Reduced clot strength upon admission, evaluated by thrombelastography (TEG), in trauma patients is independently associated with increased 30-day mortality

Point-of-care, goal-directed management of bleeding in trauma patients

PURPOSE OF REVIEW

The purpose of this review is to consider the clinical value of point-of-care (POC) testing in coagulopathic trauma patients with traumatic brain injury (TBI) and trauma-induced coagulopathy (TIC).

RECENT FINDINGS

Patients suffering from severe TBI or TIC are at risk of developing pronounced haemostatic disorders. Standard coagulation tests (SCTs) are insufficient to reflect the complexity of these coagulopathies. Recent evidence has shown that viscoelastic tests (VETs) identify haemostatic disorders more rapidly and in more detail than SCTs. Moreover, VET results can guide coagulation therapy, allowing individualised treatment, which decreases transfusion requirements. However, the impact of VET on mortality remains uncertain. In contrast to VETs, the clinical impact of POC platelet function testing is still unproven.

SUMMARY

POC SCTs are not able to characterise the complexity of trauma-associated coagulopathy. VETs provide a rapid estimation of underlying haemostatic disorders, thereby providing guidance for haemostatic therapy, which impacts allogenic blood transfusion requirements. The value of POC platelet function testing to identify platelet dysfunction and guide platelet transfusion is still uncertain.

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.

Platelet dysfunction persists after trauma despite balanced blood product resuscitation

BACKGROUND

Platelet activation and aggregation are critical to the initiation of hemostasis after trauma with hemorrhage. Platelet dysfunction is a well-recognized phenomenon contributing to trauma-induced coagulopathy. The goal of this study was to evaluate the timing and severity of platelet dysfunction in massively transfused, traumatically injured patients during the first 72 hours after injury and its association with 30-day survival.

METHODS

A retrospective secondary cohort study of platelet count and function was performed using samples from the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial. Platelet characteristics were measured at 8 timepoints during the first 72 hours of hospitalization and compared between 30-day survivors and nonsurvivors. Platelet counts were assessed via flow cytometry. Platelet function was analyzed with the use of serial thrombelastography and impedance aggregometry with agonists arachidonic acid, adenosine diphosphate, collagen, thrombin receptor activating peptide, and ristocetin.

RESULTS

In total, 680 patients were included for analysis. Platelet counts were significantly lower from baseline to 72 hours after hospital admission with further 1.3 to 2-fold reductions noted in nonsurvivors compared to survivor patients. Platelet aggregation via adenosine diphosphate, arachidonic acid, collagen, thrombin receptor activating peptide, and ristocetin was significantly lower in nonsurvivors at all time points. The nadir of platelet aggregation was 2 to 6 hours after admission with significant improvements in viscoelastic maximum clot formation and agonist-induced aggregation by 12 hours without concomitant improvement in platelet count.

CONCLUSION

Platelet aggregability recovers 12 hours after injury independent of worsening thrombocytopenia. Failure of platelet function to recover portends a poor prognosis.

Hyperfibrinolysis drives mechanical instabilities in a simulated model of trauma induced coagulopathy

INTRODUCTION

Trauma induced coagulopathy (TIC) is common after severe trauma, increasing transfusion requirements and mortality among patients. TIC has several phenotypes, with primary hyperfibrinolysis being among the most lethal. We aimed to investigate the contribution of hypercoagulation, hemodilution, and fibrinolytic activation to the hyperfibrinolytic phenotype of TIC, by examining fibrin formation in a plasma-based model of TIC. We hypothesized that instabilities arising from TIC will be due primarily to increased fibrinolytic activation rather than hemodilution or tissue factor (TF) induced hypercoagulation.

METHODS

The influence of TF, hemodilution, fibrinogen consumption, tissue plasminogen activator (tPA), and the antifibrinolytic tranexamic acid (TXA) on plasma clot formation and structure were examined using rheometry, optical properties, and confocal microscopy. These were then compared to plasma samples from trauma patients at risk of developing TIC.

RESULTS

Combining TF-induced clot formation, 15 % hemodilution, fibrinogen consumption, and tPA-induced fibrinolysis, the clot characteristics and hyperfibrinolysis were consistent with primary hyperfibrinolysis. TF primarily increased fibrin polymerization rates and reduced fiber length. Hemodilution decreased clot optical density but had no significant effect on mechanical clot stiffness. TPA addition induced primary clot lysis as observed mechanically and optically. TXA restored mechanical clot formation but did not restore clot structure to control levels. Patients at risk of TIC showed increased clot formation, and lysis like that of our simulated model.

CONCLUSIONS

This simulated TIC plasma model demonstrated that fibrinolytic activation is a primary driver of instability during TIC and that clot mechanics can be restored, but clot structure remains altered with TXA treatment.

Point-of-care viscoelastic coagulation assessment in healthy dogs during the perianesthetic period

Background

The viscoelastic coagulation monitor (VCM Vet) is a novel, portable device that provides a global assessment of hemostasis. The study aims were to evaluate serial viscoelastic analysis during the perianesthetic period in healthy dogs and to compare the agreement between two VCM Vet devices. Twenty healthy dogs undergoing orthopedic surgery were enrolled. Whole blood samples were collected from an intravenous catheter at four time points: baseline, 15 min after premedication, 60 min after inhalant initiation, and 60 min after inhalant termination. Viscoelastic tests were performed in duplicate on different devices, providing: clot time (CT; seconds), clot formation time (CFT; seconds), alpha angle (α; degrees), amplitude (units) at 10 (A10) and 20 (A20) minutes post clot time, maximum clot firmness (MCF; units), and lysis index (%) at 30 (Li30) and 45 (Li45) minutes post maximum clot formation.

Results

One hundred sixty samples were analyzed. The speed of CT and CFT significantly decreased an average of 25.5 s (95% confidence interval [CI]15.9–35.0) and 6.9 s (95% CI 3.1–10.7) per time point, respectively. There were no significant changes in clot strength or lysis variables. The Bland–Altman style plot shows an acceptable rate of agreement for all variables with intra-class correlation ranging from 0.64–0.94.

Conclusion

The rate of clot formation (CT and CFT) decreased over the perianesthetic period in healthy dogs undergoing surgery. These changes were small and occurred without changes in clot strength or fibrinolysis rate, thus were not clinically relevant. There was clinically acceptable consistency between devices.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03442-x.

