A role for decorin in improving motor deficits after traumatic brain injury.

Traumatic brain injury (TBI) is the leading cause of death and disability due to injury worldwide. Extracellular matrix (ECM) remodeling is known to significantly contribute to TBI pathophysiology. Glycosaminoglycans, which are long-chain, variably sulfated polysaccharides abundant within the ECM, have previously been shown to be substantially altered after TBI. In this study, we sought to delineate the dynamics of glycosaminoglycan alterations after TBI and discover the precise biologic processes responsible for observed glycosaminoglycan changes after injury. We performed state-of-the art mass spectrometry on brain tissues isolated from mice after TBI or craniotomy-alone. We observed dynamic changes in glycosaminoglycans at Day 1 and 7 post-TBI, with heparan sulfate, chondroitin sulfate, and hyaluronan remaining significantly increased after a week vis-à-vis craniotomy-alone tissues. We did not observe appreciable changes in circulating glycosaminoglycans in mice after experimental TBI compared to craniotomy-alone nor in patients with TBI and severe polytrauma compared to control patients with mild injuries, suggesting increases in injury site glycosaminoglycans are driven by local synthesis. We subsequently performed an unbiased whole genome transcriptomics analysis on mouse brain tissues 7 days post-TBI and discovered a significant induction of hyaluronan synthase 2, glypican-3, and decorin. The functional role of decorin after injury was further examined through multimodal behavioral testing comparing wild-type and Dcn-/- mice. We discovered that genetic ablation of Dcn led to an overall negative effect of TBI on function, exacerbating motor impairments after TBI. Collectively, our results provide a spatiotemporal characterization of post-TBI glycosaminoglycan alterations in the brain ECM and support an important adaptive role for decorin upregulation after TBI.

REBOA for the Treatment of Blast Polytrauma: Zone 3 Provides Cerebral Perfusion, Attenuates Organ Dysfunction and Reperfusion Coagulopathy Compared to Zone 1 in a Swine Model.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a lifesaving therapy for hemorrhagic shock following pelvic/lower extremity injuries in military settings. However, Zone 1 aortic occlusion (AO; above the celiac artery), while providing brain/cardiac perfusion, may induce/worsen visceral ischemia and organ dysfunction. In contrast, AO Zone 3 (below the renal arteries) provides abdominal perfusion potentially minimizing ischemia/reperfusion injury. We hypothesized that, compared with AO Zone 1, AO Zone 3 provides neuro/cardioprotection while minimizing visceral ischemia and reperfusion coagulopathy after severe traumatic hemorrhage due to pelvic/lower extremity injuries. METHODS: Fifty-kilogram male Yorkshire swine underwent a blast polytrauma injury followed by a resuscitation protocol with randomization to no AO (No AO, n = 6) or AO with REBOA at Zone 1 (AO Zone 1; n = 6) or Zone 3 (AO Zone 3; n = 4). Vital signs and intracranial pressure (ICP) were monitored for 240 minutes. Citrate native and tissue plasminogen activator challenge thrombelastography, prothrombin time, creatinine, lipase, total bilirubin, troponin, and enzyme-linked immunosorbent assays protein levels were measured at set intervals. RESULTS: Both AO groups had significant increases in mean arterial pressure during aortic occlusion. All three groups had significant increases in ICP, but final ICP in the No AO group (26 ± 5.8 mm Hg) was significantly elevated compared with AO Zone 1 (17 ± 5.2 mm Hg) and AO Zone 3 (16 ± 4.2 mm Hg) ( p < 0.01). The final mean troponin in the No AO group (4.10 ± 5.67 ng/mL) was significantly higher than baseline (0.03 ± 0.02 ng/mL, p < 0.05), while the two AO groups had no significant changes ( p > 0.05). AO Zone 1 was the only group associated with hyperfibrinolysis ( p < 0.05) and significantly increased prothrombin time ( p < 0.05). Only AO Zone 1 group had significantly higher markers of organ damage. CONCLUSION: Compared with AO Zone 1, AO Zone 3 provided similar neuro/cardioprotection but with less organ dysfunction and coagulopathy. This study suggests that Zone 3 REBOA may be preferable over Zone 1 for treating military relevant blast polytrauma with minimal intra-abdominal and chest trauma, but further clinical investigation is warranted.

Hemorrhagic shock and tissue injury provoke distinct components of trauma-induced coagulopathy in a swine model.

