Advances in the understanding of trauma-induced coagulopathy

A Machine Learning Approach for the Prediction of Traumatic Brain Injury Induced Coagulopathy

Background: Traumatic brain injury-induced coagulopathy (TBI-IC), is a disease with poor prognosis and increased mortality rate.

Objectives: Our study aimed to identify predictors as well as develop machine learning (ML) models to predict the risk of coagulopathy in this population.

Methods: ML models were developed and validated based on two public databases named Medical Information Mart for Intensive Care (MIMIC)-IV and the eICU Collaborative Research Database (eICU-CRD). Candidate predictors, including demographics, family history, comorbidities, vital signs, laboratory findings, injury type, therapy strategy and scoring system were included. Models were compared on area under the curve (AUC), accuracy, sensitivity, specificity, positive and negative predictive values, and decision curve analysis (DCA) curve.

Results: Of 999 patients in MIMIC-IV included in the final cohort, a total of 493 (49.35%) patients developed coagulopathy following TBI. Recursive feature elimination (RFE) selected 15 variables, including international normalized ratio (INR), prothrombin time (PT), sepsis related organ failure assessment (SOFA), activated partial thromboplastin time (APTT), platelet (PLT), hematocrit (HCT), red blood cell (RBC), hemoglobin (HGB), blood urea nitrogen (BUN), red blood cell volume distribution width (RDW), creatinine (CRE), congestive heart failure, myocardial infarction, sodium, and blood transfusion. The external validation in eICU-CRD demonstrated that adapting boosting (Ada) model had the highest AUC of 0.924 (95% CI: 0.902–0.943). Furthermore, in the DCA curve, the Ada model and the extreme Gradient Boosting (XGB) model had relatively higher net benefits (ie, the correct classification of coagulopathy considering a trade-off between false- negatives and false-positives)—over other models across a range of threshold probability values.

Conclusions: The ML models, as indicated by our study, can be used to predict the incidence of TBI-IC in the intensive care unit (ICU).

Multi-omic analysis in injured humans: Patterns align with outcomes and treatment responses

Trauma is a leading cause of death and morbidity worldwide. Here, we present the analysis of a longitudinal multi-omic dataset comprising clinical, cytokine, endotheliopathy biomarker, lipidome, metabolome, and proteome data from severely injured humans. A "systemic storm" pattern with release of 1,061 markers, together with a pattern suggestive of the "massive consumption" of 892 constitutive circulating markers, is identified in the acute phase post-trauma. Data integration reveals two human injury response endotypes, which align with clinical trajectory. Prehospital thawed plasma rescues only endotype 2 patients with traumatic brain injury (30-day mortality: 30.3 versus 75.0%; p = 0.0015). Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) was identified as the most predictive circulating biomarker to identify endotype 2-traumatic brain injury (TBI) patients. These response patterns refine the paradigm for human injury, while the datasets provide a resource for the study of critical illness, trauma, and human stress responses.

Exploiting polypharmacology to dissect host kinases and kinase inhibitors that modulate endothelial barrier integrity

Kinase inhibitors are promising drugs to stabilize the endothelial barrier following inflammatory damage. However, our limited knowledge of how kinase signaling activates barrier-restorative pathways and the complexity of multi-target drugs have hindered drug discovery and repurposing efforts. Here, we apply a kinase regression approach that exploits drug polypharmacology to investigate endothelial barrier regulation. A screen of 28 kinase inhibitors identified multiple inhibitors that promote endothelial barrier integrity and revealed divergent barrier phenotypes for BCR-ABL drugs. Target deconvolution predicted 50 barrier-regulating kinases from diverse kinase families. Using gene knockdowns, we identified kinases with a role in endothelial barrier regulation and dissected different mechanisms of action of barrier-protective kinase inhibitors. These results demonstrate the importance of polypharmacology in the endothelial barrier phenotype of kinase inhibitors and provide promising new leads for barrier-strengthening therapies.

An increased prothrombin time-international normalized ratio in patients with acute type A aortic dissection: contributing factors and their influence on outcomes

PURPOSE

We investigated factors contributing to coagulopathy in patients with acute type A aortic dissection (ATAAD) and coagulopathy's influence on patient outcomes.

METHODS

We grouped 420 patients who underwent ATAAD repair-none under anticoagulation therapy or with liver disease-by the prothrombin time-international normalized ratio (PT-INR) at admission:  <  1.2 (no coagulopathy, n  =  371), 1.2-1.49 (mild coagulopathy, n  =  33), or  ≥  1.5 (severe coagulopathy, n  =  16). We then compared the clinical presentation, dissection morphology, and outcomes among the groups. We assessed the PT-INR in relation to the preoperative hemodynamics and searched for factors predictive of a PT-INR  ≥  1.2.

RESULTS

The transfusion volume and operation time were increased among patients with coagulopathy (P  <  0.05). The in-hospital mortality (15.2-37.5% vs. 5.1%, P  < 0.001) and 5-year survival (61.1-74.4% vs. 87.6%) were relatively poor for these patients. The median PT-INR was 1.03 (0.97-1.1) for patients with stable hemodynamics (n  =  318), 1.11 (1.02-1.21) for those in shock (blood pressure  <  80 mmHg) not given cardiopulmonary resuscitation (CPR) (n  =  81), and 1.1 (1.0-1.54) for those in shock given CPR (n  =  21) (P  < 0.001). A multivariable analysis identified shock (P  <  0.001), a partially thrombosed false lumen (P  =  0.006), and mesenteric malperfusion (P  =  0.016) as predictive variables.

CONCLUSIONS

Shock, a partially thrombosed false lumen, and mesenteric malperfusion appear to be predictive of dissection-related coagulopathy, which influences outcomes negatively.

Viscoelastic Testing and Coagulopathy of Traumatic Brain Injury

A unique coagulopathy often manifests following traumatic brain injury, leading the clinician down a difficult decision path on appropriate prophylaxis and therapy. Conventional coagulation assays—such as prothrombin time, partial thromboplastin time, and international normalized ratio—have historically been utilized to assess hemostasis and guide treatment following traumatic brain injury. However, these plasma-based assays alone often lack the sensitivity to diagnose and adequately treat coagulopathy associated with traumatic brain injury. Here, we review the whole blood coagulation assays termed viscoelastic tests and their use in traumatic brain injury. Modified viscoelastic tests with platelet function assays have helped elucidate the underlying pathophysiology and guide clinical decisions in a goal-directed fashion. Platelet dysfunction appears to underlie most coagulopathies in this patient population, particularly at the adenosine diphosphate and/or arachidonic acid receptors. Future research will focus not only on the utility of viscoelastic tests in diagnosing coagulopathy in traumatic brain injury, but also on better defining the use of these tests as evidence-based and/or precision-based tools to improve patient outcomes.

Platelet Transfusion: An Update on Indications and Guidelines

Platelets are commonly transfused either therapeutically or prophylactically to maintain hemostasis. Most platelet transfusions are used to manage patients with hematologic malignancies. Although platelet transfusion guidelines have been published, platelet transfusion practices are still heterogeneous. Platelet transfusion guidelines partly lack recommendations or differ in the platelet threshold recommendations in some clinical situations. This article reviews platelet transfusions focusing on transfusion guidelines and platelet thresholds in different clinical settings.

Fibrinogen inhibits microRNA-19b, a novel mechanism for repair of haemorrhagic shock-induced endothelial cell dysfunction

BACKGROUND

The benefits of plasma as an adjunct to the treatment of haemorrhagic shock are well established; however, the mechanism by which plasma modulates the endotheliopathy of trauma remains unclear. Our recent data demonstrated a novel role of microRNA-19b in post-haemorrhagic shock endothelial dysfunction via targeting of syndecan-1. Additionally, fibrinogen, as a key component of plasma or an isolated haemostatic protein, protects the endothelium by stabilizing syndecan-1. We therefore hypothesized that fibrinogen would inhibit microRNA-19b to mitigate the endotheliopathy of trauma in a murine model of haemorrhagic shock.

MATERIALS AND METHODS

C57BL/6J mice were subjected to haemorrhagic shock (mean arterial pressure 35±5 mmHg for 90 minutes) followed by resuscitation with lactated Ringer's, fresh frozen plasma, fibrinogen or no resuscitation. MicroRNA-19b and syndecan-1 mRNA were measured in lung tissue by qRT-PCR. Lungs were stained for histopathologic injury, and broncheoalveolar lavage was collected for protein as a permeability indicator.

RESULTS

Pulmonary microRNA-19b was increased after haemorrhagic shock and lactated Ringers, but reduced to sham levels by plasma and fibrinogen. Conversely, pulmonary syndecan-1 mRNA was downregulated by haemorrhagic shock and lactated Ringers, but returned to sham levels by plasma and fibrinogen. Plasma and fibrinogen-based resuscitation reduced lung injury compared to haemorrhagic shock and lactated Ringers while fibrinogen also reduced broncheoalveolar lavage protein.

DISCUSSION

We have demonstrated a novel mechanism by which fibrinogen, a key component of plasma and haemostatic agent, inhibits miR-19b, possibly by mitigating the endotheliopathy of trauma. Complete demonstration of the mechanism of fibrinogen inhibition of endotheliopathy via microRNA, however, remains to be elucidated. These findings support the early and empiric use of fibrinogen in post-haemorrhagic shock resuscitation.

