Determining whether a patient needs a blood transfusion and, if so, how much blood he or she should be given, can be key to the patient’s long-term well-being. Recently, researchers found that survival rates in heart patients undergoing surgery were similar whether the amount of blood that was transfused was large or small.
Surgeons and doctors performing other procedures must judge whether blood is needed based on their observation of how much blood a patient has lost and by closely monitoring vital signs such as blood pressure. Too much transfused blood can overload a patient’s circulatory system, and cause problems with breathing.
Too much blood also can increase the risk of infection, particularly hepatitis and HIV. Because transfused blood is tested in advance, cases of those infections are rare, but as the lead researcher in a study by Rutgers University said, “why give more blood to anyone if you can’t show it benefits them?”
Dr. Jeffrey Carson, chief of the Division of Internal Medicine at Rutgers Robert Wood Johnson Medical School, led the study, which followed 2,016 patients for as long as four years. Half received large quantities of transfused blood; half received transfusions of much less blood.
The study, which was published in the journal Lancet, measured overall mortality, as well as mortality from cardiovascular disease, cancer and severe infection. The results reinforced the recent trend toward a more moderate application of transfusions.
About 5 million people in the U.S. receive transfusions each year, according to the Centers for Disease Control and Prevention. They are surgery patients, accident, burn and trauma victims, mothers and babies during and after childbirth and people whose low blood counts threaten their health.
In 2011, Carson published a study in the New England Journal of Medicine that showed that fewer transfusions during a 60-day period were safer than more transfusions for the same subjects. This time, the Rutgers team found no evidence of increased mortality from cardiovascular disease, cancer or severe infection after surgery attributed to the amount of the blood given during the operation. The results supported the earlier research that, according to the university news release, “was one of the driving forces behind a change in blood transfusion practice nationally.”
“There has been a steady decline in the amount of blood in transfusions given to patients in the
past three to five years,” Carson said. “I think it is very reassuring that we have found that using less blood is okay not just from a short term perspective, but also a long term perspective.”
Carson was chairman of the American Association of Blood Banks’ official guidelines committee in 2012. He said that fewer transfusions not only are better for individual patients, but also benefit society by preserving the blood supply and preventing shortages.
According to Rutgers, medical experts have been concerned that larger amounts of transfused blood might suppress immune function, which leaves the body more vulnerable to infection and cancer. They also wondered whether smaller transfusions could make a patient’s chronic heart disease worse by depriving the heart of oxygen and other nutrients it might have received if more blood had been pumped. But Carson found no difference in long-term death rates for either scenario, regardless of the number of transfusions.
Some health conditions, like heart attacks, still require further transfusion research, Carson acknowledged. Preliminary evidence suggests that those patients need more blood, not less. But for now, if your problem is not a heart attack, and your care team advises a transfusion, or a series of them, ask why they think this is the best, or only, approach. If the answer is “Just in case,” that might not be a good reason.