Rapid TEG efficiently guides hemostatic resuscitation in trauma patients

What, When, and Why: Viscoelastic Hemostatic Assays and Their Uses in Trauma Resuscitation

Viscoelastic hemostatic assays (VHAs) have become a valuable tool in guiding transfusion therapy, particularly in trauma care. While various forms of VHA exist, all provide a quantitative assessment of clot kinetics, strength, and dissolution. Studies have demonstrated that VHA can reduce both mortality and utilization of blood products in the general population. Interpreting VHA results requires consideration of specific patient factors, such as age and altered physiological properties as in pregnancy and the process of aging. Further research is needed to establish accurate reference ranges for these specific populations. This review article provides a comprehensive overview of the technical aspects of VHA as well as their clinical uses in trauma resuscitation.

Trauma patients with type O blood exhibit unique multiomics signature with decreased lectin pathway of complement levels

BACKGROUND

Patients with type O blood may have an increased risk of hemorrhagic complications because of lower baseline levels of von Willebrand factor and factor VIII, but the transition to a mortality difference in trauma is less clear. We hypothesized that type O trauma patients will have differential proteomic and metabolomic signatures in response to trauma beyond von Willebrand factor and factor VIII alone.

METHODS

Patients meeting the highest level of trauma activation criteria were prospectively enrolled. Blood samples were collected upon arrival to the emergency department. Proteomic and metabolomic (multiomics) analyses of these samples were performed using liquid chromatography-mass spectrometry. Demographic, clinical, and multiomics data were compared between patients with type O blood versus all other patients.

RESULTS

There were 288 patients with multiomics data; 146 (51%) had type O blood. Demographics, injury patterns, and initial vital signs and laboratory measurements were not different between groups. Type O patients had increased lengths of stay (7 vs. 6 days, p = 0.041) and a trend toward decreased mortality secondary to traumatic brain injury compared with other causes (traumatic brain injury, 44.4% vs. 87.5%; p = 0.055). Type O patients had decreased levels of mannose-binding lectin and mannose-binding lectin-associated serine proteases 1 and 2, which are required for the initiation of the lectin pathway of complement activation. Type O patients also had metabolite differences signifying energy metabolism and mitochondrial dysfunction.

CONCLUSION

Blood type O patients have a unique multiomics signature, including decreased levels of proteins required to activate the lectin complement pathway. This may lead to overall decreased levels of complement activation and decreased systemic inflammation in the acute phase, possibly leading to a survival advantage, especially in traumatic brain injury. However, this may later impair healing. Future work will need to confirm these associations, and animal studies are needed to test therapeutic targets.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Detection of glycocalyx degradation in real time: A conceptual model of thromboelastography

BACKGROUND

The endothelial glycocalyx is a critical component of the vascular barrier; its disruption after shock states may contribute to coagulopathy in a variety of conditions. Measurement of glycocalyx components in plasma have been used to index glycocalyx degradation but are not available as a point of care test. Heparanoids, such as heparan sulfate, may affect coagulation which may be detected by either thromboelastography or activated clotting time.

METHODS

Endothelial glycocalyx components syndecan-1 and heparan sulfate were added to blood samples at clinically relevant concentrations. Thromboelastography values included clot reaction time, clot amplification and fibrinogen values, and maximum clot strength (maximum amplitude, platelets). The heparinase thromboelastography cartridge was used to detect a heparin-like effect. The activated clotting time test was performed subsequently using the heparan sulfate blood samples to compare a standard coagulation test with thromboelastography clot reaction times.

RESULTS

Both thromboelastography clot reaction time (with comparison to heparinase) and activated clotting time were useful to detect effects of coagulation. Thromboelastography also detected platelet and fibrinogen abnormalities at higher heparan sulfate concentrations. Studies using thromboelastography or even activated clotting time may be useful to detect glycocalyx degradation after shock states and may guide clinical decision making.

