Optimization of single-needle red cell exchange in patients with sickle cell disease.

The hypercoagulable state associated with sickle cell disease (SCD) can be challenging for apheresis procedures. Among 62 single-needle red cell exchanges (SN-RCEs) performed over a 15-month period, 4 patients experienced 6 hemolytic events with a discolored plasma layer, elevated plasma/RBC interface in the centrifuge, and accompanying alarms of "Cells were detected in plasma line from centrifuge" or "AIM system detected RBC at top of connector." The hemolysis originated from the apheresis instrument because samples from the apheresis belt but not the patients' peripheral blood were positive for hemolysis. Further analysis showed the alarms occurred more often in SN-RCEs (20.4%) than double-needle RCEs (2.7%), and the hemolysis was probably secondary to clumping. To optimize SN-RCE, we increased the anticoagulant dosage by changing Inlet/AC ratio from 13 to 8 and lowered the inlet rate to the level comparable to double-needle RCE. The adjustments were well-tolerated with no more hemolysis.

A comparison between erythrocytapheresis and venesection for the treatment of JAK2-mutated polycythaemia.

BACKGROUND: JAK2-mutated polycythaemia vera (PV) is associated with reduced survival because of thrombotic events and haematological disease transformation. Therapeutic venesection has traditionally been used to lower haematocrit, but the technique of erythrocytapheresis has emerged over the last decade. AIM: To compare erythrocytapheresis with venesection as treatment for PV by assessing medical efficacy and financial viability. METHODS: One hundred sixteen patients with PV who received red cell depletion therapy at Barwon Health between 2014 and 2021 were identified. The haematocrit drop after each session, interval between treatment times and number of sessions required to achieve a haematocrit <0.45 were compared with an independent t test. Thrombosis rates were compared with Pearson's chi-squared test. Cost-funding analysis was done by assessing the Weighted Inlier Equivalent Separation and National Weighted Activity Unit funding models. RESULTS: Patients treated with erythrocytapheresis achieved a greater haematocrit drop each treatment session (0.075 vs 0.03, P < 0.01), required fewer sessions to achieve a haematocrit <0.45 (1 vs 4, P < 0.01) and experienced fewer thrombotic complications (8.7% vs 32.1%, P = 0.02) than those treated with venesection. Cost-funding analysis demonstrated that erythrocytapheresis was more financially viable with a surplus of AU$297 per session compared to a deficit of AU$176 with venesection. Even if funding for venesection is increased, the cost of erythrocytapheresis may be mitigated by a lower number of procedures required per year (3.8 vs 5.3, P < 0.01). CONCLUSIONS: Erythrocytapheresis is more efficacious than venesection for the treatment of PV and is accompanied by rapid reductions in haematocrit and reduced thrombotic complications.

Red Blood Cell Exchange as a Valid Therapeutic Approach for Pregnancy Management in Sickle Cell Disease: Three Explicative Cases and Systematic Review of Literature.

Pregnancy in women with sickle cell disease (SCD) is a high-risk situation, especially during the third trimester of gestation and in the post-partum period, due to chronic hypoxia and vaso-occlusive phenomena occurring in the maternal-fetal microcirculation: as a result, unfavorable outcomes, such as intra-uterine growth restriction, prematurity or fetal loss are more frequent in SCD pregnancies. Therefore, there is a consensus on the need for a strict and multidisciplinary follow-up within specialized structures. Transfusion support remains the mainstay of treatment of SCD pregnancies, whereas more targeted modalities are still controversial: the benefit of prophylactic management, either by simple transfusions or by automated red blood cell exchange (aRBCX), is not unanimously recognized. We illustrate the cases of three SCD pregnant patients who underwent aRBCX procedures at our institution in different clinical scenarios. Moreover, we carried out a careful literature revision to investigate the management of pregnancy in SCD, with a particular focus on the viability of aRBCX. Our experience and the current literature support the use of aRBCX in pregnancy as a feasible and safe procedure, provided that specialized equipment and an experienced apheresis team is available. However, further research in this high-risk population, with appropriately powered prospective trials, is desirable to refine the indications and timing of aRBCX and to confirm the advantages of this approach on other transfusion modalities.