Utility of viscoelastic hemostatic assay to guide hemostatic resuscitation in trauma patients: a systematic review

Objective

Viscoelastic hemostatic assay (VHA) provides a graphical representation of a clot’s lifespan and reflects the real time of coagulation. It has been used to guide trauma resuscitation; however, evidence of the effectiveness of VHAs is still limited. This systematic review aims to summarize the published evidence to evaluate the VHA-guided strategy in resuscitating trauma patients.

Methods

The PubMed, Embase, and Web of Science databases were searched from their inception to December 13, 2021. Randomized controlled trials (RCTs) or observational studies comparing VHA-guided transfusion to controls in resuscitating trauma patients were included in this systematic review.

Results

Of the 7743 records screened, ten studies, including two RCTs and eight observational studies, met the inclusion criteria. There was great heterogeneity concerning study design, enrollment criterion, VHA device, VHA-guided strategy, and control strategy. Thrombelastography (TEG) was used as a guiding tool for transfusion in eight studies, and rotational thromboelastometry (ROTEM), and TEG or ROTEM were used in the other two studies. The overall risk of bias assessment was severe or mild in RCTs and was severe or moderate in observational studies. The main outcomes reported from the included studies were blood transfusion (n = 10), mortality (n = 10), hospital length of stay (LOS) (n = 7), intensive care unit LOS (n = 7), and cost (n = 4). The effect of the VHA-guided strategy was not always superior to the control. Most of the studies did not find significant differences in the transfusion amount of red blood cells (n = 7), plasma (n = 5), platelet (n = 7), cryoprecipitate/fibrinogen (n = 7), and mortality (n = 8) between the VHA-guided group and control group. Notable, two RCTs showed that the VHA-guided strategy was superior or equal to the conventional coagulation test-guided strategy in reducing mortality, respectively.

Conclusion

Although some studies demonstrated VHA-guided strategy probable benefit in reducing the need for blood transfusion and mortality when resuscitating trauma patients, the evidence is still not robust. The quality of evidence was primarily downgraded by the limited number of included studies and great heterogeneity and severe risk of bias in these. Further studies are strongly recommended.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13017-022-00454-8.

Proteomics of Coagulopathy Following Injury Reveals Limitations of Using Laboratory Assessment to Define Trauma-Induced Coagulopathy to Predict Massive Transfusion

Objective

Trauma-induced coagulopathy (TIC) is provoked by multiple mechanisms and is perceived to be one driver of massive transfusions (MT). Single laboratory values using prothrombin time (INR) or thrombelastography (TEG) are used to clinically define this complex process. We used a proteomics approach to test whether current definitions of TIC (INR, TEG, or clinical judgement) are sufficient to capture the majority of protein changes associated with MT.

Methods

Eight level-I trauma centers contributed blood samples from patients available early after injury. TIC was defined as INR >1.5 (INR-TIC), TEG maximum amplitude <50mm (TEG-TIC), or clinical judgement (Clin-TIC) by the trauma surgeon. MT was defined as > 10 units of red blood cells in 24 hours or > 4 units RBC/hour during the first 4 hr. SomaLogic proteomic analysis of 1,305 proteins was performed. Pathways associated with proteins dysregulated in patients with each TIC definition and MT were identified.

Results

Patients (n=211) had a mean injury severity score of 24, with a MT and mortality rate of 22% and 12%, respectively. We identified 578 SOMAscan analytes dysregulated among MT patients, of which INR-TIC, TEG-TIC, and Clin-TIC patients showed dysregulation only in 25%, 3%, and 4% of these, respectively. TIC definitions jointly failed to show changes in 73% of the protein levels associated with MT, and failed to identify 26% of patients that received a massive transfusion. INR-TIC and TEG-TIC patients showed dysregulation of proteins significantly associated with complement activity. Proteins dysregulated in Clin-TIC or massive transfusion patients were not significantly associated with any pathway.

Conclusion

These data indicate there are unexplored opportunities to identify patients at risk for massive bleeding. Only a small subset of proteins that are dysregulated in patients receiving MT are statistically significantly dysregulated among patients whose TIC is defined based solely on laboratory measurements or clinical assessment.

Alpha-defensins: risk factor for thrombosis in COVID-19 infection

The inflammatory response to SARS/CoV-2 (COVID-19) infection may contribute to the risk of thromboembolic complications. α-Defensins, antimicrobial peptides released from activated neutrophils, are anti-fibrinolytic and prothrombotic in vitro and in mouse models. In this prospective study of 176 patients with COVID-19 infection, we found that plasma levels of α-defensins were elevated, tracked with disease progression/mortality or resolution and with plasma levels of interleukin-6 (IL-6) and D-dimers. Immunohistochemistry revealed intense deposition of α-defensins in lung vasculature and thrombi. IL-6 stimulated the release of α-defensins from neutrophils, thereby accelerating coagulation and inhibiting fibrinolysis in human blood, imitating the coagulation pattern in COVID-19 patients. The procoagulant effect of IL-6 was inhibited by colchicine, which blocks neutrophil degranulation. These studies describe a link between inflammation and the risk of thromboembolism, and they identify a potential new approach to mitigate this risk in patients with COVID-19 and potentially in other inflammatory prothrombotic conditions.

Trauma-induced coagulopathy

Uncontrolled haemorrhage is a major preventable cause of death in patients with traumatic injury. Trauma-induced coagulopathy (TIC) describes abnormal coagulation processes that are attributable to trauma. In the early hours of TIC development, hypocoagulability is typically present, resulting in bleeding, whereas later TIC is characterized by a hypercoagulable state associated with venous thromboembolism and multiple organ failure. Several pathophysiological mechanisms underlie TIC; tissue injury and shock synergistically provoke endothelial, immune system, platelet and clotting activation, which are accentuated by the 'lethal triad' (coagulopathy, hypothermia and acidosis). Traumatic brain injury also has a distinct role in TIC. Haemostatic abnormalities include fibrinogen depletion, inadequate thrombin generation, impaired platelet function and dysregulated fibrinolysis. Laboratory diagnosis is based on coagulation abnormalities detected by conventional or viscoelastic haemostatic assays; however, it does not always match the clinical condition. Management priorities are stopping blood loss and reversing shock by restoring circulating blood volume, to prevent or reduce the risk of worsening TIC. Various blood products can be used in resuscitation; however, there is no international agreement on the optimal composition of transfusion components. Tranexamic acid is used in pre-hospital settings selectively in the USA and more widely in Europe and other locations. Survivors of TIC experience high rates of morbidity, which affects short-term and long-term quality of life and functional outcome.

