Use Of Viscoelastic Haemostatic Assays Research Articles

Does the Use of Viscoelastic Hemostatic Assays for Periprocedural Hemostasis Management in Liver Disease Improve Clinical Outcomes?

Routine hemostasis parameters such as prothrombin time and fibrinogen are frequently abnormal in patients with chronic liver disease and have been demonstrated to be poor predictors for periprocedural bleeding. Alterations in procoagulant and anticoagulant factors in this population result in a state of rebalanced hemostasis, which is not reflected by routine hemostatic measures. Viscoelastic hemostatic assays (VHA) present a point of care measure of global hemostasis with an emerging role in guiding transfusion in the liver transplant setting. The potential role for VHA in guiding periprocedural transfusion is unknown. Here we critically appraise the available limited evidence on the use of VHA to guide prophylactic treatment in patients with cirrhosis undergoing procedures. We assess whether the impact of a VHA-guided approach improves clinical outcomes. Suggested areas for future research with a focus on clinically relevant outcomes, particularly periprocedural bleeding, are highlighted.

Patient blood management guideline for adults with critical bleeding.

The management of patients with critical bleeding requires a multidisciplinary approach to achieve haemostasis, optimise physiology, and guide blood component use. The 2011 Patient blood management guidelines: module 1 - critical bleeding/massive transfusion were updated and published. Systematic reviews were conducted for pre-specified research questions, and recommendations were based on meta-analyses of included studies. The critical bleeding/massive transfusion guideline includes seven recommendations and 11 good practice statements addressing: major haemorrhage protocols (MHPs) facilitating a multidisciplinary approach to haemorrhage control, correction of coagulopathy and normalisation of physiological derangement; measurement of physiological, biochemical and metabolic parameters in critical bleeding/massive transfusion; the optimal ratio of red blood cells to other blood components; the use of tranexamic acid; viscoelastic haemostatic assays; and cell salvage. The new guideline recommends MHPs be established as standard of care in all institutions managing patients with critical bleeding. In addition to routine physiological markers, the new guideline recommends temperature, biochemistry and coagulation profiles be measured early and frequently, providing parameters that define critical derangements. Ratio-based MHPs should include no fewer than four units of fresh frozen plasma and one adult unit of platelets for every eight units of red blood cells. In the setting of trauma and obstetric haemorrhage, administration of tranexamic acid within three hours of bleeding onset is recommended. The use of recombinant activated factor VII (rFVIIa) is not recommended. There was insufficient evidence to make recommendations on the use of viscoelastic haemostatic assays or cell salvage as part of MHPs.

Transfusion practices in intensive care units: An Australian and New Zealand point prevalence study

ObjectiveTo describe current transfusion practices in intensive care units (ICUs) in Australia and New Zealand, compare them against national guidelines, and describe how viscoelastic haemostatic assays (VHAs) are used in guiding transfusion decisions. Design, setting and participantsProspective, multicentre, binational point-prevalence study. All adult patients admitted to participating ICUs on a single day in 2021. Main outcome measuresTransfusion types, amounts, clinical reasons, and triggers; use of anti-platelet medications, anti-coagulation, and VHA. ResultsOf 712 adult patients in 51 ICUs, 71 (10%) patients received a transfusion during the 24hr period of observation. Compared to patients not transfused, these patients had higher Acute Physiology and Chronic Health Evaluation II scores (19 versus 17, p = 0.02), a greater proportion were mechanically ventilated (49.3% versus 37.3%, p < 0.05), and more had systemic inflammatory response syndrome (70.4% versus 51.3%, p < 0.01). Overall, 63 (8.8%) patients received red blood cell (RBC) transfusions, 10 (1.4%) patients received platelet transfusions, 6 (0.8%) patients received fresh frozen plasma (FFP), and 5 (0.7%) patients received cryoprecipitate. VHA was available in 42 (82.4%) sites but only used in 6.6% of transfusion episodes when available. Alignment with guidelines was found for 98.6% of RBC transfusions, but only 61.6% for platelet, 28.6% for FFP, and 20% for cryoprecipitate transfusions. ConclusionsNon-RBC transfusion decisions are often not aligned with guidelines and VHA is commonly available but rarely used to guide transfusions. Better evidence to guide transfusions in ICUs is needed.

