Use of Intravenous Albumin: A Guideline From the International Collaboration for Transfusion Medicine Guidelines.

BACKGROUND: Albumin is used commonly across a wide range of clinical settings to improve hemodynamics, to facilitate fluid removal, and to manage complications of cirrhosis. The International Collaboration for Transfusion Medicine Guidelines developed guidelines for the use of albumin in patients requiring critical care, undergoing cardiovascular surgery, undergoing kidney replacement therapy, or experiencing complications of cirrhosis. METHODS: Cochairs oversaw the guideline development process and the panel included researchers, clinicians, methodologists, and a patient representative. The evidence informing this guideline arises from a systematic review of randomized clinical trials and systematic reviews, in which multiple databases were searched (inception through November 23, 2022). The panel reviewed the data and formulated the guideline recommendations using Grading of Recommendations Assessment, Development and Evaluation methodology. The guidelines were revised after public consultation. RESULTS: The panel made 14 recommendations on albumin use in adult critical care (three recommendations), pediatric critical care (one recommendation), neonatal critical care (two recommendations), cardiovascular surgery (two recommendations), kidney replacement therapy (one recommendation), and complications of cirrhosis (five recommendations). Of the 14 recommendations, two recommendations had moderate certainty of evidence, five recommendations had low certainty of evidence, and seven recommendations had very low certainty of evidence. Two of the 14 recommendations suggested conditional use of albumin for patients with cirrhosis undergoing large-volume paracentesis or with spontaneous bacterial peritonitis. Twelve of 14 recommendations did not suggest albumin use in a wide variety of clinical situations where albumin commonly is transfused. CONCLUSIONS: Currently, few evidence-based indications support the routine use of albumin in clinical practice to improve patient outcomes. These guidelines provide clinicians with actionable recommendations on the use of albumin.

How do we achieve blinding in modern electronic and paper medical records during the conduct of transfusion trials?

BACKGROUND: Regulatory aspects of transfusion medicine add complexity in blinded transfusion trials when considering various electronic record keeping software and blood administration processes. The aim of this study is to explore strategies when blinding transfusion components and products in paper and electronic medical records. METHODS: Surveys were collected and interviews were conducted for 18 sites across various jurisdictions in North America to determine solutions applied in previous transfusion randomized control trials. RESULTS: Sixteen responses were collected of which 11 had previously participated in a transfusion randomized control trial. Various solutions were reported which were specific to the laboratory information system (LIS) and electronic medical record (EMR) combinations although solutions could be grouped into four categories which included the creation of a study product code in the LIS, preventing the transmission of data from the LIS to the EMR, utilizing specialized stickers and labels to conceal product containers and documents in the paper records, and modified bedside procedures and documentation. DISCUSSION: LIS and EMR combinations varied across sites, so it was not possible to determine combination-specific solutions. The study was able to highlight solutions that may be emphasized in future iterations of LIS and EMR software as well as procedural changes that may minimize the risk of unblinding.

Diagnosis and management of pyruvate kinase deficiency: international expert guidelines.

Pyruvate kinase (PK) deficiency is the most common cause of chronic congenital non-spherocytic haemolytic anaemia worldwide, with an estimated prevalence of one in 100 000 to one in 300 000 people. PK deficiency results in chronic haemolytic anaemia, with wide ranging and serious consequences affecting health, quality of life, and mortality. The goal of the International Guidelines for the Diagnosis and Management of Pyruvate Kinase Deficiency was to develop evidence-based guidelines for the clinical care of patients with PK deficiency. These clinical guidelines were developed by use of GRADE methodology and the AGREE II framework. Experts were invited after consideration of area of expertise, scholarly contributions in PK deficiency, and country of practice for global representation. The expert panel included 29 expert physicians (including adult and paediatric haematologists and other subspecialists), geneticists, laboratory specialists, nurses, a guidelines methodologist, patients with PK deficiency, and caregivers from ten countries. Five key topic areas were identified, the panel prioritised key questions, and a systematic literature search was done to generate evidence summaries that were used in the development of draft recommendations. The expert panel then met in person to finalise and vote on recommendations according to a structured consensus procedure. Agreement of greater than or equal to 67% among the expert panel was required for inclusion of a recommendation in the final guideline. The expert panel agreed on 31 total recommendations across five key topics: diagnosis and genetics, monitoring and management of chronic complications, standard management of anaemia, targeted and advanced therapies, and special populations. These new guidelines should facilitate best practices and evidence-based PK deficiency care into clinical practice.

