Improved method for automated red cell exchange in sickle cell disease

An improved method for intermittent-flow erythrocytapheresis in patients with sickle cell disease is reported. The method, a modification of the standard red cell exchange procedure for the Haemonetics 30S unit, dilutes with physiologic saline the patient's blood as it flows from the draw line and before it reaches the centrifugation bowl. The blood dilution (approximately 1.6 parts saline to 1 part blood) is used only during the first two passes, when the proportion of sickle erythrocytes in the patient's blood is still high. Only that amount of bowl supernatant (saline-diluted plasma) necessary to maintain extracorporeal volume below 500 ml is returned to the patient. The method described largely prevents the clumping of sickle erythrocytes in the centrifugation bowl, a complication frequently encountered with the Haemonetics 30S unit. Thus, changing the bowl between passes is avoided. Furthermore, the sickle red cells can be collected with the first pass and cryopreserved for possible future uses including the option of autotransfusion.     

Use of a dual lumen port for automated red cell exchange in adults with sickle cell disease

Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.     

Transfusion support for patients with sickle cell disease

Red blood cell (RBC) transfusion is an essential treatment for many patients with sickle cell disease (SCD), whose RBCs express hemoglobin S (HbS), a mutated form of hemoglobin A (HbA). Transfusion goals include increasing blood oxygen carrying capacity and decreasing the relative amount of HbS to HbA to mitigate vaso-occlusion in small blood vessels. In situations where correction of severe anemia and reduction in HbS may be achieved without removal of RBCs, simple transfusion may be utilized. Partial manual RBC exchange, which removes blood containing HbS by phlebotomy and replaces with donor blood transfusion sequentially allows for larger changes in the ratio of HbS to HbA when compared to simple transfusion. Automated RBC exchange by apheresis is useful in situations where a rapid and drastic HbS reduction is indicated. Vascular access is an important consideration for transfusion. Although peripheral access may be sufficient, central venous catheters and implantable venous access devices may be necessary for adequate access over time. Blood bank considerations include adequate RBC antigen matching to mitigate the risk of RBC alloimmunization, of which patients with SCD are at risk of developing. Transfusion may be utilized in efforts to intervene in the evolution of potentially life-threatening complications of SCD such as acute stroke, severe acute anemia and acute chest syndrome. Transfusion is also useful in several non-acute settings, such as stroke prevention, pregnancy, pre-surgery, and transfusion support for curative therapies. Individualized treatment plans are an essential component of patient care. Continuous evaluation of clinical indications and evolution of guidelines will continue to optimize care for patients with SCD.     

Use of erythrocytapheresis in the treatment of patients with sickle cell anemia

We performed exchange transfusions, utilizing the technique of automated erythrocytapheresis, for the treatment of patients with sickle cell anemia. In an attempt to determine guidelines for the use of erythrocytapheresis, we studied the use of this procedure in three distinct clinical situations in nine patients with sickle cell disease. Patients with dangerous complications of sickle cell disease such as acute respiratory distress and priapism responded well to erythrocytapheresis, showing marked improvement within 24-48 hours. Patients with prolonged painful vasoocclusive crises showed only variable improvement after erythrocytapheresis therapy, insufficient to justify exposing the patient to the risks of the procedure. Patients treated to decrease the frequency of painful crises demonstrated no prolongation in symptom-free intervals between crises. Therefore, erythrocytapheresis has its main value in the management of acute, dangerous complications of sickle cell disease.     

Therapeutic plasmapheresis and red blood cell exchange in a sickle cell trait patient with rhabdomyolysis

We report a case of a 16‐year‐old African‐American male with sickle cell trait and a past medical history significant for asthma that was transferred to our hospital for management of respiratory failure. On the fourth day of hospitalization, the patient was found to have increased creatine kinase (CK) levels and urine myoglobin levels consistent with rhabdomyolysis. No clear etiology was identified. Aggressive standard hydration and urine alkalization were applied without response. On the sixth day of hospitalization, the patient underwent a 1–1.5 plasma volume therapeutic plasma exchange (TPE) resulting in a transient reduction of serum CK and myoglobin by 50%, which became elevated once again within 4 h. Since his clinical presentation resembles exertional rhabdomyolysis documented in patients with sickle cell trait, RBC exchange was performed. The patient tolerated the procedure without complications. In addition to his improved overall condition, the patient's post‐exchange CK and serum myoglobin levels dropped dramatically without rebound. To our knowledge, this case represents the first reported case of TPE followed by RBC exchange in a SCT patient with rhabdomyolysis. J. Clin. Apheresis 2012. © 2012 Wiley Periodicals, Inc.     

The erythrocyte alloimmunisation in patients with sickle cell anaemia: a systematic review

Transfusion therapy is a common practice in the treatment of anaemia and can cause erythrocyte alloimmunisation. To systematise data related to erythrocyte alloimmunisation in patients with sickle cell disease (SCD), a bibliographic search was carried out in September 2017 to search for studies in four electronic databases. (i) Referring to the original work, (ii) being cohort or case–control, (iii) having been developed with individuals with SCD and (iv) having evaluated the erythrocyte alloimmunisation. Two reviewers identified the articles for inclusion in the study, extracted the predetermined data and carried out the evaluation of the methodological quality of the work. 21 studies were selected; the studies included data on 20 636 individuals (children and adults), were mostly published in the last 10 years, were developed in the United States and had high methodological quality. The occurrence of erythrocyte alloimmunisation ranged from 4·4 to 76%, and there was a higher rate of alloimmunisation against antigens of the Rh system. The risk factors for alloimmunisation were age; gender (female); red blood cell (RBC) units received; presence of ≥1 autoantibodies, TNF‐α, interleukin (IL1B), human leukocyte antigens (HLA)‐DRB1 gene polymorphisms; first blood transfusion (BT) after 5 years of age, transfusion episodic, multiple or during inflammatory events, acute chest syndrome (ACS) and vase‐occlusive crisis (VOC); increased percentage of CD41 T memory cells; and positive direct antiglobulin test. Transfusion policies should be developed to protect the patient and his or her health based on the main factors associated with its incidence.