How should we measure platelet count before central neuraxial blockade in parturients with thrombocytopenia?

Patients with low platelet counts are a concern to the obstetric anaesthetist as, although rare, there is a risk of a spinal epidural haematoma following central neuraxial blockade. Although conventional plasma-based tests are frequently used to guide central neuraxial blockade in patients with thrombocytopenia, interest in the use of viscoelastic haemostatic assays is increasing.

Point-of-care coagulation testing for postpartum haemorrhage.

The use of viscoelastic haemostatic assays (VHAs) to guide blood product replacement during postpartum haemorrhage is expanding. Rotem and TEG devices can be used to detect and treat clinically significant hypofibrinogenaemia, although evidence to support the role of VHAs for guiding fresh frozen plasma and platelet transfusion is less clear. If Rotem/TEG traces are normal, clinicians should investigate for another cause of bleeding, and haemostatic support is not required. Guidelines support the use of VHAs during postpartum haemorrhage as part of locally agreed algorithms. There is a wide consensus that fibrinogen replacement is needed if the Fibtem A5 is <12 mm and if there is ongoing bleeding. Guidelines recommend against using VHAs to guide tranexamic acid infusion, and this drug should be given as soon as bleeding is recognised, irrespective of the Rotem/TEG traces. The cost-effectiveness of VHAs during postpartum haemorrhage needs to be addressed.

Viscoelastic Hemostatic Assays for Orthopedic Trauma and Elective Procedures.

The application of viscoelastic hemostatic assays (VHAs) (e.g., thromboelastography (TEG) and rotational thromboelastometry (ROTEM)) in orthopedics is in its relative infancy when compared with other surgical fields. Fortunately, several recent studies describe the emerging use of VHAs to quickly and reliably analyze the real-time coagulation and fibrinolytic status in both orthopedic trauma and elective orthopedic surgery. Trauma-induced coagulopathy—a spectrum of abnormal coagulation phenotypes including clotting factor depletion, inadequate thrombin generation, platelet dysfunction, and dysregulated fibrinolysis—remains a potentially fatal complication in severely injured and/or hemorrhaging patients whose timely diagnosis and management are aided by the use of VHAs. Furthermore, VHAs are an invaluable compliment to common coagulation tests by facilitating the detection of hypercoagulable states commonly associated with orthopedic injury and postoperative status. The use of VHAs to identify hypercoagulability allows for an accurate venous thromboembolism (VTE) risk assessment and monitoring of VTE prophylaxis. Until now, the data have been insufficient to permit an individualized approach with regard to dosing and duration for VTE thromboprophylaxis. By incorporating VHAs into routine practice, orthopedic surgeons will be better equipped to diagnose and treat the complete spectrum of coagulation abnormalities faced by orthopedic patients. This work serves as an educational primer and up-to-date review of the current literature on the use of VHAs in orthopedic surgery.

Fibrinogen Early In Severe paediatric Trauma studY (FEISTY junior): protocol for a randomised controlled trial

IntroductionTrauma causes 40% of child deaths in high-income countries, with haemorrhage being a leading contributor to death in this population. There is a growing recognition that fibrinogen and platelets play...

Viscoelastic haemostatic point-of-care assays in the management of postpartum haemorrhage: a narrative review.

Viscoelastic haemostatic assays provide rapid testing at the bed-side that identify all phases of haemostasis, from initial fibrin formation to clot lysis. In obstetric patients, altered haemostasis is common as pregnancy is associated with coagulation changes that may contribute to bleeding events such as postpartum haemorrhage, as well as thrombosis events. In this narrative review, we examine the potential clinical utility of viscoelastic haemostatic assays in postpartum haemorrhage and consider the current recommendations for their use in obstetric patients. We discuss the clinical benefits associated with the use of viscoelastic haemostatic assays due to the provision of (near) real-time readouts with a short turnaround, coupled with the identification of coagulation defects such as hypofibrinogenaemia. The use of viscoelastic haemostatic assay-guided algorithms may be beneficial to diagnose coagulopathy, predict postpartum haemorrhage, reduce transfusion requirements and monitor fibrinolysis in women with obstetric haemorrhage. Further studies are required to assess whether viscoelastic haemostatic assay-guided treatment improves clinical outcomes, and to confirm the utility of prepartum viscoelastic haemostatic assay measurements for identifying patients at risk of postpartum haemorrhage.