Pregnancy outcomes and iron status in ß-thalassemia major and intermedia: a systematic review and meta-analysis.

ABSTRACT: Advancements in orally bioavailable iron chelators and MRI methods have improved life expectancy and reproductive potential in thalassemia major (TM) and thalassemia intermedia (TI). Pregnancy is associated with adverse maternal and neonatal outcomes, frequency of which has not been well delineated. This systematic review aims to provide risk estimates of maternal and fetal outcomes in TM and TI and explore pregnancy's impact on iron homeostasis. Fifteen studies (429 participants, 684 pregnancies) were included. Meta-analysis revealed a higher thrombosis risk in TI (3.7%) compared to TM (0.92%), unchanged from prepregnancy. Heart failure risks in the earlier years appeared similar (TM 1.6% vs TI 1.1%), and maternal mortality in TM was 3.7%, but with current management, these risks are rare. Gestational diabetes and pre-eclampsia occurred in 3.9% and 11.3% of TM pregnancies, respectively. Caesarean section rates were 83.9% in TM and 67% in TI. No significant difference in stillbirth, small for gestational age neonates, or preterm birth incidence between TM and TI was observed. In TM pregnancies, red cell requirements significantly increased (from 102 to 139 ml/kg/year, P = 0.001), and 70% of TI pregnancies required blood transfusions. As expected, increased transfusion alongside chelation cessation led to a significant increase in serum ferritin during pregnancy (TM by 1005 ng/mL; TI by 332 ng/mL, P < 0.0001). Deterioration in iron status was further reflected by an increase in liver iron concentration (from 4.6 to 11.9 mg/g dry weight, P < 0.0001), and myocardial T2-star (T2∗) magnetic resonance imaging decreased (from 36.2 ± 2.5 ms to 31.1 ms) during pregnancy. These findings emphasize the elevated maternal risk of iron-related cardiomyopathy during pregnancy and labor, stressing the importance of cardiac monitoring and postpartum chelation therapy resumption.

Blood pressure thresholds for the diagnosis of hypertensive disorders of pregnancy in sickle cell disease.

In this retrospective cohort study of singleton pregnancies in people with sickle cell disease (SCD) delivered at two academic centres between 1990 and 2021, we collected demographic and SCD-related data, pregnancy outcomes, and the highest systolic and diastolic blood pressure (SBP and DBP) at seven time periods. We compared the characteristics of subjects with new or worsening proteinuria (NWP) during pregnancy to those without. We then constructed receiver operating characteristic (ROC) curves to determine the blood pressure (BP) that best identifies those with NWP. The SBP or DBP thresholds which maximized sensitivity and specificity were 120 mmHg SBP (sensitivity: 55.2%, specificity: 73.5%) and 70 mmHg DBP (sensitivity: 27.6%, specificity: 67.7%). The existing BP threshold of 140/90 mmHg lacked sensitivity in both genotype groups (HbSS/HbSß0 : SBP = 21% sensitive, DBP = 5.3% sensitive; HbSS/HbSß+ : SBP = 10% sensitive, DBP = 0% sensitive). Finally, percent change in SBP, DBP and MAP were all poor tests for identifying NWP. Existing BP thresholds used to diagnose hypertensive disorders of pregnancy (HDP) are not sensitive for pregnant people with SCD. For this population, lowering the BP threshold that defines HDP may improve identification of those who need increased observation, consideration of early delivery and eclampsia prophylaxis.

Natural history of blood pressure in sickle cell disease pregnancy.

In this retrospective cohort study of singleton pregnancies in people with sickle cell disease (SCD) delivered at two academic centres between 1990 and 2021, we collected demographic and SCD-related data, pregnancy outcomes, and the highest systolic and diastolic blood pressure (SBP and DBP) at seven time periods. We compared blood pressure values and trajectories in the composite cohort and in each genotype group to control values in a non-SCD pregnancy dataset. There were 290 pregnancies among 197 patients with SCD. Sixteen per cent (n = 47) of pregnancies had a hypertensive disorder of pregnancy (HDP); the rates did not differ by genotype. The mean SBP and DBP were lower in the HbSS/HbSß0 group than in the non-SCD control group at all timepoints. Mean SBP and DBP trajectories were similar between the HbSS/HbSß0 group and non-SCD controls, whereas the mean SBP and DBP in the HbSC/HbSß+ group decreased between the first and second trimesters and plateaued between the second and third trimesters. There were no differences in blood pressure trajectory by haemoglobin >/< 10 gm/dL or by chronic transfusion status. Overall, pregnant people with SCD have lower blood pressure than unaffected pregnant people, raising the possibility that HDP are underdiagnosed, particularly in people with HbSS/HbSß0 .

