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).(AU)

Treatment decision-making among Canadian youth with severe haemophilia: a qualitative approach.

The first generation of young men using primary prophylaxis is coming of age. Important questions regarding the management of severe haemophilia with prophylaxis persist: Can prophylaxis be stopped? At what age? To what effect? Can the regimen be individualized? The reasons why some individuals discontinue or poorly comply with prophylaxis are not well understood. These issues have been explored using predominantly quantitative research approaches, yielding little insight into treatment decision-making from the perspectives of persons with haemophilia (PWH). Positioning the PWH as a source of expertise about their condition and its management, we undertook a qualitative study: (i) to explore and understand the lived experience of young men with severe haemophilia A or B and (ii) to identify the factors and inter-relationships between factors that affect young men's treatment decision-making. This manuscript reports primarily on the second objective. A modified Straussian, grounded theory methodology was used for data collection (interviews) and preliminary analysis. The study sample, youth aged 15-29, with severe haemophilia A or B, was chosen selectively and recruited through three Canadian Haemophilia Treatment Centres. We found treatment decision-making to be multi-factorial and used the Framework method to analyze the inter-relationships between factors. A typology of four distinct approaches to treatment was identified: lifestyle routine prophylaxis, situational prophylaxis, strict routine prophylaxis and no prophylaxis. Standardized treatment definitions (i.e.: 'primary' and 'secondary', 'prophylaxis') do not adequately describe the ways participants treat. Naming the variation of approaches documented in this study can improve PWH/provider communication, treatment planning and education.

First analysis of 10-year trends in national factor concentrates usage in haemophilia: data from CHARMS, the Canadian Hemophilia Assessment and Resource Management System.

The Canadian Hemophilia Assessment and Resource Management System (CHARMS) tracks factor concentrates (FC) from the sole suppliers, Canadian Blood Services (CBS) and Hema-Quebec (HQ), to hospitals and to patients' homes. Patients FC infusion data are entered into CHARMS at Canadian Hemophilia Treatment Centres (HTCs) then exported to the national database (CentrePoint). From 2000 to 2009, 2260 registered haemophilia A or B patients received FVIII (1,009,097,765 IU) and FIX (272,406,859 IU). Over 91% of FVIII and over 84% of FIX was infused at home. Utilization of FVIII progressively increased; this was accounted for by an increase in the number of patients treated (r = 0.97; P < 0.001), there being a linear relationship between the increase in utilization and the increase in number of patients treated (P < 0.001). There was also a correlation with the annual amount used per patient (r = 0.95; P < 0.001). Utilization of FIX did not increase over time. The highest proportional utilization of both FVIII and FIX was for prophylaxis, and this proportion progressively increased being, in year 10 (2009), 77% and 66% for FVIII and FIX respectively. The proportion used for bleeding remained steady; in year 10 that proportion was 14% for FVIII and 26% for FIX, the use per patient for bleeding decreasing. The HTC-based CHARMS tracking system is essential, in Canada, for analysing indications for infusion, for predicting utilization and planning for future needs.

Implementation and public acceptability: lessons from food irradiation and how they might apply to pathogen reduction in blood products.

BACKGROUND AND OBJECTIVES: The issues around food irradiation (FI) have both similarities and differences to pathogen reduction (PR) in blood products. We performed a systematic search of the FI literature to identify lessons that could help to inform the implementation of pathogen reduction technology for blood products. METHODS: A comprehensive literature search was performed in EMBASE. MEDLINE, PSYCHINFO, CINAL and Physiological Abstracts for articles related to FI that met predefined eligibility criteria. A coding scheme was developed by the investigators, and relevant information from the articles was coded using NVivo 9. Reports for each code were generated and summarized. RESULTS: One thousand two hundred and sixty-six articles were identified by the broad search, and 50 met the study eligibility criteria for inclusion. The implementation of FI was slow and has been met by significant controversy, sparked by concerns from the public and social groups about the acceptability of irradiated food. Numerous factors influenced public acceptability including: demographic factors; perceptions of safety and risk; endorsement of and trust in the FI industry and social institutions that serve as opinion leaders; knowledge and the provision of scientific information including benefits and cost; and the availability of choice. CONCLUSION: There are a number of lessons from the FI literature that may be generalizable to the implementation of PR of blood products. Based on findings from this study, six recommendations are made to facilitate public implementation of this new technology.

