 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.
For the new study, Frank and his colleagues examined the electronic anesthesia records of more than 48,000 surgical patients at The Johns Hopkins Hospital over the 18 months from February 2010 to August 2011. Overall, 2,981 patients (6.2 per cent) were given blood transfusions during surgery. The researchers found wide variation among surgeons and among anaesthesiologists, compared to their peers, and how quickly they order blood.
Blood transfusion, which introduces a foreign substance "transplant" 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, he says. Frank also cites a study showing a 42 per cent increased risk of cancer recurrence in patients having cancer surgery who received transfusions.
Frank's research at Johns Hopkins produced a list of blood use and trigger points for each individual surgeon and anesthesiologist. Frank recently told the Hopkins surgeon who uses blood most often that he held that distinction and explained the reasons he might want to wait until hemoglobin levels are lower before ordering a transfusion. In the two months before their conversation, 30 per cent of that surgeon's patients got blood transfusions. In the two months after, only 18 per cent did.
MEDICA.de; Source: Johns Hopkins Medicine