Problems with precaution: the transfusion medicine experience.

The precautionary principle is a dominant paradigm governing risk-based decision-making. Today, there are increasing pressures to re-examine aggressive precautionary approaches, and to assess how the principle should be applied in the modern system. In this paper, we examined three key applications of precautionary approaches in the field of transfusion medicine to provide insight into the risks and benefits of these approaches. The three case studies examined were the donor deferral policies to safeguard against transfusion transmission of human immunodeficiency virus, variant Creutzfeldt-Jacob disease, and, lastly, xenotropic murine leukemia virus-related virus. Characterization of precautionary applications was conducted using an embedded case study design. Our findings indicate that transfusion transmission mitigation strategies have become increasingly aggressive in the face of theoretical risks. In contrast, the review processes for implementation and reversal of precautionary policies have been slow, and historical donor deferral policies are still in place today. Application of precautionary approaches has proved challenging with both benefits and pitfalls. In light of emerging threats to the blood system, policy-makers should consider the implementation of frameworks to guide the appropriate application of precaution in transfusion medicine in the future.

An International Registry of Granulocyte Transfusions.

INTRODUCTION: Granulocyte transfusions are used to either treat or prevent life-threatening infections in neutropenic patients. Current evidence from clinical trials does not support or reject efficacy, nor guide practice. METHODS: A group of investigators have led the efforts to create an online registry to gather information on granulocyte transfusion practices from as broad a range of international settings. The data forms were adapted from an on-going study in England for electronic data management. Data is collected at the time of the request for granulocytes, weekly, at 28 days, and at 6 months. Information collected includes donor, granulocyte unit, patient and illness characteristics, and outcomes. RESULTS: The PROspective GRanulocyte usage and outcomEs Survey (ProGrES) is currently open for data entry. Centres across the UK have collected data on 80 subjects. Five institutions from 4 countries (2 from the US, 1 each from Brazil, and national services in Canada and France) are in the process of joining the study. Other countries have expressed interest. CONCLUSION: It is feasible to develop an international registry of granulocyte transfusions to characterise current practices and describe outcomes. This registry would provide a platform to explore the relationship between intervention and outcomes, and to generate evidence to inform granulocyte transfusion efficacy.

Age of transfused blood in critically ill adult trauma patients: a prespecified nested analysis of the Age of Blood Evaluation randomized trial.

BACKGROUND: Blood transfusion is common in the resuscitation of patients with traumatic injury. However, the clinical impact of the length of storage of transfused blood is unclear in this population. STUDY DESIGN AND METHODS: We undertook a prespecified nested analysis of 372 trauma victims of the 2510 critically ill patients from 64 centers treated as part of the Age of Blood Evaluation (ABLE) randomized controlled trial. Patients were randomized according to their trauma status to receive either a transfusion of fresh blood stored not more than 7 days or standard-issue blood. Our primary outcome was 90-day all-cause mortality. RESULTS: Overall, 186 trauma patients received fresh blood and 186 received standard-issue blood. Adherence to transfusion protocol was 94% (915/971) for all fresh blood transfused and 100% (753/753) for all standard-issue blood transfused. Mean ± SD blood storage duration was 5.6 ± 3.8 days in the fresh group and 22.7 ± 8.4 days in the standard-issue group (p < 0.001). Ninety-day mortality in the fresh group was 21% (38/185), compared to 16% (29/184) in the standard-issue group, with an unadjusted absolute risk difference of 5% (95% confidence interval [CI], -3.1 to 12.6) and an adjusted absolute risk difference of 2% (95% CI, -3.5 to 6.8). CONCLUSION: In critically ill trauma patients, transfusion of fresh blood did not decrease 90-day mortality or secondary outcomes, a finding similar to the overall population of the ABLE trial.

Transfusion Patterns in All Patients Admitted to the Intensive Care Unit and in Those Who Die in Hospital: A Descriptive Analysis.

While it is known that the use of health care resources increases at the end of life in patients admitted to the Intensive Care Unit (ICU), the allocation of blood products at the end of life has not been described. The objective of this study was to describe overall transfusion patterns in the ICU, and specifically in patients who die in hospital. We conducted a retrospective cohort study of adult patients admitted to the ICU of a university-affiliated hospital, who were discharged or died between November 1, 2006 and June 30, 2012. During the study period, 10,642 patients were admitted at least once to the ICU. Of these patients, 4079 (38.3%) received red blood cells (RBCs), plasma or platelets in the ICU. The ICU mortality rate was 28.1% and in-hospital mortality rate was 32.3%. Among 39,591 blood product units transfused over the course of the study in the ICU (18,144 RBC units, 16,920 plasma units and 4527 platelet units), 46.2% were administered to patients who later died within the same hospitalization (41.2% of RBCs, 50.4% of plasma and 50.8% of platelets). Of all blood product units (RBCs, plasma and platelets) administered in the ICU over the study period, 11% were given within the last 24 hours before death. A large proportion of blood products used in the ICU are administered to patients who ultimately succumb to their illness in hospital, and many of these blood units are given in close proximity to death.

