Therapeutic pediatric apheresis

Safety and efficacy of peripheral blood stem cells collection in healthy children and pediatric patients with thalassemia major weighing 20 kg or less

BACKGROUND

Peripheral blood stem cell (PBSC) collection in children poses challenges due to their small size, low body weight (BW), and unique pediatric physiology, especially among children weighing 20 kg (kg) or less.

METHODS

PBSC collection data of both healthy children and patients with thalassemia major (TM) weighing 20 kg or less between January 2013 and December 2020 were reviewed. Moreover, PBSCs characteristics along with various aspects of efficiency and safety between healthy donors and patients with TM were compared.

RESULTS

A total of 262 PBSC procedures were performed on 255 children. Of these, 91 procedures were carried out on 85 allogeneic healthy donors, and 171 auto-backup collections were performed on 170 patients with TM to ensure PBSC availability and prevent transplantation failure. A minimum pre-apheresis hemoglobin (HGB) level of 60 g/L was discovered to be safe and feasible in patients with TM. The median CD34+ cell dose in the PBSC product during the initial apheresis procedure was higher in healthy donors compared to patients with TM (7.29 ± 5.28 × 106 cells/kg vs5.88 ± 4.23 × 106 cells/kg, P = .043). The total CD34+ cells/kg recipient weight exhibited a positive correlation with pre-apheresis monocyte counts, but a negative correlation with donor weight. Apheresis significantly reduced hematocrit and platelet counts in the allogeneic group compared to the autologous group. Patients with TM experienced a higher occurrence of bone pain related to granulocyte colony-stimulating factor treatment. Notably, no serious complications related to PBSCs mobilization, central venous catheter placement, or the apheresis procedure were observed in either group.

CONCLUSIONS

PBSCs collection was both safe and effective in healthy children and pediatric patients with TM weighing 20 kg or less.

Recommendations for procurement of starting materials by apheresis for advanced therapy medicinal products

Activities involved in the production of certain advanced therapy medicinal products (ATMPs) require standardized approaches to mononuclear cell procurement to ensure the highest product quality, safety and process efficiency. These aims must be achieved while meeting regulatory and accreditation requirements for the procurement of mononuclear cells as starting materials. Mononuclear cells constitute the starting materials for many ATMPs, and this article sets out recommendations for procurement by clinical apheresis, addressing the variation among existing working practices and different manufacturers' requirements that currently poses a challenge when managing multiple different protocols.

Priming With Red Blood Cells Allows Red Blood Cell Exchange for Sickle Cell Disease in Low-Weight Children

Red blood cell exchanges are frequently used to treat and prevent cerebrovascular complications in patients with sickle cell anemia (SCA). However, the low weight of young children represents serious concerns for this procedure. The Spectra Optia device can perform automatic priming using red blood cells (RBCs) (RCE/RBC-primed) which could allow RBC exchanges (RCE) to be performed in young children without hypovolemic complications, but this method requires evaluation. We prospectively analyzed the clinical safety of the RCE/RBC-primed procedure in 12 SCA low-weight children under either a chronic RCE program or emergency treatment over 65 sessions. We monitored grade 2 adverse events (AEs) such as a decrease in blood pressure, increase in heart rate, fainting sensation, or transfusion reactions and identified the critical times during the sessions in which AEs could occur. Post-apheresis hematocrit (Hct) and a fraction of cell remaining (FCR) values were compared to the expected values. We also compared the impact of automatic RCE (n = 7) vs. RCE/RBC-primed (n = 8) on blood viscosity and RBC rheology. A low incidence of complications was observed in the 65 RCE sessions with only seven episodes of transient grade 2 AEs. Post-apheresis Hct and FCR reached expected values with the RCE/RBC-primed method. Both the automatic and priming procedures improved RBC deformability and decreased the sickling tendency during deoxygenation. Blood rheological features improved in both RCE/RBC-primed and automatic RCE without priming conditions. The RCE/RBC-primed procedure provides blood rheological benefits, and is safe and efficient to treat, notably in young children with SCA in prophylactic programs or curatively when a SCA complication occurs.

Reduced volume of red blood cell priming is safe for pediatric patients undergoing therapeutic plasma exchange

RATIONAL

Therapeutic Plasma Exchange (TPE) procedures in pediatric patients are challenging due to the large extracorporeal volume of the cell separators, which were designed for adults. Red blood cell (RBC) priming is an alternative for overpassing the risks of hypovolemia, but data referring to the volume of packed RBCs to be infused are yet incomplete. Restricting the volume of RBC priming may potentially be associated with less transfusion reactions.

GOAL

To determine the safety of administering a reduced volume of RBC priming for pediatric patients undergoing TPE, in comparison to the standard volume recommended by the cell separators' manufacturers.

