Blood is good. We cannot live without blood. In fact, when we are bleeding, we may even need to receive someone else’s blood as a transfusion. A good blood level makes us feel good and may even help us “perform” better. Athletes know this and hence, why some may engage in an illegal practice known as “blood doping”. So, it makes sense, that if you are in the hospital and your blood level is a little low, you should get a blood transfusion to “tank” you up and make you feel better… right?
Unfortunately, it is just not that simple. It turns out there is a huge difference between blood made by your own body and someone else’s blood that has also been processed and stored. Certainly, if you could choose between having a normal hemoglobin (your “blood level”) and a low hemoglobin, you would easily chose the higher level. The decision is not so straight forward when that decision includes receiving a blood transfusion. Most everyone already knows about the risks of infection with blood but those risks are very low and, it turns out, are not the most important risks. The risk of contracting a contagious disease (hepatitis, HIV, etc) through a blood transfusion are on the order of one in a million. On the other hand, the other risks are much more common and include transfusion reaction, acute lung injury, increase in cancer recurrence (in patients undergoing surgery for cancer), increased infections such as surgical wound and pneumonia, delayed wound healing, and a longer hospital stay.
Ever since the beginning days of blood transfusions, there were no rigorous scientific studies done to look at whether blood transfusion really helped patients. It just made intuitive sense that it would and so the practice of transfusion continued. Fortunately, the medical world is taking a fresh look at transfusion practice and thus is designing studies to evaluate whether patients are benefited by blood transfusions. The studies that have been done so far are showing that transfusing patients may cause more harm than good. The reasons for this are complex and include the fact that transfused blood causes many reactions of the patient’s immune system. The effect on the immune system may make it harder to fight infections and cancer cells. Also, red blood cells that have been treated and stored in a blood bank are not normal and healthy and therefore do not carry oxygen as well as was previously thought. In fact, the longer the cells are stored, the worse they become.
It is this knowledge that has led hospitals to focus on strategies that prevent patients from requiring a blood transfusion. These strategies include optimizing a patient’s hemoglobin prior to surgery, minimizing blood loss during surgery, using certain drugs to help the body make more blood, and minimizing the amount of blood that is taken from hospital patients for laboratory testing.
In summary, a blood transfusion is still life saving. However, not all patients with a low blood level will need a transfusion. The risk of transfusion is more than just the risk of contracting hepatitis or HIV. Careful thought towards the risks of transfusion are helping doctors to decrease the incidence of transfusing a patient.