Erythrocytapheresis in Children and Young Adults with Hemoglobinopathies and Iron Overload in Need of Iron Chelation Therapy.

Limited data regarding erythrocytapheresis in children, adolescents, and young adults have been published. The aim of this study was to evaluate erythrocytapheresis, either as a standalone therapy or in combination with iron chelation therapy, in children and young adults with hemoglobinopathies in whom current iron chelation therapy is not sufficient in decreasing the iron overload during management. We retrospectively analysed erythrocytapheresis in 19 patients with hemoglobinopathies in need of iron chelation therapy diagnosed with sickle cell disease (SCD) or ß-thalassemia major. Patients were divided into (1) a case cohort who received erythrocytapheresis alone or in combination with iron chelation therapy and (2) a control cohort who received oral iron chelation therapy alone. Serum ferritin and haemoglobin levels were compared at five different time points over a one-year period. In the erythrocytapheresis cohort, there was a significant decrease in serum ferritin (p < 0.001). In the iron chelation therapy alone cohort, there was no significant decrease in serum ferritin over time (p = 0.156). Comparing the evolution of median serum ferritin between therapy with erythrocytapheresis and iron chelation therapy showed a statistically significant difference (p = 0.008). Patients with ß-thalassemia major receiving erythrocytapheresis showed a greater reduction in serum ferritin compared to patients without (p = 0.036). A difference could not be shown between the erythrocytapheresis and iron chelation single therapies (p = 0.100). This study showed an overall significant reduction in serum ferritin in patients with hemoglobinopathies treated with erythrocytapheresis in addition to iron chelation. A clinical, although not statistical, trend of higher haemoglobin levels was maintained. Erythrocytapheresis in paediatric patients with ß-thalassemia major was as effective in decreasing ferritin levels as in previously reported studies with SCD. Erythrocytapheresis is a promising therapy for treating and preventing transfusion-related iron overload.

Evaluation of erythrocytapheresis compared to phlebotomy in polycythaemia vera patients.

INTRODUCTION: Polycythaemia vera patients can present with arterial or venous vascular occlusive events such as thrombosis or cardiovascular disease; disease-related symptoms may significantly impact on the quality of life. The aim of this study was to evaluate the efficacy and safety of erythrocytapheresis compared to phlebotomy in the treatment of polycythaemia patients. METHODS: This study reports the findings of a retrospective analysis of 40 polycythaemia vera patients diagnosed according to published guidelines and treated either with erythrocytapheresis or phlebotomy over a four-year period. The goal of treatment was to reduce blood volume and red blood cell count to near normal levels as both of which may attenuate the symptoms and complications associated with polycythaemia. Patients were treated by applying a mathematical model. RESULTS: Using the model, 28 erythrocytapheresis procedures were performed. Blood laboratory values (red blood cell count, haemoglobin count and haematocrit level) were significantly reduced in patients treated with erythrocytapheresis. Moreover, among treated patients, erythrocytapheresis resulted in less work absenteeism and reduced costs due to lost production, with a lower overall procedure cost in comparison to phlebotomy. CONCLUSION: This model can assist in selecting the proper treatment modality for individual patients. Especially for those with high blood volumes and high achievable haematocrit levels (delta), erythrocytapheresis offers a more efficient method in red blood cell depletion compared to phlebotomy thereby, potentially reducing the number of treatment procedures required for the induction of polycythaemia vera patients as well as the interval between procedures during the maintenance phase.

Survey on the usage of therapeutic erythrocytapheresis in transfusion services in Italy for the treatment of polycythemia vera, secondary erythrocytosis and hemochromatosis.