Identification and treatment of iron-deficiency anemia in pregnancy and postpartum: A systematic review and quality appraisal of guidelines using AGREE II.

BACKGROUND: Several international guidelines provide recommendations for the optimal management of iron-deficiency anemia (IDA) in the pregnant and postpartum populations. OBJECTIVES: To review the quality of guidelines containing recommendations for the identification and treatment of IDA in pregnancy and postpartum using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument and to summarize their recommendations. SEARCH STRATEGY: PubMed, Medline, and Embase databases were searched from inception to August 2, 2021. A web engine search was also performed. SELECTION CRITERIA: Clinical practice guidelines that focused on the management of IDA in pregnancy and/or postpartum populations were included. DATA COLLECTION AND ANALYSIS: Included guidelines were appraised using AGREE II independently by two reviewers. Domain scores greater than 70% were considered high-quality. Overall scores of six or seven (out of a possible seven) were considered high-quality guidelines. Recommendations on IDA management were extracted and summarized. MAIN RESULTS: Of 2887 citations, 16 guidelines were included. Only six (37.5%) guidelines were deemed high-quality and were recommended by the reviewers. All 16 (100%) guidelines discussed the management of IDA in pregnancy, and 10 (62.5%) also included information on the management of IDA in the postpartum period. CONCLUSIONS: The complex interplay of racial, ethnic, and socioeconomic disparities was rarely addressed, which limits the generalizability of the recommendations. In addition, many guidelines failed to identify barriers to implementation, strategies to improve uptake or iron treatment, and resource and cost implications of clinical recommendations. These findings highlight important areas to target future work.

The selection and preparation of red cell components for intrauterine transfusion: A national survey.

BACKGROUND AND OBJECTIVES: The practice regarding the selection and preparation of red blood cells (RBCs) for intrauterine transfusion (IUT) is variable reflecting historical practice and expert opinion rather than evidence-based recommendations. The aim of this survey was to assess Canadian hospital blood bank practice with respect to red cell IUT. MATERIALS AND METHODS: A survey was sent to nine hospital laboratories known to perform red cell IUT. Questions regarding component selection, processing, foetal pre-transfusion testing, transfusion administration, documentation and traceability were assessed. RESULTS: The median annual number of IUTs performed in Canada was 109 (interquartile range, 103-118). RBC selection criteria included allogeneic, Cytomegalovirus seronegative, irradiated, fresh units with most sites preferentially providing HbS negative, group O, RhD negative, Kell negative and units lacking the corresponding maternal antibody without extended matching to the maternal phenotype. Red cell processing varied with respect to target haematocrit, use of saline reconstitution (n = 4), use of an automated procedure for red cell concentration (n = 1) and incorporation of a wash step (n = 2). Foetal pre-transfusion testing uniformly included haemoglobin measurement, but additional serologic testing varied. A variety of strategies were used to link the IUT event to the neonate post-delivery, including the creation of a unique foetal blood bank identifier at three sites. CONCLUSION: This survey reviews current practice and highlights the need for standardized national guidelines regarding the selection and preparation of RBCs for IUT. This study has prompted a re-examination of priorities for RBC selection for IUT and highlighted strategies for transfusion traceability in this unique setting.

Intravenous albumin in cardiac and vascular surgery: a systematic review and meta-analysis.

BACKGROUND: Intravenous albumin is commonly utilised in cardiovascular surgery for priming of the cardiopulmonary bypass circuit, volume replacement, or both, although the evidence to support this practice is uncertain. The aim was to compare i.v. albumin with synthetic colloids and crystalloids for paediatric and adult patients undergoing cardiovascular surgery for all-cause mortality and other perioperative outcomes. METHODS: A systematic review and meta-analysis of randomised controlled trials (RCTs) of i.v. albumin compared with synthetic colloids and crystalloids on the primary outcome of all-cause mortality was conducted. Secondary outcomes included renal failure, blood loss, duration of hospital or intensive care unit stay, cardiac index, and blood component use; subgroups were analysed by age, comparator fluid, and intended use (priming, volume, or both). We searched MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CCRT) from 1946 to November 23, 2022. RESULTS: Of 42 RCTs, mortality was assessed in 15 trials (2711 cardiac surgery patients) and the risk difference was 0.00, 95% confidence interval (CI) -0.01 to 0.01, I2=0%. Among secondary outcomes, i.v. albumin resulted in smaller fluid balance, mean difference -0.55 L, 95% CI -1.06 to -0.4, I2=90% (nine studies, 1975 patients) and higher albumin concentrations, mean difference 7.77 g L-1, 95% CI 3.73-11.8, I2=95% (six studies, 325 patients). CONCLUSIONS: Intravenous albumin use was not associated with a difference in morbidity and mortality in patients undergoing cardiovascular surgery, when compared with comparator fluids. The lack of improvement in important outcomes with albumin and its higher cost suggests it should be used restrictively. SYSTEMATIC REVIEW PROTOCOL: PROSPERO; CRD42020171876.

