Plasma-reduction for Apheresis Granulocyte transfusions in pediatric patients.

Granulocyte transfusion (GT) may be used to treat and prevent infections in patients with severe neutropenia or nonfunctioning granulocytes. For pediatric patients, the volume of granulocyte unit transfused is a crucial consideration given smaller blood volume and increased risk of volume overload compared to adults. There is limited literature on the optimal dosing or the maximum amount of granulocytes that can be tolerated, especially in pediatric patients. Additionally, no consensus exists regarding granulocyte collection method, frequency, or timing of GT initiation. Previous studies have described splitting or limiting collection volume for GT in pediatric patients, but these methods yield lower absolute neutrophil count (ANC) increment. Our blood supplier provides high-volume (0.5-1 L/unit), high-dose apheresis-collected granulocytes from donors stimulated with both granulocyte colony-stimulating factor and steroids. Here, we report cases of two pediatric patients with active infection undergoing bone marrow transplant with dramatic ANC increments (median one-hour ANC increment 5524/µL, interquartile range (IQR) 4417-10087; median 24-hour ANC increment 3880/µL, IQR 2550-5263) after infusing 100 mL plasma-reduced, apheresis collected GT. Our cases indicate that pediatric patients can tolerate 4-6 × 109/kg plasma-reduced GT and have detectable ANC with GT every 3 days.

Development of a Rapid Qualitative Screen for Anticoagulant Presence.

BACKGROUND: Direct oral anticoagulants (DOACs) and fondaparinux with stable pharmacokinetics are commonly used anticoagulants for outpatient care. Due to the lack of monitoring requirements, drug-specific assays are not available in most hospital laboratories, but drug levels are needed in some urgent/emergency situations. This study describes the development of a qualitative screen for the presence of DOAC or fondaparinux using coagulation tests found in most laboratories. METHODS: The DOAC screen is composed of a heparin anti-Xa activity assay and thrombin time (TT) assay. The STA®-Liquid-Anti-Xa assay calibrated with Stago Multi Hep® and STA®-TT were run on STA-R Max® analyzers. The anti-Xa activity and TT assays were repeated 5 times in samples of commercially available calibrators and controls for each drug: fondaparinux, dabigatran, rivaroxaban, apixaban, and edoxaban. Statistical analysis and correlations were performed for anti-Xa activity and TT results for each drug and pooled normal plasma. RESULTS: A significant correlation was found between heparin-calibrated anti-Xa levels and fondaparinux, rivaroxaban, apixiban, and edoxaban (r2 = 0.99-1.0). Dabigatran showed a strong linear correlation (r2 = 0.99) with TT. Anti-Xa levels >0.3 IU/mL and TT >25 seconds were determined as cutoffs at our lab for the detection of clinically relevant drug levels of factor Xa inhibitor and direct thrombin inhibitor, respectively. CONCLUSIONS: Our study demonstrates that commonly available heparin anti-Xa activity and TT assays can be used to qualitatively detect DOACs and fondaparinux and provides a method to establish a qualitative interpretation.

Optimizing electronic blood ordering and supporting administration workflows to improve blood utilization in the pediatric hospital setting.

BACKGROUND: Red blood cell wastage occurs when blood is discarded rather than transfused, and ineffective ordering results in unnecessary crossmatch procedures. We describe how a multimodal approach to redesigning electronic ordering tools improved blood utilization in a pediatric inpatient setting and how using innovative application of time series data analysis provides insights into intervention effectiveness, which can guide future process improvement cycles. METHODS: A multidisciplinary team used best practices and Toyota Production System methodology to redesign electronic blood ordering and improve administration processes. We analyzed crossmatch to transfusion ratio and red blood cell wastage time series data extracted from our laboratory information system and electronic health record. We used changepoint analysis to identify statistically discernible breaks in each time series, compatible with known interventions. We performed causal impact analysis on red blood cell wastage time series data to estimate blood wastage avoided due to the interventions. RESULTS: Changepoint analysis estimated an 11% decrease in crossmatch to transfusion ratio and a 77% decrease in red blood cell monthly wastage rate during the intervention period. Causal impact analysis estimated a 61% reduction in expected wastage compared to the scenario if the interventions had not occurred. DISCUSSION: Our results show that electronic health record design is an important factor in reducing waste and preventing unnecessary crossmatching, and that time series analysis can be a useful tool for evaluating the long-term impact of each stage of intervention in a longitudinal process redesign effort for the purpose of effectively targeting future improvement efforts.

