Prevention and treatment of infection in patients with an absent or hypofunctional spleen: A British Society for Haematology guideline.

Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen were published by the British Committee for Standards in Haematology in 1996 and updated in 2002 and 2011. With advances in vaccinations and changes in patterns of infection, the guidelines required updating. Key aspects included in this guideline are the identification of patients at risk of infection, patient education and information and immunisation schedules. This guideline does not address the non-infective complications of splenectomy or functional hyposplenism (FH). This replaces previous guidelines and significantly revises the recommendations related to immunisation. Patients at risk include those who have undergone surgical removal of the spleen, including partial splenectomy and splenic embolisation, and those with medical conditions that predispose to FH. Immunisations should include those against Streptococcus pneumoniae (pneumococcus), Neisseria meningitidis (meningococcus) and influenza. Haemophilus influenzae type b (Hib) is part of the infant immunisation schedule and is no longer required for older hyposplenic patients. Treatment of suspected or proven infections should be based on local protocols and consider relevant anti-microbial resistance patterns. The education of patients and their medical practitioners is essential, particularly in relation to the risk of serious infection and its prevention. Further research is required to establish the effectiveness of vaccinations in hyposplenic patients; infective episodes should be regularly audited. There is no single group ideally placed to conduct audits into complications arising from hyposplenism, highlighting a need for a national registry, as has proved very successful in Australia or alternatively, the establishment of appropriate multidisciplinary networks.

Tissue factor pathway inhibitor is a potential modifier of bleeding risk in factor XI deficiency.

BACKGROUND: Factor (F) XI deficiency is associated with increased bleeding risk in some individuals. Neither FXI levels nor clinical clotting assays predict the bleeding risk. Compared with controls, FXI-deficient bleeders have reduced clot formation, decreased fibrin network density, and increased susceptibility to fibrinolysis. Tissue factor pathway inhibitor (TFPI) was recently implicated as a modifying factor in individuals with bleeding of unknown cause. OBJECTIVES: To determine the potential of TFPI in modifying the bleeding risk in FXI-deficient individuals. METHODS: The effects of TFPI on thrombin generation and clot formation, structure, and fibrinolysis in FXI-deficient plasma were measured in vitro in the absence or presence of inhibitory anti-TFPI antibody or exogenous recombinant TFPIα. Total plasma TFPI concentration was measured in 2 independent cohorts of controls and FXI-deficient individuals classified as bleeders or nonbleeders (cohort 1: 10 controls and 16 FXI-deficient individuals; cohort 2: 48 controls and 57 FXI-deficient individuals) and correlated with ex vivo plasma clot formation and fibrinolysis parameters associated with bleeding risk. RESULTS: In an in vitro FXI deficiency model, inhibition of TFPI enhanced thrombin generation and clot formation, increased the network density, and decreased fibrinolysis, whereas an increase in TFPI had the opposite effects. Compared with controls, plasma from FXI-deficient bleeders had higher TFPI concentration. Total plasma TFPI concentrations correlated with parameters from ex vivo clotting and fibrinolysis assays that differentiate FXI-deficient bleeders and nonbleeders. CONCLUSION: Coagulation and fibrinolysis parameters that differentiate FXI-deficient nonbleeders and bleeders were altered by plasma TFPIα. Total plasma TFPI was increased in FXI-deficient bleeders. TFPI may modify the bleeding risk in FXI-deficient individuals.

Transfusion-related Acute Lung Injury: 36 Years of Progress (1985-2021).