Methemoglobin as a marker of acute anemic stress in cardiac surgery.

Biological evidence supports plasma methemoglobin as a biomarker for anemia-induced tissue hypoxia. In this translational planned substudy of the multinational randomized controlled transfusion thresholds in cardiac surgery (TRICS-III) trial, which included adults undergoing cardiac surgery requiring cardiopulmonary bypass with a moderate-to-high risk of death, we investigated the relationship between perioperative hemoglobin concentration (Hb) and methemoglobin; and evaluated its association with postoperative outcomes. The primary endpoint was a composite of death, myocardial infarction, stroke, and severe acute kidney injury at 28 days. We observe weak non-linear associations between decreasing Hb and increasing methemoglobin, which were strongest in magnitude at the post-surgical time point. Increased levels of post-surgical methemoglobin were associated with a trend toward an elevated risk for stroke and exploratory neurological outcomes. Our generalizable study demonstrates post-surgical methemoglobin may be a marker of anemia-induced organ injury/dysfunction, and may have utility for guiding personalized approaches to anemia management. Clinicaltrials.gov registration NCT02042898.

Cost Effectiveness of Different Platelet Preparation, Storage, Selection and Dosing Methods in Platelet Transfusion: A Systematic Review.

BACKGROUND AND OBJECTIVE: Evidence-based guidelines on platelet transfusion therapy assist clinicians to optimize patient care, but currently do not take into account costs associated with different methods used during the preparation, storage, selection and dosing of platelets for transfusion. This systematic review aimed to summarize the available literature regarding the cost effectiveness (CE) of these methods. METHODS: Eight databases and registries, as well as 58 grey literature sources, were searched up to 29 October 2021 for full economic evaluations comparing the CE of methods for preparation, storage, selection and dosing of allogeneic platelets intended for transfusion in adults. Incremental CE ratios, expressed as standardized cost (in 2022 EUR) per quality-adjusted life-year (QALY) or per health outcome, were synthesized narratively. Studies were critically appraised using the Philips checklist. RESULTS: Fifteen full economic evaluations were identified. Eight investigated the costs and health consequences (transfusion-related events, bacterial and viral infections or illnesses) of pathogen reduction. The estimated incremental cost per QALY varied widely from EUR 259,614 to EUR 36,688,323. For other methods, such as pathogen testing/culturing, use of apheresis instead of whole blood-derived platelets, and storage in platelet additive solution, evidence was sparse. Overall, the quality and applicability of the included studies was limited. CONCLUSIONS: Our findings are of interest to decision makers who consider implementing pathogen reduction. For other preparation, storage, selection and dosing methods in platelet transfusion, CE remains unclear due to insufficient and outdated evaluations. Future high-quality research is needed to expand the evidence base and increase our confidence in the findings.

Cost-Effectiveness of Thrombopoietin Mimetics in Patients with Thrombocytopenia: A Systematic Review.