CONCLUSION

Thromboelastography and or activated clotting time may be useful to detect glycocalyx degradation as a point of care test in patients in the acute setting. Additionally, these assays may detect previous undisclosed coagulopathy due to glycocalyx degradation.

Detection of Acute Traumatic Coagulopathy by Viscoelastic Haemostatic Assays Compared to Standard Laboratory Tests: A Systematic Review

Introduction

The aim of this systematic review was to investigate whether viscoelastic haemostatic assays (VHAs) offer comparative diagnostic ability of acute traumatic coagulopathy (ATC) compared to the standard laboratory coagulation tests (SLCT). ATC is a complication of major trauma characterized by dysfunctional blood clotting, leading to an increased bleeding risk. Additionally, we aimed to analyse the association of VHA with blood product use and health outcomes.

Methods

The search protocol was pre-published and completed on December 2, 2020, assessing manuscripts from 2000 until the present. We searched MEDLINE, Embase, Cochrane Central, BIOSIS, Emcare, CINAHL, and additional online resources and referenced lists. Included were manuscripts that quantitatively reported the detection of ATC using VHAs and SLCTs. A meta-analysis was undertaken including observational studies that reported on patients with injuries to all body regions and results analysed using a random-effects model and reported using pooled odds ratio with 95% confidence intervals (CI).

Results

There were 14 observational studies and one randomized control trial involving 2,715 participants that satisfied inclusion criteria. We observed significant heterogeneity in the definitions of ATC, study design, setting, and patient population. Among observational studies that reported on patients with injuries to all body regions, VHAs were associated with higher odds of diagnosing ATC compared to SLCT (pooled OR 2.4; 95% CI: 1.4-4.1). There was inadequate evidence to suggest VHAs were associated with reduced blood product usage or lower mortality.

Conclusion

VHAs detected more patients with ATC compared to SLCTs. However, the clinical significance and applicability of this finding remains unknown as translation to management was not adequately reported.

Thromboelastography in the Perioperative Period: A Literature Review

Assessing coagulation status is essential for prompt intervention to reduce morbidity and mortality related to bleeding and thrombotic complications during the perioperative period. Traditional coagulation tests such as platelet count, activated partial thromboplastin time (aPTT), prothrombin time (PT), international normalized ratio (INR), and activated clotting time (ACT) provide only static evaluation. These tests are not designed for assessment of dynamically changing coagulation conditions during the perioperative time. However, viscoelastic coagulation testing such as thromboelastography (TEG) produces a rapid numerical and graphical representation that helps to detect and direct targeted hemostatic therapy. Searching the literature through PubMed, Medline, Ovid, CINAHL, and ClinicalTrials.gov we retrieved 210 studies, which represent the use of TEG in the perioperative period. The included studies were categorized under various settings such as trauma, obstetrics, orthopedics, intensive care unit (ICU), cardiovascular, transplant, and miscellaneous scenarios. TEG showed promising results in trauma surgeries in predicting mortality, hypercoagulability, and bleeding even when it was compared to conventional methods. TEG was also useful in monitoring anticoagulant therapy in orthopedic and obstetric surgeries; however, its role in predicting thrombotic events, hypercoagulability, or complications was questionable. In ICU patients, it showed promising results, especially in the prediction or improvement of sepsis, coagulopathy, thrombotic events, ICU duration, hospital stay, and ventilator duration. TEG parameters effectively predicted hypercoagulation in transplant surgeries. Regarding cardiovascular surgeries, they were effective in the prediction of the need for blood products, coagulopathy, thrombotic events, and monitoring anticoagulation therapy. More randomized clinical trials comparing TEG parameters with standardized tools are needed to produce robust results to standardize its use in different perioperative settings.