Viscoelastic Hemostatic Assays for Postpartum Hemorrhage.

This article discusses the importance and effectiveness of viscoelastic hemostatic assays (VHAs) in assessing hemostatic competence and guiding blood component therapy (BCT) in patients with postpartum hemorrhage (PPH). In recent years, VHAs such as thromboelastography and rotational thromboelastometry have increasingly been used to guide BCT, hemostatic adjunctive therapy and prohemostatic agents in PPH. The three pillars of identifying hemostatic competence include clinical observation, common coagulation tests, and VHAs. VHAs are advantageous because they assess the cumulative contribution of all components of the blood throughout the entire formation of a clot, have fast turnaround times, and are point-of-care tests that can be followed serially. Despite these advantages, VHAs are underused due to poor understanding of correct technique and result interpretation, a paucity of widespread standardization, and a lack of large clinical trials. These VHAs can also be used in cases of uterine atony, preeclampsia, acute fatty liver of pregnancy, amniotic fluid embolism, placental abruption, genital tract trauma, surgical trauma, and inherited and prepartum acquired coagulopathies. There exists an immediate need for a point-of-care test that can equip obstetricians with rapid results on developing coagulopathic states. The use of VHAs in predicting and treating PPH, although in an incipient state, can fulfill this need.

The incidence, aetiology, and coagulation management of massive postpartum haemorrhage: a two-year national prospective cohort study

IntroductionBetween 2017 and 2018 a national quality improvement initiative was introduced incorporating point-of-care viscoelastic haemostatic assays (VHA) to guide blood product transfusion. Laboratory coagulation profiles, use and results of VHA, and administration of blood products were investigated. MethodsA two-year prospective cohort study of maternal outcomes of women experiencing massive postpartum haemorrhage (PPH) >1000 mL in Wales. In this study, cases of massive PPH (≥2500 mL and/or ≥5 units red blood cell (RBC) transfusion) were identified. ResultsMassive PPH occurred in 349 of 60 914 maternities (rate 5.7 per 1000). There were no deaths from PPH. Intensive care unit admission and/or hysterectomy occurred in 34/311 (10.9%) and 16/347 (4.6%), respectively. The leading cause of massive PPH was genital tract trauma (107/349, 30.6%). Two hundred and seventy-nine (80.6%) required RBC transfusion and 79/345 (22.9%) received at least one blood coagulation product. Results of VHA were recorded in 245/349 (70.2%), with 44/98 (44.9%) women tested in the first six months vs 63/77 (81.8%) in the final six months. Hypofibrinogenaemia (Clauss fibrinogen <2 g/L or FIBTEM A5 <12 mm) was observed in 56/328 (17.1%) of women, thrombocytopaenia (count <75 × 109/L) in 17/334 (5.1%) and either PT or aPTT >1.5×reference range in 10/293 (3.4%). ConclusionIn Wales, the use of VHA in cases of massive PPH increased over time, enabling clinicians to adopt a targeted, patient-specific approach to blood product administration, with only 22.9% of women receiving blood coagulation products and 17.1% having a documented clotting abnormality.

Viscoelastic Haemostatic Assays in Cardiovascular Critical Care.

The initiation and management of anticoagulation is a fundamental practice for a wide variety of indications in cardiovascular critical care, including the management of patients with acute MI, stroke prevention in patients with AF or mechanical valves, as well as the prevention of device thrombosis and thromboembolic events with the use of mechanical circulatory support and ventricular assist devices. The frequent use of antiplatelet and anticoagulation therapy, in addition to the presence of concomitant conditions that may lead to a propensity to bleed, such as renal and liver dysfunction, present unique challenges. The use of viscoelastic haemostatic assays provides an additional tool allowing clinicians to strike a delicate balance of attaining adequate anticoagulation while minimising the risk of bleeding complications. In this review, the authors discuss the role that viscoelastic haemostatic assay plays in cardiac populations (including cardiac surgery, heart transplantation, extracorporeal membrane oxygenation, acute coronary syndrome and left ventricular assist devices), and identify areas in need of further study.

Thromboelastometry, Thromboelastography, and Conventional Tests to Assess Anticoagulation During Extracorporeal Support: A Prospective Observational Study.

