TEG® and ROTEM® in trauma: similar test but different results?

Advances in Platelet-Dysfunction Diagnostic Technologies

The crucial role of platelets in hemostasis and their broad implications under various physiological conditions underscore the importance of accurate platelet-function testing. Platelets are key to clotting blood and healing wounds. Therefore, accurate diagnosis and management of platelet disorders are vital for patient care. This review outlines the significant advancements in platelet-function testing technologies, focusing on their working principles and the shift from traditional diagnostic methods to more innovative approaches. These improvements have deepened our understanding of platelet-related disorders and ushered in personalized treatment options. Despite challenges such as interpretation of complex data and the costs of new technologies, the potential for artificial-intelligence integration and the creation of wearable monitoring devices offers exciting future possibilities. This review underscores how these technological advances have enhanced the landscape of precision medicine and provided better diagnostic and treatment options for platelet-function disorders.

Detection of glycocalyx degradation in real time: A conceptual model of thromboelastography

BACKGROUND

The endothelial glycocalyx is a critical component of the vascular barrier; its disruption after shock states may contribute to coagulopathy in a variety of conditions. Measurement of glycocalyx components in plasma have been used to index glycocalyx degradation but are not available as a point of care test. Heparanoids, such as heparan sulfate, may affect coagulation which may be detected by either thromboelastography or activated clotting time.

METHODS

Endothelial glycocalyx components syndecan-1 and heparan sulfate were added to blood samples at clinically relevant concentrations. Thromboelastography values included clot reaction time, clot amplification and fibrinogen values, and maximum clot strength (maximum amplitude, platelets). The heparinase thromboelastography cartridge was used to detect a heparin-like effect. The activated clotting time test was performed subsequently using the heparan sulfate blood samples to compare a standard coagulation test with thromboelastography clot reaction times.

RESULTS

Both thromboelastography clot reaction time (with comparison to heparinase) and activated clotting time were useful to detect effects of coagulation. Thromboelastography also detected platelet and fibrinogen abnormalities at higher heparan sulfate concentrations. Studies using thromboelastography or even activated clotting time may be useful to detect glycocalyx degradation after shock states and may guide clinical decision making.

CONCLUSION

Thromboelastography and or activated clotting time may be useful to detect glycocalyx degradation as a point of care test in patients in the acute setting. Additionally, these assays may detect previous undisclosed coagulopathy due to glycocalyx degradation.

SHock-INduced Endotheliopathy (SHINE): A mechanistic justification for viscoelastography-guided resuscitation of traumatic and non-traumatic shock

Irrespective of the reason for hypoperfusion, hypocoagulable and/or hyperfibrinolytic hemostatic aberrancies afflict up to one-quarter of critically ill patients in shock. Intensivists and traumatologists have embraced the concept of SHock-INduced Endotheliopathy (SHINE) as a foundational derangement in progressive shock wherein sympatho-adrenal activation may cause systemic endothelial injury. The pro-thrombotic endothelium lends to micro-thrombosis, enacting a cycle of worsening perfusion and increasing catecholamines, endothelial injury, de-endothelialization, and multiple organ failure. The hypocoagulable/hyperfibrinolytic hemostatic phenotype is thought to be driven by endothelial release of anti-thrombogenic mediators to the bloodstream and perivascular sympathetic nerve release of tissue plasminogen activator directly into the microvasculature. In the shock state, this hemostatic phenotype may be a counterbalancing, yet maladaptive, attempt to restore blood flow against a systemically pro-thrombotic endothelium and increased blood viscosity. We therefore review endothelial physiology with emphasis on glycocalyx function, unique biomarkers, and coagulofibrinolytic mediators, setting the stage for understanding the pathophysiology and hemostatic phenotypes of SHINE in various etiologies of shock. We propose that the hyperfibrinolytic phenotype is exemplified in progressive shock whether related to trauma-induced coagulopathy, sepsis-induced coagulopathy, or post-cardiac arrest syndrome-associated coagulopathy. Regardless of the initial insult, SHINE appears to be a catecholamine-driven entity which early in the disease course may manifest as hyper- or hypocoagulopathic and hyper- or hypofibrinolytic hemostatic imbalance. Moreover, these hemostatic derangements may rapidly evolve along the thrombohemorrhagic spectrum depending on the etiology, timing, and methods of resuscitation. Given the intricate hemochemical makeup and changes during these shock states, macroscopic whole blood tests of coagulative kinetics and clot strength serve as clinically useful and simple means for hemostasis phenotyping. We suggest that viscoelastic hemostatic assays such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are currently the most applicable clinical tools for assaying global hemostatic function-including fibrinolysis-to enable dynamic resuscitation with blood products and hemostatic adjuncts for those patients with thrombotic and/or hemorrhagic complications in shock states.

CREST: clinical bleeding and risk evaluation in hematology-oncology patients: a systematic review and meta-analysis of thromboelastography's role

Thrombocytopenia and bleeding are common complications of hematologic malignancies. Often, prophylactic platelets are administered to minimize bleeding risk, based on total platelet count (TPC). However, TPC is a poor predictor, and does not provide rapid information. This review presents a novel prospective in the use of point-of-care viscoelastic studies to assess bleeding risk and guide transfusion therapy in a haematological oncological population, where its use can be extended to a ward level as a bedside test. Monitoring TEG maximum amplitude trends may be useful to guide transfusion protocols, especially for patients with total platelet counts ranging 30-100 × 10 9 /l. Fibrinogen assessment in this group of patients may identify other blood components that require replacing to reduce bleeding risk. Normal maximum amplitude parameters for patients with low platelet counts can be a reassuring sign. This meta-analysis serves to remind the reader that absolute platelet quantity does not equate to the quality of clot formation.

