In order to perform an exchange transfusion, it is essential to have the ability to both remove and replace blood. In most cases, this involves the insertion of more than one intravenous (or arterial) catheter. The exchange transfusion proceeds in cycles, each generally of a few minutes duration.

The patient’s blood is slowly withdrawn (usually in increments of 5 to 20 ml depending on the patient’s size and the severity of illness), and an equal amount of fresh, prewarmed blood or plasma is transfused. This cycle is repeated until a predetermined volume of blood has been replaced.

After the exchange transfusion, catheters may be left in place in case the procedure needs to be repeated.

In diseases such as sickle cell anemia, blood is removed and replaced with donor blood. In conditions such as newborn plethora (polycythemia -- a condition where there are too many red blood cells making the blood thick and difficult to circulate), a calculated portion of the child’s blood is removed and replaced with a normal saline solution, plasma, or albumin. This decreases the total number of red blood cells in the body and makes circulation easier.

Conditions in which an exchange transfusion may be needed include:

• hemolytic disease of the newborn (Rh disease)
• sickle cell crisis (severe)
• severe disturbances in body chemistry
• toxic effects of certain drugs
• polycythemia
• severe neonatal hyperbilirubinemia (jaundice) in a newborn baby, which does not respond to phototherapy (treatment with light)

General risks are the same as with any transfusion. Other possible complications include:

• heart and respiratory problems
• shock due to inadequate replacement of blood
• infection (greatly decreased risk due to careful screening of blood)
• clot formation
• alterations in blood chemistry (high or low potassium, low calcium, low glucose, change in pH)