The prehospital use of younger age whole blood is associated with an improved arrival coagulation profile

INTRODUCTION

Recent in vitro data have shown that the hemostatic profile of whole blood (WB) degrades significantly after 14 days, yet the optimal storage remains debated. We hypothesized that arrival coagulation studies would be improved in patients receiving younger WB in the prehospital setting.

METHODS

This study was approved by our institutional institutional review board. We evaluated all trauma patients who received prehospital blood products by our helicopter service between July 2017 and July 2019. "Young" WB was defined as 14 days or less. Patients who received at least 1 U of young WB were classified as YOUNG, while the remainder was classified as OLD. Continuous data are presented as medians (25th-75th interquartile range) with comparisons performed using Wilcoxon rank sum. Assessments of clinical hemostatic potential included arrival platelet cell count and rapid thrombelastography. Multivariate regression analysis was also performed (Stata 12.1; College Station, TX).

RESULTS

A total of 220 patients received prehospital WB during the study period. Of these, 153 patients received YOUNG WB, while 67 were transfused only OLD WB units. There were no differences in demographics, prehospital or arrival physiology, or Injury Severity Score among the two groups. The measures of clot initiation (activated clotting time) and kinetics (k time) were improved, as were the measures of clot acceleration/fibrinogen function (angle) and platelet function (maximum amplitude). As well, arrival platelet count was higher in the YOUNG cohort. No significant differences in postarrival transfusion were noted (p = 0.220). Multivariate analysis showed the greatest differences in maximum amplitude and α angle but failed to reach significance.

CONCLUSION

Previous in vitro data have suggested deterioration of platelet function in cold-stored WB after 14 days. The current study demonstrated decreased global hemostasis by clinically available laboratory tests, especially related to fibrinogen and platelet interactions on univariate, but not multivariate analysis. This did not translate into increased transfusion requirements. Further studies are needed to determine the optimal storage duration for cold-stored WB for transfusion in the bleeding trauma patient, as well as rule out the presence of confounding variables.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Physicians' Perceptions of a Situation Awareness-Oriented Visualization Technology for Viscoelastic Blood Coagulation Management (Visual Clot): Mixed Methods Study

Background

Viscoelastic tests enable a time-efficient analysis of coagulation properties. An important limitation of viscoelastic tests is the complicated presentation of their results in the form of abstract graphs with a multitude of numbers. We developed Visual Clot to simplify the interpretation of presented clotting information. This visualization technology applies user-centered design principles to create an animated model of a blood clot during the hemostatic cascade. In a previous simulation study, we found Visual Clot to double diagnostic accuracy, reduce time to decision making and perceived workload, and improve care providers’ confidence.

Objective

This study aimed to investigate the opinions of physicians on Visual Clot technology. It further aimed to assess its strengths, limitations, and clinical applicability as a support tool for coagulation management.

Methods

This was a researcher-initiated, international, double-center, mixed qualitative-quantitative study that included the anesthesiologists and intensive care physicians who participated in the previous Visual Clot study. After the participants solved six coagulation scenarios using Visual Clot, we questioned them about the perceived pros and cons of this new tool. Employing qualitative research methods, we identified recurring answer patterns, and derived major topics and subthemes through inductive coding. Based on them, we defined six statements. The study participants later rated their agreement to these statements on five-point Likert scales in an online survey, which represented the quantitative part of this study.

Results

A total of 60 physicians participated in the primary Visual Clot study. Among these, 36 gave an interview and 42 completed the online survey. In total, eight different major topics were derived from the interview field note responses. The three most common topics were “positive design features” (29/36, 81%), “facilitates decision making” (17/36, 47%), and “quantification not made” (17/36, 47%). In the online survey, 93% (39/42) agreed to the statement that Visual Clot is intuitive and easy to learn. Moreover, 90% (38/42) of the participants agreed that they would like the standard result and Visual Clot displayed on the screen side by side. Furthermore, 86% (36/42) indicated that Visual Clot allows them to deal with complex coagulation situations more quickly.

Conclusions

A group of anesthesia and intensive care physicians from two university hospitals in central Europe considered Visual Clot technology to be intuitive, easy to learn, and useful for decision making in situations of active bleeding. From the responses of these possible future users, Visual Clot appears to constitute an efficient and well-accepted way to streamline the decision-making process in viscoelastic test–based coagulation management.

Comparison of thromboelastography versus conventional coagulation tests in simulated Crotalus atrox envenomation using human blood

INTRODUCTION

Pit viper bites are a source of significant morbidity and mortality. Pit viper bites can cause venom-induced consumptive coagulopathy (VICC), typically evaluated with laboratory-based conventional coagulation tests (CCTs). However, CCTs require a laboratory and average 1 h to conduct. Thromboelastography (TEG) provides real-time, point-of-care tests of coagulation that are fast and require no separate laboratory facilities, which could be advantageous in both hospital and austere settings. However, the relative efficacy of TEG versus CCTs was unclear, particularly at low venom concentrations. Therefore, the objectives of this study were to test human blood with various concentrations of pit viper venom using CCTs and TEG to determine dose-dependent changes, lowest observed effect concentration (LOEC), and sensitivity to detecting samples out of normal diagnostic range.

METHODS

Blood samples from 20 volunteers were mixed with varying concentrations of western diamond back rattlesnake (Crotalus atrox) venom based on the mouse LD50_IV (none, 0.5%, 1%, 2%, 33%, 66%, and 100% LD50_IV). Samples were split and assessed with both CCTs including prothrombin time (PT), international normalized ratio (INR), partial thromboplastin time (PTT), fibrinogen, and D-dimer, along with TEG measures of reaction time (R), kinetic time (K), rate of clot formation (α-angle), and clot strength (MA). Data were analyzed as dose-dependent concentration-based changes in raw values and in percent of samples exceeding diagnostic thresholds using ANOVA and nonparametric statistics at the p < .05 threshold.

RESULTS

All evaluations showed significant concentration-dependent changes, and 100% of samples exceeded diagnostic thresholds at 33%LD50_IV and above, save D-dimer. At 0.5%LD50_IV, R, K, α-angle, PT, and INR were significantly different from controls, and at 1%LD50_IV, mean values exceeded diagnostic thresholds for R, K, α-angle, MA, PT, and INR, but not for PTT, D-dimer, or fibrinogen. At 2%LD50_IV, 100% of samples were out of normal range for K, α-angle, and PT_. CONCLUSION: TEG is effective in coagulopathy evaluations of in vitro simulated pit viper envenomation. At low venom concentrations, TEG performed as well or better than the majority of CCTs. These findings provide empirical evidence supporting the use of TEG to rapidly and accurately evaluate VICC.