INTRODUCTION: Erythrocytapheresis, an apheresis treatment which selectively removes red blood cells, is an alternative to therapeutic phlebotomy, over which it has several advantages. Actually there is a high degree of variability in the use of this treatment. This prompted SIdEM (Italian Society of Hemapheresis and Cell Manipulation) to conduct a survey on the use of erythrocytapheresis in the Italian Transfusion Services. The purpose is to monitor this activity in the treatment of Polycythemia Vera (pv), secondary erythrocytosis and hemochromatosis. MATERIALS AND METHODS: A data collection file was sent to the SIdEM regional delegates who, in turn, involved the Transfusion Centers in the areas they cover. The data collected were processed on a Microsoft Excel spreadsheet. RESULTS: 75 centers from 14 Italian regions responded to the Survey: 36 centers (48 %) use erythrocytapheresis (35 centers perform therapeutic apheresis and 1 center only donor apheresis), 39 centers (52 %) do not (15 centers perform therapeutic apheresis, 18 centers only donor apheresis and 6 centers do not perform either therapeutic apheresis or donor apheresis). Although most centers have a substantially uniform attitude concerning the indications for which erythrocytapheresis is used, the survey shows that there are still differences more evident in the treatment of secondary erythrocytosis than in the treatment of pv or hemochromatosis. CONCLUSIONS: This survey has been useful to document the current Italian reality and to raise awareness about the need for improvement in optimizing and standardizing the use of a therapy with a great potential to exploit properly.

The implementation of automated red blood cell exchange (erythrocytapheresis) as a treatment modality in sickle cell disease patients: Single center experience.

BACKGROUND: Improvements of health infrastructure, preventive care and clinical management is important to reduce the morbidity and mortality of sickle cell disease (SCD). OBJECTIVE: This prospective, investigator-initiated non-randomized open-label intervention, single centre study describes the implementation of the automated erythrocytapheresis in low-middle income country as a treatment modality for SCD patients to improve the standard of care and highlights its benefits and challenges. METHODOLOGY: Eligible patients with SCD who had overt stroke, abnormal/conditional transcranial doppler (TCD), or other indications were subjected to regular automated erythrocytapheresis program. RESULTS: From 18th Dec 2017 till 17th Dec 2022, 21 subjects were enrolled; seventeen (80.9 %) were Egyptian and four (19.1 %) were non-Egyptian (three Sudanese and one Nigerian). Totalling 133 sessions had been performed mainly in working hours with fluctuating frequency per month. All sessions maintained isovolumic status and were performed using central venous access. The target HbS concentration was set from the start; the mean final FCR % fraction was 51, most of the session (n = 78, 58.7 %) were able to achieve target FCR. The majority of session pass smoothly with no adverse event (n = 81, 60.9 %), except for certain challenges as shortage of the required blood (n = 38), hypotension (n = 2), hypocalcaemia (n = 2). CONCLUSION: Automated erythrocytapheresis is safe and effective modality for management of patients with sickle cell disease.

Comparative study between chronic automated red blood cell exchange and manual exchange transfusion in patients with sickle cell disease: A single center experience from Saudi Arabia.

BACKGROUND: Red cell transfusion remains the gold standard in managing sickle cell disease (SCD) with severe complications. Offering red blood cell exchange (RBCX) either manual exchange transfusion (MET) or automated RBCX (aRBCX) can reduce the complications of chronic transfusion and maintain target Hb thresholds. This study audits the hospital experience of overseeing adult SCD patients treated with RBCX, both automated and manual, and compares the safety and efficacy. MATERIALS AND METHODS: This retrospective observational study was conducted as an audit for chronic RBCX for adult patients with SCD in 2015-2019 at King Saud University Medical City, Riyadh, Saudi Arabia. RESULTS: A total of 344 RBCX for 20 adult SCD patients who were enrolled in regular RBCX, (11/20) patients had regular aRBCX with a total of (157) sessions, and (9/20) patients had MET with a total of (187) sessions. The median level of HbS% post-aRBCX was significantly lower than MET (24.5.9% vs. 47.3%, P < 0.010). Patients on aRBCX had fewer sessions (5 vs. 7.5, P < 0.067) with better disease control. Although the median yearly pRBC units per patient for aRBCX was more than the double needed for MET (28.64 vs. 13.39, P < 0.010), the median ferritin level was 42 µg/L in aRBCX versus 983.7 µg/L in MET, P < 0.012. CONCLUSION: Compared to MET, aRBCX was more effective in reducing HbS, with fewer hospital visits and better disease control. Although more pRBCs were transfused, the ferritin level was better controlled in the aRBCX group without increasing alloimmunization risk.