INTRODUCTION: Tissue injury (TI) and hemorrhagic shock (HS) are the major contributors to trauma-induced coagulopathy (TIC). However, the individual contributions of these insults are difficult to discern clinically because they typically coexist. TI has been reported to release procoagulants, while HS has been associated with bleeding. We developed a large animal model to isolate TI and HS and characterize their individual mechanistic pathways. We hypothesized that while TI and HS are both drivers of TIC, they provoke different pathways; specifically, TI reduces time to clotting, whereas, HS decreases clot strength stimulates hyperfibrinolysis. METHODS: After induction of general anesthesia, 50 kg male, Yorkshire swine underwent isolated TI (bilateral muscle cutdown of quadriceps, bilateral femur fractures) or isolated HS (controlled bleeding to a base excess target of - 5 mmol/l) and observed for 240 min. Thrombelastography (TEG), calcium levels, thrombin activatable fibrinolysis inhibitor (TAFI), protein C, plasminogen activator inhibitor 1 (PAI-1), and plasminogen activator inhibitor 1/tissue-type plasminogen activator complex (PAI-1-tPA) were analyzed at pre-selected timepoints. Linear mixed models for repeated measures were used to compare results throughout the model. RESULTS: TI resulted in elevated histone release which peaked at 120 min (p = 0.02), and this was associated with reduced time to clot formation (R time) by 240 min (p = 0.006). HS decreased clot strength at time 30 min (p = 0.003), with a significant decline in calcium (p = 0.001). At study completion, HS animals had elevated PAI-1 (p = 0.01) and PAI-1-tPA (p = 0.04), showing a trend toward hyperfibrinolysis, while TI animals had suppressed fibrinolysis. Protein C, TAFI and skeletal myosin were not different among the groups. CONCLUSION: Isolated injury in animal models can help elucidate the mechanistic pathways leading to TIC. Our results suggest that isolated TI leads to early histone release and a hypercoagulable state, with suppressed fibrinolysis. In contrast, HS promotes poor clot strength and hyperfibrinolysis resulting in hypocoagulability.

Beyond uterine atony: characterizing postpartum hemorrhage coagulopathy.

BACKGROUND: Postpartum hemorrhage is a leading cause of morbidity and mortality worldwide, yet the associated early coagulopathy is not well defined. OBJECTIVE: We hypothesized that women who develop postpartum hemorrhage have a distinct derangement of thrombin generation and coagulation factors compared with postpartum women without postpartum hemorrhage. STUDY DESIGN: This prospective study of pregnant patients with postpartum hemorrhage was completed at a single urban hospital. Blood was drawn on postpartum hemorrhage diagnosis and 2 and 4 hours later. Assays of patients with postpartum hemorrhage included thrombelastography, whole blood thrombin generation, coagulation factor activity, tissue factor levels and activity, and tissue factor pathway inhibitor levels, which were compared with that of patients without postpartum hemorrhage. RESULTS: A total of 81 patients were included in this study. Of those patients, 66 had postpartum hemorrhage, and 15 served as controls. Compared with patients without PPH, patients with postpartum hemorrhage had lower fibrinogen levels (469.0 mg/dL vs 411.0 mg/dL; P=.02), increased tissue plasminogen activator resistance (fibrinolysis 30 minutes after maximal clot strength: 8.7% vs 4.2%; P=.02), decreased peak thrombin concentration (150.2 nM vs 40.7 nM; P=.01), and decreased maximal rate of thrombin generation (60.1 nM/minute vs 2.8 nM/minute; P=.02). Furthermore, compared with patients without postpartum hemorrhage, patients with postpartum hemorrhage had decreased tissue factor levels (444.3 pg/mL vs 267.1 pg/mL; P=.02) and increased tissue factor pathway inhibitor levels (0.6 U/mL vs 0.8 U/mL; P=.04), with decreased tissue factor pathway inhibitor ratios (624 vs 299; P=.01). CONCLUSION: PPH is not only an issue of uterine tone and mechanical bleeding but also a distinct coagulopathy that is characterized by decreased fibrinogen level, clot breakdown resistance, and markedly low thrombin generation. This pathology seemed to be driven by low tissue factor and high tissue factor pathway inhibitor levels.

Zone 1 REBOA in a combat DCBI swine model does not worsen brain injury.

BACKGROUND: Zone 1 resuscitative endovascular balloon occlusion of the aorta has been recommended for refractory shock after a dismounted complex blast injury for the austere combat scenario. While resuscitative endovascular balloon occlusion of the aorta should enhance coronary perfusion, there is a potential risk of secondary brain injury due to loss of cerebral autoregulation. We developed a combat casualty relevant dismounted complex blast injury swine model to evaluate the effects of resuscitative endovascular balloon occlusion of the aorta zone I on intracranial pressure and cerebral edema. We hypothesized that zone 1 aortic occlusion with resuscitative endovascular balloon occlusion of the aorta would increase mean arterial pressure transmitted in excessive intracranial pressure, thereby worsening brain injury. METHODS: 50 kg male Yorkshire swine were subjected to a combination dismounted complex blast injury model consisting of blast traumatic brain injury (50 psi, ARA Mobile Shock Laboratory), tissue injury (bilateral femur fractures), and hemorrhagic shock (controlled bleeding to a base deficit goal of 10 mEq/L). During the shock phase, pigs were randomized to no aortic occlusion (n = 8) or to 30 minutes of zone 1 resuscitative endovascular balloon occlusion of the aorta (zone 1 aortic occlusion group, n = 6). After shock, pigs in both groups received a modified Tactical Combat Casualty Care-based resuscitation and were monitored for an additional 240 minutes until euthanasia/death for a total of 6 hours. Intracranial pressure was monitored throughout, and brains were harvested for water content. Linear mixed models for repeated measures were used to compare mean arterial pressure and intracranial pressure between zone 1 aortic occlusion and no aortic occlusion groups. RESULTS: After dismounted complex blast injury, the zone 1 group had a significantly higher mean arterial pressure during hemorrhagic shock compared to the control group (41.2 mm Hg vs 16.7 mm Hg, P = .002). During balloon occlusion, intracranial pressure was not significantly elevated in the zone 1 aortic occlusion group vs control, but intracranial pressure was significantly lower in the zone 1 group at the end of the observation period. In addition, the zone 1 aortic occlusion group did not have increased brain water content (zone 1 aortic occlusion: 3.95 ± 0.1g vs no aortic occlusion: 3.95 ± 0.3 g, P = .87). Troponin levels significantly increased in the no aortic occlusion group but did not in the zone 1 aortic occlusion group. CONCLUSION: Zone 1 aortic occlusion using resuscitative endovascular balloon occlusion of the aorta in a large animal dismounted complex blast injury model improved proximal mean arterial pressure while not significantly increasing intracranial pressure during balloon inflation. Observation up to 240 minutes postresuscitation did not show clinical signs of worsening brain injury or cardiac injury. These data suggest that in a dismounted complex blast injury swine model, resuscitative endovascular balloon occlusion of the aorta in zone 1 may provide neuro- and cardioprotection in the setting of blast traumatic brain injury. However, longer monitoring periods may be needed to confirm that the neuroprotection is lasting.