METHODS

This was a case-control study which enrolled 15 pediatric patients undergoing TPE and weighting more than 10Kg. The TPE procedures (n = 406) were divided in two groups: 1) Group1: TPE with ≤150 mL of packed RBC priming and 2) Group2: TPE with 150-250 mL of RBC priming. Groups were compared in terms of hemoglobin / hematocrit and occurrence of adverse reactions.

RESULTS

Group1 and Group2 did not differ significantly in relation to pre- and post-TPE hemoglobin (Hb) levels (p = 0.19 and p = 0.18, respectively). The Δ Hb (Hb pre-TPE - Hb post-TPE) was also not statistically different between the groups. The number of adverse reactions was significantly higher in Group 2 in relation to Group 1 (p = 0.01). The number of allergic reactions was also higher in Group 2 (p = 0.06).

CONCLUSIONS

Restricting the volume of RBC priming to less than 150 mL is safe for pediatric patients weighting more than 10Kg and associated with lower rates of transfusion-related adverse reactions.

Use of therapeutic plasma exchange for pediatric neurological diseases

Therapeutic plasma exchange is used to treat neurological diseases in the pediatric population. Since its first use in pediatric patients with hepatic coma in the form of manual whole blood exchange, therapeutic plasma exchange has been increasingly used to treat these disorders of the nervous system. This expansion is a result of improved techniques and apheresis instruments suitable for small children, as well as the recognition of its applicability to many diseases in the pediatric population. This review provides a historical overview of the use of therapeutic apheresis in children and highlights the most common applications for therapeutic plasma exchange to treat neurological disorders in children.

Therapeutic plasma exchange in the pediatric intensive care unit: A single-center 5-Year experience

The objective of this study is to characterize clinical indications, safety and outcome with the use of TPE in critically ill children. All TPE procedures performed in a tertiary pediatric intensive care unit (PICU) during a 5-year period were retrospectively evaluated. A total of 75 patients underwent 249 sessions of TPE. Sepsis-induced multiple organ dysfunction syndrome (MODS) was the most common indication with 29.3 %. American Society for Apheresis classifications were as follows: Category I: 24 %, Category II: 16 %, Category III: 45.3 % and Category IV: 4%, while 10.7 % of the patients could not be classified. TPE was performed without any adjunct procedures in 188 sessions (75.5 %), while it was combined with continuous renal replacement therapy (CRRT) in 49 sessions (19.7 %) and with CRRT and extracorporeal membrane oxygenation (ECMO) in 12 (4.8 %) sessions. Overall survival rate was 73.3 %. The survival rate in patients requiring only TPE was 86.5 %, while the survival rates of patients who had CRRT and ECMO were 45 % and 33.3 %, respectively. Complications associated with the procedure occurred in 48 (19.2 %) TPE sessions. The lowest survival rate (31.9 %) was in patients with sepsis-induced MODS. Finally, we also found significantly higher organ failure rate, mechanical ventilation requirement, and PRISM III score at PICU admission in non-survivors. Our experience indicates that TPE can be performed relatively safely in critically ill children with appropriate treatment indications. Survival rate may vary depending on the underlying disease; however, it must be noted that survival rate is very high in children requiring TPE only.

Recommendations for Therapeutic Apheresis by the Section "Preparative and Therapeutic Hemapheresis" of the German Society for Transfusion Medicine and Immunohematology

The section "Preparative and Therapeutic Hemapheresis" of the German Society for Transfusion Medicine and Immunohematology (DGTI) has reviewed the actual literature and updated techniques and indications for evidence-based use of therapeutic apheresis in human disease. The recommendations are mostly in line with the "Guidelines on the Use of Therapeutic Apheresis in Clinical Practice" published by the Writing Committee of the American Society for Apheresis (ASFA) and have been conducted by experts from the DACH (Germany, Austria, Switzerland) region.

Clinical Application of Apheresis in Very Small Dogs Weighing <8 kg to Pediatric Patients

Apheresis in low body weight children and adolescents is challenging due to a variety of technical and clinical issues including vascular access, low total blood volume, and hypotension. Although dogs have been a valuable preclinical model for apheresis, the procedure can be challenging since many pure-bred dogs are extremely small. Therefore, apheresis in these very small breeds presents very similar challenges as seen when performing the procedure in very low body weight people. We describe apheresis of four very small dogs, weighing from 4.6 to 7.6 kg, using either a COBESpectra and Spectra Optia apheresis system (Terumo BCT, Lakewood, CO, USA). Two dogs underwent large volume leukapheresis to collect mononuclear cells in preparation for hematopoietic stem cell transplantation and two dogs underwent therapeutic plasma exchange to treat an immune-mediated disease. In all cases, a dual-lumen hemodialysis catheter placed in the jugular vein provided adequate machine inlet and return flow rates. Machine priming was necessary to maintain hemodynamic stability during the beginning of the procedure, and rinseback was avoided for the same reason. Anticoagulant citrate dextrose solution, solution A was used for the large volume leukapheresis procedures and a combination of anticoagulant citrate dextrose solution, solution A and heparin was used for the therapeutic plasma exchange procedures. As such, serum iCa levels were regularly monitored and 10% calcium gluconate constant rate infusions were used to prevent citrate toxicity. All dogs completed the aphereses with no life-threatening adverse events. We conclude that aphereses in very small dogs is feasible if close attention is paid to hemodynamic stability and citrate toxicity.

