Whole Blood Thrombin Generation in Severely Injured Patients Requiring Massive Transfusion

Massive transfusion in trauma

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of currently recommended treatment approaches for traumatic hemorrhage shock, with a special focus on massive transfusion.

RECENT FINDINGS

Severe trauma patients require massive transfusion, but consensual international definitions for traumatic hemorrhage shock and massive transfusion are missing. Current literature defines a massive transfusion as transfusion of a minimum of 3-4 packed red blood cells within 1 h. Using standard laboratory and/or viscoelastic tests, earliest diagnosis and treatment should focus on trauma-induced coagulopathy and substitution of substantiated deficiencies.

SUMMARY

To initiate therapy immediately massive transfusion protocols are helpful focusing on early hemorrhage control using hemostatic dressing and tourniquets, correction of metabolic derangements to decrease coagulopathy and substitution according to viscoelastic assays and blood gases analysis with tranexamic acid, fibrinogen concentrate, red blood cells, plasma and platelets are recommended. Alternatively, the use of whole blood is possible. If needed, further support using prothrombin complex, factor XIII or desmopressin is suggested.

Sex dimorphisms in coagulation: Implications in trauma-induced coagulopathy and trauma resuscitation

Trauma-induced coagulopathy (TIC) is one of the leading causes of preventable death in injured patients. Consequently, it is imperative to understand the mechanisms underlying TIC and how to mitigate this mortality. An opportunity for advancement stems from the awareness that coagulation demonstrates a strong sex-dependent effect. Females exhibit a relative hypercoagulability compared to males, which persists after injury and confers improved outcomes. The mechanisms underlying sex dimorphisms in coagulation and its protective effect after injury have yet to be elucidated. This review explores sex dimorphisms in enzymatic hemostasis, fibrinogen, platelets, and fibrinolysis, with implications for resuscitation of patients with TIC.

Platelets in Hemostasis, Thrombosis, and Inflammation After Major Trauma

Trauma currently accounts for 10% of the total global burden of disease and over 5 million deaths per year, making it a leading cause of morbidity and mortality worldwide. Although recent advances in early resuscitation have improved early survival from critical injury, the mortality rate in patients with major hemorrhage approaches 50% even in mature trauma systems. A major determinant of clinical outcomes from a major injury is a complex, dynamic hemostatic landscape. Critically injured patients frequently present to the emergency department with an acute traumatic coagulopathy that increases mortality from bleeding, yet, within 48 to 72 hours after injury will switch from a hypocoagulable to a hypercoagulable state with increased risk of venous thromboembolism and multiple organ dysfunction. This review will focus on the role of platelets in these processes. As effectors of hemostasis and thrombosis, they are central to each phase of recovery from injury, and our understanding of postinjury platelet biology has dramatically advanced over the past decade. This review describes our current knowledge of the changes in platelet behavior that occur following major trauma, the mechanisms by which these changes develop, and the implications for clinical outcomes. Importantly, supported by research in other disease settings, this review also reflects the emerging role of thromboinflammation in trauma including cross talk between platelets, innate immune cells, and coagulation. We also address the unresolved questions and significant knowledge gaps that remain, and finally highlight areas that with the further study will help deliver further improvements in trauma care.

Label-free multiplex sensing from buffer and immunoglobulin G sensing from whole blood with photonic crystal slabs using angle-tuning of an optical interference filter

Direct detection of biomarkers from unpurified whole blood has been a challenge for label-free detection platforms, such as photonic crystal slabs (PCS). A wide range of measurement concepts for PCS exist, but exhibit technical limitations, which render them unsuitable for label-free biosensing with unfiltered whole blood. In this work, we single out the requirements for a label-free point-of-care setup based on PCS and present a wavelength selecting concept by angle tuning of an optical interference filter, which fulfills these requirements. We investigate the limit of detection (LOD) for bulk refractive index changes and obtain a value of 3.4 E-4 refractive index units (RIU). We demonstrate label-free multiplex detection for different types of immobilization entities, including aptamers, antigens, and simple proteins. For this multiplex setup we detect thrombin at a concentration of 6.3 µg/ml, antibodies of glutathione S-transferase (GST) diluted by a factor of 250, and streptavidin at a concentration of 33 µg/ml. In a first proof of principle experiment, we demonstrate the ability to detect immunoglobulins G (IgG) from unfiltered whole blood. These experiments are conducted directly in the hospital without temperature control of the photonic crystal transducer surface or the blood sample. We set the detected concentration levels into a medical frame of reference and point out possible applications.