The term transfusion-related acute lung injury (TRALI) was coined in 1985 to describe acute respiratory distress syndrome (ARDS) after transfusion, when another ARDS risk factor was absent; TRALI cases were mostly associated with donor leukocyte antibody. In 2001, plasma from multiparous donors was implicated in TRALI in a randomized controlled trial in Sweden. In 2003 and in many years thereafter, the U.S. Food and Drug Administration reported that TRALI was the leading cause of death from transfusion in the United States. In 2003, the United Kingdom was the first among many countries to successfully reduce TRALI using male-predominant plasma. These successes are to be celebrated. Nevertheless, questions remain about the mechanisms of non-antibody TRALI, the role of blood products in the development of ARDS in patients receiving massive transfusion, the causes of unusual TRALI cases, and how to reduce inaccurate diagnoses of TRALI in clinical practice. Regarding the latter, a study in 2013-2015 at 169 U.S. hospitals found that many TRALI diagnoses did not meet clinical definitions. In 2019, a consensus panel established a more precise terminology for clinical diagnosis: TRALI type I and TRALI type II are cases where transfusion is the likely cause, and ARDS are cases where transfusion is not the likely cause. For accurate diagnosis using these clinical definitions, critical care or pulmonary expertise is needed to distinguish between permeability versus hydrostatic pulmonary edema, to determine whether an ARDS risk factor is present, and, if so, to determine whether respiratory function was stable within the 12 hours before transfusion.

Missed irradiation of cellular blood components for vulnerable patients: Insights from 10 years of SHOT data.

BACKGROUND: Irradiation of cellular blood components is recommended for patients at risk of transfusion-associated graft-vs-host disease (TA-GvHD). Prestorage leucodepletion (LD) of blood components is standard in the UK since 1999. STUDY DESIGN AND METHODS: Analysis of 10 years' reports from UK national hemovigilance scheme, Serious Hazards of Transfusion (2010-2019), where patients failed to receive irradiated components when indicated according to British Society for Haematology guidelines (2011). RESULTS: There were 956 incidents of failure to receive irradiated components all due to errors. One hundred and seventy two incidents were excluded from analysis, 125 of 172 (72.7%) because of missing essential information. No cases of TA-GvHD were reported in this cohort. The 784 patients received 2809 components (number unknown for 67 incidents). Most failures occurred in patients treated with purine analogues (365) or alemtuzumab (69), or with a history of Hodgkin lymphoma (HL) (192). Together these make up 626 of 784 (79.9%). Poor communication is an important cause of errors. CONCLUSION: Leucodepletion appears to reduce the risk for TA-GvHD. None of 12 cases of TA-GvHD reported to SHOT prior to introduction of LD occurred in patients with conditions recommended for irradiated components by current guidelines. Irradiation indefinitely for all stages of HL is not based on good evidence and is a difficult guideline to follow. Further research on long-term immune function in HL is required. Variation between different national guidelines reflects the very limited evidence.

The haemoglobinopathy survey: The reality of transfusion practice in sickle cell disease and thalassaemia in England.

OBJECTIVES: To establish, in an unselected population of London haemoglobinopathy patients, transfusion requirements, blood antigens/alloantibodies, transfusion modalities, burden of transfusion reactions and donor exposure. BACKGROUND: Haemoglobinopathy patients are among the most highly transfused patient populations, and the overall population and number of patients on long-term transfusion programmes are increasing. To provide a safe and efficacious transfusion service for patients, it is important to understand current practice, morbidity associated with transfusion, efficacy of different transfusion modalities and geno-/phenotype requirements. METHODS: Data on 4451 transfusion episodes in 760 patients from 12 London hospitals were collected retrospectively over a 6-month period in 2011. RESULTS: Alloimmunisation prevalence was 17% for sickle cell disease (SCD) and 22% for thalassaemia, most commonly anti-Rh/Kell/Kpa /Cw . Rh phenotypes differed between SCD (Ro r 59.8%/R1 r 15.9%/R2 r 15.6%) and thalassaemia (R1 R1 29.6%/R1 r 28.4%/R1 R2 15.4%). Recording of pheno-/genotypes fell below recommendations. A 2-weekly manual exchange and 3-weekly automated exchange came closest to achieving presumptive targets. In adults with thalassaemia, the mean blood requirement was 36 units per year; for SCD, erythrocytapheresis was carried out every 7 weeks with 66 units; for manual exchange, it was 38 units every 4 weeks; and for simple transfusion, it was 30 units p.a. every 4 weeks. CONCLUSION: Transfusion modality choice was influenced by the resources available-children mostly received simple transfusions, and adults received erythrocytapheresis; the relationships between frequency of exchanges/transfusion modality/target HbA% were not simple, possibly reflecting the difference in recipient erythropoiesis and consequent transfusion modality selection bias; adherence to existing and current guidelines regarding geno-/phenotyping was limited; and alloimmunisation had a low incidence and high prevalence in both disorders.