What should men living with haemophilia need to know? The perspectives of Canadian men with haemophilia.

Haemophilia is an inherited bleeding disorder affecting approximately 3000 Canadian men (Walker 2012). To manage their disease effectively individuals must be knowledgeable about the disease, bleed prevention strategies, treatment approaches, and complications. Data on individuals' knowledge levels are scarce. The availability of such data could lead to better educational strategies for disease management. The aim of this study was to determine current knowledge levels, needs and gaps among Canadian individuals with haemophilia to facilitate optimal disease management. A survey was disseminated to adult males with haemophilia at three Haemophilia Treatment Centres (HTCs) in Canada. Self-reported current knowledge levels and knowledge seeking were measured. Survey respondents reported highest levels of knowledge in the following areas: identifying and treating a bleed, haemophilia and physical activity, travel, career issues and genetics. Lower levels of knowledge were reported in the areas of sexual activity, product safety, information about factor, haemophilia and ageing, advocacy, timing of prophylactic infusions, and new or alternative therapies. Treating a bleed was the most commonly sought information, followed by information about factor, product safety, identifying a bleed and other health care issues. There was a positive correlation between knowledge seeking and severity of disease. HTC attendance was associated with knowledge seeking, and HTCs were the most frequented knowledge source, followed by the Canadian Haemophilia Society website. Canadian men were well informed; the HTC's role in knowledge sharing was recognized. Timing of infusions, sexual activity and ageing are areas which should be targeted in knowledge sharing.

What should men living with severe haemophilia need to know? The perspectives of Canadian haemophilia health care providers.

Haemophilia is a complex disease to manage. Home-based management of haemophilia has placed greater responsibility for disease management on individuals with haemophilia, heightening the individual's need for knowledge, particularly among individuals with severe haemophilia. The aim of this study was to identify and understand the knowledge needs and gaps of Canadian men with severe haemophilia from the perspectives of health care providers. A qualitative approach was undertaken. Data were collected using semi-structured focus groups and interviews with health care providers from Haemophilia Treatment Centres (HTCs) across Canada; data were analysed using thematic analysis. Three focus groups and two interviews were conducted; 13 individuals participated in this study. Health care providers identified the following areas of knowledge required by men with severe haemophilia: disease pathology, causes and consequences of bleeds, bleed prevention, recognition, treatment, how and when to access support, activity selection and risk reduction, benefits of exercise, genetic inheritance patterns, impact on career selection, travel and ageing. Knowledge gaps and challenges to knowledge provision were highlighted. In addition, providers emphasized the influences of timing, rapport and context on readiness to receive and assimilate information and recommended tailoring education to the individual and creating a developmental curriculum and knowledge assessment tool. Provision and uptake of disease knowledge is essential to patient self-management. To effectively receive, retain and assimilate information, individuals with severe haemophilia require the right information, from the right source, at the right time. Education should be tailored to the needs of the individual, provided throughout the lifespan.

Low prevalence of inhibitor antibodies in the Canadian haemophilia population.

Annual reporting of inhibitors to factors (FVIII) and IX (FIX) to the Canadian Haemophilia Registry has suggested a lower prevalence than that published in the literature. We performed a prospective study to determine the prevalence of patients with inhibitors directed against either FVIII or FIX. Patients with inhibitors were classified as: (i) inhibitor test positive; (ii) inhibitor test negative but on immune tolerance induction (ITI); (iii) inhibitor test negative but bypass treatment recommended; or (iv) inhibitor resolved. One year later, the cohort was re-classified. The prevalence of inhibitors on 1 May, 2007 was 3.3% for haemophilia A, 0.6% for haemophilia B and 8.9% and 2.1% for severe haemophilia A and B. One year later 17 individuals gained and 11 individuals lost inhibitor status (10 of these with ITI). This study suggests that the prevalence of inhibitors in our population is lower than that was previously published. We hypothesize that this is primarily due to the increased use of ITI, but other factors may be the unselected nature of the cohort and the restriction of the study to one date thereby conforming as close as practical to the definition of prevalence rather than incidence. The classification system used in this study was easy for clinics to apply and was important in defining the population with inhibitors.