A case report and review of literature on the role of automated red cell exchange in managing sickle cell crisis in India.

Red cell exchanges (RCE) help in the treatment of complications of sickle cell anemia (SCA) by reducing the viscosity of blood and improving the oxygen-carrying capacity. We present a case of sickle cell crisis (SCC) managed with automated RCE and also reviewed the literature to assess the utilization and clinical efficiency of this therapy in India. A 19-year-old gentleman diagnosed with SCA presented with acute chest syndrome. Hemoglobin (Hb) was 8.8 g%, hematocrit (HCT) was 24%, and HbS was 90%. As there was worsening of symptoms with conventional management, the patient underwent two procedures of automated RCE. The clinical condition of the patient was improved, HbS was reduced to 16% and HCT was remained at 21% postprocedure. Articles on automated RCE in SCA conducted in India were reviewed and four articles were analyzed based on the search strategy. All the included articles concluded automated RCE as an effective procedure for complications of SCA. Common indication in India was SCA patients undergoing surgery as a prophylactic measure. Automated RCEs are promising as an acute treatment for indicated sickle cell complications. This therapy is underutilized in the Indian scenario, especially in patients with SCC.

Effects of Erythrocytapheresis Procedures on Delayed Bone Marrow Conversion in Sickle Cell Disease.

The imaging appearances of the skeletal system have been well documented in sickle cell disease (SCD) but there is limited information about the impact of SCD treatments on skeletal abnormalities. We present two patients with SCD maintained on long-term erythrocytapheresis and the changes to their skeletal abnormalities on neuroimaging with this treatment. We observed a reversal of the bone marrow conversion process and the skull appearance was age appropriate without any radiographic findings of iron overload in the patients.

The significance of antiglobulin (Coombs) test reactivity in patients with COVID-19.

Previous case reports have described patients with COVID-19-associated autoimmune hemolytic anemia (AIHA), and cold agglutinin disease (CAD) which is characterized by a positive direct antiglobulin (DAT) or "Coombs" test, yet the mechanism is not well understood. To investigate the significance of Coombs test reactivity among COVID-19 patients, we conducted a retrospective study on hospitalized COVID-19 patients treated at NMC Royal Hospital between 15 April and 30 May 2020. There were 27 (20%) patients in the Coombs-positive group and 108 (80%) in the Coombs-negative group. The cold agglutinin titer was examined in 22 patients due to symptoms suggestive of cold agglutinin disease, and all tested negative. We demonstrated a significant association with reactive Coombs test results in univariate analysis through clinical findings such as ICU admission rate, the severity of COVID-19, and several laboratory findings such as CRP, D-dimer, and hemoglobin levels lactate dehydrogenase, and RDW-CV. However, only hemoglobin levels and disease severity had a statistically significant association in multivariate analysis. A possible explanation of COVID-19-associated positive Coombs is cytokine storm-induced hyperinflammation, complement system activation, alterations of RBCs, binding of SARS-CoV-2 proteins to hemoglobin or its metabolites, and autoantibody production. Coombs-positive patients were tested for hemolysis using indirect bilirubin, consumed haptoglobin, and/or peripheral smear that ruled out any evidence of hemolysis. Understanding this etiology sheds new light on RBC involvement as a pathophysiological target for SARS-CoV-2 by interfering with their function; consequently, therapies capable of restoring RBC function, such as erythrocytapheresis, could be repurposed for the treatment of worsening severe and critical COVID-19.

Red blood cell exchange in children with sickle cell disease.