[Pathophysiology of bleeding]

Bleeding is associated with an increased morbidity and mortality. Anatomic and hemostatic causes play a central role in the pathophysiology of bleeding, with anatomic causes being by far more common. While trauma and invasive procedures are the leading causes of bleeding in surgical disciplines, gastrointestinal bleeding is the major cause of bleeding in internal medicine. Major bleedings lead to secondary homeostatic changes, which in turn not only contribute to further bleeding, but also to the pathogenesis of organ dysfunction. Acquired coagulopathies due to antithrombotic treatment or an underlying disease also contribute to the extent and the dynamics of bleeding, while hereditary bleeding disorders are seldom. The balance between the physiological pro- and anticoagulant pathway plays a significant role in the pathophysiology of bleeding and coagulation. Therefore, the pathophysiology of bleeding cannot be described by means of easily available laboratory coagulation workup. The aim of coagulation correction during the management of life-threatening bleeding is not to normalize coagulation, but rather to stop bleeding. Besides a careful clinical evaluation of the course of bleeding coupled with basic understanding of the physiology of coagulation, targeted laboratory coagulation workup can contribute to a rational coagulation treatment concept.

Evaluation of trauma-induced coagulopathy in the fibrinogen in the initial resuscitation of severe trauma trial

BACKGROUND

Coagulopathic bleeding is frequently present after major trauma. However, trauma-induced coagulopathy (TIC) remains incompletely understood. This laboratory analysis of blood samples derived from our completed trial on fibrinogen in the initial resuscitation of severe trauma (FiiRST) was conducted to evaluate TIC and associated responses to fibrinogen replacement.

STUDY DESIGN AND METHODS

We conducted a retrospective evaluation of TIC in 45 FiiRST trial patients based on rotational thromboelastometry (ROTEM), international normalized ratio (INR), and biomarkers for hemostasis and endotheliopathy. Whole blood was analyzed by ROTEM. Plasma was analyzed for INR and biomarkers.

RESULTS

Overall, 19.0% and 30.0% of the FiiRST trial patients were coagulopathic on admission defined by EXTEM maximum clot firmness out of the range of 40-71 mm and INR >1.2, respectively. The FiiRST patients showed lower fibrinogen, factor II and V levels, protein C and antiplasmin activities, higher activated protein C, tissue plasminogen activator, d-dimer, and thrombomodulin concentrations at admission than healthy controls. Most of the biomarkers changed their activities during 48-h hospitalization, but were at abnormal levels even 48-h after admission. The fibrinogen treatment reduced hypofibrinogenemia and increased factor XIII level, but had no significant effects on other biomarkers levels. Limited development of endotheliopathy was indicated by syndean-1, thrombomodulin, and sE-selectin.

CONCLUSIONS

About 19%-30% of the trauma patients in the FiiRST trial were coagulopathic on hospital admission depending on the definition of TIC. Analyses of the TIC biomarkers demonstrated that hemostasis would not return to normal after 48-h hospitalization, and fibrinogen replacement improved hypofibrinogenemia.

Burn-Induced Coagulopathies: a Comprehensive Review

Burn-induced coagulopathy is not well understood, and consensus on diagnosis, prevention, and treatments are lacking. In this review, literature on burn-induced (and associated) coagulopathy is presented along with the current understanding of the effects of burn injury on the interactions among coagulation, fibrinolysis, and inflammation in the acute resuscitative phase and reconstructive phase of care. The role of conventional tests of coagulopathy and functional assays like thromboelastography or thromboelastometry will also be discussed. Finally, reported methods for the prevention and treatment of complications related to burn-induced coagulopathy will be reviewed.

Simplified treatment algorithm for the management of trauma-induced hemorrhage without viscoelastic testing

Uncontrolled bleeding after major trauma remains a significant cause of death, with up to a third of trauma patients presenting with signs of coagulopathy at hospital admission. Rapid correction of coagulopathy is therefore vital to improve mortality rates and patient outcomes in this population. Early and repeated monitoring of coagulation parameters followed by clear protocols to correct hemostasis is the recommended standard of care for bleeding trauma patients. However, although a number of treatment algorithms are available, these are frequently complex and can rely on the use of viscoelastic testing, which is not available in all treatment centers. We therefore set out to develop a concise and pragmatic algorithm to guide treatment of bleeding trauma patients without the use of point-of-care viscoelastic testing. The algorithm we present here is based on published guidelines and research, includes recommendations regarding treatment and dosing, and is simple and clear enough for even an inexperienced physician to follow. In this way, we have demonstrated that treatment protocols can be developed and adapted to the resources available, to offer clear and relevant guidance to the entire trauma team.

Plasma proteomic profile associated with platelet dysfunction after trauma

BACKGROUND

Coagulopathic bleeding is a major cause of mortality after trauma, and platelet dysfunction contributes to this problem. The causes of platelet dysfunction are relatively unknown, but a great deal can be learned from the plasma environment about the possible pathways involved.

OBJECTIVE

Describe the changes in plasma proteomic profile associated with platelet dysfunction after trauma.

METHODS

Citrated blood was collected from severely injured trauma patients at the time of their arrival to the Emergency Department. Samples were collected from 110 patients, and a subset of twenty-four patients was identified by a preserved (n = 12) or severely impaired (n = 12) platelet aggregation response to five different agonists. Untargeted proteomics was performed by nanoflow liquid chromatography tandem mass spectrometry. Protein abundance levels for each patient were normalized to total protein concentration to control for hemodilution by crystalloid fluid infusion prior to blood draw.

RESULTS

Patients with platelet dysfunction were more severely injured but otherwise demographically similar to those with retained platelet function. Of 232 proteins detected, twelve were significantly different between groups. These proteins fall into several broad categories related to platelet function, including microvascular obstruction with platelet activation, immune activation, and protease activation.

CONCLUSIONS

This observational study provides a description of the change in proteomic profile associated with platelet dysfunction after trauma and identifies twelve proteins with the most profound changes. The pathways involving these proteins are salient targets for immediate investigation to better understand platelet dysfunction after trauma and identify targets for intervention.

Resuscitative Strategies to Modulate the Endotheliopathy of Trauma: From Cell to Patient

Clinical data has supported the early use of plasma in high ratios of plasma to red cells to patients in hemorrhagic shock. The benefit from plasma seems to extend beyond its hemostatic effects to include protection to the post-shock dysfunctional endothelium. Resuscitation of the endothelium by plasma and one of its major constituents, fibrinogen, involves cell surface stabilization of syndecan-1, a transmembrane proteoglycan and the protein backbone of the endothelial glycocalyx. The pathogenic role of miRNA-19b to the endothelium is explored along with the PAK-1-mediated intracellular pathway that may link syndecan-1 to cytoskeletal protection. Additionally, clinical studies using fibrinogen and cyroprecipitate to aid in hemostasis of the bleeding patient are reviewed and new data to suggest a role for plasma and its byproducts to treat the dysfunctional endothelium associated with nonbleeding diseases is presented.

Inhalation Injury is Associated with Endotheliopathy and Abnormal Fibrinolytic Phenotypes in Burn Patients: A Cohort Study

Burn injury is associated with endothelial dysfunction and coagulopathy and concomitant inhalation injury increases morbidity and mortality. The aim of this work is to identify associations between inhalation injury (IHI), coagulation homeostasis, vascular endothelium, and clinical outcomes in burn patients. One-hundred and twelve patients presenting to a regional burn center were included in this retrospective cohort study. Whole blood was collected at set intervals from admission through 24 hours and underwent viscoelastic assay with rapid TEG (rTEG). Syndecan-1 (SDC-1) on admission was quantified by ELISA. Patients were grouped by the presence (n=28) or absence (n=84) of concomitant IHI and rTEG parameters, fibrinolytic phenotypes, SDC-1, and clinical outcomes were compared. Of the 112 thermally injured patients, 28 (25%) had IHI. Most patients were male (68.8%) with a median age of 40 (IQR, 29-57) years. Patients with IHI had higher overall mortality (42.68% vs. 8.3%; p<0.0001). rTEG LY30 was lower in patients with IHI at hours 4 and 12 (p<0.05). There was a pattern of increased abnormal fibrinolytic phenotypes among IHI patients. There was a greater proportion of IHI patients with endotheliopathy (SDC-1 > 34 ng/mL) (64.7% vs. 26.4%; p=0.008). There was a pattern of increased mortality among patients with inhalation injury and endotheliopathy (0% vs. 72.7%; p=0.004). Significant differences between patients with and without IHI were found in measures assessing fibrinolytic potential and endotheliopathy. Mortality was associated with abnormal fibrinolysis, endotheliopathy, and inhalation injury. However, the extent to which IHI associated dysfunction is independent of TBSA burn size remains to be elucidated.

Intelligent prediction of RBC demand in trauma patients using decision tree methods

BACKGROUND

The vital signs of trauma patients are complex and changeable, and the prediction of blood transfusion demand mainly depends on doctors' experience and trauma scoring system; therefore, it cannot be accurately predicted. In this study, a machine learning decision tree algorithm [classification and regression tree (CRT) and eXtreme gradient boosting (XGBoost)] was proposed for the demand prediction of traumatic blood transfusion to provide technical support for doctors.