Postinjury complement C4 activation is associated with adverse outcomes and is potentially influenced by plasma resuscitation.

BACKGROUND: Complement activation after trauma promotes hemostasis but is associated with increased morbidity and mortality. However, the specific pathways and downstream mediators remain unclear. Recently, the anaphylatoxin C4a has been shown to bind to thrombin receptors. While plasma-based resuscitation has been shown to modify the endotheliopathy of trauma, it may provide complement zymogens that fuel ongoing inflammatory cascades. We sought to characterize the activation of complement after injury and the effect of fresh frozen plasma (FFP) on this inflammatory response. We hypothesized that trauma induces C4 activation, which is associated with worse outcomes and influenced by FFP resuscitation. METHODS: Blood was collected from injured patients at a single level I trauma center enrolled in the Control of Major Bleeding after Trauma (COMBAT) randomized clinical trial. Proteomic analyses were performed through targeted liquid chromatography coupled with mass spectrometry. For the present observational study, concentrations of complement proteins were analyzed at multiple time points, compared between treatment groups, and correlated with outcomes. RESULTS: C4 activation occurred over the first 6 hours postinjury with peak activation 6 to 24 hours. Tissue hypoperfusion, defined as base deficit >10 mEq/L, and requirement for massive transfusion were associated with greater C4 activation. C4 activation was associated with mortality, multiple organ failure, and longer ventilator requirement. In addition, temporal trends of C1q, factor B, and C3 by outcome groups support the prevailing theory of primary classical pathway activation with alternative pathway amplification. Resuscitation with FFP over the first 6 hours was associated with increased C4 activation at 12 and 24 hours. CONCLUSION: C4 activation has an important inflammatory role postinjury, and FFP has the potential to augment this complement activation during resuscitation. LEVEL OF EVIDENCE: Prognostic/epidemiological, level III.

Role of Fibrinogen in Trauma-Induced Coagulopathy.

BACKGROUND: Fibrinogen is the first coagulation factor to decrease after massive hemorrhage. European massive transfusion guidelines recommend early repletion of fibrinogen; however, this practice has not been widely adopted in the US. We hypothesize that hypofibrinogenemia is common at hospital arrival and is an integral component of trauma-induced coagulopathy. STUDY DESIGN: This study entailed review of a prospective observational database of adults meeting the highest-level activation criteria at an urban level 1 trauma center from 2014 through 2020. Resuscitation was initiated with 2:1 red blood cell (RBC) to fresh frozen plasma (FFP) ratios and continued subsequently with goal-directed thrombelastography. Hypofibrinogenemia was defined as fibrinogen below 150 mg/dL. Massive transfusion (MT) was defined as more than 10 units RBC or death after receiving at least 1 unit RBC over the first 6 hours of admission. RESULTS: Of 476 trauma activation patients, 70 (15%) were hypofibrinogenemic on admission, median age was 34 years, 78% were male, median New Injury Severity Score (NISS) was 25, and 72 patients died (15%). Admission fibrinogen level was an independent risk factor for MT (odds ratio [OR] 0.991, 95% CI 0.987-0.996]. After controlling for confounders, NISS (OR 1.034, 95% CI 1.017-1.052), systolic blood pressure (OR 0.991, 95% CI 0.983-0.998), thrombelastography angle (OR 0.925, 95% CI 0.896-0.954), and hyperfibrinolysis (OR 2.530, 95% CI 1.160-5.517) were associated with hypofibrinogenemia. Early cryoprecipitate administration resulted in the fastest correction of hypofibrinogenemia. CONCLUSION: Hypofibrinogenemia is common after severe injury and predicts MT. Cryoprecipitate transfusion results in the most expeditious correction. Earlier administration of cryoprecipitate should be considered in MT protocols.