Comparison of assessment of coagulation in healthy dogs by the TEG 6s and TEG 5000 viscoelastic analyzers

The TEG 6s (Haemonetics) point-of-care viscoelastic analyzer is portable, compact, simple to use, and has the potential for rapid viscoelastic analysis that can guide the treatment of veterinary patients at the site of care. Although approved for use in people, the TEG 6s has yet to be evaluated for hemostatic analysis in veterinary medicine. Citrated whole blood (CWB) was collected from 27 healthy dogs. An aliquot of CWB from each dog was diluted by 33% with an isotonic crystalloid, representing an in vitro model of hemodilution. Unaltered and diluted CWB samples were analyzed using 2 TEG 6s and 6 TEG 5000 (Haemonetics) analyzers. The 6 TEG 5000 analyzers ran duplicate analyses of either unaltered or diluted samples using 1 of 3 reagents (Haemonetics): Kaolin TEG, RapidTEG, or TEG Functional Fibrinogen. Duplicate TEG 5000 analyses were averaged and compared with a single TEG 6s analysis. Lin concordance correlation coefficient and Bland-Altman plots were used to evaluate agreement of reaction time, kinetic time, alpha angle, maximum amplitude (MA), and G value (G) for samples activated with Kaolin TEG, and agreement of MA for samples activated with RapidTEG between the 2 machines. Overall, agreement between the TEG 6s and TEG 5000 analyzers was poor. Viscoelastic measurements by the TEG 6s and TEG 5000 in healthy dogs were not all interchangeable. Agreement was satisfactory only for MA and G measurements of diluted blood samples activated with Kaolin TEG, and MA measurements for both unaltered and diluted blood samples activated with RapidTEG.

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.

Hemostatic Management in Extracorporeal Membrane Oxygenation

The use of extracorporeal membrane oxygenation (ECMO) for acute cardiac and/or respiratory failure has grown exponentially in the past several decades. Systemic anticoagulation is a fundamental element of caring for ECMO patients. Hemostatic management during ECMO walks a fine line to balance the risk of safe and effective anticoagulant delivery to mitigate thromboembolic complications and minimizing hemorrhagic sequelae. This review discusses the pharmacology, monitoring parameters, and special considerations for anticoagulation in patients requiring ECMO.

Viscoelastic Hemostatic Assays: A Primer on Legacy and New Generation Devices

Viscoelastic hemostatic assay (VHAs) are whole blood point-of-care tests that have become an essential method for assaying hemostatic competence in liver transplantation, cardiac surgery, and most recently, trauma surgery involving hemorrhagic shock. It has taken more than three-quarters of a century of research and clinical application for this technology to become mainstream in these three clinical areas. Within the last decade, the cup and pin legacy devices, such as thromboelastography (TEG^® 5000) and rotational thromboelastometry (ROTEM^® delta), have been supplanted not only by cartridge systems (TEG^® 6S and ROTEM^® sigma), but also by more portable point-of-care bedside testing iterations of these legacy devices (e.g., Sonoclot^®, Quantra^®, and ClotPro^®). Here, the legacy and new generation VHAs are compared on the basis of their unique hemostatic parameters that define contributions of coagulation factors, fibrinogen/fibrin, platelets, and clot lysis as related to the lifespan of a clot. In conclusion, we offer a brief discussion on the meteoric adoption of VHAs across the medical and surgical specialties to address COVID-19-associated coagulopathy.

Pro-Con Debate: Viscoelastic Hemostatic Assays Should Replace Fixed Ratio Massive Transfusion Protocols in Trauma

Major trauma patients at risk of traumatic coagulopathy are commonly treated with early clotting factor replacement to maintain hemostasis and prevent microvascular bleeding. In the United States, trauma transfusions are often dosed by empiric, low-ratio massive transfusion protocols, which pair plasma and platelets in some ratio relative to the red cells, such as the "1:1:1" combination of 1 units of red cells, 1 unit of plasma, and 1 donor's worth of pooled platelets. Empiric transfusion increases the rate of overtransfusion when unnecessary blood products are administered based on a formula and not on at patient's hemostatic profile. Viscoelastic hemostatic assays (VHAs) are point-of-care hemostatic assays that provided detailed information about abnormal clotting pathways. VHAs are used at many centers to better target hemostatic therapies in trauma. This Pro/Con section will address whether VHA guidance should replace empiric fixed ratio protocols in major trauma.

Clinical application of viscoelastic point-of-care tests of coagulation-shifting paradigms

Bleeding during cardiac surgery, liver transplant, trauma and post partum hemorrhage are often multifactorial and these factors are dynamic as new factors crop up during the course of management. Conventional tests of coagulation offer information of a part of the coagulation system and also is time consuming. Viscoelastic point of care tests (VE POCTs) like rotational thromboelastometry, thromboelastogram and Sonoclot, are based on analysis of the viscoelastic properties of clotting blood and provide information for the entire coagulation pathway. In this comprehensive review being presented here, we have examined the pros and cons of VE POCTs including clinical, cost and survival benefits. The recommendations of the various guidelines regarding use of VE POCTs in various scenarios have been discussed. The review also tried to offer suggestions as to their optimal role in management of bleeding during cardiac surgeries, extracorporeal membrane oxygenation, left ventricular assist devices, liver transplant and briefly in trauma and postpartum hemorrhage.

Analysis of Viscoelastic Testing in Pediatric Patients Using the Pediatric Extracorporeal Membrane Oxygenation Outcomes Registry

Use of viscoelastic tests (VETs), including thromboelastography (TEG) and rotational thromboelastometry (ROTEM), is increasing in the management of anticoagulation in extracorporeal membrane oxygenation (ECMO) patients. A retrospective review of data on 265 pediatric (<20 years old) ECMO patients who underwent VET and were submitted to the Pediatric ECMO Outcomes Registry (PEDECOR) was conducted to describe common coagulopathies in patients who underwent VET; associations between the VET parameters and traditional tests of coagulation; and comparisons in blood product usage in patients who underwent VET with those who did not. We calculated patient-level summary statistics and assessed differences between the groups using χ2 tests (categorical variables) and Kruskal-Wallis and Wilcoxon rank-sum tests (continuous variables). Viscoelastic test was utilized in 77% of patients in the analysis. Platelet dysfunction was the most common abnormality identified by TEG (30.8%) and ROTEM (9.7%). Bleeding patients who had VET performed received more cryoprecipitate transfusions than those who did not have VET (VET median = 9.7 ml/kg; interquartile range (IQR) = 4.3-22.0 ml/kg vs. no VET median = 5.1 ml/kg; IQR = 0-10.4 ml/kg; p = 0.0013). Given the growing use of VET in pediatric ECMO patients, further studies evaluating VET in managing complications as well as aiding in titration of anticoagulation therapy are needed.