The aim of our study was to assess the efficacy of red blood cell exchange (RBCx) using a Spectra Optia® automated apheresis system in children with sickle cell disease (SCD). We used automated RBCx to treat acute and chronic complications in 75 children with SCD who had a median age of 10 years [7-13]. We analyzed 649 RBCx sessions. Peripheral venous access was limited in a number of the children, and thus a femoral double-lumen central venous catheter was required. We recommend heparin locking with 500 units in each lumen of the catheter. To prevent complications, we ensured that all patients had achieved a post-RCE HbS level of < 30%. For chronic transfusion, with a post-RCE Hb level of approximately 10-11 g/dL, a blood exchange volume of ≥ 32 mL/kg, and an interval between each RBCx procedure of ≤ 30 days, the residual HbS level was maintained below 30%. For acute transfusion, a post-exchange Hb level ≥ 10 g/dL (p < 0.001) and a total exchange volume ≥ 35 mL/kg (p = 0.001) were the best way to reduce HbS to < 30%. AUC was 0.84. Our results show that erythrocytapheresis was useful and safe for children with SCD.

Patients with hereditary hemochromatosis reach safe range of transferrin saturation sooner with erythrocytaphereses than with phlebotomies.

INTRODUCTION: For the maintenance treatment of patients with hereditary hemochromatosis (HH), it is advised to keep the transferrin saturation (TSAT) <70% to prevent formation of non-transferrin-bound iron and labile plasma iron. The period of the initial iron depletion may last up to 1 year or longer and during this period, the patient is exposed to elevated TSAT levels. Therapeutic erythrocytapheresis (TE) is a modality which has proven to reduce treatment duration of patients with iron overload from HH. In this study, we investigated the time to reach TSAT <70% for both treatment modalities. METHODS: From a previous randomized controlled trial comparing erythrocytaphereses with phlebotomies (PBMs), we performed an analysis in a subgroup of patients who presented with TSAT >70%. Mann-Whitney U tests were performed to compare the number of treatments and the number of weeks to reach the interim goal of a persistent level of <70% for TSAT between TE and PBM. RESULTS: The period to reach TSAT levels of <70% was statistically significant shorter for the TE group compared to the PBM treatment group (median treatment procedures [IQR] 2.0 (5) vs 16.0 (23), P-value: <.001, and median treatment duration [IQR]: 5.5 (11) vs 19.0 (29) weeks, P-value: .007). CONCLUSION: Patients with HH reach a safe TSAT <70% significantly sooner and with less treatment procedures with TE compared to PBM.

The rare hemoglobin variant Hb Mizuho: report of a Swiss family and literature review.

Hb Mizuho is a very rare unstable hemoglobin; here, we describe the clinical history of three Swiss family members with Hb Mizuho together with a systematic review of the previously six published cases. The clinical history of the adult woman we report here is unique since this is the first Hb Mizuho presenting with Moyamoya complications and the first case reported with long-term erythrocyte exchange. The literature review showed that Hb Mizuho was mainly reported as a de novo mutation, with the exception of children descended from known cases. All published patients with this unstable hemoglobin showed severe hemolytic anemia with the exception of one; all were regularly transfused. Patients with higher HbF levels might require fewer transfusions. All patients underwent splenectomy at a median age of 4 years and had variable clinical improvement; some achieved complete resolution of transfusion dependency after splenectomy. Iron overload in Hb Mizuho patients seems to be mainly attributed to transfusions and has less to do with ineffective erythropoiesis. Diagnosis might be challenging; a normal hemoglobin electrophoresis should not rule out the diagnosis of unstable hemoglobin in patients with otherwise unexplained hemolytic anemia. This series shows the enormous utility of using molecular techniques for diagnosis.

A predictive model for estimating the number of erythrocytapheresis or phlebotomy treatments for patients with naïve hereditary hemochromatosis.