How do we perform intrauterine transfusions?

BACKGROUND: Intrauterine transfusion (IUT) is an invasive but critical and potentially life-saving intervention for severe fetal anemia with demonstrated improvement in outcomes. The fetus is vulnerable to hemodynamic alterations and transfusion-related adverse events; therefore, special consideration must be given to blood component selection and modification. There is widespread IUT practice variability, and existing guidance primarily relies on expert opinion and single center experiences. STUDY DESIGN AND METHODS: Experts in Maternal Fetal Medicine, Pediatric Hematology, and Transfusion Medicine from centers across the United States, collectively performing about 120 IUT annually, offer a multidisciplinary perspective on the performance of IUT and preparation of blood components. This perspective includes strategies for identifying an at-risk fetus, communicating between disciplines, determining the necessary blood volume, selecting and processing blood components, documenting the procedure in medical record, and managing the neonate. RESULTS: Identifying an at-risk fetus relies on review of the clinical history, non-invasive monitoring, and laboratory evaluation. We recommend the use of relatively fresh, group O, cytomegalovirus-safe, freshly irradiated, red blood cells (RBC) that are Hemoglobin S negative and antigen-negative for any maternal antibody, if indicated. These RBC units should be concentrated to remove additives and increase the hematocrit thus minimizing fluctuations in fetal volume status. The units intended for IUT should be labeled clearly and the documentation of transfusion differentiated in the maternal medical record. DISCUSSION: An awareness of the technical, logistical, and regulatory considerations for IUT performance will facilitate improved communication and patient care, especially when rare units of RBC are required.

Red Blood Cell Transfusion: 2023 AABB International Guidelines.

Importance: Red blood cell transfusion is a common medical intervention with benefits and harms. Objective: To provide recommendations for use of red blood cell transfusion in adults and children. Evidence Review: Standards for trustworthy guidelines were followed, including using Grading of Recommendations Assessment, Development and Evaluation methods, managing conflicts of interest, and making values and preferences explicit. Evidence from systematic reviews of randomized controlled trials was reviewed. Findings: For adults, 45 randomized controlled trials with 20 599 participants compared restrictive hemoglobin-based transfusion thresholds, typically 7 to 8 g/dL, with liberal transfusion thresholds of 9 to 10 g/dL. For pediatric patients, 7 randomized controlled trials with 2730 participants compared a variety of restrictive and liberal transfusion thresholds. For most patient populations, results provided moderate quality evidence that restrictive transfusion thresholds did not adversely affect patient-important outcomes. Recommendation 1: for hospitalized adult patients who are hemodynamically stable, the international panel recommends a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (strong recommendation, moderate certainty evidence). In accordance with the restrictive strategy threshold used in most trials, clinicians may choose a threshold of 7.5 g/dL for patients undergoing cardiac surgery and 8 g/dL for those undergoing orthopedic surgery or those with preexisting cardiovascular disease. Recommendation 2: for hospitalized adult patients with hematologic and oncologic disorders, the panel suggests a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (conditional recommendations, low certainty evidence). Recommendation 3: for critically ill children and those at risk of critical illness who are hemodynamically stable and without a hemoglobinopathy, cyanotic cardiac condition, or severe hypoxemia, the international panel recommends a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (strong recommendation, moderate certainty evidence). Recommendation 4: for hemodynamically stable children with congenital heart disease, the international panel suggests a transfusion threshold that is based on the cardiac abnormality and stage of surgical repair: 7 g/dL (biventricular repair), 9 g/dL (single-ventricle palliation), or 7 to 9 g/dL (uncorrected congenital heart disease) (conditional recommendation, low certainty evidence). Conclusions and Relevance: It is good practice to consider overall clinical context and alternative therapies to transfusion when making transfusion decisions about an individual patient.

Current advances in 2022: A critical review of selected topics by the Association for the Advancement of Blood and Biotherapies (AABB) Clinical Transfusion Medicine Committee.

