Advances in the understanding of trauma-induced coagulopathy

Coagulopathy induced by traumatic brain injury: systemic manifestation of a localized injury

Traumatic brain injury (TBI)-induced coagulopathy is a common and well-recognized risk for poor clinical outcomes, but its pathogenesis remains poorly understood, and treatment options are limited and ineffective. We discuss the recent progress and knowledge gaps in understanding this lethal complication of TBI. We focus on (1) the disruption of the brain-blood barrier to disseminate brain injury systemically by releasing brain-derived molecules into the circulation and (2) TBI-induced hypercoagulable and hyperfibrinolytic states that result in persistent and delayed intracranial hemorrhage and systemic bleeding.

Innate immune responses to trauma

Trauma can affect any individual at any location and at any time over a lifespan. The disruption of macrobarriers and microbarriers induces instant activation of innate immunity. The subsequent complex response, designed to limit further damage and induce healing, also represents a major driver of complications and fatal outcome after injury. This Review aims to provide basic concepts about the posttraumatic response and is focused on the interactive events of innate immunity at frequent sites of injury: the endothelium at large, and sites within the lungs, inside and outside the brain and at the gut barrier.

Antifibrinolytic Therapy and Perioperative Considerations

Fibrinolysis is a physiologic component of hemostasis that functions to limit clot formation. However, after trauma or surgery, excessive fibrinolysis may contribute to coagulopathy, bleeding, and inflammatory responses. Antifibrinolytic agents are increasingly used to reduce bleeding, allogeneic blood administration, and adverse clinical outcomes. Tranexamic acid is the agent most extensively studied and used in most countries. This review will explore the role of fibrinolysis as a pathologic mechanism, review the different pharmacologic agents used to inhibit fibrinolysis, and focus on the role of tranexamic acid as a therapeutic agent to reduce bleeding in patients after surgery and trauma.

Assessment of Platelet Function in Traumatic Brain Injury-A Retrospective Observational Study in the Neuro-Critical Care Setting

BACKGROUND

Despite seemingly functional coagulation, hemorrhagic lesion progression is a common and devastating condition following traumatic brain injury (TBI), stressing the need for new diagnostic techniques. Multiple electrode aggregometry (MEA) measures platelet function and could aid in coagulopathy assessment following TBI. The aims of this study were to evaluate MEA temporal dynamics, influence of concomitant therapy, and its capabilities to predict lesion progression and clinical outcome in a TBI cohort.

MATERIAL AND METHODS

Adult TBI patients in a neurointensive care unit that underwent MEA sampling were retrospectively included. MEA was sampled if the patient was treated with antiplatelet therapy, bled heavily during surgery, or had abnormal baseline coagulation values. We assessed platelet activation pathways involving the arachidonic acid receptor (ASPI), P2Y12 receptor, and thrombin receptor (TRAP). ASPI was the primary focus of analysis. If several samples were obtained, they were included. Retrospective data were extracted from hospital charts. Outcome variables were radiologic hemorrhagic progression and Glasgow Outcome Scale assessed prospectively at 12 months posttrauma. MEA levels were compared between patients on antiplatelet therapy. Linear mixed effect models and uni-/multivariable regression models were used to study longitudinal dynamics, hemorrhagic progression and outcome, respectively.

RESULTS

In total, 178 patients were included (48% unfavorable outcome). ASPI levels increased from initially low values in a time-dependent fashion (p < 0.001). Patients on cyclooxygenase inhibitors demonstrated low ASPI levels (p < 0.001), while platelet transfusion increased them (p < 0.001). The first ASPI (p = 0.039) and TRAP (p = 0.009) were significant predictors of outcome, but not lesion progression, in univariate analyses. In multivariable analysis, MEA values were not independently correlated with outcome.

CONCLUSION

A general longitudinal trend of MEA is identified in this TBI cohort, even in patients without known antiplatelet therapies. Values appear also affected by platelet inhibitory treatment and by platelet transfusions. While significant in univariate models to predict outcome, MEA values did not independently correlate to outcome or lesion progression in multivariable analyses. Further prospective studies to monitor coagulation in TBI patients are warranted, in particular the interpretation of pathological MEA values in patients without antiplatelet therapies.