Utility of Viscoelastic Tests to Predict Flap Thrombosis: A Systematic Review

Background:

Flap thrombosis is a rare but devastating complication in microsurgery. Preoperative identification of patients at increased risk for microvascular thrombosis remains challenging. Viscoelastic testing (VET) provides a comprehensive evaluation of the clotting process and can effectively identify hypercoagulability. However, the utility of VET in microvascular reconstruction remains unclear.

Methods:

A systematic review of the association between VET and pedicle thrombosis and free flap loss was performed in accordance with Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines. Identified studies were reviewed independently by two authors for pertinent data.

Results:

Six studies met inclusion criteria. Heterogenous study design and outcome reporting complicated direct comparisons and precluded a formal meta-analysis. Four studies found a statistically significant relationship between VET results and flap thrombosis or flap loss. The maximum clot strength and the fibrinogen-to-platelet ratio (FPR) were key viscoelastic parameters in these studies, both representing a measure of maximal clot strength. Specifically, an elevated FPR (>42%) generated a sensitivity and specificity for flap loss ranging from 57% to 75% and 60% to 82%, respectively. Notably, the negative predictive value for flap failure with a normal preoperative FPR was greater than 90% in all studies reporting a correlation. The remaining two studies reported no predictive value for VET with respect to flap failure or pedicle thrombosis.

Conclusion:

The results of this review suggest that VET, particularly parameters relating to clot strength, may help clinicians identify patients at risk for flap thrombosis. However, uncontrolled and heterogenous reporting limit definitive conclusions, and high-quality diagnostic studies are needed to better determine the clinical utility of viscoelastic testing for free flap patients.

Viscoelastic monitoring in trauma resuscitation

BACKGROUND

Traumatic injury results in both physical and physiologic insult. Successful care of the trauma patient depends upon timely correction of both physical and biochemical injury. Trauma-induced coagulopathy is a derangement of hemostasis and thrombosis that develops rapidly and can be fatal if not corrected. Viscoelastic monitoring (VEM) assays have been developed to provide rapid, accurate, and relatively comprehensive depictions of an individual's coagulation profile. VEM are increasingly being integrated into trauma resuscitation guidelines to provide dynamic and individualized guidance to correct coagulopathy.

STUDY DESIGN AND METHODS

We performed a narrative review of the search terms viscoelastic, thromboelastography, thromboelastometry, TEG, ROTEM, trauma, injury, resuscitation, and coagulopathy using PubMed. Particular focus was directed to articles describing algorithms for management of traumatic coagulopathy based on VEM assay parameters.

RESULTS

Our search identified 16 papers with VEM-guided resuscitation strategies in adult patients based on TEG, 12 such protocols in adults based on ROTEM, 1 protocol for children based on TEG, and 2 protocols for children based on ROTEM.

CONCLUSIONS

This review presents evidence to support VEM use to detect traumatic coagulopathy, discusses the role of VEM in trauma resuscitation, provides a summary of proposed treatment algorithms, and discusses pending questions in the field.

Basic principles of viscoelastic testing

BACKGROUND

Viscoelastic testing is a method of hemostatic analysis that provides a real-time, holistic view of ex vivo clotting. It allows for examination of both cellular and plasma protein contributions to clotting including platelet number and function, fibrin(ogen) function, and coagulation factor function. The method assesses physical clot properties during the transition of blood from a liquid to a gel state, either by measurement of clot shear modulus using physical force transduction or by measurement of clot resonance frequency using sonometric interrogation. Results are reported in a live trace, with different trace parameters reflecting different contributors to hemostasis. These reported parameters vary between testing platforms.

RESULTS

In the United States, there are several commonly used Food and Drug Administration (FDA)-approved viscoelastic instruments available on the market. Those instruments that use sonometric clot assessment are more recently available and allow for improved portability for use near the patient's bedside. These instruments generally feature different reagent kits that allow more specific interrogation of different hemostatic pathways. Viscoelastic testing can predict the results of traditional plasma-based coagulation assays and has the added benefit of detecting hypercoagulability and severe hyperfibrinolysis. Implementation of viscoelastic testing in many clinical settings is becoming widespread and has proven to be efficacious in reducing blood transfusion rates in many settings. An impact on overall mortality and morbidity has not yet been demonstrated.

CONCLUSION

This article provides a narrative review of the basic principles of viscoelastic testing, including the science and technology behind the method, as well as currently available testing platforms and reagents.

Comparison between intraoperative bleeding score and ROTEM® measurements to assess coagulopathy during major pediatric surgery

PURPOSE

Intraoperative bleeding should be regularly assessed visually to guide coagulation management. Whereas viscoelastic testing with ROTEM® measurement has been proven to be useful in detecting coagulopathies, the visual assessment is not standardized. This study therefore aims to compare a standardized visual assessment with ROTEM® results.

METHODS

A 5-point bleeding score was created and applied in a recently published randomized controlled trial in major pediatric non-cardiac surgery. This score assesses overall bleeding tendency and the occurrence of diffuse bleeding, aqueous bleeding, bleeding outside the operative field, and the ability to control bleeding. Validity of this score was tested by post hoc comparison to the results of simultaneously performed ROTEM® measurements.

RESULTS

Signs of coagulopathic bleeding were assessed at 183 time points. Mild to moderate bleeding intensity was judged at 103 time points, in 42 % abnormal ROTEM® traces were obtained simultaneously. When severe bleeding was scored, abnormal ROTEM values occurred in 58 %, and FIBTEM-values were significantly lower than in the "no bleeding group". Altogether, the correlation between bleeding score and ROTEM® measurements was not significant.

CONCLUSIONS

The standardized visual assessment did not correlate well with ROTEM® measurements, suggesting that it is not useful to detect coagulopathy. Trial registry number: ClinicalTrials.gov identifier No. NCT01487837.

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.

Establishment of normal reference intervals in dogs using a viscoelastic point-of-care coagulation monitor and its comparison with thromboelastography

BACKGROUND

Viscoelastic coagulation devices are a useful adjunct to the evaluation of hemostasis in veterinary patients. VCM Vet is a point-of-care device that is simple in operation and could be used to diagnose and trend hemostatic abnormalities in sick patients. VCM Vet does not use activators.