Viscoelastic Monitoring to Guide the Correction of Perioperative Coagulopathy and Massive Transfusion in Patients with Life-Threatening Hemorrhage

The resuscitation of patients with traumatic hemorrhage remains a challenging clinical scenario. The appropriate and aggressive support of the patient's coagulation is of critical importance. Conventional coagulation assays present several shortcomings in this setting. The integration of viscoelastic monitoring in clinical practice has the potential to result in significant improvements. In order to be successful, the provider must understand basics of the methodology, read outs, and the limitations of the technique.

The practicalities and barriers of using TEG6s in code red traumas: an observational study in one London major trauma centre

OBJECTIVE

Trauma induced coagulopathy is a disorder of the coagulation pathway that occurs following major trauma. "Code red trauma" require massive hemorrhage protocol activation. The aim was to qualitatively establish the reasons TEG is not currently utilized and the ongoing practicalities in performing a TEG sample for trauma-related massive hemorrhage.

METHODS

A pilot study was performed using a TEG6s machine within one central London Major Trauma Centre's resuscitation department. Staff were asked to run a TEG sample on any "code red" patient who attended during the trial. Staff were given questionnaires both before and after the trial to assess the knowledge around TEG.

RESULTS

A TEG sample was performed in 75% of the sixteen "code red traumas," with one sample being unsuccessful. Only one patient had their blood component management altered due to the TEG result with only 50% of consultants and registrars surveyed feeling confident in interpreting TEG results.

CONCLUSION

TEG6s samples can be run within the resuscitation department in a "code red trauma." However, there is a significant lack of knowledge relating to TEG within the emergency department which is likely to hinder its impact on personalized blood component management. More research is required in how to provide appropriate education in a busy setting to enable TEG to be utilized appropriately.

Thromboelastography-derived parameters for the prediction of acute thromboembolism following non-steroidal anti-inflammatory drug-induced gastrointestinal bleeding: A retrospective study

Efficacy of thromboelastography (TEG)-derived parameters for the prediction of acute thromboembolism (AT) in patients with non-steroidal anti-inflammatory drug (NSAID)-induced gastrointestinal bleeding (GIB) remains to be determined. A retrospective propensity score matching (PSM) study was performed to evaluate this efficacy. Patients with NSAID-induced GIB (98 with AT; 830 without AT) were matched for age, sex and history of cardiovascular and cerebrovascular diseases using PSM. Multivariate logistic regression was used to determine the efficacy of TEG-derived predictors of AT. Mean Decrease Gini (MDG) coefficients were used to rank the importance of the variables from random forest algorithm results. Univariate analysis indicated that the following indexes were significantly different between the two groups: Reaction time (R value), coagulation forming time, solidification angle, maximum amplitude (MA), coagulation index (CI), hemoglobin levels, D-dimer levels, platelet aggregation test (pAgt) results, fibrinogen levels and Acute Physiology and Chronic Health Evaluation II score (all P<0.001). Multifactor logistic regression analysis indicated that the R value (P=0.010), solidification angle (P=0.004), MA (P=0.038), D-dimer levels (P=0.012) and pAgt results (P=0.015) were independent predictors of AT in patients with NSAID-induced GIB, achieving an area under the curve of 0.999 in receiver operating characteristic curve analyses. The five most important parameters according to the MDG scores (MDGS) were: Solidification angle (MDGS=58.14), R value (MDGS=20.42), pAgt results (MDGS=15.61), D-dimer levels (MDGS=12.78) and CI (MDGS=12.61). The results of the present study indicated that TEG-derived parameters including the R value, solidification angle, MA and CI, as well as D-dimer levels and pAgt score were significant predictors of AT in patients with NSAID-induced GIB.

The rate of deep vein thrombosis doubles in trauma patients with hypercoagulable thromboelastography

BACKGROUND

Venous thromboembolism (VTE) in trauma can occur in patients at low risk. Conventional coagulation tests do not predict VTE. Studies investigating thromboelastography (TEG) for VTE risk are conflicting and have not included routine surveillance to detect deep vein thrombosis (DVT). We undertook a prospective study of TEG to evaluate its utility in predicting VTE.

METHODS

We conducted a prospective cohort study on all adult trauma patients admitted to our Level I trauma center from 2013 to 2015. TEG was performed immediately on arrival to the trauma bay. Hypercoagulable TEG was defined as reaction time (R) below, angle (α) above, or maximum amplitude (MA) above reference ranges. All patients received mechanical and/or pharmacologic prophylaxis and were followed up for DVT with our ultrasound surveillance protocol. The primary outcome was lower-extremity DVT. After bivariate analysis of variables related to DVT, those with p values of 0.100 or less were included for multivariate logistic regression.

RESULTS

A total of 983 patients were evaluated with TEG on admission; of these, 684 (69.6%) received at least one surveillance ultrasound during the index admission. Lower-extremity DVT was diagnosed in 99 (14.5%) patients. Hypercoagulability based on admission TEG occurred in 582 (85.1%) patients. The lower-extremity DVT rate was higher in patients with hypercoagulable TEG than in those without hypercoagulable TEG (15.6% vs. 8%; p = 0.039). Multivariate analysis showed hypercoagulable TEG remained associated with DVT after adjustment for relevant covariates available at admission, with an odds ratio of 2.41 (95% confidence interval, 1.11-5.24; p = 0.026).

CONCLUSION

Most trauma patients were hypercoagulable at admission and remained at risk of developing DVT. The rate of DVT doubled in patients with hypercoagulable TEG indices despite prophylaxis. Beyond its current clinical roles, TEG is useful for assessing DVT risk, particularly in patients otherwise perceived to be at low risk.

LEVEL OF EVIDENCE

Prognostic study, level II.

Monitoring the coagulation status of trauma patients with viscoelastic devices

Coagulopathy is a physiological response to massive bleeding that frequently occurs after severe trauma and is an independent predictive factor for mortality. Therefore, it is very important to grasp the coagulation status of patients with severe trauma quickly and accurately in order to establish the therapeutic strategy. Judging from the description in the European guidelines, the importance of viscoelastic devices in understanding the disease condition of patients with traumatic coagulopathy has been widely recognized in Europe. In the USA, the ACS TQIP Massive Transfusion in Trauma Guidelines proposed by the American College of Surgeons in 2013 presented the test results obtained by the viscoelastic devices, TEG® 5000 and ROTEM®, as the standard for transfusion or injection of blood plasma, cryoprecipitate, platelet concentrate, or anti-fibrinolytic agents in the treatment strategy for traumatic coagulopathy and hemorrhagic shock. However, some studies have reported limitations of these viscoelastic devices. A review in the Cochrane Library published in 2015 pointed out the presence of biases in the abovementioned reports in trauma patients and the absence of a quality study in this field thus far. A quality study on the relationship between traumatic coagulopathy and viscoelastic devices is needed.