Traumatic brain injury provokes low fibrinolytic activity in severely injured patients.

BACKGROUND: Traumatic brain injury (TBI) in combination with shock has been associated with hypocoagulability. However, recent data suggest that TBI itself can promote a systemic procoagulant state via the release of brain-derived extracellular vesicles. The objective of our study was to identify if TBI was associated with differences in thrombelastography indices when controlling for other variables associated with coagulopathy following trauma. We hypothesized that TBI is independently associated with a less coagulopathic state. METHODS: Prospective study includes all highest-level trauma activations at an urban Level I trauma center, from 2014 to 2020. Traumatic brain injury was defined as Abbreviated Injury Scale head score greater than 3. Blood samples were drawn at emergency department admission. Linear regression was used to assess the role of independent predictors on trauma induced coagulopathy. Models adjusted for Injury Severity Score (ISS), shock (defined as ED SBP<70, or ED SBP<90 and ED HR>108, or first hospital base deficit >10), and prehospital Glasgow Coma Scale score. RESULTS: Of the 1,023 patients included, 291 (28%) suffered a TBI. Traumatic brain injury patients more often were female (26% vs. 19%, p = 0.01), had blunt trauma (83% vs. 43%, p < 0.0001), shock (33% vs. 25%, p = 0.009), and higher median ISS (29 vs. 10, p < 0.0001). Fibrinolysis shutdown (25% vs. 18%) was more common in the TBI group (p < 0.0001). When controlled for the confounding effects of ISS and shock, the presence of TBI independently decreases lysis at 30 minutes (LY30) (beta estimate: -0.16 ± 0.06, p = 0.004). This effect of TBI on LY30 persisted when controlling for sex and mechanism of injury in addition to ISS and shock (beta estimate: -0.13 ± 0.06, p = 0.022). CONCLUSION: Traumatic brain injury is associated with lower LY30 independent of shock, tissue injury, sex, and mechanism of injury. These findings suggest a propensity toward a hypercoagulable state in patients with TBI, possibly due to fibrinolysis shutdown. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level III.

The α-globin chain of hemoglobin potentiates tissue plasminogen activator induced hyperfibrinolysis in vitro.

BACKGROUND: Severe injury predisposes patients to trauma-induced coagulopathy, which may be subdivided by the state of fibrinolysis. Systemic hyperfibrinolysis (HF) occurs in approximately 25% of these patients with mortality as high as 70%. Severe injury also causes the release of numerous intracellular proteins, which may affect coagulation, one of which is hemoglobin, and hemoglobin substitutes induce HF in vitro. We hypothesize that the α-globin chain of hemoglobin potentiates HF in vitro by augmenting plasmin activity. METHODS: Proteomic analysis was completed on a pilot study of 30 injured patients before blood component resuscitation, stratified by their state of fibrinolysis, plus 10 healthy controls. Different concentrations of intact hemoglobin A, the α- and ß-globin chains, or normal saline (controls) were added to whole blood, and tissue plasminogen activator (tPA)-challenged thrombelastography was used to assess the degree of fibrinolysis. Interactions with plasminogen (PLG) were evaluated using surface plasmon resonance. Tissue plasminogen activator-induced plasmin activity was evaluated in the presence of the α-globin chain. RESULTS: Only the α- and ß-globin chains increased in HF patients (p < 0.01). The α-globin chain but not hemoglobin A or the ß-globin chain decreased the reaction time and significantly increased lysis time 30 on citrated native thrombelastographies (p < 0.05). The PLG and α-globin chain had interaction kinetics similar to tPA:PLG, and the α-globin chain increased tPA-induced plasmin activity. CONCLUSIONS: The α-globin chain caused HF in vitro by binding to PLG and augmenting plasmin activity and may represent a circulating "moonlighting" mediator released by the tissue damage and hemorrhagic shock inherent to severe injury. LEVEL OF EVIDENCE: Prognostic, level III.

Study of Alteplase for Respiratory Failure in SARS-CoV-2 COVID-19: A Vanguard Multicenter, Rapidly Adaptive, Pragmatic, Randomized Controlled Trial.

