Managing Complications with Blood Transfusion
Blood transfusions may be used for the prevention of complications associated with sickle cell disease by decreasing the concentration of sickle hemoglobin in the blood. Methods of transfusion depend upon the health goals. Patients with HbSS and HbSβ0 thalassemia most often use transfusion therapy.
Simple transfusion involves transfusing packed red blood cells without removing any of the patient’s blood volume.
Chronic Transfusion Therapy
Chronic transfusion therapy involves giving simple transfusions on an every two to four weeks schedule. This therapy may be used for stroke prevention for patients at high risk for stroke.
Exchange transfusion is the removal of a percentage of the patient’s blood and replacing with donor packed red blood cells. This is a much more time-consuming process and is usually done in the dialysis area of the hospital using an apheresis machine.
This method substantially reduces the concentration of sickle cells without increasing the overall hematocrit or blood viscosity (thickness).
Complications of Transfusion Therapy
Iron overload can occur after multiple transfusions of packed red blood cells (typically greater than 10-20 units). The iron present in the transfused red blood cells gets absorbed in the tissues and organs. Untreated iron overload can result in heart disease/failure and liver disorders/failure. A blood ferritin level is drawn to determine the amount of iron build up.
Iron overload is generally defined as serum ferritin levels great than 1000. A specialized MRI may be performed on the heart or liver to predict the amount of iron that is present in the tissue.
Chelation therapy is the use of a medication to remove the extra iron from the body. This medication can be given by mouth or by an infusion into the subcutaneous tissues (just under the skin). This is a long-term therapy for patients on chronic transfusion.
Alloimmunization to red cell antigens occurs in about 30% or more of transfused patients with sickle cell disease. This is an antibody that develops to the donor’s red blood cells.
Alloimmunization can make it difficult to find blood that can safely be used for a blood transfusion. Infusion with blood that is incompatible can result in a serious reaction called hemolytic anemia.
The risk of alloimmunization can be significantly reduced by:
- keeping accurate blood transfusion and blood typing records
- limiting the number of blood transfusions given over a lifetime
- giving transfusions for only clear-cut indications
- screening for new antibodies after transfusions
- typing the patient blood for antigens of the Rh and Kell blood groups and avoiding the transfusion of cells having these antigens (especially E, C, and Kell) if the patient lacks the antigen
- increasing the number of African American donors for more blood matches