|Year : 2021 | Volume
| Issue : 2 | Page : 156-159
Blood cell exchange in sickle cell disease: A single center experience
Mohit Chowdhry, Soma Agrawal, Ankita Sharma, Uday Kumar Thakur
Department of Transfusion Medicine, Indraprastha Apollo Hospital, New Delhi, India
|Date of Submission||25-Feb-2021|
|Date of Acceptance||25-Sep-2021|
|Date of Web Publication||30-Nov-2021|
Dr. Mohit Chowdhry
Department of Transfusion Medicine, Indraprastha Apollo Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
Background and Objectives: Red cell exchange (RCE) is a type of therapeutic apheresis procedure aimed at removing the deformed red blood cells of a patient and replacing them with those obtained from healthy donors. It is a commonly used but yet underutilized procedure for the treatment of hemoglobinopathies such as sickle cell disease (SCD) (acute or chronic), and other diseases and conditions such as ABO-incompatible hematopoietic stem cell transplantation, severe erythrocytosis, hereditary hemochromatosis, severe infection with intra-erythrocytic parasites such as malaria, babesiosis or cases of a drug overdose, poisoning and to perform envenomation. The objective of the study is to study and understand the efficacy of RCE in the management of patients in various clinical scenarios. Methods: This is a retrospective study carried out at a tertiary care hospital in North India over a period of 4 years (2016–2020). All the RCE were performed on Spectra Optia apheresis (System 1 P0 4552 (Terumo BCT, Lakewood, CO, USA) which comes with a built-in software (Version 11) for performing RCE. Results: A total of 8 exchanges were performed in five patients. Three of these patients had undergone the procedure twice. Two out of the five patients were found to be antibody screen positive. Corresponding antigen-negative units of packed red cells were issued for these patients. The targeted and final fraction of red cell remaining values which were kept at ≤30% was achieved in all cases. Conclusion: RCE is a safe and effective therapeutic treatment modality for patients of SCD. It is a simple and relatively safe treatment modality that provides immediate relief in acute complications and also prevents the risk of long-term complications such as iron overload and iron-induced organ damage.
Keywords: Aphereses, red cell exchange, sickle cell disease
|How to cite this article:|
Chowdhry M, Agrawal S, Sharma A, Thakur UK. Blood cell exchange in sickle cell disease: A single center experience. Glob J Transfus Med 2021;6:156-9
|How to cite this URL:|
Chowdhry M, Agrawal S, Sharma A, Thakur UK. Blood cell exchange in sickle cell disease: A single center experience. Glob J Transfus Med [serial online] 2021 [cited 2022 Aug 10];6:156-9. Available from: https://www.gjtmonline.com/text.asp?2021/6/2/156/331608
| Introduction|| |
Red cell exchange (RCE) or erythrocytapheresis is a type of therapeutic apheresis procedure where the red cells of the patient are replaced with the donor red cells. Indications for RCE in acute cases of sickle cell disease (SCD) include acute chest syndrome, acute neurological syndrome, vaso-occlusive crisis leading to multiorgan failure (MOF), intrahepatic cholestasis, preoperative for general anesthesia, and priapism. RCE can be performed using an automated system or manually, the former having several advantages. Automated RCE is performed through an apheresis machine that separates the red blood cells (RBCs) from whole blood and selectively removes and replaces them on a mL for mL basis with donor RBCs alone and/or colloid/crystalloids solutions, thus minimizing the fluid shifts and variations in blood pressure.
SCD is an inherited disorder caused due to a single gene mutation (missense mutation) where glutamic acid is replaced by valine at the 6th position of the beta chain of the hemoglobin. The new amino acid, valine is responsible for the distorted sickle shape of the RBCs which is also responsible for the reduced oxygen supply to the tissues and increased viscous flow of the blood.
When the hemoglobin level becomes >10 gm% even with simple transfusion, it can make the blood more viscous and can cause various complications. This may result in various sickling crises in the body, namely vaso-occlusive crisis such as stroke, painful joint crisis, acute chest syndrome, aplastic crisis, splenic sequestration crisis, and eventually organ failure.
Such patients often receive multiple blood transfusions which further make them vulnerable to other chronic complications such as iron overload and risk of alloimmunization. RCE has proven to be beneficial in managing these crises and complications by providing immediate relief by rapidly bringing down the level of sickle hemoglobin (HbS) and viscosity of the blood. At the same time, it provides healthy RBCs that supply sufficient oxygen to the tissues.
