Thrombelastography (TEG®): practical considerations on its clinical use in trauma resuscitation

Classic Light Transmission Platelet Aggregometry: Do We Still Need it?

For more than 50 years, light transmission aggregometry has been accepted as the gold standard test for diagnosing inherited platelet disorders in platelet-rich plasma, although there are other functional approaches performed in whole blood. In this article, several advantages and disadvantages of this technique over other laboratory approaches are discussed in the view of recent guidelines, and the necessity of functional assays, such as light transmission aggregometry in the era of molecular genetic testing, is highlighted.

Intrinsic or Nonintrinsic End-stage Liver Disease and Its Association With Thromboelastography-based Coagulation States in Patients Undergoing Liver Transplantation: A Retrospective Cohort Study

OBJECTIVES

Perioperative coagulation management in liver transplantation recipients is challenging. Viscoelastic testing with rotational thromboelastography (TEG) can help quantify hemostatic profiles. The current work aimed to investigate whether the etiology of end-stage liver disease, pretransplant disease severity, or pretransplant thrombotic or bleeding complications are associated with specific TEG patterns.

DESIGN

Retrospective cohort study.

SETTING

Single quaternary care hospital.

PARTICIPANTS

A total of 1,078 adult liver transplant patients.

INTERVENTIONS

The primary exposure was the etiology of end-stage liver disease classified as either intrinsic or nonintrinsic (eg, biliary obstruction or cardiovascular). Secondary exposures were patients' preoperative Model for End-Stage Liver Disease (MELD) score, Child-Pugh class, presence of major preoperative thrombotic complications, and major bleeding complications.

MEASUREMENTS AND MAIN RESULTS

Patients with intrinsic liver disease (84%) showed higher odds of hypocoagulable (odds ratio [OR]: 3.70, 95% confidence interval [CI]: 1.94-7.07, p < 0.0001) and mixed TEG patterns (OR: 4.59, 95% CI: 2.07-10.16, p = 0.0002) compared with those with nonintrinsic disease. Increasing MELD scores correlated with higher odds of hypocoagulable (OR: 1.14, 95% CI: 1.08-1.19, p < 0.0001) and mixed TEG patterns (OR: 1.08, 95% CI: 1.03-1.14, p = 0.0036). Child-Pugh class C was associated with higher odds of hypocoagulable (OR: 8.55, 95% CI: 3.26-22.42, p < 0.0001) and mixed patterns (OR: 12.48, 95% CI: 3.89-40.03, p < 0.0001). Major preoperative thrombotic complications were not associated with specific TEG patterns, although an interaction with liver disease severity was observed.

CONCLUSIONS

Liver transplantation candidates with intrinsic liver disease tend to exhibit hypocoagulable TEG patterns, while nonintrinsic disease is associated with hypercoagulability. Increasing end-stage liver disease severity, as evidenced by increasing MELD scores and higher Child-Pugh classification, was also associated with hypocoagulable TEG patterns.

Trauma-induced coagulopathy: What you need to know

ABSTRACT

Trauma-induced coagulopathy (TIC) is a global inflammatory state accompanied by coagulation derangements, acidemia, and hypothermia, which occurs after traumatic injury. It occurs in approximately 25% of severely injured patients, and its incidence is directly related to injury severity. The mechanism of TIC is multifaceted; proposed contributing factors include dysregulation of activated protein C, increased tPA, systemic endothelial activation, decreased fibrinogen, clotting factor consumption, and platelet dysfunction. Effects of TIC include systemic inflammation, coagulation derangements, acidemia, and hypothermia. Trauma-induced coagulopathy may be diagnosed by conventional coagulation tests including platelet count, Clauss assay, international normalized ratio, thrombin time, prothrombin time, and activated partial thromboplastin time; viscoelastic hemostatic assays such as thrombelastography and rotational thrombelastography; or a clinical scoring system known as the Trauma Induced Coagulopathy Clinical Score. Preventing TIC begins in the prehospital phase with early hemorrhage control, blood product resuscitation, and tranexamic acid therapy. Early administration of prothrombin complex concentrate is also being studied in the prehospital environment. The mainstays of TIC treatment include hemorrhage control, blood and component transfusions, and correction of abnormalities such as hypocalcemia, acidosis, and hypothermia.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Platelet-membrane camouflaged cerium nanoparticle-embedded gelatin methacryloyl hydrogel for accelerated diabetic wound healing

Impaired angiogenesis and excessive inflammation are major factors contributing to delayed wound healing in diabetic patients. This study presents the development of a novel multifunctional hydrogel, Pltm@CNPs/Gel, which incorporates platelet membrane camouflaged cerium nanoparticles into a gelatin methacryloyl matrix. The Pltm@CNPs/Gel nanocomposite hydrogel was characterized and tested for its effects on platelet activation, coagulation, cell viability, anti-oxidation, and anti-inflammation in vitro. Moreover, we evaluated the wound healing potential of the hydrogel in a diabetic rat model. Our findings demonstrate that the Pltm@CNPs/Gel hydrogel possesses anti-oxidative and anti-inflammatory properties. Furthermore, it accelerates diabetic wound healing by promoting neovascularization, cell proliferation, and collagen fiber organization. This study highlights the potential of the Pltm@CNPs/Gel hydrogel as a therapeutic option for diabetic wound healing and its promising applications as a diabetic wound dressing candidate.

[Surgery in patients with severe or inhibitory hemophilia A under prevention injection of emicizumab]

OBJECTIVE

To determine the features of preoperative hemostatic therapy and laboratory control in patients with severe and inhibitory forms of hemophilia A under preventive treatment by FVIII.

MATERIAL AND METHODS

Four patients with severe and inhibitory forms of hemophilia A underwent surgery between 2021 and 2022. All patients received Emicizumab (the first monoclonal drug for «non-factor» therapy of hemophilia) for prevention of specific hemorrhagic signs of hemophilia.

RESULTS

Surgical intervention under preventive Emicizumab therapy was essential. Additional hemostatic therapy was not carried out or performed in reduced mode. There were no hemorrhagic, thrombotic or other complications. Thus, the so-called «non-factor» therapy is one of the variants for uncontrollable hemostasis in patients with severe and inhibitory forms of hemophilia.

CONCLUSION

Preventive injection of Emicizumab ensures certain buffer of hemostasis system and stable lower limit of coagulation potential. This is the result of stable concentration of Emicizumab when used in any of the registered forms regardless of age and other individual characteristics. The risk of acute severe hemorrhage is excluded, while the probability of thrombosis is not increased. Indeed, FVIII has higher affinity than Emicizumab and displaces Emicizumab from coagulation cascade that does not result summation of total coagulation potential.

Citrate does not change viscoelastic haemostatic assays after cardiopulmonary bypass

CONTEXT

Viscoelastic hemostatic assays (VHA) are commonly used to identify specific cellular and humoral causes for bleeding in cardiac surgery patients. Cardiopulmonary bypass (CPB) alterations to coagulation are observable on VHA. Citrated VHA can approximate fresh whole blood VHA when kaolin is used as the activator in healthy volunteers. Some have suggested that noncitrated blood is more optimal than citrated blood for point-of-care analysis in some populations.

AIMS

To determine if storage of blood samples in citrate after CPB alters kaolin activated VHA results.

SETTINGS AND DESIGN

This was a prospective observational cohort study at a single tertiary care teaching hospital.

METHODS AND MATERIAL

Blood samples were subjected to VHA immediately after collection and compared to samples drawn at the same time and stored in citrate for 30, 90, and 150 min prior to kaolin activated VHA both before and after CPB.

STATISTICAL ANALYSIS USED

VHA results were compared using paired T-tests and Bland-Altman analysis.

RESULTS

Maximum clot strength and time to clot initiation were not considerably different before or after CPB using paired T-tests or Bland-Altman Analysis.