OBJECTIVES: Thrombopoietin (TPO) mimetics are a potential alternative to platelet transfusion to minimize blood loss in patients with thrombocytopenia. This systematic review aimed to evaluate the cost-effectiveness of TPO mimetics, compared with not using TPO mimetics, in adult patients with thrombocytopenia. METHODS: Eight databases and registries were searched for full economic evaluations (EEs) and randomized controlled trials (RCTs). Incremental cost-effectiveness ratios (ICERs) were synthesized as cost per quality-adjusted life year gained (QALY) or as cost per health outcome (e.g. bleeding event avoided). Included studies were critically appraised using the Philips reporting checklist. RESULTS: Eighteen evaluations from nine different countries were included, evaluating the cost-effectiveness of TPO mimetics compared with no TPO, watch-and-rescue therapy, the standard of care, rituximab, splenectomy or platelet transfusion. ICERs varied from a dominant strategy (i.e. cost-saving and more effective), to an incremental cost per QALY/health outcome of EUR 25,000-50,000, EUR 75,000-750,000 and EUR > 1 million, to a dominated strategy (cost-increasing and less effective). Few evaluations (n = 2, 10%) addressed the four principal types of uncertainty (methodological, structural, heterogeneity and parameter). Parameter uncertainty was most frequently reported (80%), followed by heterogeneity (45%), structural uncertainty (43%) and methodological uncertainty (28%). CONCLUSIONS: Cost-effectiveness of TPO mimetics in adult patients with thrombocytopenia ranged from a dominant strategy to a significant incremental cost per QALY/health outcome or a strategy that is clinically inferior and has increased costs. Future validation and tackling the uncertainty of these models with country-specific cost data and up-to-date efficacy and safety data are needed to increase the generalizability.

Effect of Donor Sex on Recipient Mortality in Transfusion.

BACKGROUND: Conflicting observational evidence exists regarding the association between the sex of red-cell donors and mortality among transfusion recipients. Evidence to inform transfusion practice and policy is limited. METHODS: In this multicenter, double-blind trial, we randomly assigned patients undergoing red-cell transfusion to receive units of red cells from either male donors or female donors. Patients maintained their trial-group assignment throughout the trial period, including during subsequent inpatient and outpatient encounters. Randomization was conducted in a 60:40 ratio (male donor group to female donor group) to match the historical allocation of red-cell units from the blood supplier. The primary outcome was survival, with the male donor group as the reference group. RESULTS: A total of 8719 patients underwent randomization before undergoing transfusion; 5190 patients were assigned to the male donor group, and 3529 to the female donor group. At baseline, the mean (±SD) age of the enrolled patients was 66.8±16.4 years. The setting of the first transfusion was as an inpatient in 6969 patients (79.9%), of whom 2942 (42.2%) had been admitted under a surgical service. The baseline hemoglobin level before transfusion was 79.5±19.7 g per liter, and patients received a mean of 5.4±10.5 units of red cells in the female donor group and 5.1±8.9 units in the male donor group (difference, 0.3 units; 95% confidence interval [CI], -0.1 to 0.7). Over the duration of the trial, 1141 patients in the female donor group and 1712 patients in the male donor group died. In the primary analysis of overall survival, the adjusted hazard ratio for death was 0.98 (95% CI, 0.91 to 1.06). CONCLUSIONS: This trial showed no significant difference in survival between a transfusion strategy involving red-cell units from female donors and a strategy involving red-cell units from male donors. (Funded by the Canadian Institutes of Health Research; iTADS ClinicalTrials.gov number, NCT03344887.).

Decision Analysis in SHared decision making for Thromboprophylaxis during Pregnancy (DASH-TOP): a sequential explanatory mixed-methods pilot study.

OBJECTIVES: To gain insight into formal methods of integrating patient preferences and clinical evidence to inform treatment decisions, we explored patients' experience with a personalised decision analysis intervention, for prophylactic low-molecular-weight heparin (LMWH) in the antenatal period. DESIGN: Mixed-methods explanatory sequential pilot study. SETTING: Hospitals in Canada (n=1) and Spain (n=4 sites). Due to the COVID-19 pandemic, we conducted part of the study virtually. PARTICIPANTS: 15 individuals with a prior venous thromboembolism who were pregnant or planning pregnancy and had been referred for counselling regarding LMWH. INTERVENTION: A shared decision-making intervention that included three components: (1) direct choice exercise; (2) preference elicitation exercises and (3) personalised decision analysis. MAIN OUTCOME MEASURES: Participants completed a self-administered questionnaire to evaluate decision quality (decisional conflict, self-efficacy and satisfaction). Semistructured interviews were then conducted to explore their experience and perceptions of the decision-making process. RESULTS: Participants in the study appreciated the opportunity to use an evidence-based decision support tool that considered their personal values and preferences and reported feeling more prepared for their consultation. However, there were mixed reactions to the standard gamble and personalised treatment recommendation. Some participants could not understand how to complete the standard gamble exercises, and others highlighted the need for more informative ways of presenting results of the decision analysis. CONCLUSION: Our results highlight the challenges and opportunities for those who wish to incorporate decision analysis to support shared decision-making for clinical decisions.