Plasma Filtration Versus Centrifugation in Pediatric Therapeutic Plasma Exchange: Should the Diagnosis Define the Method?†

Therapeutic plasma exchange (TPE) is used for a variety of illnesses in critically ill pediatric patients. Although both centrifugation and filtration are known to be effective methods, to our knowledge, clinical results for TPE by these methods are not compared in pediatric patient populations. One hundred patients who had TPE for a variety of diagnoses were included in the study. In 55 patients plasma exchange was implemented by centrifugation and in 45, by filtration. These two groups were further divided into subgroups according to admittance diagnoses. The demographic information, admittance Pediatric Risk of Mortality scores, Pediatric Logistic Organ Dysfunction (PELOD) scores before beginning of therapy and PELOD at the end of therapy, durations of ventilatory support, pediatric intensive care unit and hospital stay, and outcomes were compared. Although the survival was significantly better in filtration group, it included more patients with neurologic diagnoses. Filtration group standard mortality rate was 0.6. In both groups, the PELOD scores after the termination of TPE were significantly decreased compared to that before beginning of TPE. Within thrombotic microangiopathy and hemophagocytic lymphohistiocytosis subgroups, median PELOD scores before treatment were higher in centrifugation patients but survival was similar with both methods. Both methods of TPE are alike in decreasing PELOD scores. In the filtration group, survival benefit of TPE is evident. In thrombotic microangiopathy patients, despite higher PELOD scores in the centrifugation group, survival is similar for both methods. These findings should be retested in randomized studies and the underlying physiology awaits to be uncovered.

Impact of the hematocrit value of the blood prime unit on patient hematocrit values after therapeutic plasma exchange in children weighing 10 kg or less

We report the impact of measuring the hematocrit (HCT) of blood prime units (BPUs) on postprocedure patient HCT values in a small child with transverse myelitis undergoing therapeutic plasma exchange (TPE). Initially, the BPU HCT values were not measured, according to our apheresis policy of using our blood center's estimated HCT value. This approach resulted in unexpected increasing elevations of our patient's post-TPE HCT after the first two TPE procedures. Subsequent measurement of the BPU HCT prior to use stabilized the patient's post-TPE HCT. To our knowledge, this is the first case report describing the impact of using the measured BPU HCT vs the estimated HCT for very small children undergoing therapeutic apheresis. Our standard operating procedure for very small children has been updated after this patient's case to include measurements of the HCT values of BPUs for children who weigh 10 kg or less.

Development of apheresis techniques and equipment designed for patients weighing less than 10 kg

The procedure of apheresis in pediatric patients, particularly in those with low weight (body weight<10 kg) presents an important challenge due to particularities of this group. There are no specific guidelines or enough scientific evidence to standardize the practice in this group of patients. In addition to the psychological aspect, the correct calculation of the total blood volume, the extracorporeal volume of the cell separator and an estimated decrease in hematocrit must be considered. Personalized protocols for priming of the apheresis equipment, sufficient blood flow and adequate anticoagulation are essential for patient comfort and therapeutic success. The purpose of this article is to present the results of the national study of apheresis practices in low weight group of children conducted from 2012 to 2018. Protocols and patients' data collected from various apheresis centers in Argentina were compared with the apheresis protocols around the world. Our protocols and data were similar to those in other countries; however, no detailed and specific guidelines for apheresis practices in this population of patients with unique requirements have been developed to date.

Pediatric apheresis emergencies and urgencies: An update

Urgency and emergency in general, and even more in the pediatric setting, remain a thematic debate not yet fully resolved. The decision to undergo a pediatric patient to an invasive treatment not free from potentially serious side effects like an apheresis procedure should be weighted with great attention. At the moment there is no unanimous consensus about the clinical pictures in which an urgency procedure in pediatrics is indicated. Each center acts according to its own experience and not infrequently to its own fears. Consequently the difficult to draw up an unequivocal shared list of pathologies needing an intervention in urgency/emergency it is confirmed as problematic. We report the experience of a big multidisciplinary hospital that has selected and shared with the specialists of different medical disciplines during the years the pediatric clinical conditions in which an urgent intervention with apheresis technology is indicated.

Therapeutic Plasma Exchange in Critically Ill Children Requiring Intensive Care

OBJECTIVE

To characterize the clinical indications, procedural safety, and outcome of critically ill children requiring therapeutic plasma exchange.

DESIGN

Retrospective observational study based on a prospective registry.

SETTING

Tertiary and quaternary referral 30-bed PICU.