CONCLUSIONS

Citrated samples appear to be a clinically reliable substitute for fresh samples for maximum clot strength and time to VHA clot initiation after CPB. Concerns about the role of citrate in altering the validity of the VHA samples in the cardiac surgery population seem unfounded.

Investigation of Blood Coagulation Using Impedance Spectroscopy: Toward Innovative Biomarkers to Assess Fibrinogenesis and Clot Retraction

This study focused on a coagulation assessment based on the novel technique of blood-impedance-magnitude measurement. With the impedance characterization of recalcified human blood, it was possible to identify two significative biomarkers (i.e., measurable indicators) related to fibrin formation (1st marker) and clot retraction (2nd marker). The confocal microscopy of clotting blood provided a complete visual analysis of all the events occurring during coagulation, validating the significance of the impedance biomarkers. By analyzing the impedance phase angle (Φ) of blood during coagulation, as well as those of the clot and serum expelled after retraction, it was possible to further clarify the origin of the 2nd marker. Finally, an impedance-magnitude analysis and a rotational thromboelastometry test (ROTEM^®) were simultaneously performed on blood sampled from the same donor; the results pointed out that the 1st marker was related to clotting time. The developed technique gives rise to a comprehensive and evolutive insight into coagulation, making it possible to progressively follow the whole process in real time. Moreover, this approach allows coagulation to be tested on any materials’ surface, laying the ground for new studies related to contact coagulation, meaning, thrombosis occurring on artificial implants. In a near future, impedance spectroscopy could be employed in the material characterization of cardiovascular prostheses whose properties could be monitored in situ and/or online using effective biomarkers.

Platelet Transfusion for Trauma Resuscitation

Purpose of Review

To review the role of platelet transfusion in resuscitation for trauma, including normal platelet function and alterations in behavior following trauma, blood product transfusion ratios and the impact of platelet transfusion on platelet function, platelet function assays, risks of platelet transfusion and considerations for platelet storage, and potential adjunct therapies and synthetic platelets.

Recent Findings

Platelets are a critical component of clot formation and breakdown following injury, and in addition to these hemostatic properties, have a complex role in vascular homeostasis, inflammation, and immune function. Evidence supports that platelets are activated following trauma with several upregulated functions, but under conditions of severe injury and shock are found to be impaired in their hemostatic behaviors. Platelets should be transfused in balanced ratios with red blood cells and plasma during initial trauma resuscitation as this portends improved outcomes including survival. Multiple coagulation assays can be used for goal-directed resuscitation for traumatic hemorrhage; however, these assays each have drawbacks in terms of their ability to measure platelet function. While resuscitation with balanced transfusion ratios is supported by the literature, platelet transfusion carries its own risks such as bacterial infection and lung injury. Platelet supply is also limited, with resource-intensive storage requirements, making exploration of longer-term storage options and novel platelet-based therapeutics attractive. Future focus on a deeper understanding of the biology of platelets following trauma, and on optimization of novel platelet-based therapeutics to maintain hemostatic effects while improving availability should be pursued.

Summary

While platelet function is altered following trauma, platelets should be transfused in balanced ratios during initial resuscitation. Severe injury and shock can impair platelet function, which can persist for several days following the initial trauma. Assays to guide resuscitation following the initial period as well as storage techniques to extend platelet shelf life are important areas of investigation.

Response of the VCMVet viscoelastic coagulation monitor to veterinary environmental simulation challenges

BACKGROUND

Traditional viscoelastic clotting tests are significantly impacted by the operator and environmental variation. The VCMVet coagulation monitor could provide a more user-friendly alternative for veterinary practices.

OBJECTIVES

We aimed to determine if environmental vibration commonly encountered in veterinary practice alters the results of a point-of-care viscoelastic device, the VCMVet.

METHODS

Nine fresh whole blood samples from healthy dogs were evaluated simultaneously using VCMVet instruments under four environmental conditions: (normal) alone and undisturbed on a raised tabletop, (centrifuge) on a countertop 6 inches from a centrifuge that operated at 12 000 rpm for 10 minutes every 20 minutes, (workspace) on a tabletop workspace in proximity to two heavy-use computers, and (gurney) on a rolling gurney at a walking pace for 10 minutes every 20 minutes. Results were compared between conditions using a Friedman test, and if this was significant (P-value < .05), it was followed by a Wilcoxon test for paired samples.

RESULTS

Analysis of samples on a rolling gurney created obvious movement artifacts, and this condition was excluded from statistical analysis. The centrifuge condition resulted in a significantly higher alpha angle (median 49 degrees, interquartile range 4) than the normal condition (median 46 degrees, interquartile range 5, P = .0078). Other viscoelastic parameters were not significantly different between the normal, centrifuge, and workspace conditions.

CONCLUSIONS

The VCMVet is suitable for use in a busy veterinary environment but should be protected from vibration. The instrument does not produce reliable results when operated on a moving gurney, and it should be stationary during sample analysis.

Efficacy of using thromboelastography to detect coagulation function and platelet function in patients with acute cerebral infarction

Thromboelastography (TEG) is commonly used to predict coagulation state in patients with active bleeding. However, the correlation between TEG parameters and conventional tests in patients with cerebrovascular disease (CVD) remains unexplored. Here, we assessed the TEG values and their correlation with conventional tests in patients with acute cerebral infarction. Eighty-eight patients with acute cerebral infarction were enrolled from the Department of Neurology of Suzhou Medical School. Thirty healthy controls were enrolled from the preventive care department in the same hospital who were taking a physical examination. TEG 5000 thromboelastogram system was used to obtain TEG parameters. The automatic blood coagulation analyzer was used to measure the activated partial thromboplastin time (APTT), prothrombin time (PT), D-Dimer (DD) and fibrinogen (FIB) and platelet function. Among five TEG parameters, the R and K value decreased while MA value, alpha angle and CI value increased in patient group when compared with the healthy controls. The correlation between TEG parameters and conventional tests including DD, FIB, and platelet function are consistent with the high coagulation state in the patient group. Our results demonstrate that TEG parameters are sensitive indicators of high coagulation state in patients with acute cerebral infarction.

The coagulopathy of liver disease: a shift in thinking

The coagulopathy of chronic liver disease causes derangement of the results of traditional laboratory tests. As such, there is an expectation that when undergoing invasive procedures patients with cirrhosis are at increased risk of bleeding. Standard practice is to optimise laboratory values with prophylactic transfusions of platelets, plasma and fibrinogen to reduce perceived bleeding risk. There has been a shift in thinking regarding coagulation in patients with chronic liver disease, whereby a rebalancing of haemostasis occurs with reduction in both procoagulants and anticoagulants. Guidelines for the preprocedural management of patients with chronic liver disease are inconsistent and may not account for this new paradigm. The risk of prophylactic transfusion should be measured against the risk of bleeding while considering the rebalancing of haemostasis. Future management may be guided by whole blood viscoelastic tests or use of thrombopoietin receptor agonists to optimise patients in these scenarios.

Investigating the Multi-Faceted Nature of Radiation-Induced Coagulopathies in a Göttingen Minipig Model of Hematopoietic Acute Radiation Syndrome

Coagulopathies are well documented after acute radiation exposure at hematopoietic doses, and radiation-induced bleeding is notably one of the two main causes of mortality in the hematopoietic acute radiation syndrome. Despite this, understanding of the mechanisms by which radiation alters hemostasis and induces bleeding is still lacking. Here, male Göttingen minipigs received hematopoietic doses of 60Co gamma irradiation (total body) and coagulopathies were characterized by assessing bleeding, blood cytopenia, fibrin deposition, changes in hemostatic properties, coagulant/anticoagulant enzyme levels, and markers of inflammation, endothelial dysfunction, and barrier integrity to understand if a relationship exists between bleeding, hemostatic defects, bone marrow aplasia, inflammation, endothelial dysfunction and loss of barrier integrity. Acute radiation exposure induced coagulopathies in the Göttingen minipig model of hematopoietic acute radiation syndrome; instances of bleeding were not dependent upon thrombocytopenia. Neutropenia, alterations in hemostatic parameters and damage to the glycocalyx occurred in all animals irrespective of occurrence of bleeding. Radiation-induced bleeding was concurrent with simultaneous thrombocytopenia, anemia, neutropenia, inflammation, increased heart rate, decreased nitric oxide bioavailability and endothelial dysfunction; bleeding was not observed with the sole occurrence of a single aforementioned parameter in the absence of the others. Alteration of barrier function or clotting proteins was not observed in all cases of bleeding. Additionally, fibrin deposition was observed in the heart and lungs of decedent animals but no evidence of DIC was noted, suggesting a unique pathophysiology of radiation-induced coagulopathies. These findings suggest radiation-induced coagulopathies are the result of simultaneous damage to several key organs and biological functions, including the immune system, the inflammatory response, the bone marrow and the cardiovasculature.