Aims and objectives
The objective of our study was to understand and evaluate the efficacy of RCE in patients of SCD presenting with the crisis at our center.
| Materials and Methods|| |
It is a retrospective study of patients who had undergone RCE at a tertiary care hospital in North India over 4 years (2016–2020). Patients of all age groups and sexes were included in this study. RBC units used in exchange transfusion were prepared manually as per the departmental standard operating procedures from 450 ml whole blood collected in blood bags (Macopharma/Fresenius Kabi). The units used for exchange were compatible, nonreactive for infectious markers (HIV, HbsAg, HCV, malaria, and Syphilis), 3 log leukoreduced, crossmatch compatible, and <7 days old from the date of collection. For all patients, before the procedure, blood grouping (ABO and Rh) and screening for red cell antibodies were done. For those found to have a positive screen, red cell allo-and auto-antibody identification was done, and corresponding antigen-negative units were used for the procedure after antihuman globulin (AHG) crossmatching. All the exchanges were performed on Spectra Optia apheresis (System 1 P0 4552 (Terumo BCT, Lakewood, CO, USA) which comes with a built-in software (Version 11) for performing RCE. Based on the clinical data of patients such as gender, age, body weight, height, initial and final hematocrit including HbS (preprocedure or the actual value and target HbS <30%) and fluid balance, the average hematocrit of the replacement product, the machine uses its built-in software and calculates the exchange volume and helps to determine the percentage/fraction of red cell remaining (FCR) of the patient(s). This helps quantify the remaining pathological RBCs in the patients of SCD. The postprocedure FCR was kept at ≤30%.
The vitals of the patient(s) including oxygen saturation were monitored throughout the procedure(s). During the procedure(s), continuous intravenous infusion of diluted 10% calcium gluconate (at the rate of 40–50 ml/h) was given to the patients to prevent citrate-related side effects. The exchange volume for each patient per procedure was kept around 1.5 times the packed cell volume.
| Results|| |
A total of 8 RBC Exchanges were performed on five patients [Table 1]. All of these patients were known cases of SCD. Three out of these five patients underwent the procedure twice. Out of these five patients, one was female and the rest were all male patients. The age group of the patients was between 3 years and 44 years. Four of the five patients who underwent the procedure experienced sickle cell crisis in the form of chest pain, wheezing, breathing difficulties (acute chest syndrome), etc. For one patient scheduled to undergo a total hip replacement surgery, RCE was performed preoperatively for administering general anesthesia to reduce the likelihood of complications resulting from hypoxia, hypoperfusion, and acidosis which in turn can lead to vaso-occlusion and tissue injury. The patient was admitted again for the hip replacement of the other side and RCE was performed again.
|Table 1: Details and hematological parameters of all the patients who underwent red blood cell exchange procedure|
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Among the remaining 4 patients, two patients were prospective candidates for a bone marrow transplant, one for peripheral blood stem cell harvesting (which was to be performed as an autologous backup, i.e., the patient's own stem cells were to be harvested before the initiation of chemo/radiotherapy and had to be cryopreserved in order to reinfuse them into the patient in future as and when required) and one was a follow-up case of renal transplant.
Two out of the five patients were found to be antibody screen positive
Antibodies identified were anti-C and anti-E in one patient and a solitary case of anti-E in another patient. Corresponding antigen-negative units of packed red cells were issued for these patients undergoing RCE.
| Discussion|| |
SCD is an inherited disorder caused by a single, missense point mutation at the 6th position of the β-globin gene chain of the hemoglobin. The mutation may be homozygous or heterozygous resulting in various hemoglobinopathies in combination with sickle cell anemia such as Hb SCD, HbSC disease, Hb SB+ (β-thalassemia), Hb Sβ 0, HbSD, and HbSE. The sickled erythrocytes along with low oxygen supply and increased viscous flow have a cumulative effect in the form of vaso-occlusive crises such as acute chest syndrome, organ infarction, hemolysis, and eventually progressing toward MOF.
Patients with SCD pose several challenges for the blood bank. These include the assessment for acute and/or chronic exchange, assessment of simple and/or exchange transfusion, the requirement of HbS negative RBC units, provision of compatible units with or without the presence of allo and/or autoantibodies, and the provision of fresh, leukoreduced and phenotypically matched RBC units. With progress made in the understanding of the pathophysiology of SCD, we have come to realize the advantages of having a multidisciplinary approach including simple and/or exchange transfusion in management and treatment of SCD along with medication like hydroxyurea (used in the initial part of the treatment), as no single therapy is completely effective for its treatment and prevention of the complications.