METHODS

A total of 1371 trauma patients who were diverted to the Emergency Department of the First Medical Center of Chinese PLA General Hospital from January 2014 to January 2018 were collected from an emergency trauma database. The vital signs, laboratory examination parameters and blood transfusion volume were used as variables, and the non-invasive parameters and all (non-invasive + invasive) parameters were used to construct an intelligent prediction model for red blood cell (RBC) demand by logistic regression (LR), CRT and XGBoost. The prediction accuracy of the model was compared with the area under the curve (AUC).

RESULTS

For non-invasive parameters, the LR method was the best, with an AUC of 0.72 [95% confidence interval (CI) 0.657-0.775], which was higher than the CRT (AUC 0.69, 95% CI 0.633-0.751) and the XGBoost (AUC 0.71, 95% CI 0.654-0.756, P < 0.05). The trauma location and shock index are important prediction parameters. For all the prediction parameters, XGBoost was the best, with an AUC of 0.94 (95% CI 0.893-0.981), which was higher than the LR (AUC 0.80, 95% CI 0.744-0.850) and the CRT (AUC 0.82, 95% CI 0.779-0.853, P < 0.05). Haematocrit (Hct) is an important prediction parameter.

CONCLUSIONS

The classification performance of the intelligent prediction model of red blood cell transfusion in trauma patients constructed by the decision tree algorithm is not inferior to that of the traditional LR method. It can be used as a technical support to assist doctors to make rapid and accurate blood transfusion decisions in emergency rescue environment, so as to improve the success rate of patient treatment.

Role of POC INR in the early stage of diagnosis of coagulopathy

Background

Acute bleeding requires fast and targeted therapy. Therefore, knowledge of the patient's potential to form a clot is crucial. Point-of-care testing (POCT) provides fast and reliable information on coagulation. Structural circumstances, such as person-bound sample transport, can prolong the reporting of the results. The aim of the present study was to investigate the diagnostic quality and accuracy between POCT INR diagnostics and standard laboratory analysis (SLA) as well as the time advantage between a pneumatic tube and a personal-based transport system.

Methods

Two groups of haemorrhagic patients (EG: emergency department; OG: delivery room; each n = 12) were examined in the context of bleeding emergencies using POCT and SLA. Samples were transported via a pneumatic tube system or by a personal transport service.

Results

INR results between POCT and SLA showed a high and significant correlation (EG: p < 0.001; OG: p < 0.001). POCT results were reported significantly more quickly (EG: 1.1 vs. 39.6 min; OG: 2.0 vs. 75.0 min; p < 0.001) and required less time for analysis (EG: 0.3 vs. 24.0 min; OG: 0.5 vs. 45.0 min; p < 0.001) compared to SLA. The time for transportation with the pneumatic tube was significantly shorter (8.0 vs. 18.5 min; p < 0.001) than with the personal-based transport system.

Conclusion

The results of the present study suggest that POCT may be a suitable method for the emergency diagnosis and may be used as prognostic diagnostic elements in haemotherapy algorithms to initiate targeted haemotherapy at an early point in time.

Loss of GPVI and GPIbα contributes to trauma-induced platelet dysfunction in severely injured patients

Trauma-induced coagulopathy (TIC) is a complex, multifactorial failure of hemostasis that occurs in 25% of severely injured patients and results in a fourfold higher mortality. However, the role of platelets in this state remains poorly understood. We set out to identify molecular changes that may underpin platelet dysfunction after major injury and to determine how they relate to coagulopathy and outcome. We performed a range of hemostatic and platelet-specific studies in blood samples obtained from critically injured patients within 2 hours of injury and collected prospective data on patient characteristics and clinical outcomes. We observed that, although platelet counts were preserved above critical levels, circulating platelets sampled from trauma patients exhibited a profoundly reduced response to both collagen and the selective glycoprotein VI (GPVI) agonist collagen-related peptide, compared with those from healthy volunteers. These responses correlated closely with overall clot strength and mortality. Surface expression of the collagen receptors GPIbα and GPVI was reduced on circulating platelets in trauma patients, with increased levels of the shed ectodomain fragment of GPVI detectable in plasma. Levels of shed GPVI were highest in patients with more severe injuries and TIC. Collectively, these observations demonstrate that platelets experience a loss of GPVI and GPIbα after severe injury and translate into a reduction in the responsiveness of platelets during active hemorrhage. In turn, they are associated with reduced hemostatic competence and increased mortality. Targeting proteolytic shedding of platelet receptors is a potential therapeutic strategy for maintaining hemostatic competence in bleeding and improving the efficacy of platelet transfusions.

Coagulopathy and its effect on treatment and mortality in patients with traumatic intracranial hemorrhage

BACKGROUND

The role of coagulopathy in patients with traumatic brain injury has remained elusive. In the present study, we aim to assess the prevalence of coagulopathy in patients with traumatic intracranial hemorrhage, their clinical features, and the effect of coagulopathy on treatment and mortality.

METHODS

An observational, retrospective single-center cohort of consecutive patients with traumatic intracranial hemorrhage treated at Helsinki University Hospital between 01 January and 31 December 2010. We compared clinical and radiological parameters in patients with and without coagulopathy defined as drug- or disease-induced, i.e., antiplatelet or anticoagulant medication at a therapeutic dose, thrombocytopenia (platelet count < 100 E9/L), international normalized ratio > 1.2, or thromboplastin time < 60%. Primary outcome was 30-day all-cause mortality. Logistic regression analysis allowed to assess for factors associated with coagulopathy and mortality.

RESULTS

Of our 505 patients (median age 61 years, 65.5% male), 206 (40.8%) had coagulopathy. Compared to non-coagulopathy patients, coagulopathy patients had larger hemorrhage volumes (mean 140.0 mL vs. 98.4 mL, p < 0.001) and higher 30-day mortality (18.9% vs. 9.7%, p = 0.003). In multivariable analysis, older age, lower admission Glasgow Coma Scale score, larger hemorrhage volume, and conservative treatment were independently associated with mortality. Surgical treatment was associated with lower mortality in both patients with and without coagulopathy.

CONCLUSIONS

Coagulopathy was more frequent in patients with traumatic intracranial hemorrhage presenting larger hemorrhage volumes compared to non-coagulopathy patients but was not independently associated with higher 30-day mortality. Hematoma evacuation, in turn, was associated with lower mortality irrespective of coagulopathy.

Early Coagulopathy in Pediatric Traumatic Brain Injury: A Pediatric Acute and Critical Care Medicine Asian Network (PACCMAN) Retrospective Study

BACKGROUND

Although early coagulopathy increases mortality in adults with traumatic brain injury (TBI), less is known about pediatric TBI.

OBJECTIVE

To describe the prothrombin time (PT), activated partial thromboplastin time (APTT), and platelet levels of children with moderate to severe TBI to identify predictors of early coagulopathy and study the association with clinical outcomes.

METHODS

Using the Pediatric Acute and Critical Care Medicine Asian Network (PACCMAN) TBI retrospective cohort, we identified patients <16 yr old with a Glasgow Coma Scale (GCS) ≤13. We compared PT, APTT, platelets, and outcomes between children with isolated TBI and multiple trauma with TBI. We performed logistic regressions to identify predictors of early coagulopathy and study the association with mortality and poor functional outcomes.

RESULTS

Among 370 children analyzed, 53/370 (14.3%) died and 127/370 (34.3%) had poor functional outcomes. PT was commonly deranged in both isolated TBI (53/173, 30.6%) and multiple trauma (101/197, 51.3%). Predictors for early coagulopathy were young age (adjusted odds ratio [aOR] 0.94, 95% CI 0.88-0.99, P = .023), GCS < 8 (aOR 1.96, 95% CI 1.26-3.06, P = .003), and presence of multiple trauma (aOR 2.21, 95% confidence interval [CI] 1.37-3.60, P = .001). After adjusting for age, gender, GCS, multiple traumas, and presence of intracranial bleed, children with early coagulopathy were more likely to die (aOR 7.56, 95% CI 3.04-23.06, P < .001) and have poor functional outcomes (aOR 2.16, 95% CI 1.26-3.76, P = .006).

CONCLUSION

Early coagulopathy is common and independently associated with death and poor functional outcomes among children with TBI.

Alterations in platelet behavior after major trauma: adaptive or maladaptive?

Platelets are damage sentinels of the intravascular compartment, initiating and coordinating the primary response to tissue injury. Severe trauma and hemorrhage induce profound alterations in platelet behavior. During the acute post-injury phase, platelets develop a state of impaired ex vivo agonist responsiveness independent of platelet count, associated with systemic coagulopathy and mortality risk. In patients surviving the initial insult, platelets become hyper-responsive, associated with increased risk of thrombotic events. Beyond coagulation, platelets constitute part of a sterile inflammatory response to injury: both directly through release of immunomodulatory molecules, and indirectly through modifying behavior of innate leukocytes. Both procoagulant and proinflammatory aspects have implications for secondary organ injury and multiple-organ dysfunction syndromes. This review details our current understanding of adaptive and maladaptive alterations in platelet biology induced by severe trauma, mechanisms underlying these alterations, potential platelet-focused therapies, and existing knowledge gaps and their research implications.