Intravenous administration of tranexamic acid in total hip arthroplasty does not change the blood coagulopathy: a prospective thrombelastography analysis

OBJECTIVE

Despite the wide use of tranexamic acid (TXA) in the perioperative period of total hip arthroplasty (THA), whether the hemostatic state changes after the application of intravenous (IV)-TXA are still unknown. The aim of this study was to investigate whether IV administration of TXA changes the blood coagulation following primary THA via thrombelastography (TEG) analysis and conventional laboratory tests.

METHODS

A total of 174 patients who underwent primary THA from September 2016 to July 2018 were selected. They were randomly divided into two groups, 86 patients with IV administration of 15 mg/kg TXA and 88 controls without TXA usage. Demographic data, TEG paremeters, d-dimer levels, fibrin degradation products, hemoglobin, hematocrit concentration, platelet, transfusion rates, perioperative blood loss, and the occurrence of deep vein thrombosis were collected. TEG and conventional laboratory tests were performed the day before operation, the first day after operation, and seventh day after operation.

RESULTS

There were no differences with regard to TEG or conventional laboratory tests between the two groups (p > 0.05). The total blood loss and drain blood loss in the TXA group were significantly lower than those in the control group (p < 0.05). The transfusion rates and the volume of blood transfusion of the control group were higher than those of the TXA group (p < 0.05).

CONCLUSION

The administration of IV-TXA resulted in a significant reduction in total blood loss, transfusion volumes, and transfusion rates without the increase of thromboembolic complications. Moreover, it was confirmed that TXA would not change the coagulation via the TEG analysis.

Hemostasis, coagulation and thrombin in venoarterial and venovenous extracorporeal membrane oxygenation: the HECTIC study

Extracorporeal membrane oxygenation (ECMO) support has a high incidence of both bleeding and thrombotic complications. Despite clear differences in patient characteristics and pathologies between veno-venous (VV) and veno-arterial (VA) ECMO support, anticoagulation practices are often the same across modalities. Moreover, there is very little data on their respective coagulation profiles and comparisons of thrombin generation in these patients. This study compares the coagulation profile and thrombin generation between patients supported with either VV and VA ECMO. A prospective cohort study of patients undergoing VA and VV ECMO at an Intensive care department of a university hospital and ECMO referral centre. In addition to routine coagulation testing and heparin monitoring per unit protocol, thromboelastography (TEG), multiplate aggregometry (MEA), calibrated automated thrombinography (CAT) and von-Willebrand’s activity (antigen and activity ratio) were sampled second-daily for 1 week, then weekly thereafter. VA patients had significantly lower platelets counts, fibrinogen, anti-thrombin and clot strength with higher d-dimer levels than VV patients, consistent with a more pronounced consumptive coagulopathy. Thrombin generation was higher in VA than VV patients, and the heparin dose required to suppress thrombin generation was lower in VA patients. There were no significant differences in total bleeding or thrombotic event rates between VV and VA patients when adjusted for days on extracorporeal support. VA patients received a lower median daily heparin dose 8500 IU [IQR 2500–24000] versus VV 28,800 IU [IQR 17,300–40,800.00]; < 0.001. Twenty-eight patients (72%) survived to hospital discharge; comprising 53% of VA patients and 77% of VV patients. Significant differences between the coagulation profiles of VA and VV patients exist, and anticoagulation strategies for patients of these modalities should be different. Further research into the development of tailored anticoagulation strategies that include the mode of ECMO support need to be completed.

The role of cryoprecipitate in human and canine transfusion medicine

OBJECTIVE

To evaluate the current role of cryoprecipitate in human and canine transfusion medicine.

DATA SOURCES

Human and veterinary scientific reviews and original studies found using PubMed and CAB Abstract search engines were reviewed.

HUMAN DATA SYNTHESIS

In the human critical care setting, cryoprecipitate is predominantly used for fibrinogen replenishment in bleeding patients with acute traumatic coagulopathy. Other coagulopathic patient cohorts for whom cryoprecipitate is recommended include those undergoing cardiovascular or obstetric procedures or patients bleeding from advanced liver disease. Preferential selection of cryoprecipitate versus fibrinogen concentrate (when available) is currently being investigated. Also a matter of ongoing debate is whether to administer this product as part of a fixed-dose massive hemorrhage protocol or to incorporate it into a goal-directed transfusion algorithm applied to the individual bleeding patient.

VETERINARY DATA SYNTHESIS

Although there are sporadic reports of the use of cryoprecipitate in dogs with heritable coagulopathies, there are few to no data pertaining to its use in acquired hypofibrinogenemic states. Low fibrinogen in dogs (as in people) has been documented with acute traumatic coagulopathy, advanced liver disease, and disseminated intravascular coagulation. Bleeding secondary to these hypocoagulable states may be amenable to cryoprecipitate therapy. Indications for preferential selection of cryoprecipitate (versus fresh frozen plasma) remain to be determined.

CONCLUSIONS

In the United States, cryoprecipitate remains the standard of care for fibrinogen replenishment in the bleeding human trauma patient. Its preferential selection for this purpose is the subject of several ongoing human clinical trials. Timely incorporation of cryoprecipitate into the transfusion protocol of the individual bleeding patient with hypofibrinogenemia may conserve blood products, mitigate adverse transfusion-related events, and improve patient outcomes. Cryoprecipitate is readily available, effective, and safe for use in dogs. The role of this blood product in clinical canine patients with acquired coagulopathy remains unknown.

Fast-Track Liver Transplantation: Six-year Prospective Cohort Study with an Enhanced Recovery After Surgery (ERAS) Protocol

Introduction

Enhanced recovery after surgery (ERAS) has been shown to facilitate discharge, decrease length of stay, improve outcomes and reduce costs. We used this concept to design a comprehensive fast-track pathway (OR-to-discharge) before starting our liver transplant activity and then applied this protocol prospectively to every patient undergoing liver transplantation at our institution, monitoring the results periodically. We now report our first six years results.

Patients and methods

Prospective cohort study of all the liver transplants performed at our institution for the first six years. Balanced general anesthesia, fluid restriction, thromboelastometry, inferior vena cava preservation and temporary portocaval shunt were strategies common to all cases. Standard immunosuppression administered included steroids, tacrolimus (delayed in the setting of renal impairment, with basiliximab induction added) and mycophenolate mofetil. Tacrolimus dosing was adjusted using a Bayesian estimation methodology. Oral intake and ambulation were started early.

Results

A total of 240 transplants were performed in 236 patients (191♂/45♀) over 74 months, mean age 56.3±9.6 years, raw MELD score 15.5±7.7. Predominant etiologies were alcohol (n = 136) and HCV (n = 82), with hepatocellular carcinoma present in 129 (54.7%). Nine patients received combined liver and kidney transplants. The mean operating time was 315±64 min with cold ischemia times of 279±88 min. Thirty-one patients (13.1%) were transfused in the OR (2.4±1.2 units of PRBC). Extubation was immediate (< 30 min) in all but four patients. Median ICU length of stay was 12.7 hours, and median post-transplant hospital stay was 4 days (2-76) with 30 patients (13.8%) going home by day 2, 87 (39.9%) by day 3, and 133 (61%) by day 4, defining our fast-track group. Thirty-day-readmission rate (34.9%) was significantly lower (28.6% vs. 44.7% p=0.015) in the fast-track group. Patient survival was 86.8% at 1 year and 78.6% at five years.