BACKGROUND: The Association for the Advancement of Blood and Biotherapies Clinical Transfusion Medicine Committee (CTMC) composes a summary of new and important advances in transfusion medicine (TM) on an annual basis. Since 2018, this has been assembled into a manuscript and published in Transfusion. STUDY DESIGN AND METHODS: CTMC members selected original manuscripts relevant to TM that were published electronically and/or in print during calendar year 2022. Papers were selected based on perceived importance and/or originality. References for selected papers were made available to CTMC members to provide feedback. Members were also encouraged to identify papers that may have been omitted initially. They then worked in groups of two to three to write a summary for each new publication within their broader topic. Each topic summary was then reviewed and edited by two separate committee members. The final manuscript was assembled by the first and senior authors. While this review is extensive, it is not a systematic review and some publications considered important by readers may have been excluded. RESULTS: For calendar year 2022, summaries of key publications were assembled for the following broader topics within TM: blood component therapy; infectious diseases, blood donor testing, and collections; patient blood management; immunohematology and genomics; hemostasis; hemoglobinopathies; apheresis and cell therapy; pediatrics; and health care disparities, diversity, equity, and inclusion. DISCUSSION: This Committee Report reviews and summarizes important publications and advances in TM published during calendar year 2022, and maybe a useful educational tool.

Causes of red blood cell loss during extracorporeal membrane oxygenation.

BACKGROUND: Pediatric patients on extracorporeal membrane oxygenation (ECMO) often receive repeated red blood cell (RBC) transfusions. This study aims to quantify and characterize causes of RBC loss on ECMO. METHODS: This retrospective, single-center, observational study includes 91 ECMO patients (age 1 day-20 years). An RBC loss index (RLI), equal to ml RBCs lost per liter of patient + circuit volume per hour, was calculated from the changes in hematocrit and transfused RBCs. To measure the contribution of RBC injury/activation, RBC extracellular vesicle (REV) generation was measured by flow cytometry. RESULTS: Median RLI on ECMO was 1.9 ml/L/h, 13-fold higher than normal RBC production rate (0.15 ml/L/h) and equivalent to a 4.6 drop in hematocrit/day. Median RBC loss was higher in patients who died (2.95 ml/L/h) versus survived (1.70 ml/L/h, p = .0008). RLI correlated with transfusion rate (r2  = 0.71); however, transfusion rate (ml/kg) underestimated RBC loss in patients with large changes in hematocrit and over-estimated RBC loss in neonates where the circuit volume is greater than the patient blood volume. In non-bleeding patients, intravascular hemolysis represented 16% of total RBC loss and diagnostic phlebotomy 24%, suggesting that ~60% of RBC loss was due to other causes. REV generation was increased sevenfold to ninefold during ECMO. DISCUSSION: RLI (ml/L/h) is a more reliable quantitative indicator of RBC loss than transfusion rate (ml/kg) for pediatric patients on ECMO. Phlebotomy and intravascular hemolysis only account for 40% of RBC loss in non-bleeding ECMO patients. High REV generation suggests sublethal damage and extravascular clearance may be a cause of RBC loss on ECMO.

How we approach transfusions in a patient with high risk of alloimmunization from McLeod phenotype.

McLeod phenotype-caused by the missing Xk protein-is a very rare red cell phenotype, one characteristic of McLeod syndrome, and sometimes associated with X-linked chronic granulomatous disease (CGD). Diagnosis of McLeod phenotype is important for appropriate transfusion management, because red blood cells from all healthy donors will have the Xk protein with its Kx antigen and can lead to red cell antibody formation without the ability to find compatible McLeod phenotype blood for transfusion. We offer a review and approach to diagnosis of the McLeod phenotype and special transfusion considerations.

Parental Refusals of Blood Transfusions from COVID-19 Vaccinated Donors for Children Needing Cardiac Surgery.

