Trauma-Induced Coagulopathy: An Institution's 35 Year Perspective on Practice and Research

Mechanisms of early trauma-induced coagulopathy: The clot thickens or not?

Traumatic-induced coagulopathy (TIC) is a hemostatic disorder that is associated with significant bleeding, transfusion requirements, morbidity and mortality. A disorder similar or analogous to TIC was reported around 70 years ago in patients with shock, hemorrhage, burns, cardiac arrest or undergoing major surgery, and the condition was referred to as a "severe bleeding tendency," "defibrination syndrome," "consumptive disorder," and later by surgeons treating US Vietnam combat casualties as a "diffuse oozing coagulopathy." In 1982, Moore's group termed it the "bloody vicious cycle," others "the lethal triad," and in 2003 Brohi and colleagues introduced "acute traumatic coagulopathy" (ATC). Since that time, early TIC has been cloaked in many names and acronyms, including a "fibrinolytic form of disseminated intravascular coagulopathy (DIC)." A global consensus on naming is urgently required to avoid confusion. In our view, TIC is a dynamic entity that evolves over time and no single hypothesis adequately explains the different manifestations of the coagulopathy. However, early TIC is not DIC because an increased thrombin-generating potential in vitro does not imply a clinically relevant thrombotic state in vivo as early TIC is characterized by excessive bleeding, not thrombosis. DIC with its diffuse anatomopathologic fibrin deposition appears to be a latter phase progression of TIC associated with unchecked inflammation and multiple organ dysfunction.

2014 Consensus conference on viscoelastic test-based transfusion guidelines for early trauma resuscitation: Report of the panel

There has been an increased interest in the use of viscoelastic testing to guide blood product replacement during the acute resuscitation of the injured patient. Currently, no uniformly accepted guidelines exist for how this technology should be integrated into clinical care. In September 2014, an international multidisciplinary group of leaders in the field of trauma coagulopathy and resuscitation was assembled for a 2-day consensus conference in Philadelphia, Pennsylvania. This panel included trauma surgeons, hematologists, blood bank specialists, anesthesiologists, and the lay public.Nine questions regarding the impact of viscoelastic testing in the early resuscitation of trauma patients were developed before the conference by panel consensus. Early use was defined as baseline viscoelastic test result thresholds obtained within the first minutes of hospital arrival-when conventional laboratory results are not available. The available data for each question were then reviewed in person using standardized presentations by the expert panel. A consensus summary document was then developed and reviewed by the panel in an open forum. Finally, a two-round Delphi poll was administered to the panel of experts regarding viscoelastic thresholds for triggering the initiation of specific treatments including fibrinogen, platelets, plasma, and prothrombin complex concentrates. This report summarizes the findings and recommendations of this consensus conference.

Thromboelastography: A Practice Summary for Nurse Practitioners Treating Hemorrhage

Nurse practitioners may manage patients with coagulopathic bleeding which can lead to life-threatening hemorrhage. Routine plasma-based tests such as prothrombin time and activated partial thromboplastin time are inadequate in diagnosing hemorrhagic coagulopathy. Indiscriminate administration of fresh frozen plasma, platelets or cryoprecipitate for coagulopathic states can be extremely dangerous. The qualitative analysis that thromboelastography provides can facilitate the administration of the right blood product, at the right time, thereby permitting the application of goal-directed therapy for coagulopathic intervention application and patient survival.

TACTIC: Trans-Agency Consortium for Trauma-Induced Coagulopathy

Trauma-induced coagulopathy (TIC) includes heterogeneous coagulopathic syndromes with different underlying causes, and treatment is challenged by limited diagnostic tests to discriminate between these entities in the acute setting. We provide an overview of progress in understanding the mechanisms of TIC and the context for several of the hypotheses that will be tested in 'TACTIC'. Although connected to ongoing clinical trials in trauma, TACTIC itself has no intent to conduct clinical trials. We do anticipate that 'early translation' of promising results will occur. Functions anticipated at this early translational level include: (i) basic science groundwork for future therapeutic candidates; (ii) development of acute coagulopathy scoring systems; (iii) coagulation factor composition-based computational analysis; (iv) characterization of novel analytes including tissue factor, polyphosphates, histones, meizothrombin and α-thrombin-antithrombin complexes, factor XIa, platelet and endothelial markers of activation, signatures of protein C activation and fibrinolysis markers; and (v) assessment of viscoelastic tests and new point-of-care methods.

Early hemorrhage triggers metabolic responses that build up during prolonged shock

Metabolic staging after trauma/hemorrhagic shock is a key driver of acidosis and directly relates to hypothermia and coagulopathy. Metabolic responses to trauma/hemorrhagic shock have been assayed through classic biochemical approaches or NMR, thereby lacking a comprehensive overview of the dynamic metabolic changes occurring after shock. Sprague-Dawley rats underwent progressive hemorrhage and shock. Baseline and postshock blood was collected, and late hyperfibrinolysis was assessed (LY30 >3%) in all of the tested rats. Extreme and intermediate time points were collected to assay the dynamic changes of the plasma metabolome via ultra-high performance liquid chromatography-mass spectrometry. Sham controls were used to determine whether metabolic changes could be primarily attributable to anesthesia and supine positioning. Early hemorrhage-triggered metabolic changes that built up progressively and became significant during sustained hemorrhagic shock. Metabolic phenotypes either resulted in immediate hypercatabolism, or late hypercatabolism, preceded by metabolic deregulation during early hemorrhage in a subset of rats. Hemorrhagic shock consistently promoted hyperglycemia, glycolysis, Krebs cycle, fatty acid, amino acid, and nitrogen metabolism (urate and polyamines), and impaired redox homeostasis. Early dynamic changes of the plasma metabolome are triggered by hemorrhage in rats. Future studies will determine whether metabolic subphenotypes observed in rats might be consistently observed in humans and pave the way for tailored resuscitative strategies.