Time Course of Hemostatic Disruptions After Traumatic Brain Injury: A Systematic Review of the Literature

Almost two-thirds of patients with severe traumatic brain injury (TBI) develop some form of hemostatic disturbance, which contributes to poor outcome. While the initial head injury often leads to impaired clot formation, TBI is also associated with an increased risk of thrombosis. Most likely there is a progression from early bleeding to a later prothrombotic state. In this paper, we systematically review the literature on the time course of hemostatic disruptions following TBI. A MEDLINE search was performed for TBI studies reporting the trajectory of hemostatic assays over time. The search yielded 5,049 articles, of which 4,910 were excluded following duplicate removal as well as title and abstract review. Full-text assessment of the remaining articles yielded 33 studies that were included in the final review. We found that the first hours after TBI are characterized by coagulation cascade dysfunction and hyperfibrinolysis, both of which likely contribute to lesion progression. This is then followed by platelet dysfunction and decreased platelet count, the clinical implication of which remains unclear. Later, a poorly defined prothrombotic state emerges, partly due to fibrinolysis shutdown and hyperactive platelets. In the clinical setting, early administration of the antifibrinolytic agent tranexamic acid has proved effective in reducing head-injury-related mortality in a subgroup of TBI patients. Further studies evaluating the time course of hemostatic disruptions after TBI are warranted in order to identify windows of opportunity for potential treatment options.

Hemostatic Strategies in Trauma

Bleeding is a leading cause of early death from trauma. Consequently, effective hemostasis can improve the odds of survival after severe traumatic injury. Understanding the pathophysiology of trauma-induced coagulopathy can provide insights into effective strategies to assess and halt hemorrhage. Both physical assessment and appropriate laboratory studies are important in the diagnosis and evaluation of coagulopathy to identify the most effective mechanical and pharmacological strategies to achieve hemostasis. This article uses a case study approach to explore evidence-based techniques to evaluate hemorrhage and strategies to promote hemostasis.

Efficacy and Safety of Tranexamic Acid in Emergency Trauma: A Systematic Review and Meta-Analysis

In trauma patients, bleeding can lead to coagulopathy, hemorrhagic shock, and multiorgan failure, and therefore is of fundamental significance in regard to early morbidity. We conducted a meta-analysis to evaluate the efficacy and safety of tranexamic acid (TXA) in civil and military settings and its impact on in-hospital mortality (survival to hospital discharge or 30-day survival), intensive care unit and hospital length of stay, incidence of adverse events (myocardial infarct and neurological complications), and volume of blood product transfusion. The systematic review and meta-analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic review of the literature using PubMed, Scopus, EMBASE, Web of Science, and the Cochrane Central Register and Controlled Trials (CENTRAL) database was conducted from inception to 10 January 2021. In-hospital mortality was reported in 14 studies and was 15.5% for the TXA group as compared with 16.4% for the non-TXA group (OR = 0.81, 95% CI 0.62-1.06, I2 = 83%, p = 0.12). In a civilian TXA application, in-hospital mortality in the TXA and non-TXA groups amounted to 15.0% and 17.1%, respectively (OR = 0.69, 95% CI 0.51-0.93, p = 0.02, I2 = 78%). A subgroup analysis of the randomized control trial (RCT) studies showed a statistically significant reduction in in-hospital mortality in the TXA group (14.3%) as compared with the non-TXA group (15.7%, OR = 0.89, 95% CI 0.83-0.96, p = 0.003, I2 = 0%). To summarize, TXA used in civilian application reduces in-hospital mortality. Application of TXA is beneficial for severely injured patients who undergoing shock and require massive blood transfusions. Patients who undergo treatment with TXA should be monitored for clinical signs of thromboembolism, since TXA is a standalone risk factor of a thromboembolic event and the D-dimers in traumatic patients are almost always elevated.

Thrombin Generation Kinetics are Predictive of Rapid Transfusion in Trauma Patients Meeting Critical Administration Threshold

INTRODUCTION

We hypothesize that a patient (pt) with accelerated thrombin generation, time to peak height (ttPeak), will have a greater odds of meeting critical administration threshold (CAT) criteria (> 3 packed red blood cell [pRBC] transfusions [Tx] per 60 min interval), within the first 24 h after injury, independent of international normalized ratio (INR).

METHODS

In a prospective cohort study, trauma patients were enrolled over a 4.5-year period and serial blood samples collected at various time points. We retrospectively stratified pts into three categories: CAT+, CAT- but receiving some pRBC Tx, receiving no Tx within the first 24 h. Blood collected prior to Tx was analyzed for thrombin generation parameters and prothrombin time (PT)/INR.

RESULTS

A total of 484 trauma pts were analyzed: injury severity score = 13 [7,22], age = 48 [28, 64] years, and 73% male. Fifty pts met criteria for CAT+, 64 pts CAT-, and 370 received no Tx. Risk factors for meeting CAT+: decreased arrival systolic blood pressure (OR 2.82 [2.17, 3.67]), increased INR (OR 2.09, [1.66, 2.62]) and decreased time to peak OR 2.27 [1.74, 2.95]). These variables remained independently associated with increased risk of requiring Tx in a multivariable logistic model, after adjusting for sex and trauma type.

CONCLUSIONS

Pts in hemorrhagic shock, who meet CAT+ criteria, are characterized by accelerated thrombin generation. In our multivariable analysis, both ttPeak and PT/INR have a complementary role in predicting those injured patients who will require a high rate of Tx.

Exploring the utility of a novel point-of-care whole blood thrombin generation assay following trauma: A pilot study

INTRODUCTION

Plasma thrombin generation kinetics as measured by the calibrated automated thrombogram (CAT) assay is a predictor of symptomatic venous thromboembolism after trauma. We hypothesized that data from a new prototype assay for measurement of thrombin generation kinetics in fresh whole blood (near patient testing of thrombin generation), will correlate with the standard CAT assay in the same patients, making it a potential tool in the future care of trauma patients.

METHODS

Patients were enrolled from June 2018 to February 2020. Within 12 hours of injury, blood samples were collected simultaneously for both assays. Variables compared and correlated between assays were lag time, peak height, time to peak, and endogenous thrombin potential. Data are presented as median with interquartile range (IQR). Spearman and Pearson correlations were estimated and tested between both assays; a P value of <0.05 was considered to be significant.

RESULTS

A total of 64 trauma patients had samples analyzed: injury severity score = 17 (IQR), 10-26], hospital length of stay = 7.5 (IQR), 2-18) days, age = 52 (IQR, 35-63) years, 71.9% male, and 42.2% of patients received a transfusion within 24 hours of injury. Thrombin generation parameters between plasma and whole blood were compared and found that all parameters of the two assays correlate in trauma patients.

CONCLUSION

In this pilot study, we have found that a novel point-of-care whole blood thrombin generation assay yields results with modest but statistically significant correlations to those of a standard plasma thrombin generation assay. This finding supports studying this device in a larger, adequately powered study.

Post-expiry stability of freeze-dried plasma under field conditions - Can shelf life be extended?

BACKGROUND

This prospective study evaluated the effect of routine, uncontrolled, Israeli field storage conditions on the safety and efficacy of Lyo-Plas N Freeze-Dried Plasma (FDP) at the end of the manufacturer's shelf life, and up to 24 months post expiry. Clotting factors V, VIII and XI, proteins S, C, fibrinogen, PTT, ATIII, VWF, and INR as well as TEG, DDM, residual moisture, pH, and sterility of FDP returned from field units after uncontrolled storage were evaluated.

STUDY DESIGN AND METHODS

Parameters measured at the end of manufacturer shelf life, as well as 6, 12, 18, and 24 months after expiry, were compared to those of freshly supplied FDP doses.

RESULTS

Changes were found when comparing freshly supplied FDP to all field-stored groups in INR, PT, PTT, pH, fibrinogen, and factor VIII. A significant change was also seen in Factor XI in the 12, 18, and 24 months post-expiry samples, Factor V and R in the 24 months post-expiry samples, MA in the 12, 24 months post-expiry group, and Protein C in the 18 months post-expiry group. An increase in the residual moisture from 0.90% in freshly supplied FDP to 1.35% in 24 months post-expiry FDP.; all p < .05. No growth was found in sterility analysis.

CONCLUSION

Despite uncontrolled field storage conditions, the findings demonstrate that the safety and efficacy of FDP units, stored in uncontrolled conditions are only slightly affected, even beyond their expiration date. This information allows consideration of possibly extending the shelf life.

Physicians' perceptions regarding acute bleeding management: an international mixed qualitative quantitative study

Background

Acute bleeding is an omnipresent challenge for all physicians. Uncontrolled hemorrhage is the most common preventable cause of death after trauma worldwide. In different surgical disciplines, hemorrhage represents an independent risk factor for increased postoperative morbimortality, directly affecting patients’ outcomes. This study asked anesthesiologists about their personal perceived challenges when treating bleeding patients.