PATIENTS

Forty-eight critically ill children who received therapeutic plasma exchange during an 8-year period (2007-2014) were included in the study.

INTERVENTIONS

Therapeutic plasma exchange.

MEASUREMENTS AND MAIN RESULTS

A total of 48 patients underwent 244 therapeutic plasma exchange sessions. Of those, therapeutic plasma exchange was performed as sole procedure in 193 (79%), in combination with continuous renal replacement therapy in 40 (16.4%) and additional extracorporeal membrane oxygenation in 11 (4.6%) sessions. The most common admission diagnoses were hematologic disorders (30%), solid organ transplantation (20%), neurologic disorders (20%), and rheumatologic disorders (15%). Complications associated with the procedure occurred in 50 (21.2%) therapeutic plasma exchange sessions. Overall, patient survival from ICU was 82%. Although patients requiring therapeutic plasma exchange alone (n = 31; 64%) had a survival rate of 97%, those with additional continuous renal replacement therapy (n = 13; 27%) and extracorporeal membrane oxygenation (n = 4; 8%) had survival rates of 69% and 50%, respectively. Factors associated with increased mortality were lower Pediatric Index of Mortality 2 score, need for mechanical ventilation, higher number of failed organs, and longer ICU stay.

CONCLUSION

Our results indicate that, in specialized centers, therapeutic plasma exchange can be performed relatively safely in critically ill children, alone or in combination with continuous renal replacement therapy and extracorporeal membrane oxygenation. Outcome in children requiring therapeutic plasma exchange alone is excellent. However, survival decreases with the number of failed organs and the need for continuous renal replacement therapy and extracorporeal membrane oxygenation.

How we approach a patient with symptoms of leukostasis requiring emergent leukocytapheresis

Hyperleukocytosis can induce leukostasis, which can lead to vascular obstructions (usually in the lungs and central nervous system), tumor lysis syndrome, and disseminated intravascular coagulation. Although it has not been conclusively shown to improve long-term outcome, leukocytapheresis may be used as part of the management of hyperleukocytosis with or without leukostasis to rapidly reduce the white blood cell (WBC) burden. Since leukocytapheresis only temporarily decreases the WBC count, early initiation of more definite therapy, such as hydroxyurea and/or chemotherapy, is essential. In this article, clinical assessment of the patient's clinical status to determine the need for leukocytapheresis as well as a general guideline for management of the technical aspects and complications of the procedure are discussed.

Indications, technique, and outcome of therapeutic apheresis in European pediatric nephrology units

BACKGROUND

Few observations on apheresis in pediatric nephrology units have been published.

METHODS

This retrospective study involved children ≤18 years undergoing plasma exchange (PE), immunoadsorption (IA), or double filtration plasmapheresis (DFPP) in 12 European pediatric nephrology units during 2012.

RESULTS

Sixty-seven children underwent PE, ten IA, and three DFPP, for a total of 738 PE and 349 IA/DFPP sessions; 67.2 % of PE and 69.2 % of IA/DFPP patients were treated for renal diseases, in particular focal segmental glomerulosclerosis (FSGS), hemolytic-uremic syndrome (HUS), and human leukocyte antigen (HLA) desensitization prior to renal transplantation; 20.9 % of PE and 23.1 % of IA/DFPP patients had neurological diseases. Membrane filtration was the most common technique, albumin the most frequently used substitution fluid, and heparin the preferred anticoagulant. PE achieved full disease remission in 25 patients (37.3 %), partial remission in 22 (32.8 %), and had no effect in 20 (29.9 %). The response to IA/DFPP was complete in seven patients (53.8 %), partial in five (38.5 %), and absent in one (7.7 %). Minor adverse events occurred during 6.9 % of PE and 9.7 % of IA/DFPP sessions.

CONCLUSIONS

PE, IA, and DFPP are safe apheresis methods in children. Efficacy is high in pediatric patients with recurrent focal segmental glomerulosclerosis (FSGS), atypical hemolytic uremic syndrome (HUS), human leukocyte antigen (HLA) sensitization, and neurological autoimmune diseases.

Effective collection of peripheral blood stem cells in children weighing 20 kilogram or less in a single large-volume apheresis procedure

INTRODUCTION

Peripheral blood stem cell (PBSC) transplantation has become a routine procedure in pediatric oncology. A special group of PBSC donors are children weighing 20 kg or less. Limited vascular access and low blood volume puts them at a higher risk. Central line placement and a priming apheresis machine are recommended to avoid these complications.

PATIENTS AND METHODS

PBSC collections performed from July 2006 to May 2013 in children weighing less than 20 kg were included. All donors had a central venous catheter (CVC). An apheresis machine was primed with packet red blood cells.