Approach to thromboelastography-based transfusion in cirrhosis: An alternative perspective on coagulation disorders

Viscoelastic tests, specifically thromboelastography and rotational thromboelastometry, are increasingly being used in the management of postoperative bleeding in surgical intensive care units (ICUs). However, life-threatening bleeds may complicate the clinical course of many patients admitted to medical ICUs, especially those with underlying liver dysfunction. Patients with cirrhosis have multiple coagulation abnormalities that can lead to bleeding or thrombotic complications. Compared to conventional coagulation tests, a comprehensive depiction of the coagulation process and point-of-care availability are advantages favoring these devices, which may aid physicians in making a rapid diagnosis and instituting early interventions. These tests may help predict bleeding and rationalize the use of blood products in these patients.

How to Clear Polytrauma Patients for Fracture Fixation: Results of a systematic review of the literature

INTRODUCTION

Early patient assessment is relevant for surgical decision making in severely injured patients and early definitive surgery is known to be beneficial in stable patients. The aim of this systematic review is to extract parameters indicative of risk factors for adverse outcome. Moreover, we aim to improve decision making and separate patients who would benefit from early versus staged definitive surgical fixation.

METHODS

Following the PRISMA guidelines, a systematic review of peer-reviewed articles in English or German language published between (2000 and 2022) was performed. The primary outcome was the pathophysiological response to polytrauma including coagulopathy, shock/haemorrhage, hypothermia and soft tissue injury (trauma, brain injury, thoracic and abdominal trauma, and musculoskeletal injury) to determine the treatment strategy associated with the least amount of complications. Articles that had used quantitative parameters to distinguish between stable and unstable patients were summarized. Two authors screened articles and discrepancies were resolved by consensus. Quantitative values for relevant parameters indicative of an unstable polytrauma patient were obtained.

RESULTS

The initial systematic search using MeSH criteria yielded 1550 publications deemed relevant to the following topics (coagulopathy (n = 37), haemorrhage/shock (n = 7), hypothermia (n = 11), soft tissue injury (n = 24)). Thresholds for stable, borderline, unstable and in extremis conditions were defined according to the existing literature as follows: Coagulopathy; International Normalized Ratio (INR) and viscoelastic methods (VEM)/Blood/shock; lactate, systolic blood pressure and haemoglobin, hypothermia; thresholds in degrees Celsius/Soft tissue trauma: traumatic brain injury, thoracic and abdominal trauma and musculoskeletal trauma.

CONCLUSION

In this systematic literature review, we summarize publications by focusing on different pathways that stimulate pathophysiological cascades and remote organ damage. We propose that these parameters can be used for clinical decision making within the concept of safe definitive surgery (SDS) in the treatment of severely injured patients.

The regional whole blood program in San Antonio, TX: A 3-year update on prehospital and in-hospital transfusion practices for traumatic and non-traumatic hemorrhage

Low titer type O Rh-D + whole blood (LTO + WB) has become a first-line resuscitation medium for hemorrhagic shock in many centers around the World. Showing early effectiveness on the battlefield, LTO + WB is used in both the pre-hospital and in-hospital settings for traumatic and non-traumatic hemorrhage resuscitation. Starting in 2018, the San Antonio Whole Blood Collaborative has worked to provide LTO + WB across Southwest Texas, initially in the form of remote damage control resuscitation followed by in-hospital trauma resuscitation. This program has since expanded to include pediatric trauma resuscitation, obstetric hemorrhage, females of childbearing potential, and non-traumatic hemorrhage. The objective of this manuscript is to provide a three-year update on the successes and expansion of this system and outline resuscitation challenges in special populations.