Pre-hospital transfusion of plasma in hemorrhaging trauma patients independently improves hemostatic competence and acidosis

Background

The early use of blood products has been associated with improved patient outcomes following severe hemorrhage or traumatic injury. We aimed to investigate the influence of pre-hospital blood products (i.e. plasma and/or RBCs) on admission hemostatic properties and patient outcomes. We hypothesized that pre-hospital plasma would improve hemostatic function as evaluated by rapid thrombelastography (rTEG).

Methods

We conducted a prospective observational study recruiting 257 trauma patients admitted to a Level I trauma center having received either blood products pre-hospital or in-hospital within 6 hours of admission. Clinical data on patient demographics, blood biochemistry, injury severity score and mortality were collected. Admission rTEG was conducted to characterize the coagulation profile and hemostatic function.

Results

75 patients received pre-hospital plasma and/or RBCs (PH group; nearly half received both RBCs and plasma) whereas 182 patients only received in-hospital blood products (RBCs, Plasma and Platelets) within 6 hours of admission (IH group). PH patients had lower Glasgow coma scale (GCS) scores, more penetrating injuries, lower systolic blood pressures, lower hemoglobin levels, lower platelet counts and greater acidosis upon ED admission than the IH group (all p < 0.05). Despite differences in type of injury and admission vitals indicating that the PH group had more signs of bleeding than the IH group, there were no significant differences in in-hospital mortality (PH 26.7% vs. IH 20.9% p = 0.31). When comparing rTEG variables between PH patients transfused with 0, 1 or 2 units of plasma, more pre-hospital plasma transfusion was tendency towards improved rTEG variables. When adjusting for pre-hospital RBC, pre-hospital plasma was associated with significantly higher rTEG MA (p = 0.012) at hospital admission.

Discussion

After adjusting for pre-hospital RBCs, pre-hospital plasma transfusion was independently associated with increased rTEG MA, as well as arrival indices of shock and hemodynamic instability. Besides more severe injury and worse clinical presentation, the group that received pre-hospital transfusion had early and late mortality similar to patients not transfused pre-hospital.

Conclusions

These data suggest that early administration of plasma can provide significant hemostatic and potential survival benefit to severely hemorrhaging trauma patients.

Evaluation of acute traumatic coagulopathy in dogs and cats following blunt force trauma

OBJECTIVE

To evaluate the presence of acute traumatic coagulopathy (ATC) in dogs and cats following blunt trauma and to relate coagulation variables with injury severity and admission variables.

DESIGN

Prospective, single center, observational study from 2013 to 2014.

SETTING

Urban private referral hospital.

ANIMALS

Eighteen and 19 client-owned dogs and cats, respectively, sustaining blunt trauma within 8 hours of presentation without prior resuscitation; 17 healthy staff and client-owned control cats METHODS: Blood samples were collected upon presentation for measurement of blood gas, lactate, blood glucose, ionized calcium, PCV, total plasma protein, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, platelet count, and thromboelastography.

RESULTS

ATC was diagnosed in 1 dog and 1 cat on presentation. Hypercoagulability was documented in 4/18 (22%) of dogs and 1/19 (5.3%) of cats. In dogs, prolongation of PT (P = 0.018), aPTT (P = 0.013) and decrease in maximum amplitude (MA) (P = 0.027) were significantly associated with injury severity as measured by the animal trauma triage (ATT) score. In cats, PT, aPTT, MA, and clot strength (G) were not associated with injury severity. In cats, increasing blood glucose and lactate were significantly associated with decreasing MA (P = 0.041, P = 0.031) and G (P = 0.014, P = 0.03). In both dogs (P = 0.002) and cats (P = 0.007), fibrinogen concentration was significantly correlated with G.

CONCLUSIONS

ATC is rare in minimally injured dogs and cats following blunt trauma. In dogs, ATT score is significantly associated with PT, aPTT, and MA, suggesting an increased risk of ATC in more severely injured animals. ATT score does not appear to predict coagulopathies in cats. Future studies including more severely injured animals are warranted to better characterize coagulation changes associated with blunt trauma.

[Early viscoelasticity-based coagulation therapy for severely injured bleeding patients: Report of the consensus group on the consensus conference 2014 for formulation of S2k guidelines]

Although there is increasing interest in the use of a viscoelastic test procedure (ROTEM/TEG) for diagnostics and therapy guidance of severely injured and bleeding patients, currently no uniformly accepted guidelines exist for how this technology should be integrated into clinical treatment. In September 2014 an international multidisciplinary group of opinion leaders in the field of trauma-induced coagulopathy and other disciplines involved in the treatment of severely injured patients were assembled for a 2-day consensus conference in Philadelphia (USA). This panel included trauma/accident surgeons, general/abdominal surgeons, vascular surgeons, emergency/intensive care surgeons, hematologists, transfusion specialists, anesthesiologists, laboratory physicians, pathobiologists/pathophysiologists and the lay public. A total of nine questions regarding the impact of viscoelastic testing in the early treatment of trauma patients were developed prior to the conference by a 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 yet 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 2-round Delphi poll was administered to the panel of experts regarding viscoelastic thresholds for triggering the initiation of specific treatments including fibrinogen (concentrates), platelet concentrates, blood plasma products and prothrombin complex concentrates (PCC). This report summarizes the findings and recommendations of this consensus conference, which correspond to a S2k guideline according to the system of the Association of the Scientific Medical Societies in Germany (AWMF) and taking formal consensus findings including Delphi methods into consideration.

Clot Formation Is Associated With Fibrinogen and Platelet Forces in a Cohort of Severely Injured Emergency Department Trauma Patients

INTRODUCTION

Anticoagulation, fibrinogen consumption, fibrinolytic activation, and platelet dysfunction all interact to produce different clot formation responses after trauma. However, the relative contributions of these coagulation components to overall clot formation remain poorly defined. We examined for sources of heterogeneity in clot formation responses after trauma.