Pulmonary complications of transfusion: Changes, challenges, and future directions.

The pulmonary complications of transfusion (TACO, TRALI and TAD) are the leading cause of transfusion-related mortality and major morbidity. Advance in this area is essential in improving transfusion safety. This review describes the drivers for change in haemovigilance practice, the influence of recent key publications and future directions.

The World Federation of Hemophilia Annual Global Survey 1999-2018.

INTRODUCTION: The World Federation of Hemophilia (WFH) strives to achieve care for all patients with inherited bleeding disorders through research, advocacy, capacity building and education. The WFH developed and implemented the Annual Global Survey (AGS), through which comprehensive demographic and treatment data on bleeding disorders are collected each year from its constituent non-governmental national organizations. AIM: To describe the development, methodology and achievements of the WFH AGS over the past 20 years. METHODS: The AGS is a yearly cross-sectional survey. Data are collected using a standardized form (available online and on paper), quality checked and reviewed, and published in English, French and Spanish. Over time, the AGS has been modified in response to changes in treatment landscape or emerging new issues. RESULTS: Over the past 20 years, the AGS has reported an increase in the number of countries participating in the survey, a tripling in the number of people identified with rare bleeding disorders and an increase in the amount of factor used to treat people with haemophilia. Yet, a large treatment inequity gap still exists across the globe. In response to this gap, the WFH has analysed the AGS reports which has stimulated further development in quality of care indicators, estimates of the global prevalence of haemophilia, patient-level data collection efforts like the World Bleeding Disorders Registry and the Gene Therapy Registry. CONCLUSION: The AGS has provided evidence to support research, programme planning and development activities of the WFH.

National comparative audit of blood transfusion: 2014 audit of transfusion services and practice in children and adults with sickle cell disease.

OBJECTIVES: To determine the organisational resources in place; what blood was being transfused, why, how, where, when and by whom; whether laboratory support and policies met standards for patients with sickle cell disease (SCD). BACKGROUND: SCD affects 14 000 people in the United Kingdom (UK). Standards and guidelines do not cover all aspects of transfusion in SCD and there are no data on their use; people may become very sick without warning presenting to non-specialist hospitals; blood services are increasingly supplying units for transfusion in SCD with little data on their use. METHODS: A retrospective audit of transfusion services/practice for people with SCD who had received a transfusion in January-July 2014 in participating hospitals in the UK and Republic of Ireland (ROI). RESULTS: Eighty-four hospitals submitted 1290 cases, 75% of cases came from 18 hospitals submitting 25 or more cases. Transfusions (91.2% [1164/1276]) were administered to patients with HbSS, 60% (732/1227) of patients needed Rh CE negative blood. Transfusion episodes (4528) were recorded, of which 84% were elective. Stroke prevention accounted for 42% of all transfusions; adults received 56% of transfusions of which 50% were automated red cell exchange (RCE), children received 44% of transfusions of which 87% were simple transfusions. CONCLUSIONS: There was a paucity of appropriate clinical management protocols, adequately trained staff and network arrangements. The high numbers of children being transfused, disparity in transfusion modality between children and adults and the high frequency of the CE negative Rh phenotype were noted.

Transfusion errors - can they be eliminated?