Cryoprecipitate as an alternative to platelet transfusion in thrombocytopenia

Platelet transfusions are not always available for bleeding in severe thrombocytopenia, as storage outside of major centers is limited by their short shelf-life. Data are lacking to support alternative available blood products; however, additional fibrinogen has been shown to enhance clot formation in vitro. To test the hypothesis that cryoprecipitate supplementation could improve clot formation in severe thrombocytopenia, eight hematological malignancy patients with platelet counts under 10 × 109/L each had 10 units of apheresis cryoprecipitate transfused prior to planned prophylactic platelet transfusions. The primary endpoint of thromboelastometry amplitude at 20 min increased by a mean of 5.1 mm (p < 0.01) following cryoprecipitate transfusion despite persisting thrombocytopenia. Thromboelastometry clotting times reduced by a mean of 7.8 s (p < 0.05) and alpha angle increased by a mean of 10.6⁰ (p < 0.01). These results are consistent with cryoprecipitate enhancing the strength of the fibrin/platelet meshwork within the forming thrombus. While platelet transfusion remains the standard of care, where platelet supplies are limited, these data provide a rationale for the use of cryoprecipitate to obtain hemostasis in bleeding thrombocytopenic patients.

Pro-Con Debate: Viscoelastic Hemostatic Assays Should Replace Fixed Ratio Massive Transfusion Protocols in Trauma

Major trauma patients at risk of traumatic coagulopathy are commonly treated with early clotting factor replacement to maintain hemostasis and prevent microvascular bleeding. In the United States, trauma transfusions are often dosed by empiric, low-ratio massive transfusion protocols, which pair plasma and platelets in some ratio relative to the red cells, such as the "1:1:1" combination of 1 units of red cells, 1 unit of plasma, and 1 donor's worth of pooled platelets. Empiric transfusion increases the rate of overtransfusion when unnecessary blood products are administered based on a formula and not on at patient's hemostatic profile. Viscoelastic hemostatic assays (VHAs) are point-of-care hemostatic assays that provided detailed information about abnormal clotting pathways. VHAs are used at many centers to better target hemostatic therapies in trauma. This Pro/Con section will address whether VHA guidance should replace empiric fixed ratio protocols in major trauma.

Clinical Validation of Global Coagulation Tests to Guide Blood Component Transfusions in Cirrhosis and ACLF

BACKGROUND AND AIMS

Patients with cirrhosis and acute-on-chronic liver failure (ACLF) may have bleeding complications and need for invasive procedures. Point-of-care (POC) coagulation tests like thromboelastography (TEG) and Sonoclot may be better for guiding patient management than the standard coagulation tests (SCTs), like prothrombin time, platelet count and international normalized ratio.

METHODS

We prospectively compared and validated the POC tests and SCTs in 70 persons with ACLF and 72 persons with decompensated cirrhosis who had clinical bleeding and checked for episodes of re-bleeding and transfusion requirements. We assessed pre-procedure requirement of blood components when correction was done based on an SCT or POC strategy.

RESULTS

Episodes of bleeding were seen in 45% and 28% of ACLF and cirrhosis patient, respectively (p=0.036), with the major site of bleeding being gastrointestinal (31% and 16%, respectively). Platelet counts correlated with TEG-maximum amplitude in cirrhosis (p=0.045) and prothrombin time correlated positively with TEG-reaction (R) time (p=0.032), TEG-Clot kinetics (K) time (p=0.042), Son-activated clotting time (p=0.038) and negatively with clot rate (p=0.043) in ACLF, making these correctable target variables in POC transfusion algorithms. Of 223 procedures, transfusion of fresh frozen plasma and platelet concentrate was reduced by 25% (p=0.035) and 20.8% (p=0.045) by using a POC strategy in 76 patients. Correction of deranged Son-activated clotting time and TEG-reaction time was noted in 68% and 72% after 24 h of fresh frozen plasma transfusion in ACLF and 85% and 80% in cirrhosis, respectively.

CONCLUSIONS

Our study clinically validates that POC tests can better detect coagulation defects and transfusion thresholds in ACLF and cirrhosis, whereas use of conventional tests appear to be less suitable in patients with clinical bleeding.

TRIAL REGISTRATION

NCT04332484.

Establishment of normal reference intervals in dogs using a viscoelastic point-of-care coagulation monitor and its comparison with thromboelastography

BACKGROUND

Viscoelastic coagulation devices are a useful adjunct to the evaluation of hemostasis in veterinary patients. VCM Vet is a point-of-care device that is simple in operation and could be used to diagnose and trend hemostatic abnormalities in sick patients. VCM Vet does not use activators.