Guiding Management in Severe Trauma: Reviewing Factors Predicting Outcome in Vastly Injured Patients

Trauma is one of the leading causes of death worldwide, with road traffic collisions, suicides, and homicides accounting for the majority of injury-related deaths. Since trauma mainly affects young age groups, it is recognized as a serious social and economic threat, as annually, almost 16,000 posttrauma individuals are expected to lose their lives and many more to end up disabled. The purpose of this research is to summarize current knowledge on factors predicting outcome - specifically mortality risk - in severely injured patients. Development of this review was mainly based on the systematic search of PubMed medical library, Cochrane database, and advanced trauma life support Guiding Manuals. The research was based on publications between 1994 and 2016. Although hypovolemic, obstructive, cardiogenic, and septic shock can all be seen in multi-trauma patients, hemorrhage-induced shock is by far the most common cause of shock. In this review, we summarize current knowledge on factors predicting outcome - more specifically mortality risk - in severely injured patients. The main mortality-predicting factors in trauma patients are those associated with basic human physiology and tissue perfusion status, coagulation adequacy, and resuscitation requirements. On the contrary, advanced age and the presence of comorbidities predispose patients to a poor outcome because of the loss of physiological reserves. Trauma resuscitation teams considering mortality prediction factors can not only guide resuscitation but also identify patients with high mortality risk who were previously considered less severely injured.

Abnormalities of laboratory coagulation tests versus clinically evident coagulopathic bleeding: results from the prehospital resuscitation on helicopters study (PROHS)

BACKGROUND

Laboratory-based evidence of coagulopathy (LC) is observed in 25-35% of trauma patients, but clinically-evident coagulopathy (CC) is not well described.

METHODS

Prospective observational study of adult trauma patients transported by helicopter from the scene to nine Level 1 trauma centers in 2015. Patients meeting predefined highest-risk criteria were divided into CC+ (predefined as surgeon-confirmed bleeding from uninjured sites or injured sites not controllable by sutures) or CC-. We used a mixed-effects, Poisson regression with robust error variance to test the hypothesis that abnormalities on rapid thrombelastography (r-TEG) and international normalized ratio (INR) were independently associated with CC+.

RESULTS

Of 1,019 highest-risk patients, CC+ (n=41, 4%) were more severely injured (median ISS 32 vs 17), had evidence of LC on r-TEG and INR, received more transfused blood products at 4 hours (37 vs 0 units), and had greater 30-day mortality (59% vs 12%) than CC- (n=978, 96%). The overall incidence of LC was 39%. 30-day mortality was 22% vs 9% in those with and without LC. In two separate models, r-TEG K-time >2.5 min (RR 1.3, 95% CI 1.1-1.7), r-TEG mA <55 mm (RR 2.5, 95% CI 2.0-3.2), platelet count <150 x 10⁹/L (RR 1.2, 95% CI 1.1-1.3), and INR >1.5 (RR 5.4, 95% CI 1.8-16.3) were independently associated with CC+. A combined regression model was not generated because too few patients underwent both r-TEG and INR.

CONCLUSION

CC was rare compared to LC. CC was associated with poor outcomes and impairment of both clotting factor and platelet-mediated coagulation components.

Hemorrhagic Shock and the Microvasculature

The microvasculature plays a central role in the pathophysiology of hemorrhagic shock and is also involved in arguably all therapeutic attempts to reverse or minimize the adverse consequences of shock. Microvascular studies specific to hemorrhagic shock were reviewed and broadly grouped depending on whether data were obtained on animal or human subjects. Dedicated sections were assigned to microcirculatory changes in specific organs, and major categories of pathophysiological alterations and mechanisms such as oxygen distribution, ischemia, inflammation, glycocalyx changes, vasomotion, endothelial dysfunction, and coagulopathy as well as biomarkers and some therapeutic strategies. Innovative experimental methods were also reviewed for quantitative microcirculatory assessment as it pertains to changes during hemorrhagic shock. The text and figures include representative quantitative microvascular data obtained in various organs and tissues such as skin, muscle, lung, liver, brain, heart, kidney, pancreas, intestines, and mesentery from various species including mice, rats, hamsters, sheep, swine, bats, and humans. Based on reviewed findings, a new integrative conceptual model is presented that includes about 100 systemic and local factors linked to microvessels in hemorrhagic shock. The combination of systemic measures with the understanding of these processes at the microvascular level is fundamental to further develop targeted and personalized interventions that will reduce tissue injury, organ dysfunction, and ultimately mortality due to hemorrhagic shock. Published 2018. Compr Physiol 8:61-101, 2018.

Early chemoprophylaxis is associated with decreased venous thromboembolism risk without concomitant increase in intraspinal hematoma expansion after traumatic spinal cord injury

BACKGROUND

After traumatic spinal cord injury (SCI), there is increased risk of venous thromboembolism (VTE), but chemoprophylaxis (PPX) may cause expansion of intraspinal hematoma (ISH).

METHODS

Single-center retrospective study of adult trauma patients from 2012 to 2015 with SCI.