METHODS

Blood was sampled in the emergency department from patients meeting trauma team activation criteria at an urban trauma center. Plasma prothrombin time of 18 s or longer was used to define traumatic coagulopathy. Mean kaolin-activated thrombelastography (TEG) parameters were calculated and tested for heterogeneity using analysis of means. Discriminant analysis and forward stepwise variable selection with linear regression were used to determine if prothrombin time, fibrinogen, platelet contractile force (PCF), and D-dimer concentration, representing key mechanistic components of coagulopathy, each contribute to heterogeneous TEG responses after trauma.

RESULTS

Of 95 subjects, 16% met criteria for coagulopathy. Coagulopathic subjects were more severely injured with greater shock and received more blood products in the first 8 h compared with noncoagulopathic subjects. Mean (SD) TEG maximal amplitude (MA) was significantly decreased in the coagulopathic group (57.5 [SD, 4.7] mm vs. 62.7 [SD, 4.7], t test P < 0.001). The MA also exceeded the ANOM predicted upper decision limit for the noncoagulopathic group and the lower decision limit for the coagulopathic group at α = 0.05, suggesting significant heterogeneity from the overall cohort mean. Fibrinogen and PCF best discriminated TEG MA using discriminant analysis. Fibrinogen, PCF, and D-dimer were primary covariates for TEG MA using regression analysis.

CONCLUSIONS

Heterogeneity in TEG-based clot formation in emergency department trauma patients was linked to changes in MA. Individual parameters representing fibrin polymerization, PCFs, and fibrinolysis were primarily associated with TEG MA after trauma and should be the focus of early hemostatic therapies.

Viscoelastic point-of-care testing to assist with the diagnosis, management and monitoring of haemostasis: a systematic review and cost-effectiveness analysis

BACKGROUND

Patients with substantive bleeding usually require transfusion and/or (re-)operation. Red blood cell (RBC) transfusion is independently associated with a greater risk of infection, morbidity, increased hospital stay and mortality. ROTEM (ROTEM® Delta, TEM International GmbH, Munich, Germany; www.rotem.de), TEG (TEG® 5000 analyser, Haemonetics Corporation, Niles, IL, USA; www.haemonetics.com) and Sonoclot (Sonoclot® coagulation and platelet function analyser, Sienco Inc., Arvada, CO) are point-of-care viscoelastic (VE) devices that use thromboelastometry to test for haemostasis in whole blood. They have a number of proposed advantages over standard laboratory tests (SLTs): they provide a result much quicker, are able to identify what part of the clotting process is disrupted, and provide information on clot formation over time and fibrinolysis.

OBJECTIVES

This assessment aimed to assess the clinical effectiveness and cost-effectiveness of VE devices to assist with the diagnosis, management and monitoring of haemostasis disorders during and after cardiac surgery, trauma-induced coagulopathy and post-partum haemorrhage (PPH).

METHODS

Sixteen databases were searched to December 2013: MEDLINE (OvidSP), MEDLINE In-Process and Other Non-Indexed Citations and Daily Update (OvidSP), EMBASE (OvidSP), BIOSIS Previews (Web of Knowledge), Science Citation Index (SCI) (Web of Science), Conference Proceedings Citation Index (CPCI-S) (Web of Science), Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment (HTA) database, Latin American and Caribbean Health Sciences Literature (LILACS), International Network of Agencies for Health Technology Assessment (INAHTA), National Institute for Health Research (NIHR) HTA programme, Aggressive Research Intelligence Facility (ARIF), Medion, and the International Prospective Register of Systematic Reviews (PROSPERO). Randomised controlled trials (RCTs) were assessed for quality using the Cochrane Risk of Bias tool. Prediction studies were assessed using QUADAS-2. For RCTs, summary relative risks (RRs) were estimated using random-effects models. Continuous data were summarised narratively. For prediction studies, the odds ratio (OR) was selected as the primary effect estimate. The health-economic analysis considered the costs and quality-adjusted life-years of ROTEM, TEG and Sonoclot compared with SLTs in cardiac surgery and trauma patients. A decision tree was used to take into account short-term complications and longer-term side effects from transfusion. The model assumed a 1-year time horizon.

RESULTS

Thirty-one studies (39 publications) were included in the clinical effectiveness review. Eleven RCTs (n=1089) assessed VE devices in patients undergoing cardiac surgery; six assessed thromboelastography (TEG) and five assessed ROTEM. There was a significant reduction in RBC transfusion [RR 0.88, 95% confidence interval (CI) 0.80 to 0.96; six studies], platelet transfusion (RR 0.72, 95% CI 0.58 to 0.89; six studies) and fresh frozen plasma to transfusion (RR 0.47, 95% CI 0.35 to 0.65; five studies) in VE testing groups compared with control. There were no significant differences between groups in terms of other blood products transfused. Continuous data on blood product use supported these findings. Clinical outcomes did not differ significantly between groups. There were no apparent differences between ROTEM or TEG; none of the RCTs evaluated Sonoclot. There were no data on the clinical effectiveness of VE devices in trauma patients or women with PPH. VE testing was cost-saving and more effective than SLTs. For the cardiac surgery model, the cost-saving was £43 for ROTEM, £79 for TEG and £132 for Sonoclot. For the trauma population, the cost-savings owing to VE testing were more substantial, amounting to per-patient savings of £688 for ROTEM compared with SLTs, £721 for TEG, and £818 for Sonoclot. This finding was entirely dependent on material costs, which are slightly higher for ROTEM. VE testing remained cost-saving following various scenario analyses.

CONCLUSIONS

VE testing is cost-saving and more effective than SLTs, in both patients undergoing cardiac surgery and trauma patients. However, there were no data on the clinical effectiveness of Sonoclot or of VE devices in trauma patients.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005623.

FUNDING

The NIHR Health Technology Assessment programme.

Assessment of Haemostasis in Disseminated Intravascular Coagulation by Use of Point-of-Care Assays and Routine Coagulation Tests, in Critically Ill Patients; A Prospective Observational Study

Background

Disseminated intravascular coagulopathy (DIC) relates to the consumption of coagulation factors and platelets with bleeding and micro thrombosis events.

Aim

The aim of this study was to compare haemostasis parameters in critically ill patients with DIC versus patients without DIC, and in survivors versus non-survivors over time. Correlations between the DIC-score, the degree of organ failure and the haemostasis were assessed.

Method

Patients admitted to the intensive care unit with a condition known to be associated with DIC and with an expected length of stay of >3 days were included. Routine laboratory tests, prothrombin time, activated partial thromboplastin time, platelet count, fibrinogen concentration and D-dimer were measured. Coagulation and platelet function were assessed with two point-of-care devices; Multiplate and ROTEM. DIC scores were calculated according to the International Society on Thrombosis and Haemostasis and Japanese Association for Acute Medicine.