RESULTS

Twenty-seven PBSC collections were performed in 22 children weighing 20 kg or less, 14 for allogeneic and 8 for autologous transplantation, in order to collect at least 2 × 10(6) CD34+ cells/kg. In the allogeneic group, median age and weight were 3 years (0.8-7) and 15.5 kg (8-20). In the autologous group, median age and weight were 3 years (2-7) and 15.35 kg (12.5-19.5). A single large-volume apheresis was sufficient to obtain the CD34+ cells needed in 78.5% and 75% of the allogeneic and autologous groups, respectively, with a median 11.84 × 10(6) and 5.79 × 10(6) CD34+ cells collected per kilogram of weight of the recipient. No serious complications related to the apheresis procedure or CVC placement occurred.

CONCLUSION

PBSC collection in a single large-volume apheresis for allogeneic and autologous transplants in children weighing 20 kg or less is a safe and effective procedure when based on standardized protocols.

Red cell exchange: special focus on sickle cell disease

The primary function of red blood cells (RBCs) is to deliver oxygen from the lungs to tissues. Tissue hypoxia occurs when the oxygen-carrying capacity of RBCs is compromised due primarily to 3 causes: (1) a reduction in circulating RBC mass, (2) an increase in circulating RBC mass, or (3) abnormal hemoglobin (Hb) that either does not sufficiently release oxygen to tissues (high-oxygen-affinity hemoglobin) or occludes the microvasculature due to deformed RBCs (sickled RBCs). To improve oxygenation in patients with reduced or increased RBC mass, RBC administration (simple transfusion) or RBC removal (RBC depletion) is performed, respectively. However, for patients with abnormal Hb, RBCs containing abnormal Hb are removed and replaced by healthy volunteer donor RBCs by red cell exchange (RCE). RCE can be performed by manual exchange or by automated exchange using a blood cell separator (erythrocytapheresis). In this review, indications for RCE in sickle cell disease using the evidence-based American Society for Apheresis categories(1) are presented and the rationale for RCE in each disorder are discussed. Simple transfusion versus RCE and manual RCE versus automated RCE are compared. Finally, this review briefly presents some of the challenges of performing erythrocytapheresis in small children and discusses various choices for central venous access during RCE.(2.)

A safe therapeutic apheresis protocol in paediatric patients weighing 11 to 25 kg

BACKGROUND AND OBJECTIVES

Erythrocytapheresis and leukapheresis (LPE) of small children are logistically complex and many centres are reluctant to perform these procedures. In children, both sickle cell and leukaemic emergencies demand prompt action to prevent additional morbidity but detailed protocols for small children are lacking, and often are performed using guidelines shown to work in larger patients. We report a 3-year experience with children weighing 11-25 kg at a large academic medical centre.

MATERIALS AND METHODS

All patients were treated with the COBE® Spectra apheresis system; circuit was primed with blood not adjusted for haematocrit and anticoagulant citrate dextrose A was used as anticoagulation. Procedures were performed in the paediatric intensive care unit by apheresis nursing staff.

RESULTS

Twenty-five apheresis procedures in 19 patients were performed; 17 of 19 patients presented with sickle cell-related acute complications and two (2/19) with newly diagnosed acute leukaemia and hyperleucocytosis. None of the patients required medications during the procedures. Vital signs and clinical condition remained stable and did not worsen during or postapheresis. One patient had a delayed haemolytic transfusion reaction 1 week posterythrocytapheresis as he developed alloantibodies as a result of the procedure. All sickle cell patients achieved a target haematocrit of 21-30% and Haemoglobin A of ≥68%. Both leukaemia patients who underwent LPE had no further signs of leukostasis and achieved marked reductions in leucocyte counts.

CONCLUSIONS

Apheresis of children weighing 11-25 kg can be safely performed without increased morbidity. We outline a protocol that can be used to perform apheresis with minimal complications.

American Society for Apheresis guidelines on the use of apheresis in clinical practice: practical, concise, evidence-based recommendations for the apheresis practitioner

The 6th Guidelines on the use of therapeutic apheresis in clinical practice published by the American Society of Apheresis provide practical, concise, and evidence based guidance for the apheresis medicine practitioner. The overall format of the Guidelines has remained unchanged with the 6th edition, compared to the 5th edition, with enhancements in the committee process of creating the guidelines. Because of changes in the writing committee structure, a number of changes have occurred in the ASFA category and recommendation grade for the use of apheresis in the treatment for a number of previously categorized clinical indications. In addition, eight new indications for apheresis, twenty three new clinical situations for previously categorized diseases, and ten new apheresis treatments for previously categorized disorders have been added. The 6th Guidelines continue to be an invaluable resource for those involved in apheresis medicine.