Methods

This investigator-initiated, prospective, international, dual-center, mixed qualitative and quantitative study interrogated anesthesiologists about what they found easy and what difficult in treating acutely bleeding patients. Following the template approach for qualitative research, we identified major and minor topics through free inductive coding and word count. In a second step, we derived ten statements from the participants’ answers. Using a field survey, we then asked the participants to rate their level of agreement with the derived statements. We analyzed the answers using one sample Wilcoxon test and the Mann-Whitney test.

Results

We included a total of 84 physicians in the qualitative interrogations and a different group of 42 anesthesiologists in the quantitative part. We identified 11 major topics and 19 associated subtopics. The main topics and the degree of agreement (here as agree or strongly agree) were as follows: “Complexity of the topic” (52.4% agreed to find the topic complex), “Cognitive aids” (92.9% agreed to find them helpful), “Time management” (64.3% agreed to feeling time pressure), “Human factors” (95.2% agreed that human factors are essential), “Resources” (95.2% agreed that resources are essential), “Experience” and “Low frequency of cases” (57.1% agreed to lack practice), “Diagnostic methods” (31.0% agreed that the interpretation of test results is difficult), “Anticoagulation” (85.7% agreed to it being difficult), “Treatment” (81.0% agreed to knowing the first therapeutic steps), and “Nothing”.

Conclusions

Anesthesiologists in two large tertiary care facilities in different parts of the world found coagulation management, especially in anticoagulated patients, complex. We identified the delayed diagnostic test results and their interpretation as challenges. Resources, treatment protocols and human factors such as team communication were perceived to facilitate management. Future studies should explore the challenges in smaller hospitals and other parts of the world and test new technologies addressing the identified difficulties.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01269-x.

Dynamic effects of calcium on in vivo and ex vivo platelet behavior after trauma

BACKGROUND

Mobilization of intra and extracellular calcium is required for platelet activation, aggregation, and degranulation. However, the importance of alterations in the calcium-platelet axis after injury is unknown. We hypothesized that in injured patients, in vivo initial calcium concentrations (pretransfusion) predict ex vivo platelet activation and aggregation, viscoelastic clot strength, and transfusion of blood products. We additionally hypothesized that increasing calcium concentrations ex vivo increases the expression of platelet activation surface receptors and platelet aggregation responses to agonist stimulation in healthy donor blood.

METHODS

Blood samples were collected from 538 trauma patients on arrival to the emergency department. Standard assays (including calcium), platelet aggregometry (PA) and thromboelastometry (ROTEM) were performed. In PA, platelet activation (prestimulation impedance [Ω]) and aggregation responses to agonist stimulation (area under the aggregation curve [AUC]) with adenosine diphosphate (ADP), thrombin receptor-activating peptide, arachidonic acid (AA), and collagen (COL) were measured. Multivariable regression tested the associations of calcium with PA, ROTEM, and transfusions. To further examine the calcium-platelet axis, calcium was titrated in healthy blood. Platelet aggregometry and ROTEM were performed, and expression of platelet glycoprotein IIb/IIIa and P-selectin was measured by flow cytometry.

RESULTS

The patients were moderately injured with normal calcium and platelet counts. Higher calcium on arrival (pretransfusion) was independently associated with increased platelet activation (prestimulation, Ω; p < 0.001), aggregation (ADP-stimulated, AUC; p = 0.002; thrombin receptor-activating peptide-stimulated, AUC; p = 0.038), and clot strength (ROTEM max clot firmness; p < 0.001), and inversely associated with 24-hour transfusions of blood, plasma, and platelets (all p < 0.005). Up-titrating calcium in healthy blood increased platelet activation (prestimulation, Ω; p < 0.001), aggregation (ADP, AA, COL-stimulated AUCs; p < 0.050), and expression of P-selectin (p = 0.003).

CONCLUSION

Initial calcium concentrations (pretransfusion) are independently associated with platelet activation, aggregation, clot-strength, and transfusions after injury. These changes may be mediated by calcium driven expression of surface receptors necessary for platelet activation and aggregation. However, the therapeutic benefit of early, empiric calcium repletion in trauma patients remains undefined.

LEVEL OF EVIDENCE

Prognostic, level V.

Retinal hemorrhage and bleeding disorders in children: A review

BACKGROUND

Retinal hemorrhages (RH) are a common manifestation of abusive head trauma (AHT) resulting from acceleration-deceleration injury with or without blunt impact. Evaluation of a child with RH requires careful consideration of these differential diagnoses. The extent to which coagulopathy alone can cause RH would be useful to understand as coagulopathy may accompany AHT.

OBJECTIVE

In this systematic review, we sought to identify whether coagulopathies have been reported with RH similar to those of AHT.

METHODS

We performed a literature search for ocular manifestations of bleeding disorders in children less than 18 years old. We included clotting factor deficiencies, vitamin K deficiency, platelet function abnormalities, thrombocytopenia, disseminated intravascular coagulation (DIC), and trauma induced coagulopathy (TIC). We included only pediatric reports of intraocular bleeding or documented eye examinations that indicated no hemorrhages. We then re-examined cases for ocular and systemic findings that could potentially mimic abuse.

RESULTS

Our initial search yielded 816 results. Sixty-one articles met our inclusion criteria. Of these, there were 32 children within the AHT age range (less than 5 years old) who had RH and concomitant coagulopathy. Only 5 cases might potentially be confused for abuse. Of these, no classic characteristics of RH from abuse such as retinoschisis or retinal folds were found. Systemic features were inconsistent with AHT.

CONCLUSIONS

The presence of coagulopathy alone does not rule out the possibility that the child has been abused. Coagulopathy alone has not been reported as an etiology of RH that are consistent with AHT, especially when other findings are present.

Good Platelets Gone Bad: The Effects of Trauma Patient Plasma on Healthy Platelet Aggregation

BACKGROUND

Altered postinjury platelet behavior is recognized in the pathophysiology of trauma-induced coagulopathy (TIC), but the mechanisms remain largely undefined. Studies suggest that soluble factors released by injury may inhibit signaling pathways and induce structural changes in circulating platelets. Given this, we sought to examine the impact of treating healthy platelets with plasma from injured patients. We hypothesized that healthy platelets treated ex-vivo with plasma from injured patients with shock would impair platelet aggregation, while treatment with plasma from injured patients with significant injury burden, but without shock, would enhance platelet aggregation.

METHODS

Plasma samples were isolated from injured patients (pretransfusion) and healthy donors at a Level I trauma center and stored at -80°C. Plasma samples from four separate patients in each of the following stratified clinical groups were used: mild injury/no shock (injury severity score [ISS] 2-15, base excess [BE]>-6), mild injury/with shock (ISS 2-15, BE≤-6), severe injury/no shock (ISS>25, BE>-6), severe injury/with shock (ISS>25, BE≤-6), minimal injury (ISS 0/1, BE>-6), and healthy. Platelets were isolated from three healthy adult males and were treated with plasma for 30 min. Aggregation was stimulated with a thrombin receptor agonist and measured via multiple-electrode platelet aggregometry. Data were normalized to HEPES Tyrode's (HT) buffer-only treated platelets. Associations of plasma treatment groups with platelet aggregation measures were tested with Mann-Whitney U tests.

RESULTS

Platelets treated with plasma from patients with shock (regardless of degree of injury) had significantly impaired thrombin-stimulated aggregation compared with platelets treated with plasma from patients without shock (P = 0.002). Conversely, platelets treated with plasma from patients with severe injury, but without shock, had amplified thrombin-stimulated aggregation (P = 0.030).

CONCLUSION

Shock-mediated soluble factors impair platelet aggregation, and tissue injury-mediated soluble factors amplify platelet aggregation. Future characterization of these soluble factors will support development of novel treatments of TIC.

Predictors of In-Hospital Mortality for School-Aged Children with Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is the leading cause of mortality in children. There are few studies focused on school-aged children with TBI. We conducted this study to identify the early predictors of in-hospital mortality in school-aged children with severe TBI. In this 10 year observational cohort study, a total of 550 children aged 7-18 years with TBI were enrolled. Compared with mild/moderate TBI, children with severe TBI were older; more commonly had injury mechanisms of traffic accidents; and more neuroimage findings of subarachnoid hemorrhage (SAH), subdural hemorrhage (SDH), parenchymal hemorrhage, cerebral edema, and less epidural hemorrhage (EDH). The in-hospital mortality rate of children with severe TBI in our study was 23%. Multivariate analysis showed that falls, being struck by objects, motor component of Glasgow coma scale (mGCS), early coagulopathy, and SAH were independent predictors of in-hospital mortality. We concluded that school-aged children with severe TBI had a high mortality rate. Clinical characteristics including injury mechanisms of falls and being struck, a lower initial mGCS, early coagulopathy, and SAH are predictive of in-hospital mortality.