EXCLUSION CRITERIA

VTE diagnosis, death, or discharge within 48 hours. Patients were dichotomized based on early (≤48 hours) heparinoid and/or aspirin PPX. Intraspinal hematoma expansion was diagnosed intraoperatively or by follow-up radiology. We used multivariable Cox proportional hazards to estimate the effect of PPX on risk of VTE and ISH expansion controlling for age, injury severity score (ISS), complete SCI, and mechanism as static covariates and operative spine procedure as a time-varying covariate.

RESULTS

Five hundred one patients with SCI were dichotomized into early PPX (n = 260 [52%]) and no early PPX (n = 241 [48%]). Early PPX patients were less likely blunt injured (91% vs 97%) and had fewer operative spine interventions (65% vs 80%), but age (median, 43 vs 49 years), ISS (median 24 vs 21), admission ISH (47% vs 44%), and VTE (5% vs 9%) were similar. Cox analysis found that early heparinoids was associated with reduced VTE (hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.16-0.84) and reduced pulmonary embolism (PE) (HR, 0.20; 95% CI, 0.06-0.69). The estimated number needed to treat with heparinoids was 10 to prevent one VTE and 13 to prevent one PE at 30 days. Early aspirin was not associated with reduced VTE or PE. Seven patients (1%) had ISH expansion, of which four were on PPX at the time of expansion. Using heparinoid and aspirin as time-varying covariates, neither heparinoids (HR, 1.90; 95% CI, 0.32-11.41) nor aspirin (HR, 3.67; 95% CI, 0.64-20.88) was associated with ISH expansion.

CONCLUSION

Early heparinoid therapy was associated with decreased VTE and PE risk in SCI patients without concomitant increase in ISH expansion.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Effect of Intermediate-Frequency Repetitive Transcranial Magnetic Stimulation on Recovery following Traumatic Brain Injury in Rats

Traumatic brain injury (TBI) represents a significant public health concern and has been associated with high rates of morbidity and mortality. Although several research groups have proposed the use of repetitive transcranial magnetic stimulation (rTMS) to enhance neuroprotection and recovery in patients with TBI, few studies have obtained sufficient evidence regarding its effects in this population. Therefore, we aimed to analyze the effect of intermediate-frequency rTMS (2 Hz) on behavioral and histological recovery following TBI in rats. Male Wistar rats were divided into six groups: three groups without TBI (no manipulation, movement restriction plus sham rTMS, and movement restriction plus rTMS) and three groups subjected to TBI (TBI only, TBI plus movement restriction and sham rTMS, and TBI plus movement restriction and rTMS). The movement restriction groups were included so that rTMS could be applied without anesthesia. Our results indicate that the restriction of movement and sham rTMS per se promotes recovery, as measured using a neurobehavioral scale, although rTMS was associated with faster and superior recovery. We also observed that TBI caused alterations in the CA1 and CA3 subregions of the hippocampus, which are partly restored by movement restriction and rTMS. Our findings indicated that movement restriction prevents damage caused by TBI and that intermediate-frequency rTMS promotes behavioral and histologic recovery after TBI.

Clot dynamics and mortality: The MA-R ratio

INTRODUCTION

The coagulopathy of trauma, illustrated by a short R-time, is common and well understood. The physiology behind this may be early thrombin burst with rapid clot formation. Rapid consumption of fibrinogen, however, may result in weak clot and substrate depletion, resulting in low MA. While these characteristics are interesting, utilizing thromboelastography (TEG) to identify those at risk of subsequent bleeding diathesis, especially in those who do not demonstrate early signs of physiologic derangement, is challenging. We have developed a novel ratio utilizing TEG values to describe patients at specific risk of traumatic coagulopathy. The purpose of this study was to create a single TEG value, which would reflect both the hypercoagulability and hypocoagulability of TIC. We hypothesized that this ratio, at admission, would be indicative of TIC and predictive of both blood product transfusion volumes and subsequent mortality.

METHODS

Patients admitted via the highest activation criteria at one of two Level I trauma centers were included if they received at least 1 unit of packed red blood cells in the first 24 hours of admission. The admission TEG was collected, and a ratio was calculated by dividing the MA by the R-time (MA-R). MA-R quartiles were developed, and multivariable logistic regression was utilized to determine odds of mortality.

RESULTS

Three hundred thirty patients with admission TEG were included. In all patients, median age was 35 years (interquartile range, 25-54 years), Injury Severity Score (ISS) was 20 (interquartile range, 13-29), 76% were male, and 43% had penetrating trauma. The MA-R groups were based on quartiles. Multivariable analysis, controlling for mechanism of injury, ISS, and admission pH, showed that increasing ratios were associated with decreased odds of death. The lowest MA-R ratios were also significantly associated with higher ISS, higher rates of blunt injury, and higher plasma utilization without a significant difference in packed red blood cell administration.