Platelet transfusion: a clinical practice guideline from the AABB.

BACKGROUND: The AABB (formerly, the American Association of Blood Banks) developed this guideline on appropriate use of platelet transfusion in adult patients. METHODS: These guidelines are based on a systematic review of randomized, clinical trials and observational studies (1900 to September 2014) that reported clinical outcomes on patients receiving prophylactic or therapeutic platelet transfusions. An expert panel reviewed the data and developed recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. RECOMMENDATION 1: The AABB recommends that platelets should be transfused prophylactically to reduce the risk for spontaneous bleeding in hospitalized adult patients with therapy-induced hypoproliferative thrombocytopenia. The AABB recommends transfusing hospitalized adult patients with a platelet count of 10 × 109 cells/L or less to reduce the risk for spontaneous bleeding. The AABB recommends transfusing up to a single apheresis unit or equivalent. Greater doses are not more effective, and lower doses equal to one half of a standard apheresis unit are equally effective. (Grade: strong recommendation; moderate-quality evidence). RECOMMENDATION 2: The AABB suggests prophylactic platelet transfusion for patients having elective central venous catheter placement with a platelet count less than 20 × 109 cells/L. (Grade: weak recommendation; low-quality evidence). RECOMMENDATION 3: The AABB suggests prophylactic platelet transfusion for patients having elective diagnostic lumbar puncture with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 4: The AABB suggests prophylactic platelet transfusion for patients having major elective nonneuraxial surgery with a platelet count less than 50 × 109 cells/L. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 5: The AABB recommends against routine prophylactic platelet transfusion for patients who are nonthrombocytopenic and have cardiac surgery with cardiopulmonary bypass. The AABB suggests platelet transfusion for patients having bypass who exhibit perioperative bleeding with thrombocytopenia and/or evidence of platelet dysfunction. (Grade: weak recommendation; very-low-quality evidence). RECOMMENDATION 6: The AABB cannot recommend for or against platelet transfusion for patients receiving antiplatelet therapy who have intracranial hemorrhage (traumatic or spontaneous). (Grade: uncertain recommendation; very-low-quality evidence).

Platelet transfusion: a systematic review of the clinical evidence.

BACKGROUND: Platelet (PLT) transfusion is indicated either prophylactically or therapeutically to reduce the risk of bleeding or to control active bleeding. Significant uncertainty exists regarding the appropriate use of PLT transfusion and the optimal threshold for transfusion in various settings. We formulated 12 key questions to assess the role of PLT transfusion. STUDY DESIGN AND METHODS: We performed a systematic review (SR) of randomized controlled trials (RCTs) and observational studies. A comprehensive search of PubMed, Web of Science, and Cochrane registry of controlled trials was performed. Methodologic quality of included studies was assessed and a meta-analysis was performed if more than two studies with similar designs were identified for a specific question. RESULTS: Seventeen RCTs and 55 observational studies were included in the final SR. Results from RCTs showed a beneficial effect of prophylactic compared with therapeutic transfusion for the prevention of significant bleeding in patients with hematologic disorders undergoing chemotherapy or stem cell transplantation. We found no difference in significant bleeding events related to the PLT count threshold for transfusion or the dose of PLTs transfused. Overall methodologic quality of RCTs was moderate. Results from observational studies showed no evidence that PLT transfusion prevented significant bleeding in patients undergoing central venous catheter insertions, lumbar puncture, or other surgical procedures. The methodologic quality of observational studies was very low. CONCLUSION: We provide a comprehensive assessment of evidence on the use of PLT transfusions in a variety of clinical settings. Our report summarizes current knowledge and identifies gaps to be addressed in future research.

Effectiveness and safety of thiotepa as conditioning treatment prior to stem cell transplant in patients with central nervous system lymphoma.

