Blood transfusions: Is there a limit?
A blood transfusion is a common medical procedure. A transfusion may be needed to treat a long-term disease or a medical emergency.
Although there are no set parameters for how many blood transfusions a person can have, there are some guidelines for avoiding complications and improving outcomes.
Blood transfusion basics
There are guidelines for avoiding complications if a person has many blood transfusions.
A person's blood contains white and red blood cells along with platelets and plasma.
A blood transfusion involves giving whole blood or, more commonly, only a specific part of the blood.
According to the American Red Cross, common blood transfusions involve one component of the blood only. This may be the red blood cells, platelets, or plasma. White blood cells are rarely transfused.
Rules for blood transfusions
Hospitals typically have rules or protocols for how low a person's blood count must be before they are given a blood transfusion. Protocols for administering blood transfusions often involve hemoglobin levels.
Hemoglobin is a protein in red blood cells that carries oxygen to the tissues and organs in the body.
A blood test measures hemoglobin in the body. Low hemoglobin levels often indicate blood loss or a lack of red blood cell production.
A study funded by the American Association of Blood Banks recommends restricting red blood cell transfusions for hospitalized adult patients until the hemoglobin level has fallen to 7 grams per deciliter (g/dl).
Waiting until hemoglobin is at 7 g/dl is associated with administering fewer units of red blood cells.
The above parameter for hemoglobin also tends to result in shorter hospital stays and lower rates of complications, including death.
Additional rules for blood transfusions include making sure the person's blood is compatible with the donor blood. To check if the donor blood is a match, the person getting the blood has a test to determine their blood type.
A test called a crossmatch is also done to screen for antigens and make sure the recipient's blood is compatible with the donor blood.
Trained staff will monitor the person for any negative reactions during and after the blood transfusion.
Limits for blood transfusions
A blood transfusion may be limited if a person has a negative reaction or a complication.
In some cases, blood transfusions may be limited if donated blood is in short supply. For example, during a disaster or a mass casualty incident where many people may require blood, and there may not be enough.
Also, in some instances, a person can appear to need a blood transfusion, but a co-existing condition may be a contraindication or reason to avoid giving the blood. For example, certain cardiac conditions can be made worse by increasing volume through giving blood.
A large blood transfusion may create some possible complications.
A blood transfusion is not without risks. There can be complications that range from minor to life-threatening.
One rare complication is a sudden immune reaction. This occurs when the person's immune system attacks the transfused blood cells and damages the kidneys.
Additional complications of a blood transfusion can include fever and infection.
Having what is referred to as a massive blood transfusion can have additional complications.
Transfusing 10 units of blood in a 24-hour period, or 5 units of blood in 4 hours, is considered a massive blood transfusion. Such a big blood transfusion replaces a large amount of the person's blood volume.
A massive blood transfusion may be needed in cases where someone is in shock due to rapid blood loss. Traumatic injuries and complications from surgery can lead to massive blood loss.
Possible complications of a massive blood transfusion include:
- hyperkalemia or high potassium in the blood
- abnormal blood clotting
- hypothermia or low body temperature
- increased acid in the blood
Alternatives to blood transfusions
In some cases, such as if a person experienced a bad reaction to a blood transfusion, alternatives might be an option.
Possible alternatives to blood transfusions include:
Hematopoietic growth factors are substances that stimulate the bone marrow to increase blood cell production. Growth factors are naturally made in the body, but synthetic versions are also available to treat people with low blood counts.
Administering growth factors can increase platelets and red and white blood cells counts. However, it usually takes weeks to increase blood count.
Because using growth factors requires time, it is not effective in a life-threatening situation when blood counts need to be raised quickly.
Volume expanders are administered into the bloodstream through a vein. They work by expanding fluid volume in the body to help improve blood circulation to the organs. They may be given when a person is in certain types of shock.
Volume expanders do not increase the number of red blood cells in the body but may be an alternative if someone refuses a blood transfusion, or has an adverse reaction to blood products.
Currently, there is no set number of blood transfusions a person can have. But the procedure is not without risks and possible complications.
Following blood transfusion guidelines and rules, such as specific hemoglobin levels, may decrease complications and improve outcomes.