Feasibility of pediatric plasma apheresis in intensive care settings

Therapeutic plasma apheresis or exchange (TPE) in the pediatric population is technically challenging. Moreover, there is generally an apprehension in using TPE in children compared to adults. Recently, usage of TPE has evolved and is now being used in heterogenous clinical conditions. Its usefulness is classified by the American Society for Apheresis (ASFA) into various categories ranging from I to IV. The objective of this paper was to review the procedure in context of clinical indications, complications and outcomes in children. For this purpose, we retrospectively reviewed all TPE procedures performed on inpatients of 3 to 16 years of age during a 6-year period (2007-2012). A total of 130 procedures were performed on 28 patients (M : F ratio of 1:1) with median age (range) of 8.8 (4-16) years. All procedures were done using the continuous cell-separator centrifugal method. Due to organ dysfunctions, the majority of procedures (N = 26 of 28 or 92% patients) were performed in the pediatric intensive care unit. Twenty-three, four and one patient belonged to ASFA categories I, II and III, respectively. The most common indications were neurological disorders (N = 13 or 46.4%), comprised of Guillain-Barré syndrome (N = 10) and myasthenia gravis (N = 3). Hematological disorders (N = 10 or 35.7%) including thrombotic thrombocytopenic purpura-hemolytic uremic syndrome were a close second. Complete recovery was seen in 23 patients (84%). Trivial adverse effects were observed in 18/130 (13.8%) procedures. Major complications including cardiac arrest, hypotension and transfusion-related acute lung injury were observed in 5/130 or 3.8% of procedures. However, there was no procedure-related death though five patients died during treatment due to underlying pathology. In conclusion, TPE is a safe and effective option in sick children for appropriate indications. An experienced staff with sound procedural skills is imperative for successful therapy.

Anticoagulation techniques in apheresis: from heparin to citrate and beyond

Anticoagulation is essential for maintaining the fluidity of extravascular blood on the apheresis circuit. Although both citrate and heparin are used as an anticoagulant during apheresis, citrate is preferred for the majority of exchange procedures because of its safety and effectiveness. Complications of citrate are primarily due to physiologic effects of hypocalcemia. Symptoms of hypocalcemia and other citrate-induced metabolic abnormalities affect neuromuscular and cardiac function and range in severity from mild dysesthesias (most common) to tetany, seizures, and cardiac arrhythmias. Oral or intravenous calcium supplementation is advised for decreased ionized calcium levels and/or symptomatic management of hypocalcemia. Heparin-based anticoagulation is limited to certain apheresis procedures (membrane-based plasma exchange, LDL apheresis, or photopheresis) or is used in combination with citrate to reduce citrate load. While effective, heparin anticoagulation is associated with an increased frequency of bleeding complications and heparin-induced thrombocytopenia. J. Clin. Apheresis 2012. © 2012 Wiley Periodicals, Inc.

Leukapheresis in management hyperleucocytosis induced complications in two pediatric patients with chronic myelogenous leukemia

Complications caused by elevated white blood cell count in pediatric patients with CML could be a presenting feature of the disease. Here, we present two adolescents, aged 16 and 17years, who were admitted for investigation of extremely elevated leukocytes and complications of leucostasis. Initial manifestations were priapism and blurred vision, respectively. Diagnosis of chronic phase of chronic myeloid leukemia is established, and conventional measures for leucoreduction began. However, since there were no improvements, a leukapheresis procedure was initiated. After undergoing 3 daily procedures the leukocyte count declined for each patient, with resolution of pripaism and ophtalmological disturbances. Leukapheresis is safe and effective therapeutic option for patients with complications of hyperleucocytosis. If started in a timely manner, permanent organ damage or death could be avoided.

Regional citrate anticoagulation--a safe and effective procedure in pediatric apheresis therapy

Regional citrate anticoagulation (RCA) has been considered to be a standard component of pediatric apheresis therapy for more than a decade. However, data on dosing recommendations and evaluations of the effectiveness and safety of anticoagulation are rarely found in published reports. The aim of this retrospective analysis was to present our single-center experience with RCA in pediatric apheresis therapy with the aim of developing an operating procedure. Five children aged 7-14 years underwent a total of 72 (range 3-44) therapeutic apheresis sessions with RCA in the form of immunoadsorption therapy (2 patients), low-density lipoprotein (LDL)-apheresis (1 patient), and plasmapheresis (two patients). A 3% citrate solution was used. Citrate flow was started at 4.0% of the blood flow velocity and was adapted to match post-filter ionized calcium levels ≤ 0.30 mmol/l. Once the patient's ionized calcium fell to <1.05 mmol/l, an intravenous 10% calcium gluconate solution was administered. Twenty pediatric apheresis patients who received standard heparinization, matched for age, body surface area, processed plasma volume, and blood flow velocity, were enrolled in the study as a comparison group. No side effects were experienced in 72 apheresis session. The 3% citrate solution had to be reduced gradually during the apheresis session and was infused at a mean of 2.8-3.8% of the blood flow rate. Serum bicarbonate levels before and after the apheresis session with RCA [23.9 (range 18.9-30.1) vs. 26.3 (20.2-33.0) mmol/l, respectively] were significantly different (p=0.013). All patients required intravenous calcium substitution to maintain serum calcium levels within the physiological range. Due to the administration of the 3% citrate solution and calcium, all patients significantly gained weight during the procedure, with a median weight gain of 2.5% (p<0.001). The extra fluid load caused problems in patients with kidney failure. Our regimen with RCA is safe, feasible, and effective in pediatric therapeutic apheresis therapy. For RCA in apheresis, we recommend (1) a citrate (3%) flow of 3.3% of the blood flow, (2) prophylactic intravenous calcium substitution from the beginning, and (3) a more highly concentrated citrate solution in the case of oliguric patients.

