It sounds very serious when you hear that someone “needed” a blood transfusion. According to research I’ve recently read, what necessitates a transfusion varies dramatically from one hospital to the next. That’s surprising enough, but I also learned that receiving a transfusion of someone else’s blood lowers immunity to the point that it doubles the likelihood that a patient will suffer infection in the hospital. I called Neil Blumberg, MD, director of the Transfusion Medicine/Blood Bank at the University of Rochester Medical Center in New York, to learn more. With an estimated five million Americans receiving blood transfusions each year, it seems to me that this is something we need to know more about.
Now that strict safety rules regulate the nation’s blood supply, the risk for direct infection (e.g., with the hepatitis B or C virus or HIV) from transfusions is very small, observes Dr. Blumberg — but, he said, many other serious risks persist. Though doctors don’t fully understand why, they know that transfusions dramatically affect your immune system, likely in both the short and the long term. Receiving another person’s blood increases the risk for harm to lung tissue and red blood cells and can trigger an array of allergic reactions. Also, in the immediate post-procedure period, transfusions raise the risk for bacterial infection due to decreased immune function, potential organ failure and possible clotting in key veins and arteries. These problems can lead to heart attack, stroke or deep vein thrombosis.
To measure the health risks posed by transfusions, Dr. Blumberg and his colleagues examined the outcomes of a specific procedure that often involves a large transfusion of stored blood over two to six hours — cardiac bypass surgery. In nearly 25,000 people who underwent a cardiac bypass, they found that…
Findings were published in the July 2009 issue of BMC Medicine.
While guidelines regarding blood donation are safe and uniform, guidelines for when a transfusion is needed are imprecise, leaving doctors to make transfusion decisions based on prevailing practices at their own hospitals and on their own training and experience, rather than on scientific evidence, says Dr. Blumberg. He told me that some cardiac surgery programs transfuse almost all patients, others transfuse very few, and the rest are scattered along the spectrum in between.
One fact stands out, however — in most studies to date, fewer transfusions correlate with fewer complications and deaths in surgical patients. Dr. Blumberg believes these programs have better clinical outcomes because they are more conservative in their use of transfusion and have technically sophisticated surgeons who take various steps to minimize bleeding, such as using scalpels that clot blood as they cut tissue.
I also asked Dr. Blumberg about bloodless surgery, which uses new surgical techniques and equipment to minimize the use of blood and blood-related products during surgery. This was first developed in the 1960s to meet the needs of Jehovah’s Witnesses, whose religious beliefs do not permit blood transfusion, but it has since become more widely available, as its medical advantages have become apparent. In Dr. Blumberg’s opinion, the presence of a bloodless surgery program or other blood-management program at a hospital is a quality indicator, suggesting that health-care providers pay more attention to transfusion issues. This might translate to better outcomes.
There is a process that can dramatically reduce the risk for infection and death in transfusion patients, yet some hospitals still don’t use it. Called leukoreduction, it is the removal of white blood cells from donated blood. This reduces risk by lowering immunologically driven problems. An array of evidence supports the efficacy of leukoreduction, and the cost is modest. Dr. Blumberg told me that he would like to see this process made universal in every hospital.
In the meantime, if you are going to have surgery, Dr. Blumberg advises that you protect yourself by asking in advance whether you might require a transfusion. If the answer is yes…
By the way, there is no evidence that receiving blood donated by family members or friends is safer than receiving blood from the national blood supply.