[The chapters "Stop the bleed-prehospital" and "Coagulation management and volume therapy (emergency departement)" in the new S3 guideline "Polytrauma/severe injury treatment"]

The S3 guideline on the treatment of patients with severe/multiple injuries by the German Association of the Scientific Medical Societies was updated between 2020 and 2022. This article describes the essence of the new chapter "Stop the bleed-prehospital" and the revised chapter "Coagulation management and volume therapy".

Severe Trauma-Induced Coagulopathy: Molecular Mechanisms Underlying Critical Illness

Trauma remains one of the leading causes of death in adults despite the implementation of preventive measures and innovations in trauma systems. The etiology of coagulopathy in trauma patients is multifactorial and related to the kind of injury and nature of resuscitation. Trauma-induced coagulopathy (TIC) is a biochemical response involving dysregulated coagulation, altered fibrinolysis, systemic endothelial dysfunction, platelet dysfunction, and inflammatory responses due to trauma. The aim of this review is to report the pathophysiology, early diagnosis and treatment of TIC. A literature search was performed using different databases to identify relevant studies in indexed scientific journals. We reviewed the main pathophysiological mechanisms involved in the early development of TIC. Diagnostic methods have also been reported which allow early targeted therapy with pharmaceutical hemostatic agents such as TEG-based goal-directed resuscitation and fibrinolysis management. TIC is a result of a complex interaction between different pathophysiological processes. New evidence in the field of trauma immunology can, in part, help explain the intricacy of the processes that occur after trauma. However, although our knowledge of TIC has grown, improving outcomes for trauma patients, many questions still need to be answered by ongoing studies.

Age-dependent thrombin generation predicts 30-day mortality and symptomatic thromboembolism after multiple trauma

Trauma-induced coagulopathy (TIC) is a risk factor for death and is associated with deviations in thrombin generation. TIC prevalence and thrombin levels increase with age. We assayed in vivo and ex vivo thrombin generation in injured patients (n = 418) to specifically investigate how age impacts thrombin generation in trauma and to address the prognostic ability of thrombin generation. Biomarkers of thrombin generation were elevated in young (< 40 years) and older (≥ 40 years) trauma patients. In vivo thrombin generation was associated with Injury Severity Score (ISS) and this association was stronger in young than older patients. In vivo thrombin generation decreased faster after trauma in the young than the older patients. Across age groups, in vivo thrombin generation separated patients dying/surviving within 30 days at a level comparable to the ISS score (AUC 0.80 vs. 0.82, p > 0.76). In vivo and ex vivo thrombin generation also predicted development of thromboembolic events within the first 30 days after the trauma (AUC 0.70-0.84). In conclusion, younger trauma patients mount a stronger and more dynamic in vivo thrombin response than older patients. Across age groups, in vivo thrombin generation has a strong ability to predict death and/or thromboembolic events 30 days after injury.

Hyperfibrinolysis drives mechanical instabilities in a simulated model of trauma induced coagulopathy

INTRODUCTION

Trauma induced coagulopathy (TIC) is common after severe trauma, increasing transfusion requirements and mortality among patients. TIC has several phenotypes, with primary hyperfibrinolysis being among the most lethal. We aimed to investigate the contribution of hypercoagulation, hemodilution, and fibrinolytic activation to the hyperfibrinolytic phenotype of TIC, by examining fibrin formation in a plasma-based model of TIC. We hypothesized that instabilities arising from TIC will be due primarily to increased fibrinolytic activation rather than hemodilution or tissue factor (TF) induced hypercoagulation.

METHODS

The influence of TF, hemodilution, fibrinogen consumption, tissue plasminogen activator (tPA), and the antifibrinolytic tranexamic acid (TXA) on plasma clot formation and structure were examined using rheometry, optical properties, and confocal microscopy. These were then compared to plasma samples from trauma patients at risk of developing TIC.

RESULTS

Combining TF-induced clot formation, 15 % hemodilution, fibrinogen consumption, and tPA-induced fibrinolysis, the clot characteristics and hyperfibrinolysis were consistent with primary hyperfibrinolysis. TF primarily increased fibrin polymerization rates and reduced fiber length. Hemodilution decreased clot optical density but had no significant effect on mechanical clot stiffness. TPA addition induced primary clot lysis as observed mechanically and optically. TXA restored mechanical clot formation but did not restore clot structure to control levels. Patients at risk of TIC showed increased clot formation, and lysis like that of our simulated model.

CONCLUSIONS

This simulated TIC plasma model demonstrated that fibrinolytic activation is a primary driver of instability during TIC and that clot mechanics can be restored, but clot structure remains altered with TXA treatment.