CONCLUSIONS

Patients with the lowest MA-R ratios demonstrated the highest mortality rates. This novel ratio may prove highly useful to predict at-risk patients early, when other physiologic indicators are absent. The mechanism driving this finding may rest in fibrinogen depletion, resulting in weak clot. Patients with low MA-R ratios may benefit from earlier resuscitation with cryoprecipitate, rather than the traditional use of plasma found in current massive transfusion protocols.

LEVELS OF EVIDENCE

Prognostic study, Level I.

The current understanding of trauma-induced coagulopathy (TIC): a focused review on pathophysiology

The emergency management of acute severe bleeding in trauma patients has changed significantly in recent years. In particular, greater attention is now being devoted to a prompt assessment of coagulation alterations, which allows for immediate haemostatic resuscitation procedures when necessary. The importance of an early trauma-induced coagulopathy (TIC) diagnosis has led physicians to increase the efforts to better understand the pathophysiological alterations observed in the haemostatic system after traumatic injuries. As yet, the knowledge of TIC is not exhaustive, and further studies are needed. The aim of this review is to gather all the currently available data and information in an attempt to gain a better understanding of TIC. A comprehensive literature search was performed using MEDLINE database. The bibliographies of relevant articles were screened for additional publications. In major traumas, coagulopathic bleeding stems from a complex interplay among haemostatic and inflammatory systems, and is characterized by a multifactorial dysfunction. In the abundance of biochemical and pathophysiological changes occurring after trauma, it is possible to discern endogenously induced primary predisposing conditions and exogenously induced secondary predisposing conditions. TIC remains one of the most diagnostically and therapeutically challenging condition.

Syndecan-1: A Quantitative Marker for the Endotheliopathy of Trauma

BACKGROUND

Endothelial glycocalyx breakdown elicits syndecan-1 shedding and endotheliopathy of trauma (EoT). We hypothesized that a cutoff syndecan-1 level can identify patients with endothelial dysfunction who would have poorer outcomes.

STUDY DESIGN

We conducted a prospective observational study. Trauma patients with the highest level of activation admitted from July 2011 through September 2013 were eligible. We recorded demographics, injury type/severity (Injury Severity Score), physiology and outcomes data, and quantified syndecan-1 and soluble thrombomodulin from plasma with ELISAs. With receiver operating characteristic curve analysis, we defined EoT+ as the syndecan-1 cutoff level that maximized the sum of sensitivity and specificity (Youden index) in predicting 24-hour in-hospital mortality. We stratified by this cutoff and compared both groups. Factors associated with 30-day in-hospital mortality were assessed with multivariable logistic regression (adjusted odds ratios and 95% CIs reported).

RESULTS

From receiver operating characteristic curve analysis (area under the curve = 0.71; 95% CI 0.58 to 0.84), we defined EoT+ as syndecan-1 level ≥40 ng/mL (sensitivity = 0.62, specificity = 0.73). Of the 410 patients evaluated, 34% (n = 138) were EoT+ patients, who presented with higher Injury Severity Scores (p < 0.001) and blunt trauma frequency (p = 0.016) than EoT- patients. Although EoT+ patients had lower systolic blood pressure (median 119 vs 128 mmHg; p < 0.001), base excess and hemoglobin were similar between groups. The proportion of transfused (EoT+ 71.7% vs EoT- 36.4%; p < 0.001) and deceased EoT+ patients (EoT+ 24.6% vs EoT- 12.1%; p < 0.001) was higher. EoT+ was significantly associated with 30-day in-hospital mortality (adjusted odds ratio = 2.23; 95% CI 1.22 to 4.04).

CONCLUSIONS

A syndecan-1 level ≥40 ng/mL identified patients with significantly worse outcomes, despite admission physiology similar to those without the condition.

[Modern coagulation management in bleeding trauma patients : Point-of-care guided administration of coagulation factor concentrates and hemostatic agents]

BACKGROUND

Uncontrolled bleeding with trauma-induced coagulopathy (TIC) is still the leading cause of preventable death following severe multiple injury. Rapid diagnosis and treatment are associated with improved outcome. Early individualized goal-directed therapy and the use of point-of-care technology may be superior to empiric and ratio-based therapies with conventional blood products.

MATERIALS AND METHODS

Selective review of the literature considering current recommendations/expert opinion for coagulation management in bleeding trauma patients via individualized goal-directed therapy and the use of viscoelastic point-of-care (ROTEM®)-guided substitution of coagulation factor concentrates and hemostatic agents.