Conclusion

Fast-Tracking of Liver Transplant patients is feasible and can be applied as the standard of care

Do all cardiac surgery patients benefit from antifibrinolytic therapy?

BACKGROUND

In trauma patients, the recognition of fibrinolysis phenotypes has led to a re-evaluation of the risks and benefits of antifibrinolytic therapy (AF). Many cardiac patients also receive AF, but the distribution of fibrinolytic phenotypes in that population is unknown. The purpose of this hypothesis-generating study was to fill that gap.

METHODS

Seventy-eight cardiac surgery patients were retrospectively reviewed. Phenotypes were defined as hypofibrinolytic (LY30 <0.8%), physiologic (0.8%-3.0%), and hyperfibrinolytic (>3%) based on thromboelastogram.

RESULTS

The population was 65 ± 10-years old, 74% male, average body mass index of 29 ± 5 kg/m² . Fibrinolytic phenotypes were distributed as physiologic = 45% (35 of 78), hypo = 32% (25 of 78), and hyper = 23% (18 of 78). There was no obvious effect of age, gender, race, or ethnicity on this distribution; 47% received AF. For AF versus no AF, the time with chest tube was longer (4 [1] vs. 3 [1] days, p = .037), and all-cause morbidity was more prevalent (51% vs. 25%, p = .017). However, when these two groups were further stratified by phenotypes, there were within-group differences in the percentage of patients with congestive heart failure (p = .022), valve disease (p = .024), on-pump surgery (p < .0001), estimated blood loss during surgery (p = .015), transfusion requirement (p = .015), and chest tube output (p = .008), which highlight other factors along with AF that might have affected all-cause morbidity.

CONCLUSION

This is the first description of the prevalence of three different fibrinolytic phenotypes and their potential influence on cardiac surgery patients. The use of AF was associated with increased morbidity, but because of the small sample size and treatment allocation bias, additional confirmatory studies are necessary. We hope these present findings open the dialog on whether it is safe to administer AFs to cardiac surgery patients who are normo- or hypofibrinolytic.

Comparison of Thromboelastography and Conventional Coagulation Tests in Patients With Severe Liver Disease

OBJECTIVE

Thromboelastography (TEG) may provide rapid and clinically important coagulation information in acutely ill patients with chronic liver disease (CLD). Our objective was to describe the relationship between TEG and conventional coagulation tests (CCTs), which has not been previously explored in this population.

METHODS

In acutely ill patients with severe CLD (Child-Pugh score > 9, category C), we conducted a prospective observational study investigating coagulation assessment as measured by both CCTs and TEG. We used quantile regression to explore 30 associations between TEG parameters and corresponding CCTs. We compared TEG and CCT measures of coagulation initiation, clot formation, clot strength, and fibrinolysis.

RESULTS

We studied 34 patients on a total of 109 occasions. We observed inconsistent associations between TEG and CCT measures of coagulation initiation: TEG (citrated kaolin [CK] assay) standard reaction time and international normalized ratio: R ² = 0.117 (P = .044). Conversely, there were strong and consistent associations between tests of clot formation: TEG (CK) kinetics time and fibrinogen: R ² = 0.202 (P < .0001) and TEG (CK) α angle and fibrinogen 0.263 (P < .0001). We also observed strong associations between tests of clot strength, specifically TEG MA and conventional fibrinogen levels, across all TEG assays: MA (CK) and fibrinogen: R ² = 0.485 (P < .0001). There were no associations between TEG and D-dimer levels.

CONCLUSIONS

In acutely ill patients with CLD, there are strong and consistent associations between TEG measures of clot formation and clot strength and conventional fibrinogen levels. There are weak and/or inconsistent associations between TEG and all other conventional measures of coagulation.

Does the Degree of Platelet Adenosine Diphosphate and Arachidonic Acid Receptor Inhibition Correlate With the Severity of Injury in Non-Brain-Injured Trauma Patients?

BACKGROUND

Direct correlations between platelet adenosine diphosphate (ADP) and arachidonic acid (AA) receptor inhibition have been described in the traumatic brain injury (TBI) population. Our goal was to evaluate the percent inhibition of ADP receptor inhibition (ADPri) and AA receptor inhibition (AAri) receptors in non-TBI patients and correlate injury severity and outcomes.

METHODS

We performed a retrospective review of non-TBI patients admitted to our trauma center, who received thromboelastography with platelet mapping prior to blood transfusion. Exclusion criteria included patients younger than 18 years, current antiplatelet therapy, or history of renal failure. Univariate descriptive statistics and bivariate comparisons were performed on patient demographic and outcomes. Multivariable linear regression models were constructed to quantify any association between ADPri and AAri with injury outcomes. High ADP inhibition was defined >20% and high AA inhibition >7%.

RESULTS

117 patients met inclusion criteria. Mean age was 53 years with 61% male. Mean ADPri was 64% and AAri 42%. On bivariate analysis, no statistically significant differences with respect to injury severity measures or outcomes were identified. On multivariable linear regression, AAri was associated with longer hospital length of stay.

DISCUSSION

There was a high degree of platelet dysfunction in this cohort of severely injured patients without TBI. Despite this, the only correlation identified between injury severity and outcomes was AAri correlating with hospital length of stay. Irrespective of injury severity or outcomes, these patients' results were far from reported "normal" values. Further, research is needed to determine the significance and clinical implications of thromboelastography with platelet mapping use in trauma care.

Thromboelastography-guided blood transfusion during cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy: study protocol for a prospective randomised controlled trial

INTRODUCTION

Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is a well-established treatment for peritoneal cancer (PC). However, this kind of combination therapy is associated with a high incidence of complications. Moreover, relative studies have indicated that traditional laboratory testing is insufficient to demonstrate the overall haemostatic physiology of CRS/HIPEC. Thromboelastography (TEG), administered by monitoring dynamic changes in haemostasis, has been shown to contribute to reducing transfusion requirements and improving survival. However, there is no evidence to verify whether TEG can be applied to guide transfusion strategies during CRS/HIPEC. Therefore, we aim to investigate whether TEG-guided blood product transfusion (TEG-BT) therapy is superior to traditional blood product transfusion (T-BT) therapy for guiding perioperative blood transfusion treatment and improving the prognosis of patients undergoing CRS/HIPEC.

METHODS AND ANALYSIS

The TEG-BT versus T-BT study is a single-centre, randomised, blinded outcome assessment clinical trial of 162 patients with PC, aged 18-64 years and undergoing CRS/HIPEC. Participants will be randomly allocated to receive TEG-BT or T-BT. The primary outcome will be the evaluation of perioperative blood transfusion, which refers to the total amount of blood transfusion given from the time patients enter the operating room up to 72 hours postoperatively. The secondary outcomes will include the transfusion volume during surgery, total amount of intraoperative infusion, amount of blood lost during the operation, total blood transfusion between 0 and 72 hours after surgery, lowest haemoglobin level within 72 hours after surgery, intensive care unit duration, overall length of stay, total cost of hospitalisation and adverse events. Data will be analysed according to the intention-to-treat principle.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Scientific Research Ethics Committee of Beijing Shijitan Hospital Affiliated with Capital Medical University (Approval Number: sjtkyll-lx-2020-3). The results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR2000028835).

An overview of the potential sources of diagnostic errors in (classic) thromboelastography curve interpretation and preventive measures

Thromboelastography (TEG), a hemostatic point-of-care assay, provides global information about fibrin formation, platelet activation, and clot retraction in real-time. As it is an operator-dependent technique, error in any phase of the testing process can result in the misinterpretation of the thromboelastogram, and subsequently lead to mismanagement of the patient, wastage of blood products besides increasing the financial burden on the hospital and the patient. The present paper describes the possible errors leading to wrong thromboelastogram interpretation, and the respective preventive measure. In the light of limited resources available for operational challenges in TEG, this review paper can prove to be helpful.