BACKGROUND: Pulmonary vascular microthrombi are a proposed mechanism of COVID-19 respiratory failure. We hypothesized that early administration of tissue plasminogen activator (tPA) followed by therapeutic heparin would improve pulmonary function in these patients. RESEARCH QUESTION: Does tPA improve pulmonary function in severe COVID-19 respiratory failure, and is it safe? STUDY DESIGN AND METHODS: Adults with COVID-19-induced respiratory failure were randomized from May14, 2020 through March 3, 2021, in two phases. Phase 1 (n = 36) comprised a control group (standard-of-care treatment) vs a tPA bolus (50-mg tPA IV bolus followed by 7 days of heparin; goal activated partial thromboplastin time [aPTT], 60-80 s) group. Phase 2 (n = 14) comprised a control group vs a tPA drip (50-mg tPA IV bolus, followed by tPA drip 2 mg/h plus heparin 500 units/h over 24 h, then heparin to maintain aPTT of 60-80 s for 7 days) group. Patients were excluded from enrollment if they had not undergone a neurologic examination or cross-sectional brain imaging within the previous 4.5 h to rule out stroke and potential for hemorrhagic conversion. The primary outcome was Pao2 to Fio2 ratio improvement from baseline at 48 h after randomization. Secondary outcomes included Pao2 to Fio2 ratio improvement of > 50% or Pao2 to Fio2 ratio of ≥ 200 at 48 h (composite outcome), ventilator-free days (VFD), and mortality. RESULTS: Fifty patients were randomized: 17 in the control group and 19 in the tPA bolus group in phase 1 and eight in the control group and six in the tPA drip group in phase 2. No severe bleeding events occurred. In the tPA bolus group, the Pao2 to Fio2 ratio values were significantly (P < .017) higher than baseline at 6 through 168 h after randomization; the control group showed no significant improvements. Among patients receiving a tPA bolus, the percent change of Pao2 to Fio2 ratio at 48 h (16.9% control [interquartile range (IQR), -8.3% to 36.8%] vs 29.8% tPA bolus [IQR, 4.5%-88.7%]; P = .11), the composite outcome (11.8% vs 47.4%; P = .03), VFD (0.0 [IQR, 0.0-9.0] vs 12.0 [IQR, 0.0-19.0]; P = .11), and in-hospital mortality (41.2% vs 21.1%; P = .19) did not reach statistically significant differences when compared with those of control participants. The patients who received a tPA drip did not experience benefit. INTERPRETATION: The combination of tPA bolus plus heparin is safe in severe COVID-19 respiratory failure. A phase 3 study is warranted given the improvements in oxygenation and promising observations in VFD and mortality. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT04357730; URL: www. CLINICALTRIALS: gov.

Succinate Activation of SUCNR1 Predisposes Severely Injured Patients to Neutrophil-mediated ARDS.

OBJECTIVES: Identify the metabolites that are increased in the plasma of severely injured patients that developed ARDS versus severely injured patients that did not, and assay if these increased metabolites prime pulmonary sequestration of neutrophils (PMNs) and induce pulmonary sequestration in an animal model of ARDS. We hypothesize that metabolic derangement due to advanced shock in critically injured patients leads to the PMNs, which serves as the first event in the ARDS. Summary of Background Data: Intracellular metabolites accumulate in the plasma of severely injured patients. METHODS: Untargeted metabolomics profiling of 67 critically injured patients was completed to establish a metabolic signature associated with ARDS development. Metabolites that significantly increased were assayed for PMN priming activity in vitro. The metabolites that primed PMNs were tested in a 2-event animal model of ARDS to identify a molecular link between circulating metabolites and clinical risk for ARDS. RESULTS: After controlling for confounders, 4 metabolites significantly increased: creatine, dehydroascorbate, fumarate, and succinate in trauma patients who developed ARDS ( P < 0.05). Succinate alone primed the PMN oxidase in vitro at physiologically relevant levels. Intravenous succinate-induced PMN sequestration in the lung, a first event, and followed by intravenous lipopolysaccharide, a second event, resulted in ARDS in vivo requiring PMNs. SUCNR1 inhibition abrogated PMN priming, PMN sequestration, and ARDS. Conclusion: Significant increases in plasma succinate post-injury may serve as the first event in ARDS. Targeted inhibition of the SUCNR1 may decrease ARDS development from other disease states to prevent ARDS globally.

Whole Blood Thrombin Generation in Severely Injured Patients Requiring Massive Transfusion.

BACKGROUND: Despite the prevalence of hypocoagulability after injury, the majority of trauma patients paradoxically present with elevated thrombin generation (TG). Although several studies have examined plasma TG post injury, this has not been assessed in whole blood. We hypothesize that whole blood TG is lower in hypocoagulopathy, and TG effectively predicts massive transfusion (MT). STUDY DESIGN: Blood was collected from trauma activation patients at an urban Level I trauma center. Whole blood TG was performed with a prototype point-of-care device. Whole blood TG values in healthy volunteers were compared with trauma patients, and TG values were examined in trauma patients with shock and MT requirement. RESULTS: Overall, 118 patients were included. Compared with healthy volunteers, trauma patients overall presented with more robust TG; however, those arriving in shock (n = 23) had a depressed TG, with significantly lower peak thrombin (88.3 vs 133.0 nM; p = 0.01) and slower maximum rate of TG (27.4 vs 48.3 nM/min; p = 0.04). Patients who required MT (n = 26) had significantly decreased TG, with a longer lag time (median 4.8 vs 3.9 minutes, p = 0.04), decreased peak thrombin (median 71.4 vs 124.2 nM; p = 0.0003), and lower maximum rate of TG (median 15.8 vs 39.4 nM/min; p = 0.01). Area under the receiver operating characteristics (AUROC) analysis revealed lag time (AUROC 0.6), peak thrombin (AUROC 0.7), and maximum rate of TG (AUROC 0.7) predict early MT. CONCLUSIONS: These data challenge the prevailing bias that all trauma patients present with elevated TG and highlight that deficient thrombin contributes to the hypocoagulopathic phenotype of trauma-induced coagulopathy. In addition, whole blood TG predicts MT, suggesting point-of-care whole blood TG can be a useful tool for diagnostic and therapeutic strategies in trauma.