BACKGROUND AND AIMS: Standard treatment for naïve hereditary hemochromatosis patients consists of phlebotomy or a personalized erythrocytapheresis. Erythrocytapheresis is more efficient, but infrequently used because of perceived costs and specialized equipment being needed. The main aim of our study was to develop a model that predicts the number of initial treatment procedures for both treatment methods. This information may help the clinician to select the optimal treatment modality for the individual patient. METHODS: We analyzed retrospective data of 125 newly diagnosed patients (C282Y homozygous), treated either with phlebotomy (n = 54) or erythrocytapheresis (n = 71) until serum ferritin (SF) reached levels ≤100 µg/L. To estimate the required number of treatment procedures multiple linear regression analysis was used for each treatment method separately. RESULTS: The linear regression model with the best predictive quality (R2  = 0.74 and 0.73 for erythrocytapheresis and phlebotomy respectively) included initial SF, initial hemoglobin (Hb) level, age, and BMI, where initial SF was independently related to the total number of treatment procedures for both treatment methods. The prediction error expressed in RMSPE and RMSDR was lower for erythrocytapheresis than for phlebotomy (3.8 and 4.1 vs 7.0 and 8.0 respectively), CONCLUSIONS: Although the prediction error of the developed model was relatively large, the model may help the clinician to choose the most optimal treatment method for an individual patient. Generally erythrocytapheresis halves the number of treatment procedures for all patients, where the largest reduction (between 55% and 64%) is reached in patients with an initial Hb level ≥ 9 mmol/L (14.5 g/dL). ClinicalTrials.gov number NCT00202436.

Therapeutic erythroapheresis: Experience in patients with polycythemia vera and secondary erythrocytosis. / Eritroaféresis terapéutica: experiencia en pacientes con policitemia vera y eritrocitosis secundaria.

Therapeutic erythrocytapheresis (TE) is a more efficient strategy compared to phlebotomy to deplete levels of haematocrit in primary and secondary erythrocytosis. OBJECTIVE: To analyse response rate and safety profile of TE in polycythemia vera (PV) and secondary erythrocytosis (SE). PATIENTS AND METHOD: Retrospective review of all patients with PV or SE treated with TE, due to phlebotomy failure, or comorbidities that prevented changes of blood volumen. RESULTS: 217 TE sessions (48 PV and 79 SE) corresponding to 20 patients (12 ES and 8 PV). Response were achieved in 87.5% of PV patients and in 50% of SE patients. Adverse effects related to TE performance occurred in 7.08%. CONCLUSION: Despite our small sample size and the heterogeneous nature of the patients included, we can postulate that TE is a secure strategy that can achieve haematocrit depletion in a shorter time than phlebotomy, specifically in PV patients and in selected cases of SE with expected haemodynamic intolerance to phlebotomies or in patients who fail to respond to phlebotomies.

Safety and effectiveness of apheresis in the treatment of infectious diseases: A systematic review.

OBJECTIVES: Apheresis has been used as adjunctive treatment of severe falciparum malaria, loiasis and babesiosis. This systematic review aimed to investigate the safety and efficacy of apheresis in the treatment of these conditions. METHODS: MEDLINE, PUBMED, EMBASE and CINAHL databases were searched to identify studies published between January 1969 and March 2018 involving patients treated using apheresis for severe falciparum malaria, loiasis or babesiosis. Data extracted included details about the apheresis intervention, populations, study methods and outcomes relating to efficacy and safety. RESULTS: A total of 67 publications met the inclusion criteria and were included in the data synthesis, 36 for malaria (70 cases), 17 for babesiosis (22 cases) and 14 for loiasis (34 cases). Publications were case reports, case series, and cohort studies; there were no randomised controlled trials identified. Potential publication bias was considered to be high. CONCLUSIONS: Systematic review of the literature suggests that apheresis may be a useful adjunct in the treatment of patients hospitalised for babesiosis, and prior to chemotherapy in loiasis with microfilarial count >8000 parasites/mL. Data does not support the use of apheresis in patients with severe falciparum malaria.

The sex parameter in estimation of total blood volume for pediatric erythrocytapheresis.