RESULTS

The administration of fibrinogen concentrate in bleeding trauma patients may be considered if ROTEM®-FIBTEM A10 < 10 mm (FIBTEM A5 < 9 mm; FIBTEM MCF < 12 mm) and EXTEM A10 < 45 mm (EXTEM A5 < 35 mm; EXTEM MCF < 55 mm); the administration of prothrombin complex concentrate (PCC) may be considered if signs of delayed coagulation initiation (ROTEM®-EXTEM CT > 80 s). At this stage, no concluding statement can be made for monitoring or treatment guidance with factor XIII by using point-of-care technology. Viscoelastic assays display high sensitivity and specificity for the detection of hyperfibrinolysis with subsequent administration of an antifibrinolytic.

CONCLUSIONS

Individualized therapeutic concepts based upon viscoelastic point-of-care (ROTEM®) assays present an alternative to empiric and ratio-based therapies with conventional blood products in bleeding trauma patients and may be associated with reduced need for allogenic blood products and morbidity.

Coagulopathy in the Setting of Mild Traumatic Brain Injury: Truths and Consequences

Mild traumatic brain injury (mTBI) is a common, although poorly-defined clinical entity. Despite its initially mild presentation, patients with mTBI can rapidly deteriorate, often due to significant expansion of intracranial hemorrhage. TBI-associated coagulopathy is the topic of significant clinical and basic science research. Unlike trauma-induced coagulopathy (TIC), TBI-associated coagulopathy does not generally follow widespread injury or global hypoperfusion, suggesting a distinct pathogenesis. Although the fundamental mechanisms of TBI-associated coagulopathy are far from clearly elucidated, several candidate molecules (tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), tissue factor (TF), and brain-derived microparticles (BDMP)) have been proposed which might explain how even minor brain injury can induce local and systemic coagulopathy. Here, we review the incidence, proposed mechanisms, and common clinical tests relevant to mTBI-associated coagulopathy and briefly summarize our own institutional experience in addition to identifying areas for further research.

1: 1 Transfusion strategies are right for the wrong reasons

BACKGROUND

Early assessment of clot function identifies coagulopathies after injury. Abnormalities include a hypercoagulable state from excess thrombin generation, as well as an acquired coagulopathy. Efforts to address coagulopathy have resulted in earlier, aggressive use of plasma emphasizing 1:1 resuscitation. The purpose of this study was to describe coagulopathies in varying hemorrhagic profiles from a cohort of injured patients.

METHODS

All injured patients who received at least one unit of packed red blood cells (PRBC) in the first 24 hours of admission from September 2013 to May 2015 were eligible for inclusion. Group-Based Trajectory Modeling, using volume of transfusion over time, was used to identify specific hemorrhagic phenotypes. The thromboelastography profile of each subgroup was characterized and group features were compared.

RESULTS

Four hemorrhagic profiles were identified among 330 patients-minimal (MIN, group 1); patients with large PRBC requirements later in the hospital course (LH, group 2); massive PRBC usage (MH, group 3), and PRBC transfusion limited to shortly after injury (EH, group 4). All groups had an R-time shorter than the normal range (3.2-3.5, p = NS). Patients in group 3 had longer K-times (1.8 vs. 1.2-1.3, p < 0.05), significantly flatter α-angles (66.7 vs. 70.4-72.8, p < 0.05), and significantly weaker clot strength (MA 54.6 vs. 62.3-63.6, p < 0.05). Group 3 had greater physiologic derangements at admission and worse overall outcomes.

CONCLUSION

Hemorrhagic profiles suggest a rapid onset of clot formation in all subgroups but significantly suppressed thrombin burst and diminished clot strength in the most injured. Patients are both hypercoagulable, with early and precipitous clot formation, and also have a demonstrable hypocoagulability. The exact cause of traumatic hypocoagulability is likely multifactorial. Goal-directed resuscitation, as early as institution of the massive transfusion protocol, may be more effective in resuscitating the most coagulopathic patients.

LEVEL OF EVIDENCE

Prognostic study, level III.

Coagulopathy and haemorrhagic progression in traumatic brain injury: advances in mechanisms, diagnosis, and management

Normal haemostasis depends on an intricate balance between mechanisms of bleeding and mechanisms of thrombosis, and this balance can be altered after traumatic brain injury (TBI). Impaired haemostasis could exacerbate the primary insult with risk of initiation or aggravation of bleeding; anticoagulant use at the time of injury can also contribute to bleeding risk after TBI. Many patients with TBI have abnormalities on conventional coagulation tests at admission to the emergency department, and the presence of coagulopathy is associated with increased morbidity and mortality. Further blood testing often reveals a range of changes affecting platelet numbers and function, procoagulant or anticoagulant factors, fibrinolysis, and interactions between the coagulation system and the vascular endothelium, brain tissue, inflammatory mechanisms, and blood flow dynamics. However, the degree to which these coagulation abnormalities affect TBI outcomes and whether they are modifiable risk factors are not known. Although the main challenge for management is to address the risk of hypocoagulopathy with prolonged bleeding and progression of haemorrhagic lesions, the risk of hypercoagulopathy with an increased prothrombotic tendency also warrants consideration.