The European Perspective on the Management of Acute Major Hemorrhage and Coagulopathy after Trauma: Summary of the 2019 Updated European Guideline

Non-controlled hemorrhage with accompanying trauma-induced coagulopathy (TIC) remains the most common cause of preventable death after multiple injury. Rapid identification followed by aggressive treatment is the key for improved outcomes. Treatment of trauma hemorrhage begins at the scene, with manual compression, the use of tourniquets and (non) commercial pelvic slings, and rapid transfer to an adequate trauma center. Upon hospital admission, coagulation monitoring and support are to be initiated immediately. Bleeding is controlled surgically following damage control principles. Modern coagulation management includes goal-oriented, individualized therapies, guided by point-of-care viscoelastic assays. Idarucizumab can be used as an antidote to the thrombin inhibitor dabigatran, andexanet alpha as an antidote to factor Xa inhibitors. This review summarizes the key recommendations of the 2019 updated European guideline on the management of major bleeding and coagulopathy following trauma. These evidence-based recommendations may form the backbone of algorithms adapted to local logistics and infrastructure.

Whole Blood, Fixed Ratio, or Goal-Directed Blood Component Therapy for the Initial Resuscitation of Severely Hemorrhaging Trauma Patients: A Narrative Review

This narrative review explores the pathophysiology, geographic variation, and historical developments underlying the selection of fixed ratio versus whole blood resuscitation for hemorrhaging trauma patients. We also detail a physiologically driven and goal-directed alternative to fixed ratio and whole blood, whereby viscoelastic testing guides the administration of blood components and factor concentrates to the severely bleeding trauma patient. The major studies of each resuscitation method are highlighted, and upcoming comparative trials are detailed.

Variations and obstacles in the use of coagulation factor concentrates for major trauma bleeding across Europe: outcomes from a European expert meeting

Purpose

Trauma is a leading cause of mortality, with major bleeding and trauma-induced coagulopathy (TIC) contributing to negative patient outcomes. Treatments for TIC include tranexamic acid (TXA), fresh frozen plasma (FFP), and coagulation factor concentrates (CFCs, e.g. prothrombin complex concentrates [PCCs] and fibrinogen concentrate [FCH]). Guidelines for TIC management vary across Europe and a clear definition of TIC is still lacking.

Methods

An advisory board involving European trauma experts was held on 02 February 2019, to discuss clinical experience in the management of trauma-related bleeding and recommendations from European guidelines, focusing on CFC use (mainly FCH). This review summarises the discussions, including TIC definitions, gaps in the guidelines that affect their implementation, and barriers to use of CFCs, with suggested solutions.

Results

A definition of TIC, which incorporates clinical (e.g. severe bleeding) and laboratory parameters (e.g. low fibrinogen) is suggested. TIC should be treated immediately with TXA and FCH/red blood cells; subsequently, if fibrinogen ≤ 1.5 g/L (or equivalent by viscoelastic testing), treatment with FCH, then PCC (if bleeding continues) is suggested. Fibrinogen concentrate, and not FFP, should be administered as first-line therapy for TIC. Several initiatives may improve TIC management, with improved medical education of major importance; generation of new and stronger data, simplified clinical practice guidance, and improved access to viscoelastic testing are also critical factors.

Conclusions

Management of TIC is challenging. A standard definition of TIC, together with initiatives to facilitate effective CFC administration, may contribute to improved patient care and outcomes.

Novel blood coagulation molecules: Skeletal muscle myosin and cardiac myosin

Essentials Striated muscle myosins can promote prothrombin activation by FXa or FVa inactivation by APC. Cardiac myosin and skeletal muscle myosin are pro-hemostatic in murine tail cut bleeding models. Infused cardiac myosin exacerbates myocardial injury caused by myocardial ischemia reperfusion. Skeletal muscle myosin isoforms that circulate in human plasma can be grouped into 3 phenotypes. ABSTRACT: Two striated muscle myosins, namely skeletal muscle myosin (SkM) and cardiac myosin (CM), may potentially contribute to physiologic mechanisms for regulation of thrombosis and hemostasis. Thrombin is generated from activation of prothrombin by the prothrombinase (IIase) complex comprising factor Xa, factor Va, and Ca++ ions located on surfaces where these factors are assembled. We discovered that SkM and CM, which are abundant motor proteins in skeletal and cardiac muscles, can provide a surface for thrombin generation by the prothrombinase complex without any apparent requirement for phosphatidylserine or lipids. These myosins can also provide a surface that supports the inactivation of factor Va by activated protein C/protein S, resulting in negative feedback downregulation of thrombin generation. Although the physiologic significance of these reactions remains to be established for humans, substantive insights may be gleaned from murine studies. In mice, exogenously infused SkM and CM can promote hemostasis as they are capable of reducing tail cut bleeding. In a murine myocardial ischemia-reperfusion injury model, exogenously infused CM exacerbates myocardial infarction damage. Studies of human plasmas show that SkM antigen isoforms of different MWs circulate in human plasma, and they can be used to identify three plasma SkM phenotypes. A pilot clinical study showed that one SkM isoform pattern appeared to be linked to isolated pulmonary embolism. These discoveries enable multiple preclinical and clinical studies of SkM and CM, which should provide novel mechanistic insights with potential translational relevance for the roles of CM and SkM in the pathobiology of hemostasis and thrombosis.

Neglected No More: Emerging Cellular Therapies in Traumatic Injury

Traumatic injuries are a leading cause of death and disability in both military and civilian populations. Given the complexity and diversity of traumatic injuries, novel and individualized treatment strategies are required to optimize outcomes. Cellular therapies have potential benefit for the treatment of acute or chronic injuries, and various cell-based pharmaceuticals are currently being tested in preclinical studies or in clinical trials. Cellular therapeutics may have the ability to complement existing therapies, especially in restoring organ function lost due to tissue disruption, prolonged hypoxia or inflammatory damage. In this article we highlight the current status and discuss future directions of cellular therapies for the treatment of traumatic injury. Both published research and ongoing clinical trials are discussed here.

Links between thrombosis and inflammation in traumatic brain injury

Traumatic brain injury (TBI) continues to be a major healthcare problem and there is much to be explored regarding the secondary pathobiology to identify early predictive markers and new therapeutic targets. While documented changes in thrombosis and inflammation in major trauma have been well described, growing evidence suggests that isolated TBI also results in systemic alterations in these mechanisms. Here, we review recent experimental and clinical findings that demonstrate how blood-brain barrier dysfunction, systemic immune response, inflammation, platelet activation, and thrombosis contribute significantly to the pathogenesis of TBI. Despite advances in the links between thrombosis and inflammation, there is a lack of treatment options aimed at both processes and this could be crucial to treating vascular injury, local and systemic inflammation, and secondary ischemic events following TBI. With emerging evidence of newly-identified roles for platelets, leukocytes, the coagulation system and extracellular vesicles in processes of inflammation and thrombosis, there is a growing need to characterize these mechanisms within the context of TBI and whether these changes persist into the chronic phase of injury. Importantly, this review defines areas in need of further research to advance the field and presents a roadmap to identify new diagnostic and treatment options for TBI.

Sufficient Thrombin Generation Despite 95% Hemodilution: An In Vitro Experimental Study

Guidelines for the treatment of severe bleeding comprise viscoelastic-test-guided use of coagulation factor concentrates as part of their recommendations. The aim of this study is to investigate the effects of substituting fibrinogen, prothrombin complex concentrate, and a combination of both on conventional coagulation tests, viscoelastic test results, and thrombin generation. Blood was drawn from seven healthy volunteers to obtain platelet-free plasma, which later was diluted by replacing 40%, 60%, 80%, 90%, 95%, and 99% with a crystalloid solution. The diluted samples were spiked with fibrinogen concentrate, prothrombin complex concentrate, a combination of both, or a corresponding amount of crystalloid solution. Up to a dilution level of 95%, viscoelastically determined clotting time was significantly shorter in the group substituted with fibrinogen only in comparison with the additional use of prothrombin complex concentrate. Clot firmness and endogenous thrombin potential remained at relatively stable values up to a dilution level of 95% with the substitution of fibrinogen but not prothrombin complex concentrate. Substitution of prothrombin complex concentrate led to an excessive overshoot of thrombin generation. The results of our study question currently propagated treatment algorithms for bleeding patients that include the use of prothrombin complex concentrate for patients without former intake of oral anticoagulants. Even in severely bleeding patients, thrombin generation might be sufficient to achieve adequate hemostasis.

Hematotoxic Snakebite Victim with Trauma: The Role of Guided Transfusion, Rotational Thromboelastometry, and Tranexamic Acid

Hematotoxic snake bite is a leading cause of mortality in South India. However, it is rare for the emergency physician to encounter a patient with trauma associated with snakebite. Management of such a patient differs substantially from the routine management of either a trauma patient or a snakebite victim. A 59-y-old man was bitten by a snake, after which he lost consciousness, fell, and sustained facial trauma. He was rushed to the emergency department within 30 min and was discovered to have ongoing oromaxillofacial bleeding. His respiratory distress and gasping respirations warranted orotracheal intubation and ventilation. He was treated with anti-snake venom and underwent viscoelastometry-guided transfusion to correct coagulopathy. Hemostasis was achieved after administration of tranexamic acid and bilateral posterior nasal packing. Imaging studies revealed craniomaxillofacial trauma with intracranial hemorrhage. He underwent a delayed mandibular repair. Judicious, guided fluid management, adequate nutrition, and prompt weaning off the ventilator allowed early discharge of the patient from the hospital. The minimal weakness present in his left lower limb at the time of discharge had improved by the time of follow-up. This report shows the utility of early and rapid anti-snake venom in envenomated victims with coagulopathy. The role of cryoprecipitate, tranexamic acid, and viscoelastometric testing needs further exploration in specific hematotoxic snakebites.