Tranexamic acid is associated with reduced complement activation in trauma patients with hemorrhagic shock and hyperfibrinolysis on thromboelastography.

: Trauma with hemorrhagic shock causes massive tissue plasminogen activator release, plasmin generation, and hyperfibrinolysis. Tranexamic acid (TXA) has recently been used to treat bleeding in trauma by preventing plasmin generation to limit fibrinolysis. Trauma patients also have increased complement activation that correlates with mortality and organ failure, but the source of activation is not clear, and plasmin has recently been shown to efficiently cleave C3 and C5 to their activated fragments. We hypothesized that trauma patients in hemorrhagic shock with hyperfibrinolysis on thromboelastography (TEG) LY30 would have increased complement activation at early time points, as measured by soluble C5b-9 complex, and TXA would prevent this. Plasma samples were obtained from an unrelated, previously performed IRB-approved prospective randomized study of trauma patients. Three groups were studied with n = 5 patients in each group: patients without hyperfibrinolysis (TEG LY30 < 3%) (who therefore did not get TXA), patients with hyperfibrinolysis (TEG LY30 > 3%) who did not get TXA, and patients with hyperfibrinolysis who were then treated with TXA. We found that patients who did not receive TXA, regardless of fibrinolytic phenotype, had elevated soluble C5b-9 levels at 6 h relative to emergency department levels. In contrast, all five patients with initial TEG LY30 more than 3% and were then treated with TXA had reduced soluble C5b-9 levels at 6 h relative to emergency department levels. There were no differences in PF1 + 2, Bb, or C4d levels between groups, suggesting that coagulation and complement activation pathways may not be primarily responsible for the observed differences.

Association of Prehospital Plasma Transfusion With Survival in Trauma Patients With Hemorrhagic Shock When Transport Times Are Longer Than 20 Minutes: A Post Hoc Analysis of the PAMPer and COMBAT Clinical Trials.

Importance: Both military and civilian clinical practice guidelines include early plasma transfusion to achieve a plasma to red cell ratio approaching 1:1 to 1:2. However, it was not known how early plasma should be given for optimal benefit. Two recent randomized clinical trials were published, with apparently contradictory results. The Prehospital Air Medical Plasma (PAMPer) clinical trial showed a nearly 30% reduction in mortality with plasma transfusion in the prehospital environment, while the Control of Major Bleeding After Trauma (COMBAT) clinical trial showed no survival improvement. Objective: To facilitate a post hoc combined analysis of the COMBAT and PAMPer trials to examine questions that could not be answered by either clinical trial alone. We hypothesized that prehospital transport time influenced the effects of prehospital plasma on 28-day mortality. Design, Setting, and Participants: A total of 626 patients in the 2 clinical trials were included. Patients with trauma and hemorrhagic shock were randomly assigned to receive either standard care or 2 U of thawed plasma followed by standard care in the prehospital environment. Data analysis was performed between September 2018 and January 2019. Interventions: Prehospital transfusion of 2 U of plasma compared with crystalloid-based resuscitation. Main Outcomes and Measures: The main outcome was 28-day mortality. Results: In this post hoc analysis of 626 patients (467 men [74.6%] and 159 women [25.4%]; median [interquartile range] age, 42 [27-57] years) who had trauma with hemorrhagic shock, a Cox regression analysis showed a significant overall survival benefit for plasma (hazard ratio [HR], 0.65; 95% CI, 0.47-0.90; P = .01) after adjustment for injury severity, age, and clinical trial cohort (COMBAT or PAMPer). A significant association with prehospital transport time was detected (from arrival on scene to arrival at the trauma center). Increased mortality was observed in patients in the standard care group when prehospital transport was longer than 20 minutes (HR, 2.12; 95% CI, 1.05-4.30; P = .04), while increased mortality was not observed in patients in the prehospital plasma group (HR, 0.78; 95% CI, 0.40-1.51; P = .46). No serious adverse events were associated with prehospital plasma transfusion. Conclusions and Relevance: These data suggest that prehospital plasma is associated with a survival benefit when transport times are longer than 20 minutes and that the benefit-risk ratio is favorable for use of prehospital plasma. Trial Registration: ClinicalTrials.gov identifiers: NCT01838863 (COMBAT) and NCT01818427 (PAMPer).

Obesity is associated with postinjury hypercoagulability.