Use of the ZDF rat to model dietary fat induced hypercoagulability is limited by progressive and fatal nephropathy

INTRODUCTION

Zucker diabetic fatty (ZDF) rats are used widely as an animal model of metabolic syndrome and insulin resistance. Our study focused on the effects of high versus low dietary fat on the development of Type 2 diabetes in obese male ZDF rats (fa/fa), including biomarkers to detect early signs of hypercoagulability and vascular injury in the absence of overt thrombosis.

METHODS

In this study, male (5/group) 10-week-old CRL:ZDF370(obese) rats were fed low (LFD, 16.7% fat) or high fat (HFD, 60% fat) diet for 12 or 15 weeks. Cohorts of 5 rats within diet groups were scheduled for sample collection after weeks 12 and 15.

RESULTS

HFD-fed ZDF rats had oily coats, lower rates of food consumption, more accelerated weight gain and increased serum cholesterol (+15%) and triglyceride concentrations (+75%) vs. LFD-fed ZDF rats. Urinary ketones were observed only in HFD-fed ZDF rats and greater urine glucose and protein concentrations in HFD-fed ZDF vs. LFD-fed ZDF rats were seen. Hemostasis testing showed ~2-fold greater fibrinogen concentration, increased von Willebrand factor concentration, and high thrombin generation in HFD-fed ZDF vs LFD-fed ZDF rats. Increased mortality in the HFD-fed ZDF rat was attributed to exacerbations of altered carbohydrate metabolism as evidenced by ketonuria and nephropathy leading to renal failure.

DISCUSSION

This characterization shows that the ZDF rat at the age, sex and weight used in this study is highly sensitive to dietary fat content that can exacerbate prothrombotic, metabolic and renal disturbances and increase mortality.

Differences in platelet aggregometers to study platelet function and coagulation dysregulation in xenotransplantation

Xenotransplantation (ie, cross-species transplantation) using genetically engineered pig organs could be a limitless source to solve the shortage of organs and tissues worldwide. However, despite prolonged survival in preclinical pig-to-nonhuman primate xenotransplantation trials, interspecies coagulation dysregulation remains to be overcome in order to achieve continuous long-term success. Different platelet aggregometry methods have been previously used to study the coagulation dysregulation with wild-type and genetically engineered pig cells, including the impact of possible treatment options. Among these methods, while thromboelastography and rotational thromboelastometry measure the change in viscoelasticity, optical aggregometry measures the change in opacity. Recently, impedance aggregometry has been used to measure changes in platelet aggregation in electrical conductance, providing more information to our understanding of coagulation dysregulation in xenotransplantation compared to previous methods. The present study reviews the merits and differences of the above-mentioned platelet aggregometers in xenotransplantation research.

Characterizing the ability of an ice recrystallization inhibitor to improve platelet cryopreservation

Improving aspects of platelet cryopreservation would help ease logistical challenges and potentially expand the utility of frozen platelets. Current cryopreservation procedures damage platelets, which may be caused by ice recrystallization. We hypothesized that the addition of a small molecule ice recrystallization inhibitor (IRI) to platelets prior to freezing may reduce cryopreservation-induced damage and/or improve the logistics of freezing and storage. Platelets were frozen using standard conditions of 5-6% dimethyl sulfoxide (Me₂SO) or with supplementation of an IRI, N-(2-fluorophenyl)-d-gluconamide (2FA), prior to storage at -80 °C. Alternatively, platelets were frozen with 5-6% Me₂SO at -30 °C or with 3% Me₂SO at -80 °C with or without 2FA supplementation. Supplementation of platelets with 2FA improved platelet recovery following storage under standard conditions (p = 0.0017) and with 3% Me₂SO (p = 0.0461) but not at -30 °C (p = 0.0835). 2FA supplementation was protective for GPVI expression under standard conditions (p = 0.0011) and with 3% Me₂SO (p = 0.0042). Markers of platelet activation, such as phosphatidylserine externalization and microparticle release, were increased following storage at -30 °C or with 3% Me₂SO, and 2FA showed no protective effect. Platelet function remained similar regardless of 2FA, although functionality was reduced following storage at -30 °C or with 3% Me₂SO compared to standard cryopreserved platelets. While the addition of 2FA to platelets provided a small level of protection for some quality parameters, it was unable to prevent alterations to the majority of in vitro parameters. Therefore, it is unlikely that ice recrystallization is the major cause of cryopreservation-induced damage.

Site-Of-Care Viscoelastic Assay in Major Trauma Improves Outcomes and Is Cost Neutral Compared with Standard Coagulation Tests

Major hemorrhage is often associated with trauma-induced coagulopathy. Targeted blood product replacement could achieve faster hemostasis and reduce mortality. This study aimed to investigate whether thromboelastography (TEG^®) goal-directed transfusion improved blood utilization, reduced mortality, and was cost effective. Data were prospectively collected in a U.K. level 1 trauma center, in patients with major hemorrhage one year pre- and post-implementation of TEG^® 6s Hemostasis Analyzers. Mortality, units of blood products transfused, and costs were compared between groups. Patient demographics in pre-TEG (n = 126) and post-TEG (n = 175) groups were similar. Mortality was significantly lower in the post-TEG group at 24 h (13% vs. 5%; p = 0.006) and at 30 days (25% vs. 11%; p = 0.002), with no difference in the number or ratio of blood products transfused. Cost of blood products transfused was comparable, with the exception of platelets (average £38 higher post-TEG). Blood product wastage was significantly lower in the post-TEG group (1.8 ± 2.1 vs. 1.1 ± 2.0; p = 0.002). No statistically significant difference in cost was observed between the two groups (£753 ± 651 pre-TEG; £830 ± 847 post-TEG; p = 0.41). These results demonstrate TEG 6s-driven resuscitation algorithms are associated with reduced mortality, reduced blood product wastage, and are cost neutral compared to standard coagulation tests.

Thromboelastography as a tool for monitoring blood coagulation dysfunction after adequate fluid resuscitation can predict poor outcomes in patients with septic shock

BACKGROUND

Coagulation abnormalities are universal in patients with septic shock and likely play a key role in multiple organ dysfunction syndrome. Early diagnosis and management of sepsis-induced coagulopathy can influence the outcome. Thromboelastography (TEG) can effectively distinguish hypercoagulability and hypocoagulability in patients with septic shock. TEG may be a useful tool to objectively evaluate the degree and risk of sepsis.

METHODS

A total of 76 adult patients with septic shock were enrolled and divided into four groups: patients with hypotension requiring vasopressor and serum lactate level >2 mmol/L (group A), patients with hypotension requiring vasopressor and serum lactate level ≤2 mmol/L (group B), patients with mean arterial pressure ≥65 mmHg and serum lactate level >2 mmol/L (group C), and patients with mean arterial pressure ≥65 mmHg and serum lactate level ≤2 mmol/L (group D) after adequate fluid resuscitation. TEG values were obtained at the emergency room and after 6 hours of adequate fluid resuscitation. Data on fibrinogen (FIB) levels, international normalized ratio (INR), activated partial thromboplastin time (aPTT), blood gas, platelet count, and D-dimers were also collected.

RESULTS

The length of stay in the intensive care unit was 9.11 ± 5.36 days. Mortality rate was 6.58%. The values of reaction time, kinetics time, maximum amplitude, alpha angle, aPTT, INR, serum creatinine, FIB, and sepsis-related organ failure assessment (SOFA) score showed a significant differences. The results of the routine coagulation tests, blood gas volume, platelet count, procalcitonin level, D-dimer level, white blood cell count, creatinine level, disseminated intravascular coagulation score, SOFA score, and TEG values after adequate fluid resuscitation were significantly different between groups A and B, groups A and C, groups A and D, groups B and D, and groups C and D.