Manual RCE involves alternately withdrawing and transfusing blood. It is more time consuming and less precise. It may even result in large intravascular volume fluctuations. However, the automated procedure requires a sophisticated apheresis instrument and appropriate venous access. In our center, we have used the automated cell separator for all procedures. In acute manifestations of SCD, the decision of using RBC transfusion as well as manual or automated RCE is dependent on numerous criteria. These include patients' clinical condition, availability of apheresis services, venous access, and availability of compatible blood units, especially in the presence of existing antibodies and the adverse effects associated with apheresis itself. Red cell transfusion is particularly challenging in patients of SCD as the presence of these antibodies is more than in the general population. Autoantibody formation has been reported in 8% of SCD children, and in 86% of these patients, it is accompanied by underlying alloantibody/ies. Alloimmunization occurs at a rate of 2%–6% in patients of SCD who receive a blood transfusion. In our study, 2 out of five patients had alloantibodies and both had a history of blood transfusion. An antigen-negative crossmatch compatible unit was provided to both the patients. Alloimmunization not only delays the process of finding the compatible units but also increases the rate of delayed-type hemolytic transfusion reaction. Furthermore, these patients are provided with phenotype-matched blood to prevent alloimmunization. Providing partially phenotyped RBC unit (for C, E, K) has been associated with less likelihood of red cell alloimmunization and decrease the incidence of delayed hemolytic transfusion reactions. To prevent HLA alloimmunization and febrile nonhemolytic transfusion reactions, the use of 3 log or more leukoreduced component is warranted. Transfusion in SCD patients may be indicated acutely, intermittently, or chronically as a prophylactic measure. RBC transfusion in patients with SCD not only corrects anemia but also helps in reducing hemolysis and the amount of HbS by suppressing the defective RBCs. Furthermore, as oxygenation is better at lower hemoglobin concentration levels, the posttransfusion hemoglobin level should not exceed the baseline values set for the patient. The units used for exchange should be compatible, negative, and nonreactive for infectious markers, 3 log leukoreduced, crossmatch compatible, and <7 days old from the date of donation. SCD patients must be transfused with fresh blood as aged RBC concentrates may cause storage lesion of the transfused erythrocytes. All these parameters were kept in mind and were strictly followed for all our patients.
RCE is an effective means of lowering the HbS levels rapidly in a safe, simple, and effective manner. Usually, a single session of RBC exchange is effective in providing relief from acute complications of SCD. RCE is a widely practiced treatment modality. It offers more efficient and rapid removal of HbS RBCs and maintains isovolemia in the patient. It may be acute or chronic. Acute RBC exchange is used to treat severe, life-threatening complications of SCD such as acute infarctive stroke, acute chest syndrome, MOF whereas chronic RBC exchange helps in slowing down the occurrence of a new infarctive episode or halts the progression of any preexisting organ dysfunction. The American Society for Apheresis (ASFA) provides an evidence-based classification for therapeutic apheresis procedures and indications of the RCE in SCD patients. All of our cases had presented with acute complications of SCD. The ASFA and others give RCE a category I recommendation for patients suffering from SCD.,
A target hematocrit (HCT) and either the desired FCR or the target volume to be exchanged needs to be determined. In our study, the FCR was set to achieve the target HbS of <30% at the end of the procedure. Once the parameters are decided, the apheresis machine determines the volume necessary for RCE. When one patient red cell volume is exchanged, approximately 65% of the initial red cells are removed (FCR-35%) whereas 90% of the initial red cells are removed (FCR-10%) after 2 red cell volume exchange. In our study, all procedures achieved the target FCR of 30%. Before transfusing a patient with SCD, it is important to consider both the hemoglobin level and HbS level to ensure that maximum oxygen is delivered to tissues without causing an increase in the blood viscosity to avoid any deleterious effects on the health of the patients., A usual approach is to keep target HbS ≤30% to minimize any possible adverse reactions.
The side effects of RCE in SCD patients include central venous catheter thrombosis, hemorrhage, and hyper hemolysis. In our study, there were no adverse events during any of the RCE procedures. All the procedures were completed successfully.
| Conclusion|| |
RBC exchange in patients with SCD is a simple and relatively safe treatment modality that not only provides immediate relief in acute complications but also prevents the risk of long-term complications such as risks of iron overload and iron-induced organ damage. Its effectiveness in treating SCD patients outweighs the risks associated with multiple donor exposure and those of transfusion-transmitted infections.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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