OBJECTIVES

We aimed to establish reference intervals (RIs) for VCM Vet in a healthy adult canine population and concurrently perform thromboelastographic (TEG) analysis on these samples with and without tissue factor (TF) activation for RI comparisons.

METHODS

Duplicate VCM Vet tests were performed immediately upon sample collection. Two concurrent TEG tests were performed on the remaining blood, one citrated, untreated (CU), and one activated with TF at a 1:3600 dilution.

RESULTS

Fifty-two dogs were enrolled in the study. The following RIs were generated for VCM Vet machine 1 and 2, respectively: clot time (CT) (seconds) 163-480 and 172-457; clot formation time (CFT) (seconds) 104-288 and 94-252, α-angle (degrees) 41-65 and 44-66, and maximum clot firmness (MCF) (no units) 27-43 and 30-46. Moderate to good correlations were observed between the two machines with Lin's concordance correlation coefficients of 0.51-0.9 and a P < 0.002. TEG RIs were similar to previously reported values.

CONCLUSIONS

VCM Vet RIs were generated. Each VCM Vet device should have a unique RI established due to inter-device variability. Direct correlations of VCM Vet values with TEG parameters were not performed due to the narrow range of the normal values and the need to evaluate patients with a wide range of hemostatic abnormalities.

Massive Hemorrhage: The Role of Whole Blood Viscoelastic Assays

Viscoelastic whole blood tests are increasingly used to guide hemostatic therapy in bleeding patients in the perioperative, trauma, and obstetric settings. Compared with standard laboratory tests of hemostasis, they have a shorter turnaround time and provide simultaneous information on various aspects of clot formation and lysis. The two available brands TEG (thromboelastography) and ROTEM (rotational thromboelastometry) provide devices that are either manually operated or fully automated. The automation allows for the assays to be used as point-of-care tests increasing their usefulness in massively bleeding patients with rapidly changing hemostatic profiles. While the number of research papers on the subject and the number of published treatment algorithms increase rapidly, the influence of the use of these devices on patient outcome needs yet to be established. In this article, we first review the technology of these devices and the parameters provided by the assays. Next, we present the problems encountered when choosing cut-off values that trigger intervention. Furthermore, we discuss the studies examining their influence on clinical outcomes, and finally, we briefly highlight some of the most important limitations and pitfalls inherent to these assays.

A clinical coagulopathy score concurrent with viscoelastic testing defines opportunities to improve hemostatic resuscitation and enhance blood product utilization during liver transplantation

BACKGROUND

An NIH clinical coagulopathy score has been devised for trauma patients, but no such clinical score exists in transplantation surgery. We hypothesize that that this coagulopathy score can effectively identify laboratory defined coagulopathy during liver transplantation and correlates to blood product utilization.

METHODS

TEGs were performed and coagulopathy scores (1, normal bleeding - 5, diffuse coagulopathic bleeding) were assigned by the surgeons at 5 intra-operative time points. Blood products used during the case were recorded between time points. Statistical analyses were performed to identify correlations between coagulopathy scores, TEG-detected abnormalities, and blood product utilization.

RESULT

Transfusions rarely correlated with the appropriate TEG measurements of coagulation dysfunction. Coagulopathy score had significant correlation to various transfusions and TEG-detected coagulopathies at multiple points during the case. High aggregate coagulopathy scores identified patients receiving more transfusions, re-operations, and longer hospital stays CONCLUSION: The combination of viscoelastic testing and a standardized clinical coagulopathy score has the potential to optimize transfusions if used in tandem as well as standardize communication between surgery and anesthesia teams about clinically evident coagulopathy.

