Red blood cell transfusion: a clinical practice guideline from the AABB*

DESCRIPTION: Although approximately 85 million units of red blood cells (RBCs) are transfused annually worldwide, transfusion practices vary widely. The AABB (formerly, the American Association of Blood Banks) developed this guideline to provide clinical recommendations about hemoglobin concentration thresholds and other clinical variables that trigger RBC transfusions in hemodynamically stable adults and children. METHODS: These guidelines are based on a systematic review of randomized clinical trials evaluating transfusion thresholds. We performed a literature search from 1950 to February 2011 with no language restrictions. We examined the proportion of patients who received any RBC transfusion and the number of RBC units transfused to describe the effect of restrictive transfusion strategies on RBC use. To determine the clinical consequences of restrictive transfusion strategies, we examined overall mortality, nonfatal myocardial infarction, cardiac events, pulmonary edema, stroke, thromboembolism, renal failure, infection, hemorrhage, mental confusion, functional recovery, and length of hospital stay. RECOMMENDATION 1: The AABB recommends adhering to a restrictive transfusion strategy (7 to 8 g/dL) in hospitalized, stable patients (Grade: strong recommendation; high-quality evidence). RECOMMENDATION 2: The AABB suggests adhering to a restrictive strategy in hospitalized patients with preexisting cardiovascular disease and considering transfusion for patients with symptoms or a hemoglobin level of 8 g/dL or less (Grade: weak recommendation; moderate-quality evidence). RECOMMENDATION 3: The AABB cannot recommend for or against a liberal or restrictive transfusion threshold for hospitalized, hemodynamically stable patients with the acute coronary syndrome (Grade: uncertain recommendation; very low-quality evidence). RECOMMENDATION 4: The AABB suggests that transfusion decisions be influenced by symptoms as well as hemoglobin concentration (Grade: weak recommendation; low-quality evidence).     

Red blood cell transfusion in autoimmune hemolytic anemia

PURPOSE OF REVIEW: Transfusion, in the setting of autoimmune hemolytic anemia, can be a complicated and potentially dangerous proposition. RECENT FINDINGS: The selection and delivery of an appropriate red blood cell unit must focus on several areas: (1) the laboratory detection of the autoantibody, (2) the detection of clinically significant red blood cell alloantibodies potentially masked by the autoantibodies, and (3) the selection and delivery of appropriate, although potentially incompatible, units. In addition, alternatives to red blood cell transfusion, specifically red blood cell substitutes, may also play an important role in the clinical treatment of these patients in the future. SUMMARY: In this article, we will review the most recent developments in the transfusion management of patients with autoimmune hemolytic anemia, specifically focusing on published articles between the period of May 2002 to April 2003.     

Red blood cell transfusion and outcomes in acute pulmonary embolism

Background and objective

Blood transfusion has been associated with adverse outcomes in certain conditions. This study investigates the prevalence and outcomes of red blood cell (RBC) transfusion in patients with acute pulmonary embolism (PE).

Methods

Retrospective study of consecutive patients from 2000 to 2012 admitted to a tertiary hospital with a primary diagnosis of acute PE. Transfusion status during the hospital admission was ascertained. Mortality was tracked from a state‐wide death database and analysed using multivariable modelling.

Results

A total of 73 patients (5% of all patients admitted with PE) received RBC transfusion during their admission. These patients were significantly older, had more co‐morbidities, worse haemodynamics, higher simplified pulmonary embolism severity index scores, and lower plasma sodium and haemoglobin (Hb) levels at admission. Unadjusted mortality for the transfused group was significantly higher at 30‐day (19% vs 4%, P < 0.001) and 6‐month (40% vs 10%, P < 0.001) follow‐up. Multivariable modelling showed RBC transfusion to be a significant independent predictor of mortality at 30‐day (odds ratio 3.06, 95% CI: 1.17–8.01, P = 0.02) and 6‐month (hazard ratio (HR) 1.97, 95% CI: 1.12–3.46, P = 0.02). Sensitivity analysis confirmed that transfused patients had higher mortality than non‐transfused patients in the subgroup of patients with Hb <100 g/L.

Conclusion

RBC transfusion in patients hospitalized with acute PE is rare and appears to be associated with increased risk of short‐ and long‐term mortality, independent of Hb level on admission. This finding underscores the need for future randomized controlled studies on the impact of RBC transfusion in the management of patients admitted with acute PE. [Correction added on 4 May 2018, after first online publication: the word ‘serum’ was changed to ‘plasma’ throughout the article where appropriate.]

