One of the most significant medical advances to occur in the early 20th century was the discovery of how to safely provide a blood transfusion for a patient. Previous attempts had been largely unsuccessful due to a poor understanding of what was causing the side-effects associated with transfusion. It wasn’t until 1901, when Dr. Karl Landsteiner, an Austrian born American biologist and physician, discovered that there were different blood groups that transfusions became safer. Since then, more blood types than his initial discovery have been discovered and technological advances have made it possible to reduce the risk of infectious diseases being transferred that way.
In modern day medicine, thanks to discoveries about the qualities of blood and the technological advances in the lab, transfusions may be of whole blood or of the various components that make up the blood. It is possible, for example, to receive just red blood cells or just white blood cells and other components that are not whole blood. Plasma transfusions and immunoglobulin transfusions can both be performed, depending upon the needs of the patient.
Still, despite advances, there are risks associated with this procedure, chief among them being the side effects of blood transfusion. Side effects are generally considered complications and can be broken down into classifications: Immunologic, Infectious, and “other”. Let’s take a closer look at the potential blood transfusion side effects, what they are and what is generally done to avoid them.
- Acute Hemolytic Reaction: This reaction can happen when the patient is receiving red blood cells and thankfully, isn’t very common in this era. It occurs in about .016% of transfusions with only about .003% of cases being fatal.
o Caused by: Acute hemolytic reactions are caused by the obliteration of donor erythrocytes by recipient antibodies that have been preformed. Because great care is taken to be sure that a patient is not being given a blood type their body will react to, these types of reactions are more commonly clerical in error or a mistake in typing or cross-matching.
o Symptoms: fever, chills, increased heart rate, shortness of breath, rapid drop in blood pressure.
o An unfortunate side-effect of this reaction could be kidney damage or even death if not caught promptly and immediately treated.
- Delayed Hemolytic Reaction: This side effect of blood transfusion is more common than the above, happening about .025% of the time (still quite rare).
o Caused by: same as above and often occur without obvious symptoms
o Result: rarely is treatment ever needed and this reaction is not fatal nor is it associated with damage. However, it may affect future compatibility for the patient.
- Febrile Nonhemolytic Reaction: occurs when the patient has antibodies developing to the white blood cells during a transfusion, occurring in about 7% of these types of transfusions.
o Caused by: may be occur after previous transfusion
o Symptoms: fever is generally short lived.
- Allergic Reaction: This is an allergic reaction to certain chemicals in the donor blood and does not require the patient to have undergone a previous transfusion.
o Caused by: allergic reaction to chemical components in donor blood
o Symptoms: urticaria (hives) pruritus, (itching), and possibly even anaphylactic shock.
o A very small percentage of patients (.13%) are deficient in immunoglobulin IgA, causing an anaphylactic reaction to blood containing IgA
- Post transfusion purpura: The appearance of red or purple discolorations or blotches on the skin that do not respond to applied pressure by blanching.
o Caused by: transfusion that has platelets included which express a protein called HPA-1a. Patients who do not have this protein become sensitized during a previous transfusion and will experience a decrease in the platelets in their blood (thrombocytopenia) 7-10 days after any subsequent transfusions.
- TRALI (Transfusion-associated Acute Lung Injury): acute respiratory distress after or during transfusion.
o Symptoms: respiratory distress, fever, non-cardiogenic pulmonary edema (fluid in the lungs) and hypotension (abnormally low blood pressure).
o Caused by: Unfortunately, medical science has not yet completely answered the question of what causes TRALI. However, it has been consistently associated with anti-HLA antibodies which are commonly formed during pregnancy. For this reason, many transfusion organizations have begun only using plasma from men for transfusions.
o Generally speaking, TRALI happens with plasma component transfusions rather than with red blood cells (RBCs) but there is always some left over plasma in RBC transfusions.
- Transfusion Transmitted Bacterial Infection: The risk of bacterial infection from a transfusion is higher with platelet transfusions than it is with RBC (1 in 50,000 as opposed to 1 in 500,00 transfusions) because of the fact that plasma units are stored for a short time at room temperature. Overall, thanks to current understandings of the risk of bacterial contamination and how it occurs, the incidence of bacterial infection from a transfusion is still relatively small.
- HIV Contraction: While this is still a risk, since the testing of all donor blood for HIV began in the 1980’s the incidence of transfusion contracted HIV has dropped off sharply and is extremely unlikely today. There was a time when the only way to test donor blood for HIV was by testing for HIV antibodies. Unfortunately, there is a window of time after exposure to infection where a person is infectious but not yet developed enough antibodies to register during a test. In recent years, a new way of screening the blood has been developed, testing for HIV-1 RNA, which has dramatically lowered the incidence of HIV transmission via transfusion even more, to about 1 in 3 million units.
- Hepatitis C transmission: At a current rate of 1 in 2million units, it is still possible to contract Hepatitis C via transfusion. Testing of donor blood includes both antibodies and nucleic acid testing for viral RNA.
- Chagas Disease
- Hepatitis B
These complications are not classifiable as either immunologic or infectious
- Transfusion-associated Volume Overload: Relatively common side effect of blood transfusion. More prevalent in patients with cardiac or kidney disease. RCB transfusions may cause volume overload in patients that need repeated transfusions due to insufficient efficacy. Because of plasma’s hypertonicity, volume overload is more common with Plasma Transfusion.
- Hypothermia: Generally caused by large infusions of blood stored at cold temperatures. Prevention is simple: warming the blood to ambient temperature before beginning the transfusion.
- Large RBC can lead to an inclination towards bleeding.
- Metabolic Alkalosis (condition in which the pH of tissue is elevated beyond normal): caused by the breakdown of citrate in the blood into bicarbonate.
The vast majority of negative side effects from blood transfusion are avoidable by proper blood screening techniques, proper handling techniques, correct storage protocols and taking care to warm the blood to ambient temperature before transfusion. With these guidelines in place, adverse reactions to transfusion remain rare and it is hoped that as technology advances even further, allowing us to understand the human body to a greater degree, these reactions will cease altogether.