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Practical considerations for planning a therapeutic apheresis procedure

The general medicine and critical care services often care for patients that require therapeutic apheresis. Apheresis procedures are performed for various hematologic, neurological, renal, autoimmune, metabolic, and other indications. To facilitate a prompt start to the procedure, the clinical team must coordinate efforts with several services, including those that perform the apheresis procedure, establish venous access, and provide blood or replacement products, in addition to the pharmacy and clinical laboratory. Some of these tasks are performed typically by the clinical teams, while others are performed typically by the apheresis team. Presented and discussed are the indications for therapeutic apheresis, calculations for the ordering of blood products, and several important and practical details to consider, thus preventing delays in starting the apheresis procedure.

Training courses for pediatric apheresis on site; how apheresis technology transfer can be performed

Apheresis technology for pediatric patients and donors is still cumbersome, it is rare, mostly done in departments specialized for apheresis in adult patients, and therefore the staff is more or less anxious about dealing with especially little pediatric patients or donors. Our center is specialized in pediatrics and has a department for apheresis. We offered training courses for interested centers, which want to use the AMICUS™ system for leukapheresis in small children. In a 1-2 ay course the principles of leukapheresis in very small children were trained. To investigate the reproducibility of this training courses we invited the centers to share their data with us. As a standard we used a formula (C=[(AD):B×0.5]:1000) for predicting the CD34+ cell yield (C) by calculating the yield from total blood volume (D) processed, bodyweight (B), CD34+ cell count in peripheral blood (A) and an assumption of the collection efficiency of 50% (0.5). We hypostasized that the deviation of different centers should be in comparable limits of agreement as our own data. Thirteen centers from Germany, Poland, Ukraine, Romania, Italy, Hungary, and Slovakia asked from 1999 until today for support for pediatric leukapheresis. 6 centers sent 20 case report forms back (9 blood priming, 6 saline priming), from which 15 were completely filled in and available for the evaluation. The data were compared to 129 leukapheresis (41 blood priming, 88 saline priming) performed in our institution. The limit of agreement to the formula was -17.6% (±43) compared to -10.5% (±36). There was no statistically differences by the Mann-Whitney-U-test (p=0.5607). We conclude that training course held on site in different centers in different country could led to reproducible performance of standardized leukapheresis procedures in small children. In the future this could be a way for quality control in pediatric apheresis.

The use of fluid boluses to safely perform extracorporeal photopheresis (ECP) in low-weight children: a novel procedure

Apheresis procedures in small children are technically challenging and require special planning with attention to extracorporeal volume. Discontinuous procedures such as extracorporeal photopheresis (ECP) require additional consideration. Alternative methods to perform ECP have been utilized in small children that require manipulation of mononuclear cells outside the standard closed-loop system. We present a safe and feasible alternative to the procedure for children who weigh less than 40 Kg, while maintaining a closed loop, sterile system utilizing the UVAR XTS device. A retrospective chart review was performed analyzing the use of fluid boluses (normal saline in those between 20 and 40 Kg, 5% albumin in those under 20 Kg) before ECP. Eleven patients underwent 334 ECP procedures for acute and chronic graft-versus-host disease (n = 9), and for prevention of graft-versus-host disease (n = 2). Volumes of fluid boluses were calculated based on the expected extracorporeal volume during the first draw cycle. Treatments consisted of at least three draw cycles using the 125 mL bowl. The median weight was 28.5 Kg (range 19 to 39); nine of 11 required red cell transfusions to maintain adequate hematocrit. Complications attributed to ECP included tachycardia, dizziness, nausea, and hypotension; these occurred either in combination or isolation in 31% of the procedures and resolved following additional fluid boluses. Only three (0.8%) required early photoactivation due to these complications. The median time to completion of treatment was 2 h and 58 min (range 1:30 to 5:03). ECP is well tolerated in low-weight pediatric patients if hematocrit and hydration are carefully maintained.

Photopheresis in pediatric patients with low-body weight using the UVAR XTS system

BACKGROUND

Photopheresis (ECP) with the UVAR XTS system has been limited to patients with a body weight > 40 kg, because extracorporeal blood volumes (ECV) may exceed 15% of the total blood volumes in low-body-weight patients. Because of these instrument characteristics, the use of ECP is limited in pediatric patients.