BACKGROUND: Thiothepa is a cytostatic agent used in managing solid malignancies, and also as conditioning treatment before hematopoietic stem cell transplantation [HSCT]. This systematic review summarizes evidence on its effectiveness and safety, in patients with central nervous system [CNS] lymphoma. METHODS: We searched 3 databases for clinical studies. When feasible, we performed meta-analyses. RESULTS: We identified 13 eligible studies, none of which with a priori controls. So data synthesis focused on the 226 patients who received thiotepa. Based on pooled estimates, 75.9% of thiotepa-treated patients achieved a complete remission (95% confidence interval [CI] = 67.5-82.8), and 61.7% had a progression-free survival for up to 125 months post-treatment (95% CI = 49.4-72.7). However, 25.5% relapsed, 24.6% experienced infection, and 13.2% experienced neurotoxicity. DISCUSSION: Thiotepa-based conditioning followed by HSCT may be effective in most CNS lymphoma patients, with a manageable toxicity profile. But adequately powered randomized trials are needed to better evaluate and isolate the effects of thiotepa.

Blood component transfusion in critically ill patients.

PURPOSE OF REVIEW: This review summarizes the current evidence base for commonly transfused blood components with a particular focus on the nonacutely bleeding patient. RECENT FINDINGS: There remains little definitive evidence to guide transfusion practices in the critically ill. The most rigorous evidence to guide red blood cell (RBC) transfusion practice is derived from the Transfusion in Critical Care Trial (TRICC Trial) that was published in 1999. Specific subgroups of patients may be at particular risk of the adverse effects of anemia, and require further study. There are no randomized controlled trials addressing clinically important outcomes evaluating frozen plasma, platelet thresholds, or impaired platelet activity in the critically ill. SUMMARY: As all blood components have some level of risk, the general approach to transfusion should be one of minimization. For the nonacutely bleeding critically ill patient, a RBC transfusion trigger of 70 g/l is clinically acceptable. For patients at potentially higher risk of adverse effects related to anemia such as those with septic shock, severe and/or acute ischemic heart disease, or brain injury, a higher threshold (80-90 g/l) may be considered. There is insufficient evidence to recommend specific thresholds for transfusion of frozen plasma or platelets in the critically ill.

The effect of rituximab on vaccine responses in patients with immune thrombocytopenia.

B-cell depletion may impair vaccine responses and increase infection risk in patients with immune thrombocytopenia (ITP). We investigated the effects of rituximab on antibody and cellular responses to Streptococcus pneumoniae polysaccharide and Haemophilus influenzae type b (Hib) vaccines in ITP patients. Of 60 patients in the main trial, 24 patients received both vaccines 6 months after rituximab (n = 17) or placebo (n = 7). Among 20 evaluable patients, 3 of 14 (21%) in the rituximab group and 4 of 6 (67%) in the placebo group achieved a fourfold increase in anti-pneumococcal antibodies (P = .12). For anti-Hib antibodies, 4 of 14 (29%) and 5 of 6 (83%), respectively, achieved a fourfold increase (P < .05). Fewer patients in the rituximab group demonstrated Hib killing (2 of 14 [14%], 5 of 6 [83%], P < .05). Three of 14 rituximab-treated patients failed to respond to vaccines by any criteria. After vaccinations, preplasma cell blasts and interferon-γ-secreting T cells were reduced in rituximab-treated patients. Antibody responses were impaired for at least 6 months after rituximab. Cellular immunity was reduced in parallel with depleted B-cell pools. These findings have implications for the timing of vaccinations and the mechanism of infection after rituximab in ITP patients.

A cross-country comparison of intensive care physicians' beliefs about their transfusion behaviour: a qualitative study using the Theoretical Domains Framework.

