Red Cell Exchange: A Concise Review of Indications and Management

Sickle cell disease (SCD), a common hemoglobinopathy in the United States affecting approximately one in 500 African-Americans, is associated with numerous potential complications related to both anemia and the presence of hemoglobin S (HbS). Red blood cell (RBC) transfusion and exchange (RCE) to improve oxygen carrying capacity and to treat or decrease the risk of complications due to sickling has been an important part of treatment for many years. While some treatment guidelines exist, there is still significant variation in the management of SCD patients.

Fifteen physicians in the active practice of apheresis from 12 institutions representing different geographic regions within the United States discussed how they manage RCE. Additionally, a literature review was performed and data from a prior practice survey were evaluated.

Simple transfusion is recommended to treat symptomatic anemia with hemoglobin <9 g/dL. RCE is indicated to prevent or reverse complications arising from the presence of HbS.

Indications for RCE in SCD : Common indications include treatment of stroke, acute chest syndrome, and sickle hepatopathy. Primary and secondary stroke prevention is an accepted, well studied indication, although optimal duration of treatment is unknown. RCE may be indicated prior to planned surgical procedures, may be necessary during pregnancy in women who have a history of severe SCD-related complications, and is indicated prior to stem cell mobilization. Pain crisis in the absence of other symptoms is generally not accepted as an indication. The role of RCE is not determined for pulmonary hypertension, end stage renal disease, and progressive sickle retinopathy.

Goals of RCE : The most important goals are to reduce the level of HbS while also preventing development of hyperviscosity. In most situations, a target HbS of ≤30% and target hemoglobin <10 g/dL (or hematocrit <30%) will treat and/or prevent SCD related complications without causing hyperviscosity.

Access: Peripheral veins are the preferred means of access when possible. Treatment of acute complications of SCD usually requires a temporary central venous catheter. Options for long-term access include tunneled central venous catheters, implantable ports, or arteriovenous fistulas.

RBC units: These should be HbS negative and leukodepleted. Units are commonly matched for C, E, and Kell antigens to help prevent alloimmunization in addition to being negative for antigens against which the patient has already formed antibodies. RBC phenotyping commonly is performed and molecular typing may be indicated in selected patients.

Complications: These include risks related to central venous access, transfusion reactions, iron overload, alloimmunization, transfusion-transmitted infection, development of warm autoantibodies, and hyperhemolysis syndrome.

There are many issues that need to be taken into consideration when evaluating a patient with SCD for transfusion treatment. A prior practice survey indicated that there are variations in the clinical management of these patients. While every case must be evaluated individually, we have presented some common practices.