Dense and dangerous: The tissue plasminogen activator-resistant fibrinolysis shutdown phenotype is due to abnormal fibrin polymerization

BACKGROUND

Both hyperfibrinolysis and fibrinolysis shutdown can occur after severe trauma. The subgroup of trauma patients with fibrinolysis shutdown resistant to tissue plasminogen activator (t-PA)-mediated fibrinolysis have increased mortality. Fibrin polymerization and structure may influence fibrinolysis subgroups in trauma, but fibrin architecture has not been characterized in acutely injured subjects. We hypothesized that fibrin polymerization measured in situ will correlate with fibrinolysis subgroups.

METHODS

Blood samples were collected from trauma patients and noninjured controls. We selected samples across a range of fibrinolysis phenotypes (shutdown, physiologic, hyperfibrinolysis) and t-PA sensitivities (sensitive, physiologic, resistant) determined by thrombelastography. Plasma clots were created in situ with fluorescent fibrinogen and imaged using confocal microscopy for analysis of clot architecture in three dimensions. For each clot, we quantified the fiber resolvability, a metric of fiber distinctness or clarity, by mapping the variance of fluorescence intensity relative to background fluorescence. We also determined clot porosity by measuring the size and distribution of the gaps between fibrin fibers in three-dimensional space. We compared these measures across fibrinolysis subgroups.

RESULTS

Fiber resolvability was significantly lower in all trauma subgroups compared with controls (n = 35 and 5, respectively; p < 0.05). We observed markedly different patterns of fibrin architecture among trauma patients stratified by fibrinolysis subgroup. Subjects with t-PA-resistant fibrinolysis shutdown exhibited abnormal, densely packed fibrin clots nearly devoid of pores. Individuals with t-PA-hypersensitive fibrinolysis shutdown had highly irregular clots with pores as large as 2500 μm to 20,000 μm, versus 78 μm to 1250 μm in noninjured controls.

CONCLUSION

Fiber resolvability was significantly lower in trauma patients than controls, and subgroups of fibrinolysis differ in the porosity of the fibrin clot structure. The dense fibrin network in the t-PA-resistant group may prevent access to plasmin, suggesting a mechanism for thrombotic morbidity after injury.

Emergency Transfusions

Successful emergency transfusions require early recognition and activation of resources to minimize treatment delays. The initial goals should focus on replacement of blood in a balanced fashion. There is an ongoing debate regarding the best approach to transfusions, with some advocating for resuscitation with a fixed ratio of blood products and others preferring to use viscoelastic assays to guide transfusions. Whole-blood transfusion also is a debated strategy. Despite these different approaches, it generally is accepted that transfusions should be started early and crystalloid infusions limited. As hemodynamic stability is restored, endpoints of resuscitation should be used to guide the resuscitation.

It's sooner than you think: Blunt solid organ injury patients are already hypercoagulable upon hospital admission - Results of a bi-institutional, prospective study

INTRODUCTION

The optimal time to initiate venous thromboembolism (VTE) chemoprophylaxis in blunt solid organ injury (BSOI) patients is debated. We hypothesize that 1) BSOI patients are hypercoagulable within 12 h of injury and 2) hypercoagulability dominates in patients who develop clot complications (CC).

MATERIAL AND METHODS

This is a prospective study of BSOI patients admitted to two Level-1 Trauma Centers' trauma intensive care units (ICU). Serial kaolin thrombelastography (TEG) and tissue plasminogen activator (tPA)-challenge TEGs were performed. CC included VTE and cerebrovascular accidents.

RESULTS

On ICU admission, all patients (n = 95) were hypercoagulable, 58% were in fibrinolysis shutdown, and 50% of patients were tPA-resistant. Twelve patients (13%) developed CC. Compared to those without CC, they demonstrated decreased fibrinolysis at 12 h and higher clot strength at 48 h CONCLUSIONS: BSOI patients are universally hypercoagulable upon ICU admission. VTE chemoprophylaxis should be started immediately in BSOI patients with hypercoagulability on TEG.