Flow chamber and microfluidic approaches for measuring thrombus formation in genetic bleeding disorders

Platelet adhesion and aggregation, coagulation, fibrin formation, and fibrinolysis are regulated by the forces and flows imposed by blood at the site of a vascular injury. Flow chambers designed to observe these events are an indispensable part of doing hemostasis and thrombosis research, especially with human blood. Microfluidic methods have provided the flexibility to design flow chambers with complex geometries and features that more closely mimic the anatomy and physiology of blood vessels. Additionally, microfluidic systems with integrated optics and/or pressure sensors and on-board signal processing could transform what have been primarily research tools into clinical assays. Here, we describe a historical review of how flow-based approaches have informed biophysical mechanisms in genetic bleeding disorders, challenges and potential solutions for developing models of bleeding in vitro, and outstanding issues that need to be addressed prior to their use in clinical settings.

Role of Vascular Endothelial Cells in Disseminated Intravascular Coagulation Induced by Seawater Immersion in a Rat Trauma Model

Trauma complicated by seawater immersion is a complex pathophysiological process with higher mortality than trauma occurring on land. This study investigated the role of vascular endothelial cells (VECs) in trauma development in a seawater environment. An open abdominal injury rat model was used. The rat core temperatures in the seawater (SW, 22°C) group and normal sodium (NS, 22°C) group declined equivalently. No rats died within 12 hours in the control and NS groups. However, the median lethal time of the rats in the SW group was only 260 minutes. Among the 84 genes involved in rat VEC biology, the genes exhibiting the high expression changes (84.62%, 11/13) on a qPCR array were associated with thrombin activity. The plasma activated partial thromboplastin time and fibrinogen and vWF levels decreased, whereas the prothrombin time and TFPI levels increased, indicating intrinsic and extrinsic coagulation pathway activation and inhibition, respectively. The plasma plasminogen, FDP, and D-dimer levels were elevated after 2 hours, and those of uPA, tPA, and PAI-1 exhibited marked changes, indicating disseminated intravascular coagulation (DIC). Additionally, multiorgan haemorrhagia was observed. It indicated that seawater immersion during trauma may increase DIC, elevating mortality. VECs injury might play an essential role in this process.

Performance of point-of-care international normalized ratio measurement to diagnose trauma-induced coagulopathy

Background

Trauma-induced coagulopathy (TIC) is a common feature after severe trauma. Detection of TIC is based upon classic coagulation tests including international normalized ratio (INR) value. Point-of-care (POC) devices have been developed to rapidly measure INR at the bedside on whole blood. The aim of the study was to test the precision of the Coagucheck® XS Pro device for INR measurement at hospital admission after severe trauma.

Methods

We conducted a prospective observational study in a French level I trauma center. From January 2015 to May 2016, 98 patients with a suspicion of a post-traumatic acute hemorrhage had POC-INR measurement on whole blood concomitantly to classic laboratory INR determination (lab-INR) on plasma at hospital admission. The agreement between the two methods in sorting three predefined categories of INR (normal coagulation, moderate TIC and severe TIC) was evaluated using the Cohen’s kappa test with a quadratic weighting. The correlation between POC-INR and lab-INR was measured using the Pearson’s coefficient. We also performed a Bland and Altman analysis.

Results

The agreement between the lab-INR and the POC-INR was moderate (Kappa = 0.45 [95% CI 0.36–0.50]) and the correlation between the two measurements was also weak (Pearson’s coefficient = 0.44 [95% CI 0.27–0.59]). Using a Bland and Altman analysis, the mean difference (bias) for INR was 0.22 [95% CI 0.02–0.42], and the standard deviation (precision) of the difference was 1.01.

Discussion/conclusion

POC Coagucheck® XS Pro device is not reliable to measure bedside INR. Its moderate agreement with lab-INR weakens the usefulness of such device after severe trauma.

Trial registration

NCT02869737. Registered 9 August 2016.

Updated concepts on the pathophysiology and the clinical management of trauma hemorrhage and coagulopathy

Uncontrolled hemorrhage and subsequent trauma-induced coagulopathy (TIC) are still the principle causes for preventable death after trauma and early detection and aggressive management have been associated with reduced mortality. Despite increasing knowledge about trauma resuscitation, best practice to treat this newly defined entity is still under debate. A synopsis of best current knowledge with reference to the updated European trauma guideline on the management of severe trauma hemorrhage and TIC is presented. The implementation of evidence-based local protocols and algorithms including clinical quality and safety management systems together with parameters to assess key measures of bleeding control and outcome is advocated.