There is a growing trend of refusal of blood transfusions from COVID-19 vaccinated donors. We highlight three cases where parents have refused blood transfusions from COVID-19 vaccinated donors on behalf of their children in the setting of congenital cardiac surgery. These families have also requested accommodations such as explicit identification of blood from COVID-19 vaccinated donors, directed donation from a COVID-19 unvaccinated family member, or use of a non-standard blood supplier. We address the ethical challenges posed by these issues. We describe the current screening and safety processes for standard blood donation and explore the importance of donor anonymity and challenges with directed donation and non-standard blood suppliers. We present an ethical framework using the Best Interest Standard, the Zone of Parental Discretion, and the Harm Principle when considering these refusals. Finally, we provide recommendations for how to approach these requests as they potentially become more commonplace in pediatrics.

Transfusion-associated hyperkalemia in pediatric population: Analyses for risk factors and recommendations.

BACKGROUND: Transfusion-associated hyperkalemia (TAH) is a potentially life-threatening complication of red blood cell (RBC) transfusion. Previously, we reported features of RBC transfusions from 35 pediatric patients (TAH group) who had hyperkalemia with RBC transfusion in one-year period at four facilities. In this study, we used multivariate analyses and artificial intelligence to compare the TAH group to newly collected control group (non-TAH group) to identify factors associated with TAH occurrence. STUDY DESIGN: A review of RBC transfusion with TAH was compared to non-TAH group who did not develop TAH with RBC transfusion at each facility during the same one-year period. The non-TAH group included 12 patients each in 5 age groups. Wilcoxon rank-sum tests recursive feature elimination, least absolute shrinkage, and selection operator (LASSO), and other artificial intelligence techniques were employed to identify the most salient features associated with predicting specific clinical outcomes for TAH occurrence. RESULTS/FINDINGS: Pre-transfusion creatinine, comorbidities of kidney and/or liver dysfunctions, and total transfused volume within 12 h (tV-12) per kg and per estimated total blood volume (eTBV) showed statistically significant differences between TAH and non-TAH groups. Multivariate analysis revealed the biggest factor in TAH occurrence was tV-12/kg followed by age of RBC units. The thresholds of risks were tV-12/kg of 30 ml/kg, tV-12/eTBV of 30%, and RBC unit age of 7.95 days. CONCLUSIONS: The study findings suggest that the biggest factor on TAH occurrence is tV-12/kg. More importantly, 30% of eTBV transfusion could cause TAH in patients with multiple comorbidities.

Current advances in transfusion medicine 2021: A critical review of selected topics by the AABB Clinical Transfusion Medicine Committee.

BACKGROUND: Each year the AABB Clinical Transfusion Medicine Committee (CTMC) procures a synopsis highlighting new, important, and clinically relevant studies in the field of transfusion medicine (TM). This has been made available as a publication in Transfusion since 2018. METHODS: CTMC members reviewed and identified original manuscripts covering TM-related topics published electronically (ahead-of-print) or in print from December 2020 to December 2021. Selection of publications was discussed at committee meetings and chosen based on perceived relevance and originality. Next, committee members worked in pairs to create a synopsis of each topic, which was then reviewed by additional committee members. The first and senior authors assembled the final manuscript. Although this synopsis is extensive, it is not exhaustive, and some articles may have been excluded or missed. RESULTS: The following topics are included: blood products; convalescent plasma; donor collections and testing; hemoglobinopathies; immunohematology and genomics; hemostasis; patient blood management; pediatrics; therapeutic apheresis; and cell therapy. CONCLUSIONS: This synopsis highlights and summarizes recent key developments in TM and may be useful for educational purposes.

Benefits of lower neonatal platelet transfusion thresholds.

Degree of thrombocytopenia is not a predictor of bleeding risk in neonates, yet most platelet transfusions are given prophylactically in non-bleeding premature infants. Recent data support a lower platelet transfusion threshold of 25 × 109 /L in non-bleeding premature neonates and indicate that higher transfusion thresholds may be associated with harm including increased risk of death and bleeding. The mechanism of increased adverse events with higher platelet transfusion threshold is unknown, but considerations include adult platelets disrupting the neonatal hemostatic balance of hypoactive platelets in a hypercoagulable and fragile environment and having a pro-inflammatory effect.

Monitoring Hemostasis During Extracorporeal Life Support.

