Sickle cell disease (SCD) is a genetic disorder that causes the formation of an abnormal hemoglobin (HbS). Patients with SCD suffer from hemolysis and anemia. Studies have shown that maintaining HbS below 30% is effective for stroke prevention.
Red cell exchange (RBCX) is a procedure in which the patient’s RBCs are removed and replaced with donor RBCs. RBCX is more effective than simple transfusions in reducing HbS, consequently reducing the risk of stroke. Also, RBCX is better able to manage iron overload. RBCX can be performed manually by phlebotomizing the patient prior to giving simple transfusions. Automated RBCX requires an apheresis machine, is more efficient, and allows for better control of the patient’s HbS and hematocrit. Data regarding the indications for performing RBCX and typical therapeutic targets will be summarized.
Depletion-Exchange is a modification of the automated RBCX. During the depletion-phase, the patient’s hematocrit is reduced by removing RBCs and replacing with either saline or albumin. Subsequently, during the exchange-phase, the hematocrit is slowly increased to achieve the target. Compared to conventional RBCX, depletion-exchange procedure has the potential to more efficiently suppress HbS formation, reduce blood utilization and increase the interval between exchanges. Data regarding indications for depletion-exchange procedures and therapeutic protocols will be discussed.
Plasma-to red cell exchange (PRX) is a modified procedure wherein an apheresis machine is used to remove patient’s plasma, while replacing with donor RBCs. This procedure allows for a rapid euvolemic transfusion of RBCs to patients that are severely anemic and intolerant to excess fluid volume. An overview of this procedure will be discussed and data from five years of experience with it will be summarized, along with proposed indications and a protocol.
Identify the indications for RBCX procedures.
List the advantages for performing depletion-exchange procedures.
Recognize the indications for performing plasma-to-red cell exchange procedure.
Co-Editor-in-Chief, "Transfusion and Apheresis Science” Journal, John H. Childers, MD, Professorship in Pathology, Professor (Tenure) of Pathology and Internal Medicine (Hematology/Oncology), Chief of Pathology and Medical Director, UTSW Clinical Laborato,
UT Southwestern Medical Center, Department of Pathology, Division of Transfusion Medicine and Hemostasis