Progresses in understanding trauma-induced coagulopathy and the underlying mechanism

Trauma-induced coagulopathy (TIC) is a clinical syndrome caused by imbalance between clotting, anti-coagulation and fibrinolysis resulting from multiple pathological factors such as hemorrhage and tissue injury in the early stage of trauma, and is closely related to the outcome of trauma patients. It is proved in growing evidence that the endogenous coagulation disturbance in trauma itself is the activating factor of TIC, rather than dilution or other acquired coagulopathy. Therefore, a thorough understanding of the molecular mechanisms in the pathogenesis and progression is crucial for effective prevention and treatment in patients with TIC. This review focuses on transitions in the concept of TIC and mechanical progress.

Uncontrolled Hemorrhagic Shock Modeled via Liver Laceration in Mice with Real Time Hemodynamic Monitoring

Uncontrolled hemorrhage is an important cause of preventable deaths among trauma patients. We have developed a murine model of uncontrolled hemorrhage via a liver laceration that results in consistent blood loss, hemodynamic alterations, and survival. Mice undergo a standardized resection of the left-middle lobe of the liver. They are allowed to bleed without mechanical intervention. Hemostatic agents can be administered as pre-treatment or rescue therapy depending on the interest of the investigator. During the time of hemorrhage, real-time hemodynamic monitoring via a left femoral arterial line is performed. Mice are then sacrificed, blood loss is quantified, blood is collected for further analysis, and organs are harvested for analysis of injury. Experimental design is described to allow for simultaneous testing of multiple animals. Liver hemorrhage as a model of uncontrolled hemorrhage exists in the literature, primarily in rat and porcine models. Some of these models utilize hemodynamic monitoring or quantify blood loss but lack consistency. The present model incorporates quantification of blood loss, real-time hemodynamic monitoring in a murine model that offers the advantage of using transgenic lines and a high-throughput mechanism to further investigate the pathophysiologic mechanisms in uncontrolled hemorrhage.

Hemotherapy algorithm for the management of trauma-induced coagulopathy: the German and European perspective

PURPOSE OF REVIEW

This review presents a synopsis of best current knowledge with reference to the updated German and European guidelines and recommendations on the management of severe trauma hemorrhage and trauma-induced coagulopathy as well as a viscoelastic-based treatment algorithm based upon international expert consensus to trigger the administration of hemostatic agents and blood products.

RECENT FINDINGS

Uncontrolled hemorrhage and trauma-induced coagulopathy are the major causes for preventable death after trauma and early detection and aggressive management have been associated with improved outcomes. However, best practice to treat this newly defined entity is still under debate. In the acute phase, the clinical management usually follows the 'Damage Control Resuscitation' concept, which advocates the empiric administration of blood products in predefined and fixed ratios. As an alternative, several European but also a few US trauma centers have instituted the concept of 'Goal-directed Coagulation Therapy' based upon results obtained from early point-of-care viscoelastic testing.

SUMMARY

Current guidelines urge for the implementation of evidence-based local protocols and algorithms including clinical quality and safety management systems together with parameters to assess key measures of bleeding control and outcome.

Cellular microparticles and pathophysiology of traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. The finding that cellular microparticles (MPs) generated by injured cells profoundly impact on pathological courses of TBI has paved the way for new diagnostic and therapeutic strategies. MPs are subcellular fragments or organelles that serve as carriers of lipids, adhesive receptors, cytokines, nucleic acids, and tissue-degrading enzymes that are unique to the parental cells. Their sub-micron sizes allow MPs to travel to areas that parental cells are unable to reach to exercise diverse biological functions. In this review, we summarize recent developments in identifying a casual role of MPs in the pathologies of TBI and suggest that MPs serve as a new class of therapeutic targets for the prevention and treatment of TBI and associated systemic complications.