Diagnostic utility of light transmission platelet aggregometry: results from a prospective study of individuals referred for bleeding disorder assessments.

BACKGROUND: Light transmission aggregometry (LTA) is commonly performed to assess individuals for bleeding disorders. OBJECTIVES: The goal was to evaluate the incidence and spectrum of platelet function abnormalities in a prospective cohort of individuals referred for bleeding disorder assessments after exclusion of thrombocytopenia and von Willebrand disease. PATIENTS/METHODS: Subjects were healthy controls and patients from a prospective cohort of individuals referred for bleeding disorder assessments after exclusion of thrombocytopenia and von Willebrand disease. LTA was performed by standardized methods using platelet-rich plasma adjusted to 250x10(9) platelets L(-1). Maximal aggregation data were analyzed to determine the likelihood of detecting a platelet function disorder by LTA, and the sensitivity and specificity of LTA for platelet disorders. RESULTS: The incidence of false positive LTA among subjects excluded of having bleeding disorders was similar to healthy controls. Abnormal LTA was more common in subjects with bleeding disorders and the likelihood of a bleeding disorder was significantly increased (odds ratio 32) when maximal aggregation was reduced with two or more agonists. Receiver operator curve analyses indicated that LTA had high specificity and moderate sensitivity for detecting inherited defects in platelet function and that the LTA agonists 1.25 microg mL(-1) collagen, 6 microM epinephrine, 1.6 mM arachidonic acid and 1.0 microM thromboxane analogue U44619 detected most inherited disorders with abnormal LTA. CONCLUSIONS: LTA is valuable for detecting platelet function abnormalities among individuals referred for bleeding problems, particularly when the test indicates abnormal responses to multiple agonists.

Utilization of recombinant activated factor VII in southern Ontario in 85 patients with and without haemophilia.

Recombinant activated factor VII (rFVIIa) is licensed for the treatment of bleeding in individuals with haemophilia and inhibitors. The use of rFVIIa appears to be increasing, and an increase in unlicensed use is suspected. There are currently few data about the specific indications for its use. The aim of this study was to describe the patterns of utilization of rFVIIa. We performed a retrospective cohort study using rFVIIa infusion data collected prospectively and clinical data collected retrospectively. Patients were identified using a tracking system designed to account for use of all coagulation factor concentrates issued in southern Ontario. Between 1 January 2001 and 31 December 2005, 85 patients received rFVIIa. 1164 infusions were given (8246.4 mg). Haemophilia patients with inhibitors accounted for 82.9% of rFVIIa infused and represented 8.2% of patients. The total amount of rFVIIa used increased each year from 2001 to 2004 and then decreased in 2005. The total number of infusions of rFVIIa administered annually increased. Both on-label and off-label use of rFVIIa increased. The number of patients with haemophilia receiving rFVIIa remained small and constant. The number of patients receiving rFVIIa for off-label indications increased markedly. Most rFVIIa infusions were given for licensed indications; however, these infusions represented <10% of patients treated. Overall, the utilization of rFVIIa is increasing, mostly for approved indications; however, the number of patients being prescribed rFVIIa for off-label indications has increased. The tracking system used in this study is a valuable tool to describe ongoing utilization patterns of rFVIIa.

Trends in the utilization and wastage of coagulation factor concentrates: the application of a regional tracking programme.

The Commission of Inquiry on the Blood System in Canada ('Krever Commission', 1997) recommended an active programme of surveillance for all blood products. To describe trends in the utilization of coagulation factor concentrates using a comprehensive factor tracking programme. Between 2001 and 2004 in the region of Southern Ontario, we prospectively tracked all coagulation factor concentrates that were distributed from the national blood supplier, issued by hospitals for inpatient use or for home infusions, infused at hospital facilities or at home and wasted. Discrepancies were reconciled by independent audits. Trends in the utilization of FVIII, FIX and FVIIa concentrates are reported. A total of 466 patients with inherited or acquired bleeding disorders were registered. Utilization of FVIII, FIX and FVIIa increased by an average of 13.7%, 33.2% and 34.2% per year respectively. Most FVIII and FIX infusions were administered at home while most FVIIa infusions were in hospital. The increase in FVIII and FIX usage was attributable to an increase in per-patient use, predominantly for prophylaxis. In total, 1.7% of coagulation factor concentrates was wasted during the study period, at a cost of over 1 million Canadian dollars. Utilization of coagulation factor concentrates increased steadily during the study period. A regional programme to track utilization is feasible and may be used to describe trends, assist planning, and reduce costs by minimizing wastage.