Multiple electrode aggregometry and thromboelastography in thrombocytopenic patients with haematological malignancies

BACKGROUND

In thrombocytopenic patients better assessment of bleeding risk than that provided by platelet count alone is required. Multiplate® aggregometry and thromboelastography (TEG) could be used, but information on their role in such patients is limited. The primary aim of this study was to investigate the feasibility of Multiplate® analyses in patients with haematological malignancies. A secondary aim was to explore whether a multiple logistic regression model combining Multiplate®, TEG, clinical and laboratory variables was associated with risk of bleeding.

MATERIALS AND METHODS

This was an exploratory, prospective observational study of thrombocytopenic patients with haematological malignancies. Total platelet count (TPC), white blood cell count, C-reactive protein (CRP) level, temperature and bleeding status were recorded daily. TEG and Multiplate® analyses with four agonists were performed on weekdays.

RESULTS

Ten patients were enrolled into the study. The median number of days in a study period was 21. Bleeding was observed on 64 of 298 study days. TPC <20×109/L and <10×109/L occurred on 119 and 25 days, respectively. When TPC was <33×109/L, many samples showed no aggregation, regardless of bleeding status. Despite this, the odds of World Health Organization (WHO) grade 2 bleeding decreased significantly as aggregation increased and Multiplate® had a negative predictive value (NPV) of 96% and a positive predictive value (PPV) of 19% for significant bleeding. In the multiple logistic regression model collagen-activated Multiplate® aggregation, TEG angle, TEG reaction time and CRP significantly affected the odds of WHO grade 2 bleeding. The combined model had a NPV of 99% and a PPV of 19%.

DISCUSSION

Our findings suggest that the markers of platelet function and haemostasis provided by Multiplate® aggregometry and TEG may add information to support prediction of bleeding, although platelet count still remains the most accessible analysis for routine testing.

Redefining postinjury fibrinolysis phenotypes using two viscoelastic assays

INTRODUCTION

Fibrinolysis was initially defined using rapid thrombelastography (rTEG). The cutoffs for the pathologic extremes of the fibrinolytic system, hyperfibrinolysis and shutdown, were both defined based on association with mortality. We propose to redefine these phenotypes for both TEG and for rotational thrombelastometry, the other commonly used viscoelastic assay.

METHODS

Rotational thrombelastometry, rTEG, and clinical data were prospectively collected on trauma patients admitted to an urban Level I trauma center from 2010 to 2016. Hyperfibrinolysis was defined as the Youden index from EXTEM-clot lysis index 60 minutes after clotting time (CLI60) and rTEG-fibrinolysis 30 minutes after achieving MA (LY30) for predicting massive transfusion (>10 red blood cell units, or death per 6 hours after injury) as a surrogate for severe bleeding. Patients identified as having hyperfibrinolysis were then removed from the data set, and the cutoff for fibrinolysis shutdown was derived as the optimal cutoff for predicting mortality in the remaining patients.

RESULTS

Overall, 216 patients (median age, 36 years (interquartile range, 27-49 years), 82% men, 58% blunt injury) were included. Of these, 16% required massive transfusion, and 12.5% died. Rapid thrombelastography phenotypes were redefined as hyperfibrinolysis: rTEG-LY30 greater than7.7%, physiologic rTEG-LY30 0.6% to7.6%, and shutdown rTEG-LY30 less than 0.6%. EXTEM-CLI60 fibrinolysis phenotypes were hyperfibrinolysis CLI60 less than 82%, physiologic (CLI60, 82-97.9%), and shutdown (CLI60 > 98%). Weighted kappa statistics revealed moderate agreement between rotational thrombelastometry- and rTEG-defined fibrinolysis (k = 0.51; 95% confidence interval, 0.39-0.63), with disagreement mostly in the shutdown and physiologic categories.

CONCLUSION

We confirmed the U-shaped distribution of death related to fibrinolysis system abnormalities. Both rTEG LY30 and EXTEM CLI60 can identify the spectrum of fibrinolytic phenotypes, have moderate agreement, and can be used to guide hemostatic resuscitation.

LEVEL OF EVIDENCE

Diagnostic study, 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.