CONCLUSION

TEG is helpful in predicting the severity of sepsis and outcome of patients.

Effect of 7.5% hypertonic saline solution on whole blood coagulation in healthy dogs using thromboelastography

Objective

To evaluate the effects of 7.5% hypertonic saline solution (HSS) on whole blood coagulation in healthy dogs and to compare electrolyte and osmolality measurements between in vivo and in vitro dilution with HSS.

Design

Experimental study.

Setting

University teaching hospital.

Animals

Twelve adult purpose‐bred Beagles.

Interventions

All 12 dogs received 5 mL/kg 7.5% HSS at 1 mL/kg/min. After a 14‐day washout period, 5 of these dogs were randomly selected and received the same volume of 0.9% NaCl. Blood samples were collected before infusion, immediately after infusion, and at 30, 60, and 90 minutes after infusion for the measurement of coagulation using thromboelastography. For comparison of electrolyte concentrations and osmolality between in vitro dilution and in vivo dilution of HSS, 6‐mL blood samples were diluted with 7.5% HSS (1:18 ratio) at baseline.

Measurements and Main Results

None of the thromboelastography variables differed significantly between the 7.5% HSS group and the 0.9% NaCl group. The sodium and chloride levels, and the osmolality, were significantly increased at all postinfusion time points compared to baseline, while those levels were significantly higher with in vitro dilution than all postinfusion time points. However, almost all the values gradually decreased and became similar to baseline values in case of in vivo dilution.

Conclusions

The clinically relevant dose of 7.5% HSS (5 mL/kg) did not affect whole blood coagulation significantly in healthy Beagles. Further studies are necessary to assess the effect of HSS on blood coagulation in canine patients with shock.

Novel Treatment Strategy for Patients with Venom-Induced Consumptive Coagulopathy from a Pit Viper Bite

Pit viper venom commonly causes venom-induced consumptive coagulopathy (VICC), which can be complicated by life-threatening hemorrhage. VICC has a complex pathophysiology affecting multiple steps of the coagulation pathway. Early detection of VICC is challenging because conventional blood tests such as prothrombin time (PT) and activated partial thromboplastin time (aPTT) are unreliable for early-stage monitoring of VICC progress. As the effects on the coagulation cascade may differ, even in the same species, the traditional coagulation pathways cannot fully explain the mechanisms involved in VICC or may be too slow to have any clinical utility. Antivenom should be promptly administered to neutralize the lethal toxins, although its efficacy remains controversial. Transfusion, including fresh frozen plasma, cryoprecipitate, and specific clotting factors, has also been performed in patients with bleeding. The effectiveness of viscoelastic monitoring in the treatment of VICC remains poorly understood. The development of VICC can be clarified using thromboelastography (TEG), which shows the procoagulant and anticoagulant effects of snake venom. Therefore, we believe that TEG may be able to be used to guide hemostatic resuscitation in victims of VICC. Here, we aim to discuss the advantages of TEG by comparing it with traditional coagulation tests and propose potential treatment options for VICC.

Thromboelastography in pre-surgery monitoring in Hemophilia A with high inhibitor titer: case report and literature review

The development of factor VIII inhibitors (allo-antibodies) continues to be a major complication in the management of severe forms of hemophilia A, especially as far as treatment and treatment response monitoring is concerned. The need to implement a reliable laboratory assay is all the more obvious if major surgery occurs, when conventional tests (activated partial thromboplastin time APTT, prothrombin time PT, factor VIII level) are of no avail and there is a very fragile balance between bleeding and thrombosis.

We report the case of a 32 year-old patient diagnosed with severe Hemophilia A, referred to the Comprehensive Center for the Diagnosis and Treatment of Hemophilia of the Fundeni Clinical Institute for a multidisciplinary assessment in view of a total left hip arthroplasty due to aseptic necrosis of the femoral neck.

Workup showed a high inhibitor titer (>200 BU). Taking into consideration the interindividual variability of the response to bypassing agents, as well as the bleeding risk associated with a major orthopedic surgery, we used thromboelastography (TEG) to assess the patient’s response to aPCC (activated prothrombin complex concentrate) and rFVIIa (activated recombinant factor VII). The findings helped select the optimal replacement scheme to ensure perioperative hemostasis.

Establishment of thromboelastography reference intervals by indirect method and relevant factor analyses

Thromboelastography (TEG) as a global coagulation test has been continuously developed for many decades in either research or clinical practice. The versatility of TEG test leads to difficulty in standardization and result interpretation. Reference intervals (RIs) of TEG may be one of the most controversial factors that influence its wide applications. RIs establishment with the traditional method is time‐consuming and laborious as well as beyond general laboratory capability. Indirect method using stored data and with statistical calculation and small cost is emerging as an alternative approach for RIs determination. Gender, age, or both affect RIs and must be taken into account before RIs estimation. The present study retrospectively collected a total of 930 TEG results as subjects and established RIs with indirect method for Kaolin‐activated TEG, including the parameters of R, K, αAngle, MA, and CI. Furthermore, gender, age, and gender‐dependent age subsets analyses were performed to determine their effects on RIs of TEG. In this study, we found that TEG parameters showed more hypercoagulability in female than male, most of the measured TEG variables were significantly associated with aging, but only in male statistical significance was found among different age stratification and 60‐year‐old could be considered as cutting point to differentiate coagulation ability in male. In addition, RIs of TEG were estimated by indirect method suitably and verified to be valid in our study. Finally, the RIs of TEG by indirect method were basically significantly different to the RIs recommended by manufacturer, but the consistent percentage is relatively high in the most of measured parameters. In conclusion, it is suggestive that the indirect method for RIs establishment is feasible, but relevant factors, such as gender and age, specifically gender‐dependent age effect, should be considered before RIs determinations.

Emergency medicine misconceptions: Utility of routine coagulation panels in the emergency department setting

BACKGROUND

Coagulation panels are ordered for a variety of conditions in the emergency department (ED).

OBJECTIVE

This narrative review evaluates specific conditions for which a coagulation panel is commonly ordered but has limited utility in medical decision-making.

DISCUSSION

Coagulation panels consist of partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT), prothrombin time (PT), and international normalized ratio (INR). These tests evaluate the coagulation pathway which leads to formation of a fibrin clot. The coagulation panel can monitor warfarin and heparin therapy, evaluate for vitamin K deficiency, evaluate for malnutrition or severe systemic disease, and assess hemostatic function in the setting of bleeding. The utility of coagulation testing in chest pain evaluation, routine perioperative assessment, prior to initiation of anticoagulation, and as screening for admitted patients is low, with little to no change in patient management based on results of these panels. Coagulation testing should be considered in systemically ill patients, those with a prior history of bleeding or family history of bleeding, patients on anticoagulation, or patients with active hemorrhage and signs of bleeding. Thromboelastography and rotational thromboelastometry offer more reliable measures of coagulation function.

CONCLUSIONS

Little utility for coagulation assessment is present for the evaluation of chest pain, routine perioperative assessment, initiation of anticoagulation, and screening for admitted patients. However, coagulation panel assessment should be considered in patients with hemorrhage, patients on anticoagulation, and personal history or family history of bleeding.

A droplet-based microfluidic viscometer for the measurement of blood coagulation

A continuous microfluidic viscometer is used to measure blood coagulation. The viscometer operates by flowing oil and blood into a cross section where droplets are generated. At a set pressure, the length of the droplets is inversely proportional to the viscosity of the blood sample being delivered. Because blood viscosity increases during coagulation as the blood changes from a liquid to a solid gel, the device allows to monitor coagulation by simply measuring the drop length. Experiments with swine blood were carried out in its native state and with the addition of coagulation activators and inhibitors. The microfluidic viscometer detected an earlier initiation of the coagulation process with the activator and a later initiation with the inhibitor compared to their corresponding controls. The results from the viscometer were also compared with the clinical method of thromboelastography (TEG), which was performed concurrently for the same samples. The time to initiation of coagulation in the microfluidic viscometer was correlated with the reaction time in TEG. Additionally, the total time for the measurement of clot strengthening in TEG correlated with the time for the maximum viscosity observed in the microfluidic viscometer. The microfluidic viscometer measured changes in viscosity due to coagulation faster than TEG detected the clot formation. The present viscometer is a simple technology that can be used to further study the entire coagulation process.