"Smoker's Paradox" in Patients Treated for Severe Injuries: Lower Risk of Mortality After Trauma Observed in Current Smokers

BACKGROUND

Studies evaluating the effect of smoking status on mortality outcomes in trauma patients have been limited, despite the fact that survival benefits of smoking have been reported in other critical care settings. The phenomenon "smoker's paradox" refers to the observation that following acute cardiovascular events, such as acute myocardial infarction and cardiac arrest, smokers often experience decreased mortality in the hospital setting. The objective of our study was to determine whether smoking imparts a survival benefit in patients with traumatic injuries.

METHODS

We performed a retrospective cohort study that analyzed cases included in the National Trauma Data Bank research dataset. Hierarchical logistic regression analyses were used to determine whether smoking alters the risk of mortality and complications in patients who smoke.

RESULTS

The percentage of patients experiencing mortality differed significantly between smokers (n = 38,564) and nonsmokers (n = 319,249) (1.8% vs. 4.3%, P < .001); however, the percentage experiencing a major complication did not (9.7% vs. 9.6%, P = .763). Regression analyses indicated that smokers were significantly less likely to die during the hospital stay compared to nonsmokers after adjusting for individual and hospital factors (OR = 0.15; CI = 0.10, 0.22). Additionally, smokers were also less likely to develop a major complication than nonsmokers (OR = 0.73, CI = 0.59-0.91).

CONCLUSIONS

Patients who smoke appear to have a much lower risk of in-hospital mortality than nonsmokers. Further investigation into biological mechanisms responsible for this effect should be carried out in order to potentially develop therapeutic applications.

Platelet dysfunction in injured patients

A renewed understanding of Trauma Induced Coagulopathy (TIC) has implicated platelets as a crucial mediator and potential therapeutic target in hemostasis. While the importance of abnormal coagulation tests is well described in trauma, there is a paucity of data regarding the role of platelets in coagulopathy. New coagulation models, namely the cell-based-model of hemostasis, have refocused attention toward the platelet and endothelium as key regulators of clot formation. Although platelet dysfunction has been associated with worse outcomes in trauma, the mechanisms which platelet dysfunction contributes to coagulopathy are poorly understood. The goal of this review article is to outline recent advances in understanding hemostasis and the ensuing cellular dysfunction that contributes to the exsanguination of a critically injured patient.

Platelet dysfunction in injured patients

A renewed understanding of Trauma Induced Coagulopathy (TIC) has implicated platelets as a crucial mediator and potential therapeutic target in hemostasis. While the importance of abnormal coagulation tests is well described in trauma, there is a paucity of data regarding the role of platelets in coagulopathy. New coagulation models, namely the cell-based-model of hemostasis, have refocused attention toward the platelet and endothelium as key regulators of clot formation. Although platelet dysfunction has been associated with worse outcomes in trauma, the mechanisms which platelet dysfunction contributes to coagulopathy are poorly understood. The goal of this review article is to outline recent advances in understanding hemostasis and the ensuing cellular dysfunction that contributes to the exsanguination of a critically injured patient.

Thromboelastometric Monitoring of the Hemostatic Effect of Platelet Concentrates Transfusion in Thrombocytopenic Children Undergoing Chemotherapy

Prophylactic platelet concentrates transfusion represents a therapeutic choice in patients with chemotherapy-induced thrombocytopenia. This prospective, non-interventional study evaluated the effects of platelet concentrates transfusion on thromboelastometric parameters of platelet function in 36 transfusion occasions for 11 thrombocytopenic children undergoing chemotherapy. Pre- and posttransfusion (1-2 hours) blood samples were analyzed using standard coagulation tests and thromboelastometry (ROTEM) measurements (EXTEM and FIBTEM tests). Platelet component of the clot was calculated based on the EXTEM and FIBTEM maximum clot elasticity (MCE) results. After transfusion, mean platelet count increased from 16.5 × 10⁹/L to 43.0 × 10⁹/L (P < .001) and platelet component increased from 34.1 to 73.0 (P < .001). Statistically significant increases for posttransfusion EXTEM parameters A10, A20, and maximum clot firmness (MCF) were observed compared to pretransfusion values (P < .001). The EXTEM α-angle values increased posttransfusion (P < .05). The FIBTEM measurements were comparable pre- and posttransfusion. The study showed that platelet concentrates transfusion in thrombocytopenic children undergoing chemotherapy improves platelet-related coagulation pattern.

Creatine kinase inhibits ADP-induced platelet aggregation

Bleeding risk with antiplatelet therapy is an increasing clinical challenge. However, the inter-individual variation in this risk is poorly understood. We assessed whether the level of plasma creatine kinase, the enzyme that utilizes ADP and phosphocreatine to rapidly regenerate ATP, may modulate bleeding risk through a dose-dependent inhibition of ADP-induced platelet activation. Exogenous creatine kinase (500 to 4000 IU/L, phosphocreatine 5 mM) added to human plasma induced a dose-dependent reduction to complete inhibition of ADP-induced platelet aggregation. Accordingly, endogenous plasma creatine kinase, studied in 9 healthy men (mean age 27.9 y, SE 3.3; creatine kinase 115 to 859 IU/L, median 358), was associated with reduced ADP-induced platelet aggregation (Spearman's rank correlation coefficient, -0.6; p < 0.05). After exercise, at an endogenous creatine kinase level of 4664, ADP-induced platelet aggregation was undetectable, normalizing after rest, with a concomitant reduction of creatine kinase to normal values. Thus, creatine kinase reduces ADP-induced platelet activation. This may promote bleeding, in particular when patients use platelet P2Y12 ADP receptor inhibitors.