OBJECTIVES

We aimed to establish reference intervals (RIs) for VCM Vet in a healthy adult canine population and concurrently perform thromboelastographic (TEG) analysis on these samples with and without tissue factor (TF) activation for RI comparisons.

METHODS

Duplicate VCM Vet tests were performed immediately upon sample collection. Two concurrent TEG tests were performed on the remaining blood, one citrated, untreated (CU), and one activated with TF at a 1:3600 dilution.

RESULTS

Fifty-two dogs were enrolled in the study. The following RIs were generated for VCM Vet machine 1 and 2, respectively: clot time (CT) (seconds) 163-480 and 172-457; clot formation time (CFT) (seconds) 104-288 and 94-252, α-angle (degrees) 41-65 and 44-66, and maximum clot firmness (MCF) (no units) 27-43 and 30-46. Moderate to good correlations were observed between the two machines with Lin's concordance correlation coefficients of 0.51-0.9 and a P < 0.002. TEG RIs were similar to previously reported values.

CONCLUSIONS

VCM Vet RIs were generated. Each VCM Vet device should have a unique RI established due to inter-device variability. Direct correlations of VCM Vet values with TEG parameters were not performed due to the narrow range of the normal values and the need to evaluate patients with a wide range of hemostatic abnormalities.

Fibrinogen Diagnostics in Major Hemorrhage

Fibrinogen is one of the first factors to fall to critically low levels in the blood in many coagulopathic events. Patients with hypofibrinogenemia are at a significantly greater risk of major hemorrhage and death. The rapid replacement of fibrinogen early on in hypofibrinogenemia may significantly improve outcomes for patients. Fibrinogen is present at concentrations between 2 and 4 g/L in the plasma of healthy people. However, hypofibrinogenemia is diagnosed when the fibrinogen level drops below 1.5-2 g/L. This review analyses different types of fibrinogen assays that can be used for diagnosing hypofibrinogenemia. The scientific mechanisms and limitations behind these tests are then presented. Additionally, the current state of clinical major hemorrhage protocols (MHPs) is presented and the structure, function and physiological role of fibrinogen is summarized.

The use of low-titer group O whole blood is independently associated with improved survival compared to component therapy in adults with severe traumatic hemorrhage

BACKGROUND

There is a resurgence in the use of low-titer group O whole blood (LTOWB) for hemorrhagic shock. We hypothesized the use of LTOWB compared to component therapy (CT) would be independently associated with improved 24-hour mortality.

STUDY DESIGN AND METHODS

In this prospective observational study, trauma patients 18 years of age or older with massive transfusion protocol activations were included from August 17, 2018, to May 14, 2019. The primary outcome was 24-hour mortality. Secondary outcomes included 72-hour blood product totals, multiple organ dysfunction scores (MODS), and 28-day mortality. Multivariable logistic regression (MVLR) and Cox regression were performed to determine independent associations.

RESULTS

There were no clinically meaningful differences in measures of injury severity between study groups (CT, n = 42; LTOWB, n = 44). There was no difference in MODS between study groups. The unadjusted mortality was not statistically different between the study groups (9/42 [21%] for CT vs. 7/44 [16%] for LTOWB; p = 0.518). In the MVLR model, LTOWB increased the odds of 24-hour survival by 23% (odds ratio 0.81, 95% confidence interval 0.69-0.96; p = 0.017). Adjusted survival curve analysis indicated improved survival at both 24 hours and 28 days for LTOWB patients (p < 0.001). Further stratification showed an association between LTOWB use and survival when maximum clot firmness (MCF) was 60 mm or less (p = 0.009).

CONCLUSIONS

The use of LTOWB is independently associated with improved 24-hour and 28-day survival, and does not increase organ dysfunction at 72 hours. Use of LTOWB most impacted survival of patients with reduced clot firmness (MCF ≤60 mm). Collectively, these data support the clinical use and continued study of LTOWB for hemostatic resuscitation.

Correlation between thromboelastography and rotational thromboelastometry values in adult liver transplant recipients

Background and Aims:

Viscoelastic haemostatic assays (VHA) namely Thromboelastogram (TEG) and Rotational thromboelastometry (ROTEM) are used for global assessment of coagulopathy and guiding transfusion during living donor liver transplant (LDLT).We conducted a study to compare the interchangeability of the values obtained from these devices in patients with End stage liver disease (ESLD) undergoing LDLT.

Methods:

In 76 patients undergoing LDLT, ROTEM and TEG were performed and assessed for interchangeability using Spearman Correlation. The direction and strength of correlation between equivalent parameters was calculated using Inter Class Correlation (ICC) and Bland Altman analysis.

Results:

The correlation ρ between CT (clotting time) of ROTEM and R of TEG was 0.16 (P = 0.19).The ICC was 0.15, with 95% confidence interval (CI) of -0.38-0.48 (P = 0.25).The ρ of CFT (ROTEM) with K (TEG) was 0.425 (P=<0.001). The ICC was0.49 with 95% CI of 0.17-0.69, P = 0.003.Alpha of ROTEM correlated with Angle of TEG with ρ of 0.475 (P=<0.001). The ICC was 0.61, with 95% CI of 0.36-0.76, P=<0.001.Maximum Clot firmness (MCF) correlated with maximum amplitude (MA) with ρ=0.76 (P=<0.001).The ICC was 0.86, with 95% CI of 0.77-0.92, P=<0.001. Lysis index (L30) of ROTEM correlated clot lysis (CL30) of TEG with ρ of 0.16 (P = 0.18).However, the ICC was 0.45, with 95% CI of 0.11-0.66, P = 0.08. The correlation between CT of ROTEM and R of TEG as well as L30 of ROTEM and CL30 of TEG was not significant.The strongest correlation was found between MCF and MA (P < 0.001). However the MCF/MA showed an agreement of only 86% (ICC = 0.86).

Conclusion:

Values from ROTEM and TEG were not found to be interchangeable.

Modern Management of Bleeding, Clotting, and Coagulopathy in Trauma Patients: What Is the Role of Viscoelastic Assays?