The Serious Hazards of Transfusion haemovigilance scheme has documented adverse transfusion incidents for 22 years. Transmission of infection (three in 2018), transfusion-related lung injury (one in 2018) and transfusion-associated graft-versus-host disease (none since 2012) are rare. Despite national recommendations, guidelines and protocols, most incidents more than 85% of incidents are still due to errors in the transfusion process. European regulation and mandatory competency assessments have been associated with a reduction in ABO-incompatible transfusion, but errors continue to put patients at risk. What can be done? Errors are reduced by the use of electronic identification systems. Exploration of human factors and ergonomics (HFE) results in amended approaches away from blaming individuals to a full review of the systems and environment. Research examining how transfusion is performed (work-as-done) compared to work-as-imagined (set out in protocols and guidelines) discovers where variability results in either resilience or error. All staff require HFE training, but this should be alongside employment of suitably qualified and experienced HFE professionals. Good teamwork is key and is undermined by insufficient staffing and poor morale. The five choosing wisely recommendations for transfusion (to ensure appropriate use) need to be widely disseminated to medical staff in all specialties to ensure patients participate in the decision-making.

Electronic identification systems reduce the number of wrong components transfused.

BACKGROUND: Errors in hospital transfusion may cause wrong (blood) components to be transfused. This study assessed the value of electronic identification systems (EISs) in reducing wrong component transfusions (WCTs). METHODS: UK hospitals reporting to Serious Hazards of Transfusion were invited to complete an electronic survey about transfusion including the use of EISs. Further information was requested for WCTs and near-miss WCTs. RESULTS: A response rate of 93 of 222 (42%) hospitals accounted for 38% of UK blood component issues in 2015 and 2016. Thirty-three of 93 (35%) hospitals employ manual procedures and 16 (17%) use EISs throughout the transfusion process; most of the remainder use EISs for blood collection only. Fifty-seven WCTs were identified in approximately two million blood components. The primary error was at blood draw and sample labeling (3), blood collection (15), and administration (2); the remainder were mostly blood bank errors. No WCTs occurred with blood draw and sample labeling or administration with use of EISs. Three WCTs occurred with EISs for blood collection due to incorrect processes for emergency transfusions of group O blood without any adverse effects. Seventeen WCTs occurred with manual processes; one was an ABO-incompatible red blood cell transfusion resulting in renal impairment. Near-miss WCTs were also more frequent with manual procedures than EISs at blood draw and sample labeling and blood collection. CONCLUSIONS: This is the first multicenter study to demonstrate a lower incidence of WCTs and near-miss WCTs with EISs compared to manual processes, and highlights some limitations of both manual and EIS procedures.

Revised international surveillance case definition of transfusion-associated circulatory overload: a classification agreement validation study.

BACKGROUND: Transfusion-associated circulatory overload (TACO) is a major cause of transfusion-related morbidity and mortality in countries with well developed transfusion services. The International Society of Blood Transfusion, the International Haemovigilance Network, and AABB (formerly American Association of Blood Banks), have developed and validated a revised definition of TACO. METHODS: International Haemovigilance Network-member haemovigilance systems (Australia, Austria, Denmark, Finland, Greece, India, Ireland, Italy, Japan, Malta, Netherlands, New Zealand, Norway, Slovenia, United Kingdom and United States) provided cases of respiratory complications categorised by their systems, including clinical parameters listed in the 2017 draft definition (part 1). Individual transfusion professionals were then invited to assess 24 case descriptions according to the draft definition (part 2). Positive and negative agreement and inter-rater agreement (κ) were calculated. Based on validation results, cases were reanalysed and slight adjustments made to yield the final 2018 TACO definition. FINDINGS: In part 1, 16 (44%) of 36 haemovigilance systems provided 178 cases, including 126 TACO cases. By use of the 2018 definition, 96 (76%) of 126 cases of TACO were in positive agreement. 19 (37%) of 52 cases were recognised as non-TACO respiratory complications. In part 2 (47 experts from 20 countries), moderate all-case agreement (κ=0·43) and TACO-specific agreement (κ=0·54) were observed. Excluding cases missing some clinical information (eg, N terminal pro-brain natriuretic peptide, distinctive chest x-ray findings, and relationship with existing respiratory co-morbidities like pneumonia and chronic obstructive pulmonary disease) improved all-case agreement to κ=0·50 (moderate) and κ=0·65 (good) for TACO cases. INTERPRETATION: The two-part validation exercise showed that the revised 2018 TACO surveillance case definition captures 76% of cases endorsed as TACO by participating haemovigilance systems. This definition can become the basis for internationally consistent surveillance reporting and contribute towards increased awareness and mitigation of TACO. Further research will require reporting more complete clinical information to haemovigilance systems and should focus on improved distinction between TACO and other transfusion respiratory complications. FUNDING: International Society of Blood Transfusion, International Haemovigilance Network, and AABB.