Full-length plasma skeletal muscle myosin isoform deficiency is associated with coagulopathy in acutely injured patients

BACKGROUND

Skeletal muscle myosin (SkM) molecules are procoagulant both in vitro and in vivo. The association of plasma SkM isoforms with blood coagulability and hemostatic capacity has not been defined.

OBJECTIVES

We hypothesized that coagulopathy in acutely injured patients is associated with procoagulant plasma SkM heavy chain levels.

METHODS

To test this hypothesis, citrated whole blood and plasma from 104 trauma patients were collected and studied to obtain data for rapid thrombelastography, international normalized ratios, and plasma SkM levels. Coagulability parameters were dichotomized by the threshold for the hypercoagulable trauma-induced coagulopathy.

RESULTS

Lower plasma full-length SkM heavy chain (full-SkM) levels were associated with higher international normalized ratio values (>1.3) (p = .03). The full-SkM levels were also associated with a lower rate of clot propagation (thrombelastography angle <65°) (p = .004), and plasma full-SkM levels were positively correlated with the thrombelastography angle (r2  = .32, p = .0007). The trauma patient group with the lower plasma full-SkM levels showed an association with lower clot strength (maximum amplitude <55 mm) (p = .002), and plasma full-SkM levels positively correlated with maximum amplitude (r2  = .27, p = .005). Hyperfibrinolysis was associated with significantly decreased full-SkM levels (p = .03). Trauma patients who required red blood cells and fresh frozen plasma transfusions had lower plasma full-SkM levels compared with those without transfusions (p = .04 and .02, respectively).

CONCLUSIONS

In acutely injured trauma patients, lower levels of plasma full-SkM levels are linked to hypocoagulability in trauma-induced coagulopathy, implying that SkM plays a role in the hemostatic capacity in trauma patients and may contribute to trauma-induced coagulopathy.

Emergency Blood Transfusion for Trauma and Perioperative Resuscitation: Standard of Care

Uncontrolled and massive bleeding with derangement of coagulation is a major challenge in the management of both surgical and seriously injured patients. The underlying mechanism of trauma-induced or -associated coagulopathy is tissue injury in the presence of shock and acidosis provoking endothelial damage, activation of inflammation, and coagulation disbalancing. Furthermore, the combination of ongoing blood loss and consumption of blood components that are essential for effective coagulation worsens uncontrolled hemorrhage. Additionally, therapeutic actions, such as resuscitation with replacement fluids or allogeneic blood products, can further aggravate coagulopathy. Of the coagulation factors essential to the clotting process, fibrinogen is the first to be consumed to critical levels during acute bleeding and current evidence suggests that normalizing fibrinogen levels in bleeding patients improves clot formation and clot strength, thereby controlling hemorrhage. Three different therapeutic approaches are discussed controversially. Whole blood transfusion is used especially in the military scenario and is also becoming more and more popular in the civilian world, although it is accompanied by a strong lack of evidence and severe safety issues. Transfusion of allogeneic blood concentrates in fixed ratios without any targets has been investigated extensively with disappointing results. Individualized and target-controlled coagulation management based on point-of-care diagnostics with respect to the huge heterogeneity of massive bleeding situations is an alternative and advanced approach to managing coagulopathy associated with massive bleeding in the trauma as well as the perioperative setting.

Trauma-induced coagulopathy

Uncontrolled haemorrhage is a major preventable cause of death in patients with traumatic injury. Trauma-induced coagulopathy (TIC) describes abnormal coagulation processes that are attributable to trauma. In the early hours of TIC development, hypocoagulability is typically present, resulting in bleeding, whereas later TIC is characterized by a hypercoagulable state associated with venous thromboembolism and multiple organ failure. Several pathophysiological mechanisms underlie TIC; tissue injury and shock synergistically provoke endothelial, immune system, platelet and clotting activation, which are accentuated by the 'lethal triad' (coagulopathy, hypothermia and acidosis). Traumatic brain injury also has a distinct role in TIC. Haemostatic abnormalities include fibrinogen depletion, inadequate thrombin generation, impaired platelet function and dysregulated fibrinolysis. Laboratory diagnosis is based on coagulation abnormalities detected by conventional or viscoelastic haemostatic assays; however, it does not always match the clinical condition. Management priorities are stopping blood loss and reversing shock by restoring circulating blood volume, to prevent or reduce the risk of worsening TIC. Various blood products can be used in resuscitation; however, there is no international agreement on the optimal composition of transfusion components. Tranexamic acid is used in pre-hospital settings selectively in the USA and more widely in Europe and other locations. Survivors of TIC experience high rates of morbidity, which affects short-term and long-term quality of life and functional outcome.