BACKGROUND: Obesity is linked to hypercoagulability with an increased risk of venous thromboembolic events (VTE) in the uninjured population. Therefore, we hypothesize that obesity (body mass index [BMI] ≥30 kg/m [BMI30]) is associated with a hypercoagulable state postinjury characterized by increased clot strength and resistance to fibrinolysis. METHODS: Our prospective Trauma Activation Protocol database includes all trauma activations patients for whom a rapid thrombelastography is obtained within 60 minutes postinjury prior to any transfusions. The data set was then stratified by BMI and subjects with BMI30 were compared with those with BMI less than 30 kg/m). The following thrombelastography measurements were obtained: activated clotting time, clot formation rate (angle), maximum clot strength (MA), and % clot lysis 30 minutes after MA (LY30, %). Fibrinolysis shutdown (SD) was defined as LY30 < 0.6% and hyperfibrinolysis (HF) as LY30 greater than 7.6%. Continuous variables are expressed as median (interquartile range). RESULTS: Overall, 687 patients were included of whom 161 (23%) had BMI30. The BMI30 group was older, had a lower proportion of males and of blunt trauma, and was less severely injured. After adjustment for confounders, BMI30 was independently associated with lower odds of MA less than 55 mm (odds ratio [OR], 0.28; 95% confidence interval [CI], 0.13-0.60) and of HF (OR, 0.31; 95% CI, 0.10-0.97) and higher odds of SD (OR, 1.82; 95% CI, 1.09-3.05). No independent association was observed with angle less than 65° (OR 0.57 95% CI 0.30-1.05). While VTEs were more frequent among BMI30 patients (5.0 vs. 3.3%), this did not reach significance after confounding adjustment (p = 0.11). CONCLUSION: Obesity was protective against diminished clot strength and hyperfibrinolysis, and obesity was associated with an increased risk of fibrinolytic SD in severely injured patients. These findings suggest a relative hypercoagulability. Although no difference in VTEs was noted in this study, these findings may explain the higher rate of VTEs reported in other studies. LEVEL OF EVIDENCE: Prognostic and Epidemiological, level III.

Variability in international normalized ratio and activated partial thromboplastin time after injury are not explained by coagulation factor deficits.

BACKGROUND: Conventional coagulation assays (CCAs), prothrombin time (PT)/international normalized ratio (INR) and activated partial thromboplastin time (aPTT), detect clotting factor (CF) deficiencies in hematologic disorders. However, there is controversy about how these CCAs should be used to diagnose, treat, and monitor trauma-induced coagulopathy. Study objectives were to determine whether CCA abnormalities are reflective of deficiencies of coagulation factor activity in the setting of severe injury. METHODS: Patients without previous CF deficiency within a prospective database at an ACS-verified Level I trauma center had CF activity levels, PT/INR, aPTT, and fibrinogen levels measured upon emergency department arrival from 2014 to 2017. Linear regression assessed how CF activity explained the aPTT and PT/INR variation. Prolonged CCA values were set as INR greater than 1.3 and aPTT greater than 34 seconds. CF deficiency was defined as less than 30% activity, except for fibrinogen, defined as less than 150 mg/dL. RESULTS: Sixty patients with a mean age of 35.8 (SD, 13.6) years and median New Injury Severity Score of 32 (interquartile range, 12-43) were included; 53.3% sustained blunt injuries, 23.3% required massive transfusion, and mortality was 11.67%. Overall, 44.6% of the PT/INR variance and 49.5% of the aPTT variance remained unexplained by CF activity. Deficiencies of CFs were: common pathway, 25%; extrinsic pathway, 1.7%; and intrinsic pathway, 6.7%. The positive predictive value for CF deficiencies were: (1) PT/INR greater than 1.3:4.4% for extrinsic pathway, 56.5% for the common pathway; (2) aPTT greater than 34 seconds:16.7% for the intrinsic pathway, 73.7% for the common pathway. CONCLUSION: Almost half of the variances of PT/INR and aPTT were unexplained by CF activity. Prolonged PT/INR and aPTT were poor predictors of deficiencies in the intrinsic or extrinsic pathways; however, they were indicators of common pathway deficiencies. LEVEL OF EVIDENCE: Prognostic, level III.

Trauma Resuscitation Consideration: Sex Matters.

BACKGROUND: Sex dimorphisms in coagulation have been recognized, but whole blood assessment of these dimorphisms and their relationship to outcomes in trauma have not been investigated. This study characterizes the viscoelastic hemostatic profile of severely injured patients by sex, and examines how sex-specific coagulation differences affect clinical outcomes, specifically, massive transfusion (MT) and death. We hypothesized that severely injured females are more hypercoagulable and therefore, have lower rates of MT and mortality. STUDY DESIGN: Hemostatic profiles and clinical outcomes from all trauma activation patients from 2 level I trauma centers were examined, with sex as an experimental variable. As part of a prospective study, whole blood was collected and thrombelastography (TEG) was performed. Coagulation profiles were compared between sexes, and association with MT and mortality were examined. Poisson regression with robust standard errors was performed. RESULTS: Overall, 464 patients (23% female) were included. By TEG, females had a more hypercoagulable profile, with a higher angle (clot propagation) and maximum amplitude (MA, clot strength). Females were less likely to present with hyperfibrinolysis or prolonged activating clotting time than males. In the setting of depressed clot strength (abnormal MA), female sex conferred a survival benefit, and hyperfibrinolysis was associated with higher case-fatality rate in males. CONCLUSIONS: Severely injured females have a more hypercoagulable profile than males. This hypercoagulable status conferred a protective effect against mortality in the setting of diminished clot strength. The mechanism behind these dimorphisms needs to be elucidated and may have treatment implications for sex-specific trauma resuscitation.

