Blood Transfusions and Sickle Cell Disease

Blood transfusion therapy is a procedure that is used to treat and prevent certain complications of sickle cell disease (SCD). Transfusions decrease the percentage of red blood cells that are sickled. This can help treat severe anemia or reduce the risk of stroke and other complications of blocked blood flow.

There are potentially serious risks of blood transfusions, including allergic reactions and iron overload. The decision to perform a blood transfusion must balance the benefits with these risks.

What is a blood transfusion?

A blood transfusion is a medical procedure where you receive donated blood through a tube into your vein. This procedure may be used to:¹

• Replace blood that was lost after surgery or injury
• Help people with illnesses that decrease certain blood components

Blood has several components, including red blood cells and white blood cells. Transfusions usually provide only the parts of blood that you need. Red blood cell transfusions are the most common.¹

There are 2 types of transfusions: simple and exchange transfusions. Simple transfusion involves the addition of new blood cells without removing any of your own blood. Exchange transfusion removes your blood cells and “exchanges” them for transfused, healthy donor red blood cells.²

How are they used in sickle cell disease?

People with SCD usually have chronic anemia that can worsen suddenly. They also have a higher risk of stroke and other complications from blocked blood flow. Transfusions of red blood cells can be life-saving as prevention or treatment in many of these settings. For example, regular blood transfusions have reduced the rate of stroke from about 10 percent to 1 percent.^3,4

Blood transfusion therapy reduces complications of SCD by decreasing the percentage of sickle cells. This has been shown to reduce in the frequency of acute pain episodes and acute chest syndrome events.^5,6

An acute transfusion may be done to treat certain acute complications of SCD, including:^2,7

• Stroke
• Acute chest syndrome
• Multi-organ failure
• Symptomatic anemia
• Splenic sequestration
• Parvovirus B19 infection

Regular or ongoing blood transfusions may be done to prevent complications of SCD, including:^2,8

• Primary and secondary stroke
• Acute chest syndrome
• Severe, frequent episodes of acute pain
• Priapism (prolonged and unwanted erection)
• Reduced SCD complications during pregnancy
• Pulmonary hypertension (high blood pressure in the lung)

Blood transfusions are not usually used to treat acute pain in the hospital. There is no evidence that transfusion therapy reduces pain during an episode.²

Regular blood transfusions are sometimes only used when hydroxyurea does not work. However, transfusions may be more appropriate if the need is more urgent. In some cases, people undergo regular blood transfusions first and then transition to hydroxyurea. Other screening and preventive techniques help determine when transfusions are necessary.^2,9,10

Experts recommend exchange transfusions for most regular transfusions. This reduces the percentage of sickle cells better than simple transfusion and helps prevent iron accumulation. Doctors perform simple transfusions to treat severe anemia quickly. Doctors also perform simple transfusions before surgeries to reduce the risk of complications during surgery.^7,11

What should I expect during and after the procedure?

Before the transfusion, doctors test your blood to determine your blood type. The donated blood must be compatible with yours.¹

The transfusion procedure usually takes 1 to 4 hours, depending on how much blood you need. During the procedure, doctors insert an IV into a blood vessel. Donated blood flows into your bloodstream. You will be monitored for any reactions throughout the procedure.¹

After the procedure, you may have blood tests to see how your body is responding. You may develop a bruise around the insertion site that goes away within a few days. Talk to your doctor if you have any symptoms of a reaction to the transfusion, such as shortness of breath and chest pain.¹

What are the risks?

Blood transfusions can cause potentially serious complications. Many of the risks are greater in people with SCD. When done appropriately, blood transfusion therapy has a positive impact on quality of life.^12,13

Some of these risks include:^14,15

• Transfusion reactions and alloimmunization (when your immune system attacks transfused cells)
• Infections with blood-borne viruses or bacteria (now rare in the United States because of blood screening)
• Iron overload (excess iron, which damages the liver and heart)
• Fluid overload or inflammatory reaction in the lungs (TACO/TRALI)

Alloimmunization can lead to hemolysis (bursting of donated red blood cells). When this happens at the same time as hemolysis of your own sickle cells, this is called “hyperhemolysis.” This leads to severe anemia.

These risks can be life-threatening or make it harder to perform blood transfusions in the future. The best way to avoid these risks is to reduce the need for blood transfusions. Talk to your doctor about ways to limit blood transfusions. Doctors also use techniques to minimize the risk of complications. This includes:^2,16,17

• Matching blood types to reduce the risk of alloimmunization
• Filtering out white blood cells to reduce the risk of transfusion reactions
• Iron chelation therapy to reduce the risk of iron overload