     

Red blood cell polyagglutination: clinical aspects

Polyagglutination is the term applied to red blood cells (RBCs) that are agglutinated by almost all samples of human sera from adults but not by autologous serum or sera of newborns. The polyagglutinable state may be transient or persistent. Transient polyagglutinability results from the exposure of normally cryptic antigens by bacterial enzymatic activity during the course of an infectious process. RBCs are polyagglutinable because most sera from adults contain agglutinins for the exposed antigens. This type of polyagglutination can often be reproduced in vitro with bacterial culture fluids or isolated enzymes. Persistent polyagglutination may be a consequence of somatic mutation leading to a cellular lineage characterized by an enzyme deficiency that results in exposure of a normally cryptic antigen, Tn. Most human sera contain anti-Tn. Tn polyagglutination is regularly accompanied by leukopenia and thrombocytopenia and has been associated with leukemia. Other forms of persistent polyagglutination are due to the inheritance of rare blood groups or are associated with a hematologic dyscrasia.     

Red cell transfusion and alloimmunization in sickle cell disease

Red cell transfusion remains a critical component of care for acute and chronic complications of sickle cell disease. Randomized clinical trials demonstrated the benefits of transfusion therapy for prevention of primary and secondary strokes and postoperative acute chest syndrome. Transfusion for splenic sequestration, acute chest syndrome, and acute stroke are guided by expert consensus recommendations. Despite overall improvements in blood inventory safety, adverse effects of transfusion are prevalent among patients with sickle cell disease and include alloimmunization, acute and delayed hemolytic transfusion reactions, and iron overload. Judicious use of red cell transfusions, optimization of red cell antigen matching, and the use of erythrocytapheresis and iron chelation can minimize adverse effects. Early recognition and management of hemolytic transfusion reactions can avert poor clinical outcomes. In this review, we discuss transfusion methods, indications, and complications in sickle cell disease with an emphasis on alloimmunization.     

Red blood cell transfusion in the treatment and management of anaemia: the search for the elusive transfusion trigger

Therapeutic red blood cell (RBC) transfusion is widely utilized in the management of anaemia. Critically ill intensive care unit (ICU) patients in particular, as well as medical and haematology–oncology patients, are among the largest groups of users of RBC products. While anaemia is common in these patients, its treatment and management, including appropriate thresholds for RBC transfusion, remain controversial. We review here the function of RBCs in oxygen transport and physiology, with a view to their role in supporting and maintaining systemic tissue oxygenation. Adaptive and physiological compensatory mechanisms in the setting of anaemia are discussed, along with the limits of compensation. Finally, data from clinical studies will be examined in search of evidence for, or against, a clinically relevant transfusion trigger.     

Red blood cell alloimmunization in sickle cell disease: pathophysiology, risk factors, and transfusion management

Red blood cell transfusions have reduced morbidity and mortality for patients with sickle cell disease. Transfusions can lead to erythrocyte alloimmunization, however, with serious complications for the patient including life-threatening delayed hemolytic transfusion reactions and difficulty in finding compatible units, which can cause transfusion delays. In this review, we discuss the risk factors associated with alloimmunization with emphasis on possible mechanisms that can trigger delayed hemolytic transfusion reactions in sickle cell disease, and we describe the challenges in transfusion management of these patients, including opportunities and emerging approaches for minimizing this life-threatening complication.     

输血科在临床输血工作中的作用

<正>输血科肩负临床输血工作,是临床参与临床急救及危重患者救治的重点科室。为了进一步规范临床用血,提高血液使用效能,本文就如何科学、合理、安全用血进行剖析,特别是通过对临床输血流程科学合理的管理,加强输血科与临床用血科室沟通,把握临床用血指征,规范临床用血疗效评估,持续改进临床输血工作,提高临床用血质量,把安全输血提高到重要地位。1输血科要对临床医护人员进行输血相关知识的针对性培训     

医院输血科在输血质量管理中的实践探讨

<正>临床输血医学的迅速发展,给我们带来严峻的挑战!即如何保证输血质量,确保输血安全[1]。对拥有650张病床,年用血量6 000U的二等甲级综合医院的输血科来说,如何管理、提高输血质量是我们的工作重点。下面是我科近几年里实践探索和积累的部分经验,现报告如下。1积极开展创建活动,参加室间质评,提高输血质量2011年我院输血科申报了创建湖北省临床输血重点专科[2],参加了湖北省临检中心室间质量控制,从参加室间质控以来,每次质评(ABO正定型;     