Damage control resuscitation: a practical approach for severely hemorrhagic patients and its effects on trauma surgery

Coagulopathy observed in trauma patients was thought to be a resuscitation-associated phenomenon. The replacement of lost and consumed coagulation factors was the mainstay in the resuscitation of hemorrhagic shock for many decades. Twenty years ago, damage control surgery (DCS) was implemented to challenge the coagulopathy of trauma. It consists of three steps: abbreviated surgery to control the hemorrhage and contamination, resuscitation in the intensive care unit (ICU), and planned re-operation with definitive surgery. The resuscitation strategy of DCS focused on the rapid reversal of acidosis and prevention of hypothermia through the first two steps. However, direct treatment of coagulopathy was not emphasized in DCS.Recently, better understanding of the pathophysiology of coagulopathy in trauma patients has led to the logical opinion that we should directly address this coagulopathy during major trauma resuscitation. Damage control resuscitation (DCR), the strategic approach to the trauma patient who presents in extremis, consists of balanced resuscitation, hemostatic resuscitation, and prevention of acidosis, hypothermia, and hypocalcemia. In balanced resuscitation, fluid administration is restricted and hypotension is allowed until definitive hemostatic measures begin. The administration of blood products consisting of fresh frozen plasma, packed red blood cells, and platelets, the ratio of which resembles whole blood, is recommended early in the resuscitation.DCR strategy is now the most beneficial measure available to address trauma-induced coagulopathy, and it can change the treatment strategy of trauma patients. DCS is now incorporated as a component of DCR. DCR as a structured intervention begins immediately after rapid initial assessment in the emergency room and progresses through the operating theater into the ICU in combination with DCS. By starting from ground zero with the performance of DCS, DCR allows the trauma surgeon to correct the coagulopathy of trauma. The effect of the reversal of coagulopathy in massively hemorrhagic patients may change the operative strategy with DCS.

Prehospital tranexamic acid: what is the current evidence?

Many trauma systems are examining whether to implement prehospital tranexamic acid (TXA) protocols since hemorrhage remains the leading cause of potentially preventable early trauma mortality, and early in-hospital administration of TXA within 3 hours of injury is associated with reduced mortality. But robust evidence regarding the efficacy of prehospital administration of the antifibrinolytic drug TXA on trauma outcomes is lacking. This review examines the current evidence available regarding prehospital TXA efficacy in both military and civilian trauma, and updates available evidence regarding in-hospital TXA efficacy in trauma.

Early plasma transfusion is associated with improved survival after isolated traumatic brain injury in patients with multifocal intracranial hemorrhage

BACKGROUND

Plasma-based resuscitation improves outcomes in trauma patients with hemorrhagic shock, while large-animal and limited clinical data suggest that it also improves outcomes and is neuroprotective in the setting of combined hemorrhage and traumatic brain injury. However, the choice of initial resuscitation fluid, including the role of plasma, is unclear for patients after isolated traumatic brain injury.

METHODS

We reviewed adult trauma patients admitted from January 2011 to July 2015 with isolated traumatic brain injury. "Early plasma" was defined as transfusion of plasma within 4 hours. Purposeful multiple logistic regression modeling was performed to analyze the relationship of early plasma and inhospital survival. After testing for interaction, subgroup analysis was performed based on the pattern of brain injury on initial head computed tomography: epidural hematoma, intraparenchymal contusion, subarachnoid hemorrhage, subdural hematoma, or multifocal intracranial hemorrhage.

RESULTS

Of the 633 isolated traumatic brain injury patients included, 178 (28%) who received early plasma were injured more severely coagulopathic, hypoperfused, and hypotensive on admission. Survival was similar in the early plasma versus no early plasma groups (78% vs 84%, P = .08). After adjustment for covariates, early plasma was not associated with improved survival (odds ratio 1.18, 95% confidence interval 0.71-1.96). On subgroup analysis, multifocal intracranial hemorrhage was the largest subgroup with 242 patients. Of these, 61 (25%) received plasma within 4 hours. Within-group logistic regression analysis with adjustment for covariates found that early plasma was associated with improved survival (odds ratio 3.34, 95% confidence interval 1.20-9.35).

CONCLUSION

Although early plasma transfusion was not associated with improved in-hospital survival for all isolated traumatic brain injury patients, early plasma was associated with increased in-hospital survival in those with multifocal intracranial hemorrhage.

In Vitro Evaluation of Aptamer-Based Reversible Inhibition of Anticoagulant Activated Protein C as a Novel Supportive Hemostatic Approach

Activated protein C (APC) is a critical regulator of thrombin formation and thereby protects against thrombosis. On the other hand, overwhelming formation of APC increases the risk of bleeding such as in trauma-induced coagulopathy. Thus, pharmacological inhibition of APC activity may improve blood clottability in certain clinical situations. In this study, we demonstrate that the DNA aptamer HS02-52G binds with fast onset (1.118 ± 0.013 × 10⁵ M^-1 s^-1) to APC and possesses a long residence time of 13.5 min within the aptamer-APC complex. Functional analysis revealed HS02-52G as a highly potent and specific inhibitor of APC in plasma and whole blood with IC₅₀ values ≤30 nM, whose activity can be readily neutralized by the short complementary DNA molecule AD22. These features qualify the novel aptamer-antidote pair as a candidate treatment option for acute APC-related bleedings.