To balance the risk of bleeding versus circuit thrombosis during extracorporeal life support (ECLS), it is important to monitor anticoagulants and hemostasis. We evaluated the prothrombin time (PT), partial thromboplastin time (PTT), activated clotting time (ACT), and antifactor Xa heparin activity (aXa) correlation with changes in coagulation factor and heparin levels using in vitro and in vivo samples. aXa correlated with heparin (r = 0.97) and antithrombin (r = 0.98) but was unaffected by other parameters. PT correlated with coagulation factors (r = 0.88) but was minimally affected by heparin or other parameters. When single parameters were changed, ACT was insensitive to <0.5 U/ml heparin, correlated with coagulation factors (r = 0.99), and was affected by factor XII and platelets. When multiple parameters changed in vitro and in vivo, ACT was not correlated with heparin or coagulation factors. PTT correlated with heparin and coagulation factors individually but had low correlation when multiple parameters changed in vitro and in vivo. In conclusion, aXa is the most specific for heparin levels, and PT is most specific for coagulation factor levels making these assays well suited to monitor anticoagulation and hemostasis for patients on ECLS. PTT is highly variable when multiple parameters are changing in vitro and in vivo, but may be useful when aXa cannot be used because of interference. ACT is too insensitive to heparin, sensitive to too many other factors, and too imprecise to be useful for monitoring hemostasis during ECLS.

Filling in the gaps with non-standard body fluids.

OBJECTIVES: Body fluid specimens other than serum, plasma or urine are generally not validated by manufacturers, but analysis of these non-standard fluids can be important for clinical diagnosis and management. Laboratories, therefore, rely on the published literature to better understand the validation and implementation of such tests. This study utilized a data-driven approach to determine the clinical reportable range for 11 analytes, evaluated a total bilirubin assay, and assessed interferences from hemolysis, icterus, and lipemia in non-standard fluids. DESIGN AND METHODS: Historical measurements in non-standard body fluids run on a Beckman Coulter DxC800 were used to optimize population-specific clinical reportable ranges for albumin, amylase, creatinine, glucose, lactate dehydrogenase, lipase, total bilirubin, total cholesterol, total protein, triglyceride and urea nitrogen run on the Beckman Coulter AU680. For these 11 analytes, interference studies were performed by spiking hemolysate, bilirubin, or Intralipid® into abnormal serous fluids. Precision, accuracy, linearity, and stability of total bilirubin in non-standard fluids was evaluated on the Beckman Coulter AU680 analyzer. RESULTS: The historical non-standard fluid results indicated that in order to report a numeric result, 4 assays required no dilution, 5 assays required onboard dilutions and 2 assays required both onboard and manual dilutions. The AU680 total bilirubin assay is suitable for clinical testing of non-standard fluids. Interference studies revealed that of the 11 total AU680 analyte measurements on non-standard fluids, lipemia affected 1, icterus affected 3, and hemolysis affected 5. CONCLUSIONS: Chemistry analytes measured on the AU680 demonstrate acceptable analytical performance for non-standard fluids. Common endogenous interference from lipemia, icterus, and hemolysis (LIH) are observed and flagging rules based on LIH indices were developed to help improve the clinical interpretation of results.

SCF(FBXL3) ubiquitin ligase targets cryptochromes at their cofactor pocket.

The cryptochrome (CRY) flavoproteins act as blue-light receptors in plants and insects, but perform light-independent functions at the core of the mammalian circadian clock. To drive clock oscillations, mammalian CRYs associate with the Period proteins (PERs) and together inhibit the transcription of their own genes. The SCF(FBXL3) ubiquitin ligase complex controls this negative feedback loop by promoting CRY ubiquitination and degradation. However, the molecular mechanisms of their interactions and the functional role of flavin adenine dinucleotide (FAD) binding in CRYs remain poorly understood. Here we report crystal structures of mammalian CRY2 in its apo, FAD-bound and FBXL3-SKP1-complexed forms. Distinct from other cryptochromes of known structures, mammalian CRY2 binds FAD dynamically with an open cofactor pocket. Notably, the F-box protein FBXL3 captures CRY2 by simultaneously occupying its FAD-binding pocket with a conserved carboxy-terminal tail and burying its PER-binding interface. This novel F-box-protein-substrate bipartite interaction is susceptible to disruption by both FAD and PERs, suggesting a new avenue for pharmacological targeting of the complex and a multifaceted regulatory mechanism of CRY ubiquitination.