临床输血病历管理与临床输血医疗纠纷的防范

目的：探讨在临床输血工作管理中,通过对临床输血病历的管理,达到提高临床输血安全性,防范因输血导致的医疗纠纷。方法：以《中华人民共和国献血法》及卫生部《医疗机构临床用血管理办法》、《临床输血技术规范》、《医院感染管理规范》为依据,制定医院临床输血病历的管理办法。对我院2005年1月～2006年9月临床住院患者输血病历进行检查分析。结果：2005年1月～2006年9月住院患者输血病历为2650例,检查了输血病历2321例,占总输血病历的87．6％,合格输血病历2109例,占检查输血病历90．9％,不合格输血病历212例,占检查输血病历9．1％。结论：通过对临床输血病历的检查,医护人员对临床输血管理相关的法律法规的认识,风险意识有所增加,提高了临床输血的安全性,起到了防范临床用血管理不善及输血传播病毒性疾病引起的医疗纠纷。     

输血前不规则抗体筛查与临床安全输血

目的：回顾性分析本院输血患者血型不规则抗体的检出情况,探讨输血前不规则抗体筛查的重要性和高危科室。方法：微柱凝胶法和聚凝胺法对需要输血的2500例患者血清进行不规则抗体筛检。结果：2500例申请输血的患者不规则抗体总阳性率为1.0%;微柱凝胶检出的敏感度为100%,聚凝胺法敏感度为88.0%,2种方法的敏感度差异具有统计学意义（P〈0.05）。肝病科、肛肠科以及肾病科不规则抗体检出阳性率占了总阳性率的80.0%。结论：微柱凝胶法进行输血前不规则抗体的筛检敏感度高,更有利于保证临床上的输血安全;对于肝病科、肛肠科以及肾病科等出现反复输血的科室,在输血前更应该进行不规则抗体的筛查,以减少输血风险。     

Red blood cell substitutes

Soluble polymerized haemoglobin (polyhaemoglobin) is now in a phase III clinical trials. Patients have received up to 20 units (10 litres) in trauma surgery and other surgery. Polyhaemoglobin can be stored for more than 1 year. Haemoglobin solutions have no blood group antigen and can be used as a 'universal donor' oxygen carrier. They can also be sterilized. With a circulation half-life of 24 hours they are undergoing trials for peri-operative use. For conditions with potential for ischaemia-reperfusion injuries, a new polyhaemoglobin-superoxide dismutase-catalase, which can reduce oxygen radicals, is being developed. Recombinant human haemoglobin has been tested in clinical trials, and a new type of recombinant human haemoglobin that has low affinity for nitric oxide is being developed for clinical trials. To increase the circulation time, artificial red blood cells have been prepared with a bilayer lipid membrane (haemoglobin liposomes) or with a biodegradable polymer membrane-like polylactide (haemoglobin nanocapsules). Synthetic chemicals such as perfluorochemicals are also being developed and tested in clinical trials as red blood cell substitutes.     

Red blood cell generation from human induced pluripotent stem cells: perspectives for transfusion medicine

Background

Ex vivo manufacture of red blood cells from stem cells is a potential means to ensure an adequate and safe supply of blood cell products. Advances in somatic cell reprogramming of human induced pluripotent stem cells have opened the door to generating specific cells for cell therapy. Human induced pluripotent stem cells represent a potentially unlimited source of stem cells for erythroid generation for transfusion medicine.

Design and Methods

We characterized the erythroid differentiation and maturation of human induced pluripotent stem cell lines obtained from human fetal (IMR90) and adult fibroblasts (FD-136) compared to those of a human embryonic stem cell line (H1). Our protocol comprises two steps: (i) differentiation of human induced pluripotent stem cells by formation of embryoid bodies with indispensable conditioning in the presence of cytokines and human plasma to obtain early erythroid commitment, and (ii) differentiation/maturation to the stage of cultured red blood cells in the presence of cytokines. The protocol dispenses with major constraints such as an obligatory passage through a hematopoietic progenitor, co-culture on a cellular stroma and use of proteins of animal origin.

Results

We report for the first time the complete differentiation of human induced pluripotent stem cells into definitive erythrocytes capable of maturation up to enucleated red blood cells containing fetal hemoglobin in a functional tetrameric form.

Conclusions

Red blood cells generated from human induced pluripotent stem cells pave the way for future development of allogeneic transfusion products. This could be done by banking a very limited number of red cell phenotype combinations enabling the safe transfusion of a great number of immunized patients.     

Red cell transfusion thresholds in myelodysplastic syndromes: a clinician survey to inform future clinical trials

Optimal red cell transfusion thresholds in myelodysplastic syndrome are not established. In this survey of 110 Australasian haematologists’ practice in myelodysplastic syndrome‐related anaemia, 92% of respondents set transfusion thresholds, and would typically transfuse at a haemoglobin <80 g/L aiming for a post‐transfusion haemoglobin 90–100 g/L, reflecting a restrictive transfusion strategy. Higher thresholds were typically used for patients with cardiovascular disease or anaemia symptoms. These results will inform the design of clinical trials comparing transfusion thresholds.