PATIENTS AND METHODS

In 5 patients (age 4 to 15 years) with graft-versus-host disease and with a body weight between 13 and 34 kilograms, photopheresis was performed using the UVAR XTS system. In 3 patients ECP could be performed by balancing the ECV with saline infusions. In 2 patients the system was modified in that the instrument was primed with packed red cells. During the treatment, fluid balance was guaranteed by a reservoir from a transfusion bag connected in parallel.

RESULTS

Together 223 procedures were performed, among them 28 with the modification of the system. The treatments were well tolerated, and no episodes of hypotension were observed.

CONCLUSIONS

It is possible to run ECP in low-body weight patients with the UVAR XTS system.

World apheresis registry data from 2003 to 2007, the pediatric and adolescent side of the registry

OBJECTIVES

Paediatric patients are a special group in apheresis. It is general accepted to use adult indications in paediatric patients, but data in this age group are rare. In order to provide more information of apheresis practise in children and young adults (<21a) we will report of knowledge learnt by data from the registry from 2003 until 2007.

METHODS

This is a web-based registry. A link is available from the WAA homepage (www.worldapheresis.org). So far data from 12,448 procedures have been included. Six hundred and twelve procedures were performed in 135 children and young adults (308 procedures<16a, 237 from 17 to 20a, and 67 with 21a) representing 5% of the total population. The median age was 14 years (range 1-21 years), 74 male and 61 female. These data were entered by 15 centres with a frequency of in median 18 aphereses in young patients per centre (range 1-287) from 2003 to 2007.

RESULTS

Main indications: haematological diseases and also nephrological, and neurological. The type of aphereses was mainly Leukapheresis (196, 33%), plasma exchange (149, 25%), photopheresis (127, 21%), and lipid aphereses (79, 13%). Blood access: peripheral vessels in 305 procedures (50%, compared to 73% in adults), central venous catheter in 239 (38%), and AV-fistula in 2% and 0.3%, and in 8 (1.31%) procedures an arterial line was used. Anticoagulation was mostly by ACD (71%), heparin (18% or the combination of both (3%). 39 adverse events (AE) were registered in 22 (=3.59%) of the procedures, mostly graded as mild. Treatment was interrupted in 14 procedures (2.29%). AE's were abdominal pain, anaphylactic shock, flush, hyper- and hypotension, nausea, vertigo, cephalea and need for sedation and technical problems with the device and problems with the venous access. The rate of AE's was similar for stem cell harvesting and for plasma exchange (4% and 4.7%, respectively).

CONCLUSION

The paediatric data compared to the whole registry data set are showing that aphereses are performed as safe in paediatrics as in adults. Centres are mostly handling only a few cases younger than 21. Therefore more exchange of information and experience in paediatric apheresis is warranted.

False-positive pregnancy test after passive transfusion of ?-human chorionic gonadotropin from donor red blood cells during erythrocytapheresis

BACKGROUND

Patients transfused with blood products may passively receive soluble antibodies, proteins, and other analytes that persist during the collection, processing, and transfusion of the blood product. In this report, a female patient who received transfusion of five red blood cell (RBC) units during erythrocytapheresis later demonstrated an unexpected positive result in assays for the beta-subunit of human chorionic gonadotropin (bHCG), a screening test for pregnancy. The result caused postponement of an elective surgical procedure. A follow-up test 1 week later was negative.

STUDY DESIGN AND METHODS

To investigate the possibility of passive transfusion of the hormone from a donor RBC unit, a sample from each of the units transfused was assayed for the level of bHCG.

RESULTS

One of the 5 units transfused to the patient had a high level of bHCG. The observed bHCG level in the recipient was found to be comparable to the predicted level, given the donor's plasma bHCG level and accounting for the dilution factors in the preparation of the RBC unit and the erythrocytapheresis procedure and the in vivo t((1/2)) of the hormone.

CONCLUSION

The donor, who was unaware of her pregnancy status at the time of donation, harbored a high bHCG level that caused the positive test result in the recipient patient's serum and urine. If an unexpected analyte or serology is detected in a recipient of a blood transfusion, it is important to consider the possibility of passive transfusion of the analyte.

Guidelines on the use of therapeutic apheresis in clinical practice—Evidence-based approach from the apheresis applications committee of the American society for apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. This elaborate process had been undertaken every 7 years resulting in three prior publications in 1986, 1993, and 2000 of "The ASFA Special Issues." This article is the integral part of the Fourth ASFA Special Issue. The Fourth ASFA Special Issue is significantly modified in comparison to the previous editions. A new concept of a fact sheet has been introduced. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet is provided. The article consists of 53 fact sheets devoted to each disease entity currently categorized by the ASFA. Categories I, II, and III are defined as previously in the Third Special Issue. However, a few new therapeutic apheresis modalities, not yet approved in the United States or are currently in clinical trials, have been assigned category P (pending) by the ASFA Clinical Categories Subcommittee. The diseases assigned to category IV are discussed in a separate article in this issue.