Purpose of Review

The purpose of this review is to briefly outline the current state of hemorrhage control and resuscitation in trauma patients with a specific focus on the role viscoelastic assays have in this complex management, to include indications for use across all phases of care in the injured patient.

Recent Findings

Viscoelastic assay use to guide blood-product resuscitation in bleeding trauma patients can reduce mortality by up to 50%. Viscoelastic assays also reduce total blood products transfused, reduce ICU length of stay, and reduce costs. There are a large number of observational and retrospective studies evaluating viscoelastic assay use in the initial trauma resuscitation, but only one randomized control trial. There is a paucity of data evaluating use of viscoelastic assays in the operating room, post-operatively, and during ICU management in trauma patients, rendering their use in these settings extrapolative/speculative based on theory and data from other surgical disciplines and settings.

Summary

Both hypocoagulable and hypercoagulable states exist in trauma patients, and better indicate what therapy may be most appropriate. Further study is needed, particularly in the operating room and post-operative/ICU settings in trauma patients.

Reference intervals for rotational thromboelastometry measurements using the ROTEM® delta device in dogs

Aims of the present study were to define reference intervals for viscoelastic analyses of canine haemostasis using the ROTEM® delta analyser, and as a secondary aspect to determine the precision (repeatability) of this method. Blood samples from 125 clinically healthy dogs were included. Measurements were performed with commercially available activating reagents (ex-tem, in-tem and kaolin solution) as well as without activation. Additional fourfold measurements were done in 3 of the normal blood samples and in 3 samples with haemostatic alterations to evaluate the precision of the method. Coefficients of variation (CVs) for most of the ROTEM variables were < 10%. Clot formation time and maximum clot elasticity showed a wide inter-individual variation in comparison with alpha angle and maximum clot firmness. A multivariate analysis on various ROTEM parameters revealed particularly a significant influence of neuter status and a significant interrelationship between the factors sex and neuter status for measurements with different activating reagents. These results reflected the fact that significant differences occurred only between intact and neutered females, but not in males. No or only occasionally significant differences were found between groups of sex, age, and size. In conclusion, CVs demonstrated that the method delivers repeatable results in canine citrated whole blood. Established reference intervals should deliver valuable orientation for the evaluation of viscoelastic properties of clotting whole blood in dogs using the ROTEM delta analyser. Neuter status in females appeared to be the most relevant influencing factor and should be considered for the interpretation of ROTEM delta test results.

The effect of normobaric hypoxic exposure on coagulation as measured by thromboelastography

INTRODUCTION

The physiological impact of hypoxia on coagulation has significant importance in the clinical setting, but it is not yet fully understood. Various static methods exist to investigate the process of coagulation, however, thromboelastography (TEG) provides a dynamic assessment of clot formation that can be quantitatively assessed.

METHOD

Twenty-five participants were exposed to normobaric hypoxia (12.5% oxygen) for 8 h. Venous blood was taken from the participants directly pre- and post-hypoxic exposure, and coagulation was tested using TEG. Coagulation variables assessed included reaction time, split point, alpha angle, kinetics and maximum amplitude.

RESULTS

Time taken for clot initiation, (assessed using the split point and reaction time) was significantly reduced after 8 h of hypoxic exposure. The split point reduced from a mean of 5.20 to 4.23 min (p = 0.022), whilst the reaction time reduced from 6.09 to 4.94 min (p = 0.004). Maximum amplitude, alpha angle and kinetics did not change significantly after hypoxic exposure.

CONCLUSION

The results demonstrate that subacute normobaric hypoxic exposure increases the tendency for whole blood to coagulate, as demonstrated by a reduced split and reaction time using TEG.

Citrated kaolin thrombelastography (TEG) thresholds for goal-directed therapy in injured patients receiving massive transfusion

INTRODUCTION

Goal-directed hemostatic resuscitation based on thrombelastography (TEG) has a survival benefit compared with conventional coagulation assays such as international normalized ratio, activated partial thromboplastin time, fibrinogen level, and platelet count. While TEG-based transfusion thresholds for patients at risk for massive transfusion (MT) have been defined using rapid TEG, cutoffs have not been defined for TEG using other activators such as kaolin. The purpose of this study was to develop thresholds for blood product transfusion using citrated kaolin TEG (CK-TEG) in patients at risk for MT.

METHODS

CK-TEG was assessed in trauma activation patients at two Level 1 trauma centers admitted between 2010 and 2017. Receiver operating characteristic (ROC) curve analyses were performed to test the predictive performance of CK-TEG measurements in patients requiring MT, defined as >10 units of red blood cells or death within the first 6 hours. The Youden Index defined optimal thresholds for CK-TEG-based resuscitation.

RESULTS

Of the 825 trauma activations, 671 (81.3%) were men, 419 (50.8%) suffered a blunt injury, and 62 (7.5%) received a MT. Patients who had a MT were more severely injured, had signs of more pronounced shock, and more abnormal coagulation assays. CK-TEG R-time was longer (4.9 vs. 4.4 min, p = 0.0084), angle was lower (66.2 vs. 70.3 degrees, p < 0.0001), maximum amplitude was lower in MT (57 vs. 65.5 mm, p < 0.0001), and LY30 was greater (1.8% vs. 1.2%, p = 0.0012) in patients with MT compared with non-MT. To predict MT, R-time yielded an area under the ROC curve (AUROC) = 0.6002 and a cut point of >4.45 min. Angle had an AUROC = 0.6931 and a cut point of <67 degrees. CMA had an AUROC = 0.7425, and a cut point of <60 mm. LY30 had an AUROC = 0.623 with a cut point of >4.55%.

CONCLUSION

We have identified CK-TEG thresholds that can guide MT in trauma. We propose plasma transfusion for R-time >4.45 min, fibrinogen products for an angle <67 degrees, platelet transfusion for MA <60 mm, and antifibrinolytics for LY30 >4.55%.

LEVEL OF EVIDENCE

Therapeutic study, level V.

Assessment of hypercoagulability using thromboelastography predicts advanced status in renal cell carcinoma

Background

Thromboelastography (TEG) has been established as a sensitive method to assess the whole coagulation process. The aim of the study was to evaluate the diagnosis significance of TEG on hypercoagulability in patients suffering renal mass.