Does the evidence support the importance of high transfusion ratios of plasma and platelets to red blood cells in improving outcomes in severely injured patients: a systematic review and meta-analyses

BACKGROUND

Deaths by exsanguination in trauma are preventable with hemorrhage control and resuscitation with allogeneic blood products (ABPs). The ideal transfusion ratio is unknown. We compared efficacy and safety of high transfusion ratios of FFP:RBC and PLT:RBC with low ratios in trauma.

STUDY DESIGN AND METHODS

Medline, Embase, Cochrane, and Controlled Clinical Trials Register were searched. Observational and randomized data were included. Risk of bias was assessed using validated tools. Primary outcome was 24-h and 30-day mortality. Secondary outcomes were exposure to ABPs and improvement of coagulopathy. Meta-analysis was conducted using a random-effects model. Strength and evidence quality were graded using GRADE profile RESULTS: 55 studies were included (2 randomized and 53 observational), with low and moderate risk of bias, respectively, and overall low evidence quality. The two RCTs showed no mortality difference (odds ratio [OR], 1.35; 95% confidence interval [CI], 0.40-4.59). Observational studies reported lower mortality in high FFP:RBCs ratio (OR, 0.38 [95% CI, 0.22-0.68] for 1:1 vs. <1:1; OR, 0.42 [95% CI, 0.22-0.81] for 1:1.5 vs. <1:1.5; and OR, 0.47 [95% CI, 0.31-0.71] for 1:2 vs. <1:2, respectively). Meta-analyses in observational studies showed no difference in exposure to ABPs. No data on coagulopathy for meta-analysis was identified.

CONCLUSIONS

Meta-analyses in observational studies suggest survival benefit and no difference in exposure to ABPs. No survival benefit in RCTs was identified. These conflicting results should be interpreted with caution. Studies are mostly observational, with relatively small sample sizes, nonrandom treatment allocation, and high potential for confounding. Further research is warranted.

Cartridge-Based Thromboelastography Can Be Used to Monitor and Quantify the Activity of Unfractionated and Low-Molecular-Weight Heparins

Thromboelastography is increasingly utilized in the management of bleeding and thrombotic complications where heparin management remains a cornerstone. This study assessed the feasibility of the cartridge-based TEG ^® 6s system (Haemonetics Corp., Braintree, Massachusetts, United States) to monitor and quantify the effect of unfractionated and low-molecular-weight heparin (UFH and LMWH). Blood samples from healthy donors were spiked with UFH ( n  = 23; 0–1.0 IU/mL) or LMWH (enoxaparin; n  = 22; 0–1.5 IU/mL). Functional fibrinogen maximum amplitude (CFF.MA), RapidTEG activated clotting time (CRT.ACT), and kaolin and kaolin with heparinase reaction time (CK.R and CKH.R) were evaluated for their correlation with heparin concentrations, as well as the combination parameters ΔCK.R − CKH.R, ratio CK.R/CKH.R, and ratio CKH.R/CK.R. Nonlinear mixed-effect modelling was used to study the relationship between concentrations and parameters, and Bayesian classification modelling for the prediction of therapeutic ranges. CK.R and CRT.ACT strongly correlated with the activity of LMWH and UFH ( p  < 0.001). Using combination parameters, heparin activity could be accurately quantified in the range of 0.05 to 0.8 IU/mL for UFH and 0.1 to 1.5 IU/mL for LMWH. CRT.ACT was able to quantify heparin activity at higher concentrations but was only different from the reference range ( p  < 0.05) at >0.5 IU/mL for UFH and >1.5 IU/mL for LMWH. Combination parameters classified blood samples into subtherapeutic, therapeutic, and supratherapeutic heparin ranges, with an accuracy of >90% for UFH, and >78% for LMWH. This study suggests that TEG 6s can effectively monitor and quantify heparin activity for LMWH and UFH. Additionally, combination parameters can be used to classify blood samples into therapeutic ranges based on heparin activity.

Emergency Reversal of Anticoagulation

Owing to the propensity of anticoagulated patients to bleed, a strategy for reversal of anticoagulation induced by any of the common agents is essential. Many patients are anticoagulated with a variety of agents, including warfarin, low molecular weight heparin, and the direct oral anticoagulants such as factor Xa and factor IIa inhibitors. Patients may also be using antiplatelet agents. Recommendations to reverse bleeding in these patients are constantly evolving with the recent development of specific reversal agents. A working knowledge of hemostasis and the reversal of anticoagulation and antiplatelet drugs is required for every emergency department provider. This article reviews these topics and presents the currently recommended strategies for dealing with bleeding in the anticoagulated patient.

Monitoring of blood coagulation with non-contact drop oscillation rheometry

BACKGROUND

Thromboelastography is widely used as a tool to assess the coagulation status of critical-care patients. It allows observation of changes in the material properties of whole blood brought about by clot formation and clot lysis. However, contact activation of the coagulation cascade at surfaces of thromboelastographic systems leads to inherent variability and unreliability in predicting bleeding or thrombosis risks, while also requiring large sample volumes.

OBJECTIVES

To develop a non-contact drop oscillation rheometry (DOR) method to measure the viscoelastic properties of blood clots and to compare the results with current laboratory standard measurements.

METHODS

Drops of human blood and plasma (5-10 μL) were acoustically levitated. Acoustic field modulation induced drop shape oscillations, and the viscoelastic properties of the sample were calculated by measuring the resonance frequency and damping ratio.

RESULTS

DOR showed sensitivity to coagulation parameters. An increase in platelet count resulted in an increase in the maximum clot stiffness. An increase in the calcium ion level enhanced the coagulation rate prior to saturation. An increase in hematocrit resulted in a higher rate of clot formation and increased clot stiffness. Comparison of the results with those obtained with thromboelastography showed that coagulation started sooner with DOR, but with a lower rate and lower maximum stiffness.

CONCLUSIONS

DOR can be used as a monitoring tool to assess blood coagulation status. The advantages of small sample size, the lack of contact and small strain (linear viscoelasticity) makes this technique unique for real-time monitoring of blood coagulation.

Preeclampsia Induced Liver Dysfunction Complicated by Disseminated Intravascular Coagulopathy and Placental Abruption: A Case Report and Review of the Literature

A 33-year-old primigravida at 32-week gestation was admitted to labor and delivery complaining of severe right upper quadrant pain and worsening coagulopathy. We report the anesthetic and obstetrical management of a complex case of a parturient with a mixed picture of hemolysis, elevated liver enzymes and low platelets who was delivered under general anesthesia further complicated by Disseminated Intravascular Coagulopathy (DIC) and placental abruption.

Effect of Frequency of Platelet Apheresis on Coagulation Function in Donors: A Prospective Cohort Study

The maximum number of plateletpheresis donation was permitted up to 24 times every year for each donor in China. This study was investigated the effect of donation frequency on coagulation function of the plateletpheresis donors. A total of 96 plateletpheresis regular donors (splitted into A, B, C groups with 32 donors each group. A was 6–11 times donations, B with 12–17 times and C with 18–24 times) and 32 first time plateletpheresis donors (D group) were analyzed. The coagulation reaction time (R), blood clot formation time (K), α-Angle, normal maximum amplitude (MA) were tested using thromboelastography instrument. Platelet (PLT) count was measured using a hematology analyzer. The ratio of the male to female were 23:9, 24:8, 27:5 and 24:8, the mean age were 40.7 ± 7.6, 39.8 ± 8.3, 40.2 ± 7.9 and 37.0 ± 9.3, and the platelet collection amount were 1.55 ± 0.37 U, 1.58 ± 0.38 U, 1.61 ± 0.33 U and 1.46 ± 0.31 U in the A, B, C, D groups respectively. There were significant difference in the values of the R, K, α-Angle, MA and PLT count between before and after plateletpheresis donation in each group (p < 0.05). However, the values of R, K, α-Angle, MA and PLT count in the before donation were not difference among the A, B, C, D groups (p > 0.05). Similar results were found in the after plateletpheresis donation. The number of the PLT was significantly correlated with the values of the R, K, α-Angle and MA (p < 0.05). However, the frequency of plateletpheresis were not significantly correlated with R, k, α and MA parameters (p > 0.05) using Spearman correlation analysis. The regular donation of apheresis platelets and the frequency of annual blood donation had no adverse effect upon coagulation function of the donors in China.