A consensus redefinition of transfusion-related acute lung injury.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is a serious complication of blood transfusion and is among the leading causes of transfusion-related morbidity and mortality in most developed countries. In the past decade, the pathophysiology of this potentially life-threatening syndrome has been increasingly elucidated, large cohort studies have identified associated patient conditions and transfusion risk factors, and preventive strategies have been successfully implemented. These new insights provide a rationale for updating the 2004 consensus definition of TRALI. STUDY DESIGN AND METHODS: An international expert panel used the Delphi methodology to develop a redefinition of TRALI by modifying and updating the 2004 definition. Additionally, the panel reviewed issues related to TRALI nomenclature, patient conditions associated with acute respiratory distress syndrome (ARDS) and TRALI, TRALI pathophysiology, and standardization of reporting of TRALI cases. RESULTS: In the redefinition, the term "possible TRALI" has been dropped. The terminology of TRALI Type I (without an ARDS risk factor) and TRALI Type II (with an ARDS risk factor or with mild existing ARDS) is proposed. Cases with an ARDS risk factor that meet ARDS diagnostic criteria and where respiratory deterioration over the 12 hours before transfusion implicates the risk factor as causative should be classified as ARDS. TRALI remains a clinical diagnosis and does not require detection of cognate white blood cell antibodies. CONCLUSIONS: Clinicians should report all cases of posttransfusion pulmonary edema to the transfusion service so that further investigation can allow for classification of such cases as TRALI (Type I or Type II), ARDS, transfusion-associated circulatory overload (TACO), or TRALI or TACO cannot distinguish or an alternate diagnosis.

Abnormal plasma clot formation and fibrinolysis reveal bleeding tendency in patients with partial factor XI deficiency.

Individuals with factor XI (FXI) deficiency have a variable bleeding risk that cannot be predicted from plasma FXI antigen or activity. This limitation can result in under- or overtreatment of patients and risk of bleeding or thrombosis. Previously, plasma clot fibrinolysis assays showed sensitivity to bleeding tendency in a small cohort of patients with severe FXI deficiency. Here, we determined the ability of plasma clot formation, structure, and fibrinolysis assays to predict bleeding tendency in a larger, independent cohort of patients with severe and partial FXI deficiency. Patients were characterized as nonbleeders or bleeders based on bleeding after tonsillectomy and/or dental extraction before diagnosis of FXI deficiency. Blood was collected in the absence or presence of the contact pathway inhibitor corn trypsin inhibitor (CTI). Clotting was triggered in platelet-poor plasma with tissue factor, CaCl2, and phospholipids in the absence and presence of thrombomodulin or tissue plasminogen activator. Clot formation and fibrinolysis were assessed by turbidity and confocal microscopy. CTI-treated plasmas from bleeders showed significantly reduced clot formation and decreased resistance to fibrinolysis compared with plasmas from controls or nonbleeders. Differences were enhanced in the presence of CTI. A model that combines activated partial thromboplastin time with the rate of clot formation and area under the curve in fibrinolysis assays identifies most FXI-deficient bleeders. These results show assays with CTI-treated platelet-poor plasma reveal clotting and clot stability deficiencies that are highly associated with bleeding tendency. Turbidity-based fibrinolysis assays may have clinical utility for predicting bleeding risk in patients with severe or partial FXI deficiency.