Results

Blood was sampled on days 0–1, 2–3 and 4–10 from 136 patients with mixed diagnoses during 290 sampling events. The point-of-care assays indicated a hypocoagulative response (decreased platelet aggregation and reduced clot strength) in patients with DIC and, over time, in non-survivors compared to survivors. Patients with DIC as well as non-survivors had decreased fibrinolysis as shown by ROTEM. DIC scores were higher in non-survivors than in survivors.

Conclusions

Patients with DIC displayed signs of a hypocoagulative response and impaired fibrinolysis, which was also evident over time in non-survivors. Patients with DIC had a higher mortality rate than non-DIC patients, and DIC scores were higher in non-survivors than in survivors.

Coagulopathy and transfusion therapy in pediatric liver transplantation

Bleeding and coagulopathy are critical issues complicating pediatric liver transplantation and contributing to morbidity and mortality in the cirrhotic child. The complexity of coagulopathy in the pediatric patient is illustrated by the interaction between three basic models. The first model, "developmental hemostasis", demonstrates how a different balance between pro- and anticoagulation factors leads to a normal hemostatic capacity in the pediatric patient at various ages. The second, the "cell based model of coagulation", takes into account the interaction between plasma proteins and cells. In the last, the concept of "rebalanced coagulation" highlights how the reduction of both pro- and anticoagulation factors leads to a normal, although unstable, coagulation profile. This new concept has led to the development of novel techniques used to analyze the coagulation capacity of whole blood for all patients. For example, viscoelastic methodologies are increasingly used on adult patients to test hemostatic capacity and to guide transfusion protocols. However, results are often confounding or have limited impact on morbidity and mortality. Moreover, data from pediatric patients remain inadequate. In addition, several interventions have been proposed to limit blood loss during transplantation, including the use of antifibrinolytic drugs and surgical techniques, such as the piggyback and lowering the central venous pressure during the hepatic dissection phase. The rationale for the use of these interventions is quite solid and has led to their incorporation into clinical practice; yet few of them have been rigorously tested in adults, let alone in children. Finally, the postoperative period in pediatric cohorts of patients has been characterized by an enhanced risk of hepatic vessel thrombosis. Thrombosis in fact remains the primary cause of early graft failure and re-transplantation within the first 30 d following surgery, and it occurs despite prolongation of standard coagulation assays. Data, however, are currently lacking regarding the use of anti-aggregation/anticoagulation therapies and how to best monitor for thrombosis in the early postoperative period in pediatric patients. Therefore, further studies are necessary to elucidate the interaction between the development of the coagulation system and cirrhosis in children. Moreover, strategies to optimize blood transfusion and anticoagulation must be tested specifically in pediatric patients. In conclusion, data from the adult world can be translated with difficulty into the pediatric field as indication for transplantation, baseline pathologies and levels of pro- and anticoagulation factors are not comparable between the two populations.

Diversity in clinical management and protocols for the treatment of major bleeding trauma patients across European level I Trauma Centres

Background

Uncontrolled haemorrhage is still the leading cause of preventable death after trauma and the primary focus of any treatment strategy should be related to early detection and control of blood loss including haemostasis.

Methods

For assessing management practices across six European level I trauma centres with academic interest and research in the field of coagulopathy an online survey was conducted addressing local management practice for bleeding trauma patients including algorithms for detection, management and monitoring coagulation disorders and immediate interventions. Each centre provided their locally applied massive transfusion protocol.

Results

All participating trauma centres have developed and implemented a local algorithm and protocol for the bleeding trauma patient. These are uniformly activated by clinical triggers and deactivated once the bleeding has stopped according to clinical assessment in combination with laboratory signs of achieved haemostasis. The severity of coagulopathy and shock is mostly assessed via standard coagulation tests and partially used extended viscoelastic tests. All centres have implemented the immediate use of tranexamic acid. Initial resuscitation is started either pre-hospital or after hospital admission by using transfusion packages with pre-fixed universal blood product combinations and ratios following the concept of “damage control resuscitation” at which applied ratios substantially vary. Two centres initially start with transfusion packages but with viscoelastic tests running in parallel to quickly allow a shift towards a viscoelastic test-guided therapy.

Conclusion

Diversity in the management of bleeding trauma patients such as pre-hospital blood administration and routinely performed viscoelastic tests exists even among level I trauma centres. The paucity of consensus among these centres highlights the need for further primary research followed by clinical trials to improve the evidence for sophisticated guidelines and strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13049-015-0147-6) contains supplementary material, which is available to authorized users.

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 (TEG) and rotational thromboelastometry (ROTEM) for trauma induced coagulopathy in adult trauma patients with bleeding

BACKGROUND

Trauma-induced coagulopathy (TIC) is a disorder of the blood clotting process that occurs soon after trauma injury. A diagnosis of TIC on admission is associated with increased mortality rates, increased burdens of transfusion, greater risks of complications and longer stays in critical care. Current diagnostic testing follows local hospital processes and normally involves conventional coagulation tests including prothrombin time ratio/international normalized ratio (PTr/INR), activated partial prothrombin time and full blood count. In some centres, thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are standard tests, but in the UK they are more commonly used in research settings.

OBJECTIVES

The objective was to determine the diagnostic accuracy of thromboelastography (TEG) and rotational thromboelastometry (ROTEM) for TIC in adult trauma patients with bleeding, using a reference standard of prothrombin time ratio and/or the international normalized ratio.

SEARCH METHODS

We ran the search on 4 March 2013. Searches ran from 1970 to current. We searched The Cochrane Library, MEDLINE (OvidSP), EMBASE Classic and EMBASE, eleven other databases, the web, and clinical trials registers. The Cochrane Injuries Group's specialised register was not searched for this review as it does not contain diagnostic test accuracy studies. We also screened reference lists, conducted forward citation searches and contacted authors.

SELECTION CRITERIA

We included all cross-sectional studies investigating the diagnostic test accuracy of TEG and ROTEM in patients with clinically suspected TIC, as well as case-control studies. Participants were adult trauma patients in both military and civilian settings. TIC was defined as a PTr/INR reading of 1.2 or greater, or 1.5 or greater.

DATA COLLECTION AND ANALYSIS

We piloted and performed all review stages in duplicate, including quality assessment using the QUADAS-2 tool, adhering to guidance in the Cochrane Handbook for Diagnostic Test Accuracy Reviews. We analysed sensitivity and specificity of included studies narratively as there were insufficient studies to perform a meta-analysis.