Fibrin monomers and association with significant hemorrhage or mortality in severely injured trauma patients

BACKGROUND

Post-traumatic hemorrhage is still the leading cause of potentially preventable death in patients with severe trauma. Traumatic-induced coagulopathy has been described as a risk factor for significant hemorrhage and mortality in this population. Fibrin monomers (FMs) are a direct marker of thrombin action, and thus reflect coagulation activation. This study sought to determine the association of FMs levels at admission with significant hemorrhage and 28-day mortality after a severe trauma.

METHODS

We conducted a retrospective, observational study including all severe trauma patients admitted in a level-1 trauma center between January 2012 and December 2017. Patients with severe traumatic brain injury or previous anticoagulant / antiaggregant therapies were excluded. FMs measurements and standard coagulation test were taken at admission. Significant hemorrhage was defined as a hemorrhage requiring the transfusion of ≥ 4 Red Blood Cells units during the first 6 h. Multivariable analysis was applied to identify predictors of significant hemorrhage and a simple logistic regression analysis was applied to identify an association between FMs and 28-day mortality.

RESULTS

Overall, 299 patients were included. A total of 47 (16%) experienced a significant hemorrhage. The ROC curve demonstrated that FMs had a poor accuracy to predict the occurrence of significant hemorrhage with an AUC of 0.65 (0.57-0.74). The best threshold at 92.45 µg/ml had excellent sensitivity (87%) and negative predictive value (95%), but was not independently associated with significant hemorrhage (OR = 1.5; 95%CI (0.5-4.2)). The 28-day mortality rate was 5%. In simple logistic regression analysis, FMs values ≥109.5 µg/ml were significantly associated with 28-day mortality (unadjusted OR = 13.2; 95%CI (1.7-102)).

CONCLUSIONS

FMs levels at admission are not associated with the occurrence of a significant hemorrhage in patients with severe trauma. However, the excellent sensitivity and NPV of FMs could help to identify patients with a low risk of severe bleeding during hospital care. In addition, FMs levels ≥109.5 µg/ml might be predictive of 28-day mortality.

D-Dimer and Fibrin Degradation Products Impair Platelet Signaling: Plasma D-Dimer Is a Predictor and Mediator of Platelet Dysfunction During Trauma

BACKGROUND

Platelet dysfunction often accompanies trauma-induced coagulopathy. Because soluble fibrin impairs platelet glycoprotein VI (GPVI) signaling and platelets of trauma patients can display impaired calcium mobilization, we explored the role of fibrinolysis on platelet dysfunction during trauma.

METHODS

Convulxin-induced GPVI calcium mobilization was investigated in healthy platelet-rich plasma (PRP) pretreated with thrombin and tissue plasminogen activator (tPA). Blood samples from healthy participants (n = 7) and trauma patients (n = 22) were tested for platelet calcium mobilization, plasma D-dimer, platelet D-dimer binding (via flow cytometry), and platelet lumi-aggregometry.

RESULTS

For healthy platelets, maximal platelet dysfunction was observed when cross-linked soluble fibrin (no tPA) or cross-linked fibrin degradation products (FDPs) were generated in suspension before convulxin stimulation. Lack of fibrin polymerization (inhibited by Gly-Pro-Arg-Pro [GPRP]) or lack of factor XIIIa cross-linking (T101-inhibited) restored GPVI signaling, whereas non-cross-linked FDPs only partially blocked signaling induced by convulxin. In addition, D-dimer added to healthy PRP impaired platelet aggregation and dense granule release induced by various agonists. Plasma D-dimer level was strongly correlated (R = 0.8236) with platelet dysfunction as measured by platelet calcium mobilization induced with various agonists. By 48 to 120 h after trauma, plasma D-dimer levels declined, and platelet function increased significantly but not to healthy levels. Trauma platelets displayed elevated D-dimer binding that was only partially reduced by αIIbβ3-inhibitor GR144053. After 60-minute incubation, washed healthy platelets resuspended in plasma from trauma patients captured approximately 10 000 D-dimer equivalents per platelet.

CONCLUSIONS

During trauma, D-dimer and FDPs inhibit platelets, potentially via GPVI and integrin αIIbβ3 engagement, contributing to a fibrinolysis-dependent platelet loss-of-function phenotype.

Resuscitation After Hemorrhagic Shock in the Microcirculation: Targeting Optimal Oxygen Delivery in the Design of Artificial Blood Substitutes

Microcirculatory preservation is essential for patient recovery from hemorrhagic shock. In hemorrhagic shock, microcirculatory flow and pressure are greatly reduced, creating an oxygen debt that may eventually become irreversible. During shock, tissues become hypoxic, cellular respiration turns to anaerobic metabolism, and the microcirculation rapidly begins to fail. This condition requires immediate fluid resuscitation to promote tissue reperfusion. The choice of fluid for resuscitation is whole blood; however, this may not be readily available and, on a larger scale, may be globally insufficient. Thus, extensive research on viable alternatives to blood has been undertaken in an effort to develop a clinically deployable blood substitute. This has not, as of yet, achieved fruition, in part due to an incomplete understanding of the complexities of the function of blood in the microcirculation. Hemodynamic resuscitation is acknowledged to be contingent on a number of factors other than volume expansion. The circulation of whole blood is carefully regulated to optimize oxygen delivery to the tissues via shear stress modulation through blood viscosity, inherent oxygen-carrying capacity, cell-free layer variation, and myogenic response, among other variables. Although plasma expanders can address a number of these issues, hemoglobin-based oxygen carriers (HBOCs) introduce a method of replenishing the intrinsic oxygen-carrying capacity of blood. There continue to be a number of issues related to HBOCs, but recent advances in the next-generation HBOCs show promise in the preservation of microcirculatory function and limiting toxicities. The development of HBOCs is now focused on viscosity and the degree of microvascular shear stress achieved in order to optimize vasoactive and oxygen delivery responses by leveraging the restoration and maintenance of physiological responses to blood flow in the microcirculation. Blood substitutes with higher viscous properties tend to improve oxygen delivery compared to those with lower viscosities. This review details current concepts in blood substitutes, particularly as they relate to trauma/hemorrhagic shock, with a specific focus on their complex interactions in the microcirculation.

Factors associated with the progression of traumatic intracranial hematoma during interventional radiology to establish hemostasis of extracranial hemorrhagic injury in severe multiple trauma patients

Aim

To identify factors affecting the progression of traumatic intracranial hemorrhagic injury (t‐ICH) during interventional radiology (IVR) for the hemostasis of extracranial hemorrhagic injury.

Methods

This was a retrospective comparative study. Fifty‐two patients with t‐ICH who underwent hemostasis using IVR for extracranial trauma at our institute were included. Clinical and computed tomography scan data were collected to investigate factors associated with t‐ICH progression.

Results

Fifty‐two subjects (36 men/16 women) with a mean age of 70.9 ± 19.2 years were analyzed. The mean Injury Severity Score was 34.9 ± 11.2. In 29 patients (55.7%), t‐ICH progressed during IVR. Hematoma progression frequently occurred in patients with acute subdural hematoma (56.2%) and traumatic intracerebral hematoma/hemorrhagic brain contusion (66.6%). Factors associated with t‐ICH progression included age (P = 0.029), consciousness level at admission (P = 0.001), Revised Trauma Scale (P = 0.036), probability of survival (P = 0.043), platelet count (P = 0.005), fibrinogen level (P = 0.016), hemoglobin level (P = 0.003), D‐dimer level (P = 0.046), and red blood cell transfusion volume (P = 0.023).

Conclusion

Aggressive correction of anemia, thrombocytopenia, and low fibrinogen levels in severe consciousness disturbance patients with acute subdural hematoma and traumatic intracerebral hematoma/hemorrhagic brain contusion could improve the prognosis after IVR for hemostasis of extracranial hemorrhagic injuries.

Fibrinolysis Index as a new predictor of deep vein thrombosis after traumatic lower extremity fractures

BACKGROUND

Deep vein thrombosis (DVT) is a common complication in patients with traumatic injury. The purpose of this study was to develop a potential predictor of DVT.

METHODS

This case-control study enrolled adult trauma patients and healthy volunteers. Patients underwent angiography before surgery to diagnose DVT. Patients with or without DVT were matched by gender, age and fracture sites. Laboratory parameters included lysis potential (LP), lysis time (LT), blood cell counts, conventional coagulation tests, tissue plasminogen activator inhibitor complex (tPAIC) and others.

RESULTS

41 of 319 patients with DVT were matched with 41 patients without DVT and 80 healthy volunteers were controls. LP and LT were significantly decreased in patients with DVT than without (P = 0.043 and P = 0.014, respectively). The level of tPAIC in the DVT group was significantly higher than in patients without DVT (P = 0.042). We defined the Fibrinolysis Index as (-10.707) × LP + (-0.607) × LT (min) + 0.012 × fibrinogen (mg/dl) + 0.299 × tPAIC (ng/ml) + 9.917, and found that the area under the receiver operating characteristic curve for the Fibrinolysis Index was 0.802, making it a novel indicator.