Severe traumatic brain injury is associated with a unique coagulopathy phenotype.

BACKGROUND: Traumatic brain injury (TBI) patients present on a spectrum from hypocoagulability to hypercoagulability, depending on the injury complexity, severity, and time since injury. Prior studies have found a unique coagulopathy associated with TBI using conventional coagulation assays such as INR; however, few studies have assessed the association of TBI and coagulopathy using viscoelastic assays that comprehensively evaluate the coagulation in whole blood. This study aims to reevaluate the TBI-specific trauma-induced coagulopathy using arrival thrombelastography. Because brain tissue is high in key procoagulant molecules, we hypothesize that isolated TBI is associated with procoagulant and hypofibrinolytic profiles compared with injuries of the torso, extremities, and polytrauma, including TBI. METHODS: Data are from the prospective Trauma Activation Protocol study. Activated clotting time (ACT), angle, maximum amplitude (MA), 30-minute percent lysis after MA (LY30), and functional fibrinogen levels (FFLEV) were recorded. Patients were categorized into isolated severe TBI (I-TBI), severe TBI with torso and extremity injuries (TBI + TORSO/EXTREMITIES), and isolated torso and extremity injuries (I-TORSO/EXTREMITIES). Poisson regression was used to adjust for multiple confounders. RESULTS: Overall, 572 patients (48 I-TBI, 45 TBI + TORSO/EXTREMITIES, 479 I-TORSO/EXTREMITIES) were included in this analysis. The groups differed in INR, ACT, angle, MA, and FFLEV but not in 30-minute percent lysis. When compared with I-Torso/Extremities, after adjustment for confounders, severe I-TBI was independently associated with ACT less than 128 seconds (relative risk [RR], 1.5; 95% confidence interval [CI], 1.1-2.2), angle less than 65 degrees (RR, 2.2; 95% CI, 1.4-3.6), FFLEV less than 356 (RR, 1.7; 95% CI, 1.2-2.4) but not MA less than 55 mm, hyperfibrinolysis, fibrinolysis shutdown, or partial thromboplastin time (PTT) greater than 30. CONCLUSION: Severe I-TBI was independently associated with a distinct coagulopathy with delayed clot formation but did not appear to be associated with fibrinolysis abnormalities. Low fibrinogen and longer ACT values associated with I-TBI suggest that early coagulation factor replacement may be indicated in I-TBI patients over empiric antifibrinolytic therapy. Mechanisms triggering coagulopathy in TBI are unique and warrant further investigation. LEVEL OF EVIDENCE: Retrospective cohort study, prognostic, level III.

Plasma-first resuscitation to treat haemorrhagic shock during emergency ground transportation in an urban area: a randomised trial.

BACKGROUND: Plasma is integral to haemostatic resuscitation after injury, but the timing of administration remains controversial. Anticipating approval of lyophilised plasma by the US Food and Drug Administration, the US Department of Defense funded trials of prehospital plasma resuscitation. We investigated use of prehospital plasma during rapid ground rescue of patients with haemorrhagic shock before arrival at an urban level 1 trauma centre. METHODS: The Control of Major Bleeding After Trauma Trial was a pragmatic, randomised, single-centre trial done at the Denver Health Medical Center (DHMC), which houses the paramedic division for Denver city. Consecutive trauma patients in haemorrhagic shock (defined as systolic blood pressure [SBP] ≤70 mm Hg or 71-90 mm Hg plus heart rate ≥108 beats per min) were assessed for eligibility at the scene of the injury by trained paramedics. Eligible patients were randomly assigned to receive plasma or normal saline (control). Randomisation was achieved by preloading all ambulances with sealed coolers at the start of each shift. Coolers were randomly assigned to groups 1:1 in blocks of 20 according to a schedule generated by the research coordinators. If the coolers contained two units of frozen plasma, they were defrosted in the ambulance and the infusion started. If the coolers contained a dummy load of frozen water, this indicated allocation to the control group and saline was infused. The primary endpoint was mortality within 28 days of injury. Analyses were done in the as-treated population and by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01838863. FINDINGS: From April 1, 2014, to March 31, 2017, paramedics randomly assigned 144 patients to study groups. The as-treated analysis included 125 eligible patients, 65 received plasma and 60 received saline. Median age was 33 years (IQR 25-47) and median New Injury Severity Score was 27 (10-38). 70 (56%) patients required blood transfusions within 6 h of injury. The groups were similar at baseline and had similar transport times (plasma group median 19 min [IQR 16-23] vs control 16 min [14-22]). The groups did not differ in mortality at 28 days (15% in the plasma group vs 10% in the control group, p=0·37). In the intention-to-treat analysis, we saw no significant differences between the groups in safety outcomes and adverse events. Due to the consistent lack of differences in the analyses, the study was stopped for futility after 144 of 150 planned enrolments. INTERPRETATION: During rapid ground rescue to an urban level 1 trauma centre, use of prehospital plasma was not associated with survival benefit. Blood products might be beneficial in settings with longer transport times, but the financial burden would not be justified in an urban environment with short distances to mature trauma centres. FUNDING: US Department of Defense.