An exchange transfusion is a blood transfusion in which the patient's blood or components of it are exchanged with (replaced by) other blood or blood products. The patient's blood is removed and replaced by donated blood or blood components. This exchange transfusion can be performed manually or using a machine (apheresis).
Most blood transfusions involve adding blood or blood products without removing any blood, these are also known as simple transfusions or top-up transfusions.
Nearly all exchange transfusions are allogeneic (that is, the new blood or blood products come from another person or persons, via donated blood); autologous exchange transfusion is possible (using autologous blood banking), but there are not many situations in which a need for it arises, as most autologous transfusions involve no exchange.
An exchange transfusion requires that the patient's blood can be removed and replaced. In most cases, this involves placing one or more thin tubes, called catheters, into a blood vessel. The exchange transfusion is done in cycles: each one usually lasts a few minutes.
The patient’s blood is slowly withdrawn (usually about 5 to 20 mL at a time, depending on the patient’s size and the severity of illness) and a slightly larger amount of fresh, prewarmed blood or plasma flows into the patient's body. This cycle is repeated until the correct 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 conditions such as neonatal polycythemia, a specific amount of the child’s blood is removed and replaced with normal saline, plasma (the clear liquid portion of blood), or an albumin solution. This decreases the total number of red blood cells in the body and makes it easier for blood to flow through the body.
The commonest emergency reason is to treat an acute chest syndrome.
Prior to surgery in people with sickle cell anemia (HbSS) who already have a hemoglobin above 85g/L, or who require a prolonged operation with general anesthetic, or who need high-risk surgery
To optimise hemoglobin S levels, for example to prevent a stroke occurring in a child. The target is usually to maintain a hemoglobin S level below 30% to prevent complications occurring.
The commonest routine reason is to prevent a stroke occurring or re-occurring.
Polycythemia is a condition in which the number of red cells in the blood is too high, usually diagnosed when the hematocrit is above 65%. Polycythemia can occur in neonates for multiple different reasons including: babies born after 42 weeks gestation (post-term), babies born to diabetic mothers, twin to twin transfusion, intrauterine growth restriction, and babies with genetic abnormalities. Polycythemia can make the blood thicker than normal and therefore lead to complications. Partial exchange transfusion has been used as a treatment to prevent complications, and has been shown to improve cerebral blood flow, but there is no evidence that it prevents any long term complications.
Exchange transfusion has been used for the treatment of severe malaria in the past. However, the CDC has now recommended that there is no evidence that exchange transfusion has any beneficial effects (decreased mortality) in people with very high parasite loads (> 10%), although the evidence is limited. Also, although uncommon, exchange transfusion can cause complications (low blood pressure (Hypotension), abnormal heart rhythms (Ventricular fibrillation) and breathing problems (acute respiratory distress syndrome)). Based on this evidence the CDC no longer recommend the use of exchange transfusion in addition to anti-malarial medication.
General risks are the same as with any transfusion. Other possible complications include:
^ abcdeDavis, Bernard A.; Allard, Shubha; Qureshi, Amrana; Porter, John B.; Pancham, Shivan; Win, Nay; Cho, Gavin; Ryan, Kate (2017). "Guidelines on red cell transfusion in sickle cell disease. Part I: principles and laboratory aspects". British Journal of Haematology. 176 (2): 179–191. doi:10.1111/bjh.14346. ISSN1365-2141. PMID28092109.
^ abcdefgDavis, Bernard A.; Allard, Shubha; Qureshi, Amrana; Porter, John B.; Pancham, Shivan; Win, Nay; Cho, Gavin; Ryan, Kate (2017). "Guidelines on red cell transfusion in sickle cell disease Part II: indications for transfusion". British Journal of Haematology. 176 (2): 192–209. doi:10.1111/bjh.14383. ISSN1365-2141. PMID27858994.
^Bada, H. S.; Korones, S. B.; Kolni, H. W.; Fitch, C. W.; Ford, D. L.; Magill, H. L.; Anderson, G. D.; Wong, S. P. (1986). "Partial plasma exchange transfusion improves cerebral hemodynamics in symptomatic neonatal polycythemia". The American Journal of the Medical Sciences. 291 (3): 157–163. ISSN0002-9629. PMID3953635.