Optimal anticoagulation monitoring in patients with extracorporeal membrane oxygenation (ECMO) is fundamental to avoid hemorrhagic and thromboembolic complications. Besides conventional coagulation tests, there is growing interest in the use of viscoelastic hemostatic assays (VHA), in particular of tromboelastography (TEG). Evidence on the use of rotational thromboelastometry (ROTEM) is lacking in this setting. The aim of the study was to evaluate ROTEM as a tool for assessing hemostasis during ECMO, by comparing it to TEG and conventional coagulation assays. We conducted a prospective, observational, single-center study on adult patients on ECMO support anticoagulated with unfractioned heparin (UFH). Kaolin reaction time (R, min) for TEG and INTEM clotting time (CT, sec) for ROTEM were analyzed and compared with conventional coagulation tests. In the study period, we included 25 patients on ECMO support (14 V-A and 11 V-V); 84 data points were available for the analysis. Median UFH infusion rate was 15 [11-18] IU/min/kg. Median values for activated partial thromboplastin time (aPTT) ratio, Kaolin TEG R time, and INTEM CT were 1.44 [1.21-1.7], 22 [13-40] min, and 201 [183-225] sec, respectively. INTEM CT (ROTEM) showed a moderate correlation with standard coagulation tests (R2 = 0.34 and 0.3 for aPTT and activated clotting time (ACT), respectively, p < 0.001). No significant correlation was found between INTEM CT and Kaolin R time (R2 = 0.01). Further studies are needed to identify an appropriate anticoagulation target for ROTEM during ECMO.

Viscoelastic Hemostatic Assays and Platelet Function Testing in Patients with Atherosclerotic Vascular Diseases.

Platelets play crucial role in acute vascular atherosclerotic diseases, including myocardial infarction and stroke. Additionally, platelet aggregation is a key target of antiplatelet agents, forming the keystone of pharmacotherapy of various atherosclerotic cardiovascular diseases. Thromboelastography and thromboelastometry, representing currently available viscoelastic hemostatic assays (VHA), are designed as whole blood, real-time analyzers of clot formation and clot resolution. These assays could, in theory, overcome some limitations of currently available platelet function testing assays. This article reviews the current experience with the use of VHA for platelet function testing and for monitoring of the response to antiplatelet therapy.

Viscoelastic hemostasis assays in septic, critically ill coronavirus disease 2019 patients: a practical guide for clinicians.

Coronavirus disease 2019 (COVID-19)-associated coagulopathy is unusual, poorly defined and is linked with significant hypercoagulability and microthrombotic and macrothrombotic complications leading to worse outcomes and higher mortality. Conventional coagulation assays do not always actively reflect these derangements and might fail to detect this coagulopathy. Viscoelastic hemostatic assays (VHA) provide a possible tool that adds to conventional coagulation assays in identifying this hypercoagulable state. VHA has been mostly used in surgery and trauma but it's still not well defined in sepsis patients with lack of large randomized trials. Few studies described VHA findings in patients with COVID-19 showing significant hypercoagulability and fibrinolysis shutdown. Clinicians taking care of these patients might have little experience interpreting VHA results. By reviewing the available literature on the use of VHA in sepsis, and the current knowledge on COVID-19-associated coagulopathy we provide clinicians with a practical guide on VHA utilization in patients with COVID-19.

Damage control resuscitation in patients with major trauma: prospects and challenges

: Trauma is the leading cause of death for younger ages across the world, with acute traumatic hemorrhage one of the main reasons of trauma mortality. In the last decade trauma resuscitation has significantly evolved away from the era of massive crystalloid transfusion where the endpoint was to keep a normal perfusing volume. A better understanding of homeostatic mechanisms of hemostasis, and of the systemic inflammatory and counter-inflammatory response syndromes gave birth to damage control and hemostatic resuscitation. Modern trauma resuscitation aims to control the lethal triad of coagulopathy, hypothermia and acidosis with the understanding that any deregulation from the steady state will lead to a cascade of adverse events. This review paper analyzes the latest evidence-based concepts of trauma resuscitation. These new strategies are the early transfusion of blood products in a ratio of ≤2:1:1 [packed red blood cells (PRBCs): fresh frozen plasma (FFP): platelets], the warming of the patient and of the administered fluids, the intravenous administration of 1 g of tranexamic acid (TXA) within 3 h of injury and then infusion of another 1 g for 8 hours, the use of viscoelastic hemostatic assays (VHAs) for optimization of the transfusion strategy, the minimization of active bleeding through permissive hypotension, and the early bleeding control with mechanical, interventional and surgical methods. Emphasis is placed in the evidence supporting each one of these interventions, and their application during the different stages of trauma care, from the prehospital to the hospital setting.