CONCLUSION

The Fibrinolysis Index represents a new discriminator for predicting DVT after traumatic lower extremity fractures.

Platelet Function Analysis by Flowcytometry in Thrombocytopenic Trauma Patients

Hemostasis is dependent on sufficient quantity and quality of circulating functional platelets. Platelet function in trauma patients with thrombocytopenia and its impact on the clinical outcome is not adequately explored. Whether platelet dysfunction has a role in the pathogenesis of acute traumatic coagulopathy needs to be studied. Blood samples were collected from 70 thrombocytopenic trauma patients before transfusing platelets and assessed for platelet activation and platelet aggregation using flowcytometry. Primary outcome was in-hospital mortality. Platelet dysfunction was identified in 57.1% of thrombocytopenic trauma patients. A weak inverse correlation between percentage of activated platelets and APTT was observed (Spearman coefficient - 0.25, p = 0.03). A sensitivity and specificity of 66.6% was achieved for a cut off of ≤ 6.5% of platelet activation post trauma with ROC-AUC of 0.658 for identifying coagulopathy. No correlation with mortality however was observed (p > 0.05). Platelet dysfunction had a weak association with coagulopathy suggesting limited contribution of platelet dysfunction in pathogenesis of acute traumatic coagulopathy and warrants further research.

Identification of injury and shock driven effects on ex vivo platelet aggregometry: A cautionary tale of phenotyping

BACKGROUND

Platelet behavior in trauma-induced coagulopathy is poorly understood. Injured patients have impaired platelet aggregation (dysfunction) in ex vivo agonist-stimulated platelet aggregometry (PA). However, PA assumes that platelets are inactivated before ex vivo stimulated aggregation, which may be altered by injury. We hypothesized that following trauma, platelet aggregation (area under the curve) is decreased regardless of injury burden, but that (1) minor injury is associated with an increased baseline electrical impedance, characteristic of a functional platelet phenotype (platelets that activate in response to injury), and that (2) severe injury is not associated with an increased baseline electrical impedance, characteristic of a dysfunctional phenotype (platelets that do not activate well in response to injury) compared with healthy controls.

METHODS

Blood from 458 trauma patients and 30 healthy donors was collected for PA. Baseline electrical impedance (Ω); platelet aggregation stimulated by adenosine diphosphate, collagen, thrombin, and arachidonic acid; and rotational thromboelastometry were measured. Multivariate regression was performed to identify associations of PA measures with blood transfusion.

RESULTS

Compared with healthy controls, injured patients had impaired platelet aggregation in response to ex vivo stimulation, regardless of injury burden. However, minorly injured patients had increased endogenous platelet activation (baseline electrical impedance, Ω: with shock, p = 0.012; without shock, p = 0.084), but severely injured patients did not have significant increases in endogenous platelet activation (baseline electrical impedance, Ω: with shock, p = 0.86; without shock, p = 0.37). For every 10 Ω increase in baseline electrical impedance, there was an 8% decrease in units of blood transfused in the first 24 h (-0.08; confidence interval, -0.14 to -0.02; p = 0.015).

CONCLUSION

Injury and shock confer differential patterns of platelet aggregation in PA. Minor injury overestimates the presence of platelet dysfunction, while severe injury induces a truly dysfunctional phenotype-platelets that do not activate nor aggregate appropriately after injury. This is consequential in improving accurate phenotyping of postinjury platelet behavior for platelet-based therapeutics.

LEVEL OF EVIDENCE

Prognostic, level IV.

The Impact of Accidental Hypothermia on Mortality in Trauma Patients Overall and Patients with Traumatic Brain Injury Specifically: A Systematic Review and Meta-Analysis

Background

Accidental hypothermia is a known predictor for worse outcomes in trauma patients, but has not been comprehensively assessed in a meta-analysis so far. The aim of this systematic review and meta-analysis was to investigate the impact of accidental hypothermia on mortality in trauma patients overall and patients with traumatic brain injury (TBI) specifically.

Methods

This is a systematic review and meta-analysis using the Ovid Medline/PubMed database. Scientific articles reporting accidental hypothermia and its impact on outcomes in trauma patients were included in qualitative synthesis. Studies that compared the effect of hypothermia vs. normothermia at hospital admission on in-hospital mortality were included in two meta-analyses on (1) trauma patients overall and (2) patients with TBI specifically. Meta-analysis was performed using a Mantel–Haenszel random-effects model.

Results

Literature search revealed 264 articles. Of these, 14 studies published 1987–2018 were included in the qualitative synthesis. Seven studies qualified for meta-analysis on trauma patients overall and three studies for meta-analysis on patients with TBI specifically. Accidental hypothermia at admission was associated with significantly higher mortality both in trauma patients overall (OR 5.18 [95% CI 2.61–10.28]) and patients with TBI specifically (OR 2.38 [95% CI 1.53–3.69]).

Conclusions

In the current meta-analysis, accidental hypothermia was strongly associated with higher in-hospital mortality both in trauma patients overall and patients with TBI specifically. These findings underscore the importance of measures to avoid accidental hypothermia in the prehospital care of trauma patients.

Electronic supplementary material

The online version of this article (10.1007/s00268-020-05750-5) contains supplementary material, which is available to authorized users.

Compound amino acid combined with high-dose vitamin B6 attenuate traumatic coagulopathy via inhibiting inflammation by HMGB1/TLR4/NF-κB pathway

BACKGROUND

Traumatic coagulopathy (TC) arises primarily from coagulation system failure to maintain adequate hemostasis after serious blood loss or trauma. Circulatory homeostasis restoration is the mainstay of the therapeutic approach to TC, but the effects are significantly inhibited by coagulopathy.

OBJECTIVE

To identify the therapeutic effects and underlying mechanism of compound amino acid (CAA) combined with high-dosage of vitamin B6 (VB6) on TC.

METHODS

Rabbit traumatic model and cellular model were used to evaluate the effect of CAA combined with high-dosage of VB6 in TC. Blood concentrations of AST and ALT were measured using the Vitros 250 device while blood APTT, PT and TT concentrations were measured using commercial diagnostics kits. Furthermore, qRT-PCR, ELISA and Western blotting were used to determine the expression of clotting factor (II, VII, IX, X and XI), inflammatory factors (TNF-α, IL-6 and IL-1β) and HMGB1/TLR4/NF-κB signaling-related proteins, respectively.

RESULTS

In the rabbit traumatic model, CAA combined with high-dosage of VB6 therapy inhibited the high expression of AST and ALT, but increased the expression of coagulation factors. Additionally, in both the rabbit trauma model and cellular injury model, CAA combined with high-dosage of VB6 inhibited the expression of inflammatory factors (IL-6, TNF-α and IL-1β) and proteins (HMGB1, TLR4 and p-p65) in HMGB1/TLR4/NF-κB pathway. Most importantly, over-expression of HMGB1 reversed the effect of CAA and VB6 in HUVECs and EA.hy926 cells injury model.

CONCLUSION

CAA combined with high-dosage of VB6 alleviated TC and inhibited the expression and secretion of inflammatory factors by inhibiting HMGB1-mediated TLR4/NF-κB pathway.

Trends and outcomes of blunt renal trauma management: a nationwide cohort study in Japan

Background

There is a paucity of information for predicting patient outcomes other than the American Association for the Surgery of Trauma (AAST) renal injury scale. The aim of this study was to evaluate the association between the patient characteristics and outcomes of patients with blunt renal trauma using a nationwide database in Japan.

Methods

We performed a retrospective analysis of the Japan Trauma Data Bank (JTDB) from 2004 to 2018. We identified patients with blunt renal trauma by AIS codes converted to AAST grades. We evaluated trends in patient characteristics and management and assessed factors associated with mortality and nephrectomy using a multivariable logistic regression analysis.

Results

We identified 3550 patients with blunt renal trauma. Their median age was 43 years and 74.2% were male. Nephrectomy was performed in 3.8%, and the overall mortality rate was 9.5%. We found increasing trends in age and emergency abdominal angiography and decreasing trends in nephrectomy and mortality over the 15-year period. The following factors were associated with mortality: age ≥ 65 years (adjusted OR 3.36); pedestrian accident (adjusted OR 1.94); fall from height (adjusted OR 1.91); shock on arrival (adjusted OR 4.02); concomitant injuries to the head/neck (adjusted OR 3.14), pelvis/lower-extremity (adjusted OR 1.59), liver (adjusted OR 1.68), spleen (adjusted OR 1.45), and gastrointestinal tract (adjusted OR 1.90); AAST grades III–V (adjusted ORs 1.42, 2.16, and 5.55); and emergency abdominal angiography (adjusted OR 0.70). The following factors were associated with nephrectomy: shock on arrival (adjusted OR 1.98), concomitant injuries to the thorax (adjusted OR 0.46) and spleen (adjusted OR 2.07), AAST grades III, IV, and V (adjusted ORs 18.40, 113.89, and 468.17), and emergency abdominal angiography (adjusted OR 0.28).

Conclusions

We demonstrated that the AAST grade and emergency angiography were associated with mortality and nephrectomy in blunt renal trauma in the Japanese population.