Methods

A total of 478 patients were diagnosed with renal tumor by histolopathologic examination and were assigned to three groups. Group A: 79 patients with benign renal tumor; Group B: 317 patients with renal cell carcinoma (RCC, Fuhrman grades I and II); Group C: 82 patients with high‐risk RCC (Fuhrman grades III and IV). Subgroup analysis was performed in malignant renal tumor patients according to the TMN classification. The clinical data, whole blood TEG, and conventional coagulation tests were reviewed.

Results

There was no statistically significant difference between subgroups in respect to conventional coagulation tests. Hypercoagulablity was marked in Group C according to the TEG parameters. The elevated platelets and fibrinogen is linked with hypercoagulability in renal tumor. The positive correlation was between fibrinogen and MA value (r = .663, P < .05). The pathologic tumor stages were also associated with the TEG parameters.

Conclusion

Patients suffering advanced RCC are hypercoagulable which can be identified by TEG. MA value could be potential diagnosis indicators for detecting high‐grade RCC.

Bad blood: A coagulopathy associated with trauma and massive transfusion review

Coagulopathy in trauma patients is a known contributor to death due to hemorrhage. In fact, it seen as frequently as 35% of the time. The complexity of the coagulopathy pathway requires a deliberate and planned approach. The methods used to assess and detect if a patient is coagulopathic remain challenging, but tools have been developed to assist the practitioner to effectively manage and even quickly reverse the coagulopathy. The purpose of this review is to educate trauma and emergency medicine staff on the currently available diagnostic tools to assess coagulopathy, to provide an overview of the coagulopathy pathway, as well as provide examples of how to intervene and treat coagulopathy, including the use of crew resource management during mass transfusion protocol activations.

Diagnostic accuracy of thromboelastometry and its correlation with the HPLC-MS/MS quantification test

The aim of the study was to evaluate the diagnostic accuracy of thromboelastometry for assessing rivaroxaban concentrations. The accuracy of thromboelastometry was compared with the high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method, which is the gold standard for drug plasma monitoring (the reference standard). Forty-six clinically stable patients were treated with 10, 15, or 20 mg of rivaroxaban once daily (OD group) or 15 mg twice a day (BID group) (no particular indication for treatment). Patient samples were collected 2 h after the use of the medication (peak) and 2 h before the next dose (trough). The rivaroxaban plasma concentrations were determined via HPLC-MS/MS, and thromboelastometry was performed using a ROTEM® delta analyzer. There were significant prolongations in clotting time (CT) for the 10, 15, and 20 mg of rivaroxaban treatments in the OD groups. In the 15 mg BID group, the responses at the peak and trough times were similar. At the peak times, there was a positive correlation between the plasma concentration of rivaroxaban and CT (Spearman correlation rho=0.788, P<0.001) and clot formation time (rho=0.784, P<0.001), and a negative correlation for alpha angle (rho=−0.771, P<0.001), amplitude after 5 min (rho=−0.763, P<0.001), and amplitude after 10 min (rho=−0.680, P<0.001). The CT presented higher specificity and sensitivity using the cut-off determined by the receiver characteristics curve. ROTEM has potential as screening tool to measure possible bleeding risk associated with rivaroxaban plasma levels.

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.

Effect of Liver Disease Etiology on ROTEM Profiles in Patients Undergoing Liver Transplantation

BACKGROUND

Coagulation abnormalities in liver transplant patients are complex and may be related to the underlying liver disease. We evaluated the effects of disease etiology on whole-blood rotational thromboelastometry (ROTEM; Pentapharm GmbH, Munich, Germany) profile and association with thrombotic complications following liver transplantation.

METHODS

Analysis of perioperative data from patients undergoing liver transplantation between January 1, 2012 and December 31, 2016. Patients were grouped based on the biology of their underlying liver disease: hepatocellular carcinoma (HCC), biliary etiology, and non-biliary etiology. The primary outcome was the EXTEM A10 value of the pre-incision ROTEM. Secondary outcomes included associations between EXTEM A10 value and incidence of postoperative thrombotic complications.

RESULTS

Three hundred fifty patients met the eligibility criteria: 60 had biliary etiologies, 203 had non-biliary etiologies, and 87 had HCC. EXTEM A10 values were significantly higher in patients with biliary etiologies than those with non-biliary etiologies (mean difference, 13.8; 95% CI: 10.1 to 17.5; P = .001) and those with HCC (mean difference, 10.4; 95% CI: 6.2 to 14.7; P = .001). Patients with non-biliary etiologies had slightly higher values than those with HCC (mean difference, -3.3; 95% CI: -6.6 to -0.1; P = .04). Higher values for biliary etiologies remained after adjusting for liver disease severity, platelet count, and fibrinogen level. There was no significant difference in EXTEM A10 values between patients who suffered thrombotic complications and those who did not (mean difference: 4.3, 95% CI: -1.3 to 9.9, P = .13).

CONCLUSION

Patients with biliary diseases demonstrated higher EXTEM A10 values compared to those with non-biliary diseases or HCC. This was not fully explained by differences in disease severity, platelet count, or fibrinogen level. Pre-incision EXTEM A10 values do not predict incidence of postoperative thrombotic complications.

In-vitro study of species-specific coagulation differences in animals and humans using rotational thromboelastometry (ROTEM)

Animal tests are conducted in all fields of trauma research, but transferability of these data to humans is limited. For example, it is still unclear which animal species is most similar to humans in terms of physiology of blood coagulation. To improve transferability and raise awareness of the existing differences, we compared human coagulation to coagulation of different animals. Rotational thromboelastometry was used to analyse the blood of pigs, sheep, rabbits and dogs. Animal data were compared with human coagulation based on the number of significant differences of the test parameters and on a descriptive comparison of the extent of relative deviation of the single values. All animal species showed significant differences in coagulation properties when compared with humans. Coagulation parameters of dogs and sheep were on average most similar to humans. However, there is no animal which is most similar to humans concerning all aspects of coagulation. Differences in coagulation between humans and animals are significant. This must be taken into account when transferring animal test data to humans.