Референсные интервалы параметров ротационной тромбоэластометрии у беременных и родильниц: одноцентровое рандомизированное исследование

Введение: В последнее время стали востребованы интегральные тесты оценки системы гемостаза у женщин во время беременности, а также во время акушерских операций, связанных с кровотечением. В нашей стране отсутствуют работы по определению популяционных норм ротационной тромбоэластометрии (РОТЕМ) у беременных, рожениц и родильниц. Цель исследования: определить пределы референсных интервалов показателей РОТЕМ во время физиологически протекающей беременности и в раннем послеродовом периоде и провести корреляционный анализ со стандартными показателями коагулограммы. Материалы и методы: Обследовано 229 женщин Красноярского края, которые были поделены на 5 групп: небеременные (контроль), беременные II и III триместров, женщины раннего послеродового периода после операции кесарева сечения и естественных родов. Все женщины были сопоставимы по возрасту, индексу массы тела, сопутствующей патологии. Референсные интервалы рассчитывали либо через среднее и стандартное отклонение (для нормального распределения), либо через медиану и 2,5 и 97,5% перцентили (для ненормального распределения). Результаты: В процессе исследования подтвердилось, что во время беременности и в раннем послеродовом периоде происходят изменения в системе гемостаза в сторону гиперкоагуляции. Показатели ROTЕM у женщин в III триместре беременности и раннем послеродовом периоде существенно отличаются от показателей небеременных в популяции. У женщин после родов вне зависимости от способа родоразрешения различий между параметрами ROTЕM не установлено. Корреляция между параметрами ROTЕM и традиционными лабораторными тестами коагуляции выявила взаимосвязь между амплитудой плотности сгустка в тесте FIBTEM и уровнем фибриногена по Клаусу. Заключение: Представлены референсные интервалы параметров РОТЕМ у женщин Красноярского края. Найдена корреляция между параметрами РОТЭМ и уровнем фибриногена. Background: Recently, integral tests for hemostasis assessment in pregnant women as well as during obstetric surgery associated with bleeding have become popular. In our country, there are no studies of population norms for rotational thromboelastometry (ROTEM) in pregnant women, parturients and puerperants. Objectives: to identify reference intervals limits for ROTEM parameters during physiological pregnancy and in early postpartum period and to carry out correlation analysis with standard coagulogram parameters. Patients/Methods: We examined 229 women in Krasnoyarsk region; they were divided into 5 groups: nonpregnant (control), pregnant women in II and III trimesters, women in early postpartum period after cesarean section and after vaginal delivery. All women were comparable in age, body mass index, and concomitant pathology. Reference intervals were calculated either as the mean and standard deviation (for normal distribution), or as the median and 2.5 and 97.5% percentiles (for abnormal distribution). Results: The study confirmed hemostasis hypercoagulation changes during pregnancy and in early postpartum period. ROTEM parameters in women in III trimester of pregnancy and in early postpartum period differ significantly from those in non-pregnant women. Differences between ROTEM parameters in puerperants, regardless of the delivery method, not found. The correlation between ROTEM parameters and traditional laboratory coagulation tests revealed a relationship between clot density amplitude in FIBTEM test and Klaus fi brinogen level. Conclusions: Reference intervals of ROTEM parameters in women of Krasnoyarsk region are presented. A correlation was found between ROTEM parameters and fibrinogen level

Viscoelastic haemostatic assays and fibrinogen in paediatric acute traumatic coagulopathy: A comprehensive review.