Methods for the analysis of bleeding outcomes in randomized trials of PLT transfusion triggers.

BACKGROUND: A number of methodologic challenges arise in the analysis of bleeding data from clinical trials of PLT transfusion triggers. It is important to understand the assumptions and role of the various methods of analysis to interpret published trials and to design future studies appropriately. STUDY DESIGN AND METHODS: The methods of analysis used for testing the effectiveness and safety of transfusion strategies are reviewed from several recent PLT transfusion trigger trials. The underlying assumptions of these methods are discussed, as well as the clinical interpretations of the resulting summary statistics. Four methods of analysis were applied to data from a large PLT transfusion trigger study to illustrate the differences in the interpretations that can arise from various approaches. RESULTS: PLT transfusion trigger trials of patients with leukemia have based their primary analyses on 1) simple dichotomous classifications of whether or not at least 1 day of clinically important bleeding was experienced; 2) the time to the first day of clinically important bleeding; and 3) the proportion of days at risk with clinically important bleeding. Recurrent event methods provide a robust alternative approach to the analysis of this kind of data and should be considered if interest is in capturing the overall burden of bleeding over time. These four methods differ in the extent to which they utilize information on the number of days with bleeding and the temporal variation in bleeding patterns. Inferences drawn regarding the relative safety and efficacy of different transfusion triggers can vary depending on the method of analysis. CONCLUSION: To rigorously design and analyze future PLT transfusion studies based on bleeding outcomes, it is important to have a clear understanding of the interpretation of the different ways of analyzing bleeding outcomes. The analysis strategy should be selected based on the clinical question being addressed.

Effects of inhaled nitric oxide in a rat model of Pseudomonas aeruginosa pneumonia.

OBJECTIVE: Antimicrobial effects of nitric oxide (NO) have been demonstrated in vitro against a variety of infectious pathogens, yet in vivo evidence of a potential therapeutic role for exogenous NO as an antimicrobial agent is limited. Thus, we assessed the effects of inhaled NO on pulmonary infection, leukocyte infiltration, and NO synthase (NOS) activity in a rat model of Pseudomonas aeruginosa pneumonia. DESIGN: Controlled animal study. SETTING: Research laboratory of an academic institution. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: After intratracheal instillation of either P. aeruginosa or saline (sham), rats were randomly exposed to either 40 ppm of inhaled NO or room air (RA) for 24 hrs before they were killed. MEASUREMENTS AND MAIN RESULTS: Inhaled NO in pneumonia rats markedly reduced pulmonary bacterial load (0.02+/-0.01% vs. 0.99+/-0.59% of bacterial input in pneumonia with room air, p < .05) and pulmonary myeloperoxidase activity, a marker of leukocyte infiltration (21.7+/-3.8 vs. 55.0+/-8.1 units in pneumonia with room air, p < .05), but had no effect on systemic hemodynamics or gas exchange. Pneumonia was associated with enhanced pulmonary NOS activity (8.8+/-2.4 vs. 0.2+/-0.1 pmol citrulline/min/mg protein in sham, p < .01) and increased plasma levels of nitrites/nitrates (NOx-; 45+/-7 vs. 16+/-3 micromol/L in sham, p < .01). Inhaled NO therapy attenuated the pneumonia-induced increase in pulmonary calcium-independent NOS activity (p < .05) and markedly increased plasma NOx- levels. Exposure of P. aeruginosa in culture to 40 ppm of ambient NO confirmed a delayed antibacterial effect of NO in vitro. CONCLUSIONS: Inhaled NO has an important antibacterial effect both in vitro and in vivo against P. aeruginosa and is associated with reduced pulmonary leukocyte infiltration in vivo. These results in a rat model of P. aeruginosa pneumonia suggest that future studies should address the possible clinical effects of inhaled NO therapy in pneumonia.