Impact of mutations on pregnancy outcome in patients with myeloproliferative neoplasms.

The impact of driver and other somatic mutations on pregnancy outcomes is unknown. The purpose of this study was to report the management and outcome of pregnancies in a cohort of myeloproliferative neoplasms (MPN) patients, particularly to evaluate the impact of somatic mutations. The cohort included consecutive patients with MPN who had a least one confirmed pregnancy. The primary outcome was live births. Secondary outcomes were thrombotic and major bleeding events. Between 2010 and 2021, 29 pregnancies occurred in 24 individuals with MPN. Aspirin was used in 24 cases (83%) and interferon alfa in five (17%). There were 24 live births (83%). There were three thrombotic events, two antepartum and one postpartum. Miscarriages and thrombotic events occurred in JAK2-mutated and triple negative, but not CALR-mutated, MPN. Additional somatic mutations were rare, and there were no apparent associations with pregnancy loss or complications. While JAK2 V617F is associated with an increased risk of thrombosis, its impact on pregnancy outcome has been inconsistently reported. The association between triple negative MPN and adverse pregnancy outcome has not previously been reported. While limited by small numbers, this study underscores the importance of describing driver and other mutations to direct optimal antenatal care in individuals with MPN.

Transfusion camp: A retrospective study of self-reported impact on postgraduate trainee transfusion practice.

BACKGROUND: The optimal method of postgraduate transfusion medicine (TM) education remains understudied. One novel approach is Transfusion Camp, a longitudinal 5-day program that delivers TM education to Canadian and international trainees. The purpose of this study was to determine the self-reported impact of Transfusion Camp on trainee clinical practice. STUDY DESIGN AND METHODS: A retrospective analysis of anonymous survey evaluations from Transfusion Camp trainees over three academic years (2018-2021) was conducted. Trainees were asked, "Have you applied any of your learning from Transfusion Camp into your clinical practice?". Through an iterative process, responses were categorized into topics according to program learning objectives. The primary outcome was the rate of self-reported impact of Transfusion Camp on clinical practice. Secondary outcomes were to determine impact based on specialty and postgraduate year (PGY). RESULTS: Survey response rate was 22%-32% over three academic years. Of 757 survey responses, 68% of respondents indicated that Transfusion Camp had an impact on their practice, increasing to 83% on day 5. The most frequent areas of impact included transfusion indications (45%) and transfusion risk management (27%). Impact increased as PGY increased with 75% of PGY-4+ trainees reporting impact. In multivariable analysis, the impact of specialty and PGY varied depending on the objective. DISCUSSION: The majority of trainees report applying learnings from Transfusion Camp to their clinical practice with variations based on PGY and specialty. These findings support Transfusion Camp as an effective means of TM education and help identify high-yield areas and gaps for future curriculum planning.

Systematic reviews on platelet transfusions: Is there unnecessary duplication of effort? A scoping review.

BACKGROUND AND OBJECTIVES: Platelet transfusions are used across multiple patient populations to prevent and correct bleeding. This scoping review aimed to map the currently available systematic reviews (SRs) and evidence-based guidelines in the field of platelet transfusion. MATERIALS AND METHODS: A systematic literature search was conducted in seven databases for SRs on effectiveness (including dose and timing, transfusion trigger and ratio to other blood products), production modalities and decision support related to platelet transfusion. The following data were charted: methodological features of the SR, population, concept and context features, outcomes reported, study design and number of studies included. Results were synthesized in interactive evidence maps. RESULTS: We identified 110 SRs. The majority focused on clinical effectiveness, including prophylactic or therapeutic transfusions compared to no platelet transfusion (34 SRs), prophylactic compared to therapeutic-only transfusion (8 SRs), dose, timing (11 SRs) and threshold for platelet transfusion (15 SRs) and the ratio of platelet transfusion to other blood products in massive transfusion (14 SRs). Furthermore, we included 34 SRs on decision support, of which 26 evaluated viscoelastic testing. Finally, we identified 22 SRs on platelet production modalities, including derivation (4 SRs), pathogen inactivation (6 SRs), leucodepletion (4 SRs) and ABO/human leucocyte antigen matching (5 SRs). The SRs were mapped according to concept and clinical context. CONCLUSION: An interactive evidence map of SRs and evidence-based guidelines in the field of platelet transfusion has been developed and identified multiple reviews. This work serves as a tool for researchers looking for evidence gaps, thereby both supporting research and avoiding unnecessary duplication.