Viscoelastic Monitoring to Guide the Correction of Perioperative Coagulopathy and Massive Transfusion in Patients with Life-Threatening Hemorrhage

The resuscitation of patients with traumatic hemorrhage remains a challenging clinical scenario. The appropriate and aggressive support of the patient's coagulation is of critical importance. Conventional coagulation assays present several shortcomings in this setting. The integration of viscoelastic monitoring in clinical practice has the potential to result in significant improvements. In order to be successful, the provider must understand basics of the methodology, read outs, and the limitations of the technique.

Thromboelastography and Thromboelastometry in Assessment of Fibrinogen Deficiency and Prediction for Transfusion Requirement: A Descriptive Review

Fibrinogen is crucial for the formation of blood clot and clinical outcomes in major bleeding. Both Thromboelastography (TEG) and Rotational Thromboelastometry (ROTEM) have been increasingly used to diagnose fibrinogen deficiency and guide fibrinogen transfusion in trauma and surgical bleeding patients. We conducted a comprehensive and comparative review on the technologies and clinical applications of two typical functional fibrinogen assays using TEG (FF TEG) and ROTEM (FIBTEM) for assessment of fibrinogen level and deficiency, and prediction of transfusion requirement. Clot strength and firmness of FF TEG and ROTEM FIBTEM were the most used parameters, and their associations with fibrinogen levels as measured by Clauss method ranged from 0 to 0.9 for FF TEG and 0.27 to 0.94 for FIBTEM. A comparison of the interchangeability and clinical performance of the functional fibrinogen assays using the two systems showed that the results were correlated, but are not interchangeable between the two systems. It appears that ROTEM FIBTEM showed better associations with the Clauss method and more clinical use for monitoring fibrinogen deficiency and predicting transfusion requirements including fibrinogen replacement than FF TEG. TEG and ROTEM functional fibrinogen tests play important roles in the diagnosis of fibrinogen-related coagulopathy and guidance of transfusion requirements. Despite the fact that high-quality evidence is still needed, the two systems are likely to remain popular for the hemostatic management of bleeding patients.

Rotational thromboelastometry thresholds for patients at risk for massive transfusion

BACKGROUND

Goal-directed hemostatic resuscitation based on thrombelastography has a survival benefit compared to conventional coagulation assays. While thrombelastography transfusion thresholds for patients at risk for massive transfusion (MT) have been defined, similar cutoffs do not exist for the other commonly used viscoelastic assay, rotational thromboelastometry (ROTEM). The purpose of this study was to develop ROTEM blood product thresholds in patients at risk for MT.

METHODS

ROTEM was assessed in trauma activation patients admitted from 2010 to 2016 (n = 222). Receiver operating characteristic curve analyses were performed to test the predictive performance of ROTEM measurements in patients requiring MT. The Youden Index defined optimal thresholds for ROTEM-based resuscitation.

RESULTS

Patients who required MT (n = 37, 17%) were more severely injured. EXTEM clotting time (CT) was longer in patients with MT compared to non-MT (87 versus 64 s, P < 0.0001). EXTEM angle was shallower in MT patients compared to non-MT (54° versus 69°, P < 0.0001). Clot amplitude after 10 min (CA10) was less in MT compared to non-MT patients (30.5 versus 50 mm, P < 0.0001). Clot lysis index 60 min (CLI60) was lower in patients who had MT than non-MT (47 versus 94%, P = 0.0006). EXTEM CT yielded an area under the receiver operating characteristic curve (AUROC) = 0.7116 and a cut point of >78.5 s. EXTEM angle had an AUROC = 0.865 and a cut point of <64.5°. EXTEM CA10 had an AUROC = 0.858, with a cut point of <40.5 mm. CLI60 had an AUROC = 0.6788 with a cut point at <74%.

CONCLUSIONS

We have identified ROTEM thresholds for transfusion of blood components in severely injured patients requiring an MT. Based on our analysis, we propose plasma transfusion for EXTEM CT > 78.5 s, fibrinogen for angle <64.5°, platelet transfusion for CA10 < 40.5 mm, and antifibrinolytics for CLI60 < 74%.

Hemorrhage under veno-venous extracorporeal membrane oxygenation in acute respiratory distress syndrome patients: a retrospective data analysis

Background

Despite being still invasive and challenging, technical improvement has resulted in broader and more frequent application of extracorporeal membrane oxygenation (ECMO), to prevent hypoxemia and to reduce invasiveness of mechanical ventilation (MV). Heparin-coated ECMO-circuits are currently standard of care, in addition to heparin based anticoagulation (AC) regimen guided by activated clotting time (ACT) or activated partial thromboplastin time (aPTT). Despite these advances, a reliable prediction of hemorrhage is difficult and the risk of hemorrhagic complication remains unfortunately high. We hypothesized, that there are coagulation parameters that are indices for a higher risk of hemorrhage under veno-venous (VV)-ECMO therapy.

Methods

Data from 36 patients with severe respiratory failure treated with VV-ECMO at a University Hospital intensive care unit (ICU) were analyzed retrospectively. Patients were separated into two groups based on severity of hemorrhagic complications and transfusion requirements. The following data were collected: demographics, hemodynamic data, coagulation samples, transfusion requirements, change of ECMO-circuit during treatment and adverse effects, including hemorrhage and thrombosis.

Results

In this study 74 hemorrhagic events were observed, one third of which were severe. Patients suffering from severe hemorrhage had a lower survival rate on VV-ECMO (43% vs. 91%; P=0.002) and in ICU (36% vs. 86%; P=0.002). SAPS II, factor VII and X were different between mild and severe hemorrhage group.

Conclusions

Severe hemorrhage under VV-ECMO is associated with higher mortality. Only factor VII and X differed between groups. Further clinical studies are required to determine the timing of initiation and targets for AC therapies during VV-ECMO.