BACKGROUND: Evidence of variations in red blood cell transfusion practices have been reported in a wide range of clinical settings. Parallel studies in Canada and the United Kingdom were designed to explore transfusion behaviour in intensive care physicians. The aim of this paper is three-fold: first, to explore beliefs that influence Canadian intensive care physicians' transfusion behaviour; second, to systematically select relevant theories and models using the Theoretical Domains Framework (TDF) to inform a future predictive study; and third, to compare its results with the UK study. METHODS: Ten intensive care unit (ICU) physicians throughout Canada were interviewed. Physicians' responses were coded into theoretical domains, and specific beliefs were generated for each response. Theoretical domains relevant to behaviour change were identified, and specific constructs from the relevant domains were used to select psychological theories. The results from Canada and the United Kingdom were compared. RESULTS: Seven theoretical domains populated by 31 specific beliefs were identified as relevant to the target behaviour. The domains Beliefs about capabilities (confident to not transfuse if patients' clinical condition is stable), Beliefs about consequences (positive beliefs of reducing infection and saving resources and negative beliefs about risking patients' clinical outcome and potentially more work), Social influences (transfusion decision is influenced by team members and patients' relatives), and Behavioural regulation (wide range of approaches to encourage restrictive transfusion) that were identified in the UK study were also relevant in the Canadian context. Three additional domains, Knowledge (it requires more evidence to support restrictive transfusion), Social/professional role and identity (conflicting beliefs about not adhering to guidelines, referring to evidence, believing restrictive transfusion as professional standard, and believing that guideline is important for other professionals), and Motivation and goals (opposing beliefs about the importance of restrictive transfusion and compatibility with other goals), were also identified in this study. Similar to the UK study, the Theory of Planned Behaviour, Social Cognitive Theory, Operant Learning Theory, Action Planning, and Knowledge-Attitude-Behaviour model were identified as potentially relevant theories and models for further study. Personal project analysis was added to the Canadian study to explore the Motivation and goals domain in further detail. CONCLUSIONS: A wide range of beliefs was identified by the Canadian ICU physicians as likely to influence their transfusion behaviour. We were able to demonstrate similar though not identical results in a cross-country comparison. Designing targeted behaviour-change interventions based on unique beliefs identified by physicians from two countries are more likely to encourage restrictive transfusion in ICU physicians in respective countries. This needs to be tested in future prospective clinical trials.

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).

The conundrum of persistent inappropriate use of frozen plasma.

Frozen plasma (FP) is commonly used for the treatment of bleeding or the prevention of bleeding in critically ill patients, but clinical evidence to help aid the critical care clinician make decisions on whether to transfuse or not is at present limited. Despite the limited evidence, it appears FP is administered not infrequently in the absence of bleeding or with no required procedure when the international normalized ratio (INR) is essentially normal (<1.5) or only mildly deranged (<2.5). The study by Stanworth and colleagues in a recent issue of Critical Care raises awareness of FP transfusion use in the critically ill, should prompt a consideration of curbing its use when it is not clearly appropriate, and illustrates the need for future high quality evidence to guide FP use in the critically ill when the risk:benefit ratio is less clear.

Blood conservation strategies to reduce the need for red blood cell transfusion in critically ill patients.

Anemia commonly affects critically ill patients. The causes are multifactorial and include acute blood loss, blood loss from diagnostic testing and blunted red blood cell production. Blood transfusions are frequently given to patients in intensive care units to treat low hemoglobin levels due to either acute blood loss or subacute anemia associated with critical illness. Although blood transfusion is a life-saving therapy, evidence suggests that it may be associated with an increased risk of morbidity and mortality. A number of blood conservation strategies exist that may mitigate anemia in hospital patients and limit the need for transfusion. These strategies include the use of hemostatic agents, hemoglobin substitutes and blood salvage techniques, the reduction of blood loss associated with diagnostic testing, the use of erythropoietin and the use of restrictive blood transfusion triggers. Strategies to reduce blood loss associated with diagnostic testing and the use of hemostatic agents and erythropoietin result in higher hemoglobin levels, but they have not been shown to reduce the need for blood transfusions or to improve clinical outcomes. Lowering the hemoglobin threshold at which blood is transfused will reduce the need for transfusions and is not associated with increased morbidity or mortality among most critically ill patients without active cardiac disease. Further research is needed to determine the potential roles for other blood conservation strategies.

Prophylactic platelet transfusions: which dose is the best dose? A review of the literature.

Routine platelet transfusions for patients with acute leukemia were introduced in the early 1960s, and since then platelet use has increased steadily. Despite widespread use, good clinical evidence supporting prophylactic platelet transfusions is limited, and there are very few studies that have examined the dose for prophylactic platelet transfusions. Review of the platelet dose used in both early studies of routine platelet transfusions and more recent clinical trials of platelet transfusions shows wide variation in dosing, which is also reflected in clinical practice. As such, only limited recommendations for platelet dose have been forthcoming from consensus conferences or guidelines. The results from 3 recent clinical trials and a mathematical model examining the dose for prophylactic platelet transfusions suggest that lower dose transfusions may decrease the total number of platelets transfused; however, no definitive conclusions about the optimal platelet dose can be reached as these trials were not designed to evaluate bleeding outcomes or total platelet utilization. Future large clinical trials of platelet dose, which examine these critical outcomes, are required. Only with these results can the optimal platelet dose be determined.