Monroe Carell Jr. Children's Hospital at Vanderbilt
Monroe Carell Jr. Children's Hospital at Vanderbilt
Monroe Carell Jr. Children's Hospital at Vanderbilt
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Monroe Carell Jr.
Children's Hospital
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Blood Transfusions


Will my child need a blood transfusion?
For some types of surgery, such as heart surgery, the need for blood is great. If your child is less than a year old and the operation involves use of the bypass pump (the "heart-lung machine"), it is almost certain that your child will need blood. This is because the bypass circuit needs a certain volume of blood to fill it before it's connected to your child.

If your child is between two and 10 years old, the need for blood is still very high but is not always required. This is because these patients have larger blood volumes and are better able to tolerate a dilution of their own blood within the bypass system. Larger patients in this age range and those having their first heart operation are sometimes able to avoid transfusion altogether.

Patients with cyanotic heart conditions (sometimes called "blue" patients) and those taking certain medications are at higher risk for needing blood. Also, avoiding blood use in the operating room does not necessarily mean that blood will not need be needed in the intensive care unit or later during hospitalization.

Older children and adolescents are often able to avoid transfusion completely. This can depend on many factors. For any patient, the need for blood can only be estimated for individual patients by the surgical team at the time of surgery.

What kinds of blood products may my child receive?
When blood is donated, it is separated into its components. Each component has separate indications for its use and different optimal storage requirements. 

Red cells are the most obvious component of blood. These are stored in a special solution at refrigerated temperatures. A unit of red cells has a storage time of about eight weeks. Because the primary job of the red cells is to carry oxygen to tissues, the only reason for transfusing red cells is if there is a need to increase the blood's oxygen-carrying capacity.

Platelets are small cell fragments that are separated from the rest of the blood after the red cells are removed. Platelets require no special storage solution, and are kept in their plasma at room temperature. The shelf life of a unit of platelets is about seven days. Platelets are essential to blood's clotting function. During cardiac surgery, a patient's platelets often become diluted, consumed, or inactivated, which is why platelet transfusion after cardiac surgery is very common.

Plasma is the liquid portion of blood left over after the cells and platelets have been removed. Plasma is stored frozen for several months, and must be thawed completely to body temperature prior to use. Because plasma contains all the circulating proteins found in blood, it is transfused in order to replace these proteins. Most frequently, it is used to replace clotting factors that have been either consumed or diluted during cardiac surgery.

Other products: Plasma is sometimes divided into other components, such as cryoprecipitate, cryo-supernatant, prothrombin complex concentrate, and factor concentrates. Each has its own specific indications, but these are less commonly used in cardiac surgery.

What are the risks of receiving blood?
Blood transfusion is very safe. However, the risk is not zero. There are several identifiable risks to receiving a unit of blood, including immune reactions to blood components, allergic reactions, bacterial and viral infections, and white cell reactions.

Immune reactions: A blood transfusion should be thought of as a transplant of a tissue. An immune reaction to an incompatible blood component may be considered a form of "rejection," although this term is rarely used in this situation.

Blood is always typed and cross-matched in the laboratory to verify that a reaction to the red cells will not occur during transfusion. Although there are multiple checks and redundancies built into blood banking and transfusion practices, errors in identification, processing, and administration do occur, and account for the great majority of transfusion reactions. Mortality from such reactions is estimated at around one per one million units.

Allergic reactions to proteins in the plasma are rare, and occur in about one in 500 to one in 1,000 units. Although uncommon, these are significantly more common than the immune reactions or infections. These reactions are generally mild, but can be life-threatening.

Bacterial infections can be caused by many different kinds of bacteria. These organisms can work their way into any unit of blood during collection or processing. The most commonly affected component is platelets, because these units are stored at room temperature. Reactions can range from mild to life-threatening blood infections. The risk of bacterial contamination is about one in 2,000 units, and mortality from transfusion-acquired bacterial infection is between two and 100 per one million units transfused.

Viral infections seem to inspire the most fear regarding blood transfusions. Yet today these infections are among the rarest of all transfusion-related complications.

Many levels of safeguards are in place to prevent transmission of viral illnesses through the blood supply. All blood donors are volunteers, and do not receive compensation for their efforts. All donors are carefully selected prior to donation. Historical information that may place the donor at risk for AIDS, hepatitis, or other viral illnesses results in deferral.

Donors are also able to privately self-defer, or prevent their blood from being used, apart from the pre-donation interview. Finally, all products undergo a very elaborate screening procedure to test for human immunodeficiency virus (HIV, the "AIDS virus"), about a half-dozen hepatitis viruses, and numerous other infections. Still, the risk of receiving a unit of blood containing HIV or a hepatitis virus is low but not zero: about two to three per one million units.

White cell reactions occur when donated white cells react with proteins or tissues in the recipient. These reactions are among the most common, about one percent of all transfusions, but are incompletely understood. Most reactions are mild, but can include lung injury and multiple organ failure.

Although it is tempting to avoid blood at all costs, the risks of not transfusing a patient include decreased oxygen delivery to the tissues, increased workload of the heart, stroke, heart attack, kidney failure, and hemorrhage. It is the responsibility of the surgical and intensive care teams to balance these risks with the identifiable risks of receiving banked units of blood.

What does the surgical team do to decrease the need for blood? 
There are many steps and procedures taken to decrease the need for transfusion. The surgeon often "recycles" blood suctioned from the surgical field. The bypass circuit is made as small as possible to decrease the volume of blood needed outside the body. Coagulation function of the blood is carefully monitored to ensure that the blood retains its active proteins. Specific drugs that preserve clot formation ("antifibrinolytic" drugs) can be administered during the operation. The use of these procedures varies between hospitals, and often depends on the type of surgical procedure.

Cardiac surgery consumes 10 to 20 percent of the nation's blood supply. The surgical team is aware that efforts to minimize transfusion will likely benefit not only the individual patients, but significantly decrease the load on the blood banks as well.

Should I donate blood or have my family members donate blood for my child?
It is understandable to want to circumvent banked blood and donate yourself or ask people you know to donate blood for your child. This is called "directed donation." However, studies on this practice have not shown that it reduces the rate of transfusion-associated complications, including infections. In fact, the risk of infection may be even higher for directed donations because simply asking a person to donate blood no longer makes the donor a volunteer. People are less willing to truthfully answer questions about their history when they have been asked to donate.

I wanted to donate, but they told me I'm the wrong type for my child.
If you are a healthy person, you may want to consider donation as your way of giving back to the system that has cared for your child. In this case, you are always welcome to donate blood. It will always be needed for someone.

Last Edited: August 2, 2016
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