Redefining postinjury fibrinolysis phenotypes using two viscoelastic assays

INTRODUCTION

Fibrinolysis was initially defined using rapid thrombelastography (rTEG). The cutoffs for the pathologic extremes of the fibrinolytic system, hyperfibrinolysis and shutdown, were both defined based on association with mortality. We propose to redefine these phenotypes for both TEG and for rotational thrombelastometry, the other commonly used viscoelastic assay.

METHODS

Rotational thrombelastometry, rTEG, and clinical data were prospectively collected on trauma patients admitted to an urban Level I trauma center from 2010 to 2016. Hyperfibrinolysis was defined as the Youden index from EXTEM-clot lysis index 60 minutes after clotting time (CLI60) and rTEG-fibrinolysis 30 minutes after achieving MA (LY30) for predicting massive transfusion (>10 red blood cell units, or death per 6 hours after injury) as a surrogate for severe bleeding. Patients identified as having hyperfibrinolysis were then removed from the data set, and the cutoff for fibrinolysis shutdown was derived as the optimal cutoff for predicting mortality in the remaining patients.

RESULTS

Overall, 216 patients (median age, 36 years (interquartile range, 27-49 years), 82% men, 58% blunt injury) were included. Of these, 16% required massive transfusion, and 12.5% died. Rapid thrombelastography phenotypes were redefined as hyperfibrinolysis: rTEG-LY30 greater than7.7%, physiologic rTEG-LY30 0.6% to7.6%, and shutdown rTEG-LY30 less than 0.6%. EXTEM-CLI60 fibrinolysis phenotypes were hyperfibrinolysis CLI60 less than 82%, physiologic (CLI60, 82-97.9%), and shutdown (CLI60 > 98%). Weighted kappa statistics revealed moderate agreement between rotational thrombelastometry- and rTEG-defined fibrinolysis (k = 0.51; 95% confidence interval, 0.39-0.63), with disagreement mostly in the shutdown and physiologic categories.

CONCLUSION

We confirmed the U-shaped distribution of death related to fibrinolysis system abnormalities. Both rTEG LY30 and EXTEM CLI60 can identify the spectrum of fibrinolytic phenotypes, have moderate agreement, and can be used to guide hemostatic resuscitation.

LEVEL OF EVIDENCE

Diagnostic study, level III.

Suboptimal use of pharmacological venous thromboembolism prophylaxis in cirrhotic patients

BACKGROUND

Cirrhosis was previously perceived as a haemorrhagic disease state due to frequent associations with coagulopathy and bleeding. However, the coagulopathy of cirrhosis is complex with defects in both procoagulant and anticoagulant factors. Derangements in common laboratory indices of coagulation do not accurately reflect bleeding risk or protection from thrombotic events.

AIMS

To assess the rate of pharmacological prophylaxis for venous thromboembolism (VTE) among hospital inpatients with cirrhosis and analyse factors associated with prophylaxis being inappropriately withheld.

METHODS

A retrospective cohort study was performed in a tertiary teaching hospital. Patients included were admitted for greater than 48 h with discharge diagnosis codes corresponding to chronic liver disease and/or cirrhosis. The use of VTE chemoprophylaxis with enoxaparin was assessed in cirrhotic patients and non-cirrhotic controls. Patient data collected included contraindications to prophylaxis, known high-risk varices, international normalised ratio (INR), creatinine, bilirubin, haemoglobin and platelet count.

RESULTS

Of 108 patients with cirrhosis eligible for VTE prophylaxis, 61 (56.5%) received prophylaxis compared to 104 (96.3%) non-cirrhotic patients. Platelets and INR were significantly different between those who did and did not receive VTE prophylaxis. On multivariate analysis, platelet count and INR were independent predictors for VTE not being administered.

CONCLUSION

The administration of chemoprophylaxis in accordance with the hospital guidelines was suboptimal in patients with cirrhosis. Platelet count and INR were independent predictors of prophylaxis use. Our results suggest persistent misperceptions that prolonged INR and thrombocytopenia predict bleeding risk in cirrhosis.

The practicalities and barriers of using TEG6s in code red traumas: an observational study in one London major trauma centre

OBJECTIVE

Trauma induced coagulopathy is a disorder of the coagulation pathway that occurs following major trauma. "Code red trauma" require massive hemorrhage protocol activation. The aim was to qualitatively establish the reasons TEG is not currently utilized and the ongoing practicalities in performing a TEG sample for trauma-related massive hemorrhage.

METHODS

A pilot study was performed using a TEG6s machine within one central London Major Trauma Centre's resuscitation department. Staff were asked to run a TEG sample on any "code red" patient who attended during the trial. Staff were given questionnaires both before and after the trial to assess the knowledge around TEG.

RESULTS

A TEG sample was performed in 75% of the sixteen "code red traumas," with one sample being unsuccessful. Only one patient had their blood component management altered due to the TEG result with only 50% of consultants and registrars surveyed feeling confident in interpreting TEG results.

CONCLUSION

TEG6s samples can be run within the resuscitation department in a "code red trauma." However, there is a significant lack of knowledge relating to TEG within the emergency department which is likely to hinder its impact on personalized blood component management. More research is required in how to provide appropriate education in a busy setting to enable TEG to be utilized appropriately.

Comparison of Thrombelastography (TEG) in Patients with Acute Cerebral Hemorrhage and Cerebral Infarction

Background

The aim of this study was to analyze the changing role of thrombelastography (TEG) by detecting the indexes of TEG in patients with acute cerebral hemorrhage and cerebral infarction, combined with pathogenesis, and to find objective laboratory indexes for the diagnosis and treatment of cerebrovascular diseases.

Material/Methods

Data from 150 patients were collected, including 69 cases identified as the cerebral infarction group and 81 cases identified as the cerebral hemorrhage group. In addition, 50 healthy adults were selected as a control group. The cerebral hemorrhage group was divided into 3 subgroups according to the amount of bleeding: small hemorrhage group, moderate hemorrhage group, and large hemorrhage group. The diagnosis for each participant was mainly based on computed tomography (CT) and magnetic resonance imaging (MRI). TEG indexes [R value (coagulation reaction time), K value (coagulation time), Angle (reflecting the formation rate of blood clot and the function of fibrinogen), MA (maximum thrombus amplitude), CI (coagulation index)] were measured by TEG YZ5000 instrument.

Results

The cerebral infarction group had lower R and K values and higher Angle and CI (P<0.05). The cerebral hemorrhage group had higher K value; the Angle and MA were lower in the moderate hemorrhage group and in the large hemorrhage groups (P<0.05). In the cerebral hemorrhage group, Angle and MA were negatively correlated with the amount of cerebral hemorrhage (r=−0.475, −0.394 respectively, P<0.05), and the K value was positively correlated with the amount of cerebral hemorrhage (r=0.337, P<0.05), while the R value had no significant correlation with the amount of cerebral hemorrhage (r=0.251, P>0.05). R and K values in the cerebral infarction group were significantly lower, while Angle, MA, and CI were significantly higher in the cerebral hemorrhage group.

Conclusions

K value, Angle, and MA may be of value in the assessment of the amount of cerebral hemorrhage.