Nanomechanical clinical coagulation diagnostics and monitoring of therapies

Clinical coagulation diagnostics often requires multiple tests. Coagulation times are a first indication of an abnormal coagulation process, such as a coagulation factor deficiency. To determine the specific deficient factor, additional immuno- and/or enzyme assays are necessary. Currently, every clinical laboratory has to normalize their assays (international normalized ratio, INR), and therefore, certain variability within the clinical analytics exists. We report a novel strategy for a quick, reliable and quantitative diagnosis of blood coagulation diseases (e.g. haemophilia) and for monitoring factor replacement and anticoagulant therapies (e.g. heparin treatment). We exploit nano-oscillations of microcantilevers for real-time measurements of the evolving blood plasma clot strength (viscosity). The sensors are oscillated at multiple high resonance mode numbers, in order to minimise the oscillation amplitude (a few nanometers), to provide direct internal control and to increase the quality factor. Along with the activated thromboplastin time (aPTT) and prothrombin time (PT) other parameters important for thrombosis diagnostics can be obtained, including the final clot strength and the fibrinolysis time. We demonstrate the dependence of the parameters on factor deficiencies and we diagnose a specific factor deficiency through an integrated and quantitative in situ immunoassay. This approach does not require continuous calibration since it delivers an absolute quantity (clot strength). The low sample volume required (a few μl) and the ability to measure different parameters within the same test (PT, aPTT and global coagulation assay) make the presented technique a versatile point-of-care device for clinical coagulation diagnostics.

Viscoelastic Monitoring to Guide Hemostatic Resuscitation in Liver Transplantation Surgery

Coagulopathic bleeding must be anticipated during liver transplantation (LT) surgery. Patients with end-stage liver disease (ESLD) often present with disease-related hematologic disturbances, including the loss of hepatic procoagulant and anticoagulant clotting factors and thrombocytopenia. Transplantation surgery itself presents additional hemostatic changes, including hyperfibrinolysis. Viscoelastic monitoring (VEM) is often used to provide targeted, personalized hemostatic therapies for complex bleeding states including cardiac surgery and major trauma. The use in these coagulopathic conditions led to its application to LT, although the mechanisms of coagulopathy in these patients are quite different. While VEM is often used during transplant surgeries in Europe and North America, evidence supporting its use is limited to a few small clinical studies. The theoretical and clinical applications of the standard and specialized VEM assays are discussed in the setting of LT and ESLD.

Coagulopathies in cyanotic cardiac patients: An analysis with three point - of - care testing devices (Thromboelastography, rotational thromboelastometry, and sonoclot analyzer)

Introduction:

In the last few years, viscoelastic point-of-care (POC) coagulation devices such as thromboelastography (TEG), rotational thromboelastometry (ROTEM), and Sonoclot (SON) analyzer have been increasingly used in major surgeries for timely assessment and management of coagulopathies. The aim of the present study was to evaluate coagulation profile of cyanotic cardiac patients with TEG, ROTEM, and SON analyzer. In addition, we assessed the correlation of standard laboratory coagulation tests and postoperative chest drain output (CDO) with the parameters of POC testing devices.

Materials and Methods:

Thirty-five patients of either gender, belonging to the American Society of Anesthesiologists Grade I–III, and undergoing elective cardiac surgery on cardiopulmonary bypass for cyanotic congenital heart disease were included in this study. To identify possible coagulation abnormalities, blood samples for TEG, ROTEM, SON, and standard laboratory coagulation were collected after induction of anesthesia. The correlations between variables were assessed using Pearson's correlation coefficient. P < 0.05 was considered statistically significant.

Results and Discussion:

EXTEM clot time (CT) and clot formation time (CFT) were prolonged in 87% and 45% patients whereas INTEM CT and CFT were prolonged in 36% and 73% patients, respectively. FIBTEM maximum clot firmness (MCF) was decreased in 30% patients. We observed significant correlation between fibrinogen concentration and ROTEM FIBTEM MCF (r = 0.94, P < 0.001). The SON platelet function (SON PF) showed good correlation with platelet count (r = 0.85, P < 0.001). We also found significant correlation between preoperative FIBTEM MCF and CDO in first 4 postoperative hours (r = 0.49, P = 0.004) and 24 postoperative hours (r = 0.52, P = 0.005). Receiver operating characteristic analysis demonstrated that SON PF and TEG maximum amplitude are highly predictive of thrombocytopenia below 100 × 10⁹/L (area under the curve [AUC] - 0.97 and 0.92, respectively), while FIBTEM-MCF is highly predictive of hypofibrinogenemia (fibrinogen <150 mg/dL (AUC, 0.99).

Conclusion:

Cyanotic cardiac patients have preoperative coagulation abnormalities in ROTEM, TEG, and SON parameters. ROTEM FIBTEM is highly predictive of hypofibrinogenemia while SON PF is highly predictive of thrombocytopenia. ROTEM FIBTEM can be studied as a marker of increased postoperative CDO.

Viscoelastic Studies: Effective Tools for Trauma and Surgical Resuscitation Efforts

Trauma-induced coagulopathy (TIC) is an abrupt disruption of all hemostatic components of coagulation resulting from severe tissue injury and hypoperfusion. The effective management of TIC has remained elusive to clinicians using traditional laboratory methods, challenging efforts to improve outcomes related to uncontrolled bleeding. Recent initiatives have aimed to reduce TIC-associated morbidity and mortality, further invoking trauma experts to explore innovative modalities in the field of viscoelastic studies, such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM). These tests are able to guide proper blood product administration more effectively during trauma and surgical resuscitation compared with conventional laboratory tests. Although TEG and ROTEM are similar tests, inherent differences in their features produce variation in output results. This article calls on the perioperative clinician to evaluate TEG and ROTEM tests and consider their implementation based on the benefits of their application to clinical practice.

Targeted Thromboelastographic (TEG) Blood Component and Pharmacologic Hemostatic Therapy in Traumatic and Acquired Coagulopathy

Trauma-induced coagulopathy (TIC) is a recently described condition which traditionally has been diagnosed by the common coagulation tests (CCTs) such as prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), platelet count, and fibrinogen levels. The varying sensitivity and specificity of these CCTs have led trauma coagulation researchers and clinicians to use Viscoelastic Tests (VET) such as Thromboelastography (TEG) to provide Targeted Thromboelastographic Hemostatic and Adjunctive Therapy (TTHAT) in a goal directed fashion to those trauma patients in need of hemostatic resuscitation. This review describes the utility of VETs, in particular, TEG, to provide TTHAT in trauma and acquired non-trauma-induced coagulopathy.