BACKGROUND AND OBJECTIVES: Estimation of the total blood volume (TBV) is fundamental to the control of automated red cell exchange (RCE). Error in the TBV estimate can produce outcomes that deviate from the prescribed targets, and may endanger the patient. Both the Spectra Optia and the COBE Spectra use the Nadler formulae to estimate TBV. There is a potential for large overestimates of TBV when the Nadler formula for males is applied to prepubertal boys. MATERIALS AND METHODS: This study uses our large clinical experience with RCE to examine procedure outcomes when RCE in prepubertal boys is programed with the female parameter instead of male. We determined the differences between programmed and measured values for three outcomes: (a) Programmed End Hematocrit - Post spun HCT by Hemata Stat II, (b) Programmed End Hematocrit - Post CBC HCT, and (c) Predicted Post Hgb S+C - Measured Post Hgb S+C. We defined the experimental group as Male-Female, where the biological sex was male but programmed sex was female, and two control groups where programmed and biological sex were the same. RESULTS: Small but statistically significant differences were demonstrated between the mean programmed-to-observed deviations of these outcome measures in all but two group and subgroup comparisons; however, the absolute magnitudes of the observed differences were not clinically significant. The suggested weight cutoff to begin programming males as male is 35 kg. CONCLUSION: The study provides experiential validation that performing RCE in prepubertal boys using the female parameter is safe.

Triple Tick Attack.

Tick-borne diseases are frequently seen in tick-inhabited areas. Lyme disease is the most common tick-borne illness. However, patients with co-infections can present with nonspecific symptoms, which can make the diagnosis far more challenging. We present a case of triple infection with babesiosis, Lyme disease, and anaplasmosis treated with antibiotics and red blood cell (RBC) exchange (erythrocytapheresis). A 74-year-old, avid female gardener presented with one week of progressive dyspnea, cough with mucoid expectoration, and fatigue. On presentation, she was afebrile, hypotensive, and tachycardic. General examination was significant for altered mental status, dyspnea, pallor, and peripheral edema. Lung examination was remarkable for bibasilar crackles. Pertinent laboratory findings were significant for hemolytic anemia and thrombocytopenia. A peripheral blood smear revealed the presence of intracytoplasmic parasites consistent with Babesia. The patient was started on azithromycin and atovaquone. Doxycycline was added empirically for Lyme disease, which was later confirmed by serology. In addition, Anaplasma titers were also positive. Further investigation revealed that the parasitic load was 9.04%, and RBC exchange (erythrocytapheresis) was performed for severe babesiosis. Repeat laboratory tests demonstrated an inadequate reduction in parasitic load (6.54%), requiring a second round of RBC exchange. Antimicrobials were changed to clindamycin, quinine, and doxycycline for a total of 14 days. There was an improvement in the patient's anemia and thrombocytopenia along with clinical improvement.

Red Blood Cells: Exchange, Transfuse, or Deplete.

Erythrocytapheresis, red blood cell (RBC) depletion, and RBC exchange transfusions are apheresis techniques used to rapidly lower the circulating RBC mass or to exchange the patient erythrocyte mass with donor RBC. Automated RBC exchange is performed using an apheresis device, while manual RBC exchange is based on sequential phlebotomies and isovolemic replacement. Compared to simple RBC transfusions, RBC exchange offers several advantages, e.g., a lower risk for iron accumulation and efficient control of pathological erythrocyte populations. Disadvantages are the higher costs of the procedure, the increased use of donor RBC, and the requirement of apheresis devices and trained hospital staff. The most frequent indication for RBC exchange is sickle cell disease (SCD). RBC exchange transfusions are standard treatment in SCD patients with a history of or a risk for acute stroke and are clinical options for other acute complications of SCD. The most common indication for RBC depletion is the removal of donor RBC from the bone marrow grafts in major ABO-incompatible allogeneic hematopoietic stem cell transplantation to avoid immediate hemolysis. Rare indications for RBC exchange are severe infections with intraerythrocytic pathogens such as malaria or babesiosis and severe erythrocytosis or hereditary hemochromatosis where the aim is to rapidly decrease RBC populations or the iron content. However, only few high-quality studies are available looking at the efficacy of RBC exchange in the different disease entities, and treatment is often based on low levels of evidence and should therefore be decided in close collaboration with a transfusion medicine specialist.