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The patient’s blood is slowly withdrawn (usually in increments of 5 to 20 ml depending on the patient’s size and the severity of illness), and an equal amount of fresh, prewarmed blood or plasma is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.
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