Haemorrhage in paediatric trauma remains a significant cause of morbidity and mortality. Over recent years there has been increasing attention to the role of fibrinogen in traumatic haemorrhage and the association of low fibrinogen levels with poor patient outcomes. In addition, there has been a move towards using viscoelastic haemostatic assays (VHAs) to rapidly assess coagulation status and guide clinicians in the replacement of coagulation factors, including fibrinogen. In the paediatric population, there has been limited uptake of these principles and a paucity of data to support a change in practice. This paper summarises the available evidence in the published literature through a systematic review, presented in narrative format. There is limited high-quality prospective data on the use of VHA in the management of acute traumatic coagulopathy in the paediatric population. While the use of fibrinogen early in major haemorrhage is becoming standard practice, there are currently no randomised prospective studies comparing fibrinogen concentrate to cryoprecipitate. The early identification of hypo-fibrinogenemia and acute traumatic coagulopathy in paediatric trauma using VHA testing and subsequent early fibrinogen replacement with a concentrated off the shelf product is an attractive treatment option. However, there is currently insufficient high-level evidence to support the use of fibrinogen concentrate over cryoprecipitate in the paediatric trauma population. Pilot studies currently under way will go some way to addressing this important knowledge gap, and facilitate the design of larger definitive multi-centre randomised trials.

Strategies to minimize intraoperative blood loss during major surgery.

Reducing operative blood loss improves patient outcomes and reduces healthcare costs. The aim of this article was to review current surgical, anaesthetic and haemostatic intraoperative blood conservation strategies. This narrative review was based on a literature search of relevant databases up to 31 July 2019 for publications relevant to reducing blood loss in the surgical patient. Interventions can begin early in the preoperative phase through identification of patients at high risk of bleeding. Directly acting anticoagulants can be stopped 48 h before most surgery in the presence of normal renal function. Aspirin can be continued for most procedures. Intraoperative cell salvage is recommended when anticipated blood loss is greater than 500 ml and this can be continued after surgery in certain situations. Tranexamic acid is safe, cheap and effective, and routine administration is recommended when anticipated blood loss is high. However, the optimal dose, timing and route of administration remain unclear. The use of topical agents, tourniquet and drains remains at the discretion of the surgeon. Anaesthetic techniques include correct patient positioning, avoidance of hypothermia and regional anaesthesia. Permissive hypotension may be beneficial in selected patients. Promising haemostatic strategies include use of pharmacological agents such as desmopressin, prothrombin complex concentrate and fibrinogen concentrate, and use of viscoelastic haemostatic assays. Reducing perioperative blood loss requires a multimodal and multidisciplinary approach. Although high-quality evidence exists in certain areas, the overall evidence base for reducing intraoperative blood loss remains limited.

The use of viscoelastic haemostatic assays in the management of major bleeding: A British Society for Haematology Guideline.

The use of viscoelastic haemostatic assays in the management of major bleeding: A British Society for Haematology Guideline.

The use of viscoelastic haemostatic assays in non-cardiac surgical settings: a systematic review and meta-analysis.

Thrombelastography (TEG) and rotational thromboelastometry (ROTEM) are viscoelastic haemostatic assays (VHA) which exploit the elastic properties of clotting blood. The aim of this systematic review and meta-analysis was to evaluate the usefulness of these tests in bleeding patients outside the cardiac surgical setting. We searched the Cochrane Library, MEDLINE, EMBASE and SCOPUS. We also searched clinical trial registries for ongoing and unpublished studies, and checked reference lists to identify additional studies. We found 4 randomised controlled trials (RCTs) that met our inclusion criteria with a total of 229 participants. The sample size was small (from 28 to 111 patients) and the follow-up periods very heterogenous (from 4 weeks to 3 years). Pooled data from the 3 trials reporting on mortality (199 participants) do not show any effect of the use of TEG on mortality as compared to standard monitoring (based on the average treatment effect from a fixed-effects model): Risk Ratio (RR) 0.71; 95% Confidence Interval (CI): 0.43 to 1.16. Likewise, the use of VHA does not reduce the need for red blood cells (mean difference -0.64; 95% CI: -1.51 to 0.23), platelet concentrates (mean difference -1.12; 95% CI: -3.25 to 1.02), and fresh frozen plasma (mean difference -0.91; 95% CI: -2.02 to 0.19) transfusion. The evidence on mortality and other outcomes was uncertain (very low-certainty evidence, down-graded due to risk of biases, imprecision, and inconsistency). Overall, the certainty of the evidence provided by the trials was too low for us to be certain of the benefits and harms of viscoelastic haemostatic assay in non-cardiac surgical settings. More, larger, and better-designed RCTs should be carried out in this area.