MAIN RESULTS

Three studies were included in the final analysis. All three studies used ROTEM as the test of global haemostatic function, and none of the studies used TEG. Tissue factor-activated assay EXTEM clot amplitude (CA) was the focus of the accuracy measurements in blood samples taken near to the point of admission. These CAs were not taken at a uniform time after the start of the coagulopathic trace; the time varied from five minutes, to ten minutes and fifteen minutes. The three included studies were conducted in the UK, France and Afghanistan in both civilian and military trauma settings. In two studies, median Injury Severity Scores were 12, inter-quartile range (IQR) 4 to 24; and 22, IQR 12 to 34; and in one study the median New Injury Severity Score was 34, IQR 17 to 43.There were insufficient included studies examining each of the three ROTEM CAs at 5, 10 and 15 minutes to make meta-analysis and investigation of heterogeneity valid. The results of the included studies are thus reported narratively and illustrated by a forest plot and results plotted on the receiver operating characteristic (ROC) plane.For CA5 the accuracy results were sensitivity 70% (95% CI 47% to 87%) and specificity 86% (95% CI 82% to 90%) for one study, and sensitivity 96% (95% CI 88% to 100%) and specificity 58% (95% CI 44% to 72%) for the other.For CA10 the accuracy results were sensitivity 100% (95% CI 94% to 100%) and specificity 70% (95% CI 56% to 82%).For CA15 the accuracy results were sensitivity 88% (95% CI 69% to 97%) and specificity 100% (95% CI 94% to 100%).No uninterpretable ROTEM study results were mentioned in any of the included studies.Risk of bias and concerns around applicability of findings was low across all studies for the patient and flow and timing domains. However, risk of bias and concerns around applicability of findings for the index test domain was either high or unclear, and the risk of bias for the reference standard domain was high. This raised concerns around the interpretation of the sensitivity and specificity results of the included studies, which may be misleading.

AUTHORS' CONCLUSIONS

We found no evidence on the accuracy of TEG and very little evidence on the accuracy of ROTEM. The value of accuracy estimates are considerably undermined by the small number of included studies, and concerns about risk of bias relating to the index test and the reference standard. We are unable to offer advice on the use of global measures of haemostatic function for trauma based on the evidence on test accuracy identified in this systematic review. This evidence strongly suggests that at present these tests should only be used for research. We consider more thoroughly what this research could be in the Discussion section.

Transfusion therapy in paediatric trauma patients: a review of the literature

Haemorrhage is a leading cause of death in paediatric trauma patients. Predefined massive transfusion protocols (MTP) have the potential to significantly reduce mortality by treating haemorrhagic shock and coagulopathy, in adhering to the principles of haemostatic resuscitation with rapid administration of balanced ratios of packed red blood cells (RBC), fresh frozen plasma (FFP) and platelets (PLT).

Because of their substantial physiological reserve, initial vital signs may not be good predictors of early haemorrhage in paediatric patients. Determining the triggers for MTP activation in paediatric trauma patients is challenging, and the optimal blood product ratio that will increase survival in massively bleeding paediatric trauma patients has yet to be determined. To date, only a few small descriptive studies and case reports have investigated the use of predefined MTP in paediatric trauma patients.

MTP with increased FFP or PLT to RBC ratios combined with viscoelastic haemostatic assay (VHA) guided haemostatic resuscitation have not yet been tested in paediatric populations but based on results from adult trauma patients, this therapeutic approach seems promising.

Considering the high prevalence of early coagulopathy in paediatric trauma patients, immediate identification and implementation of VHA-directed treatment of traumatic coagulopathy could ensure faster haemostasis and thereby, potentially, reduce bleeding as well as the total transfusion requirements and further improve outcome in paediatric trauma patients. Prospective randomized trials investigating this therapeutic approach in paediatric trauma patients are highly warranted.

Assays of different aspects of haemostasis - what do they measure?

Haemostasis is a complex process affected by many factors including both cellular and plasma components. It is a multistep process starting with platelet adhesion to damaged endothelium and ending in clot fibrinolysis. There are several methods available to study different aspects of haemostasis including adhesion, aggregation, coagulation and fibrinolysis. This review describes the different methods, what aspects of haemostasis they measure and their limitations. Methods discussed include methods to study adhesion (e.g. PFA-100, cone and platelet(let) analyzer and perfusion chambers) and aggregation (e.g. Multiplate, VerifyNow and Plateletworks). Furthermore the principles behind viscoelastic haemostatic assays are presented as well as methods that can analyse aspects of haemostasis in plasma or platelet-rich-plasma samples (thrombin generation, overall haemostasis potential and Thrombodynamics Analyzer).

A high throughput array microscope for the mechanical characterization of biomaterials

In the last decade, the emergence of high throughput screening has enabled the development of novel drug therapies and elucidated many complex cellular processes. Concurrently, the mechanobiology community has developed tools and methods to show that the dysregulation of biophysical properties and the biochemical mechanisms controlling those properties contribute significantly to many human diseases. Despite these advances, a complete understanding of the connection between biomechanics and disease will require advances in instrumentation that enable parallelized, high throughput assays capable of probing complex signaling pathways, studying biology in physiologically relevant conditions, and capturing specimen and mechanical heterogeneity. Traditional biophysical instruments are unable to meet this need. To address the challenge of large-scale, parallelized biophysical measurements, we have developed an automated array high-throughput microscope system that utilizes passive microbead diffusion to characterize mechanical properties of biomaterials. The instrument is capable of acquiring data on twelve-channels simultaneously, where each channel in the system can independently drive two-channel fluorescence imaging at up to 50 frames per second. We employ this system to measure the concentration-dependent apparent viscosity of hyaluronan, an essential polymer found in connective tissue and whose expression has been implicated in cancer progression.

Thromboelastometry and organ failure in trauma patients: a prospective cohort study

INTRODUCTION

Data on the incidence of a hypercoagulable state in trauma, as measured by thromboelastometry (ROTEM), is limited and the prognostic value of hypercoagulability after trauma on outcome is unclear. We aimed to determine the incidence of hypercoagulability after trauma, and to assess whether early hypercoagulability has prognostic value on the occurrence of multiple organ failure (MOF) and mortality.

METHODS

This was a prospective observational cohort study in trauma patients who met the highest trauma level team activation. Hypercoagulability was defined as a G value of ≥ 11.7 dynes/cm(2) and hypocoagulability as a G value of <5.0 dynes/cm(2). ROTEM was performed on admission and 24 hours later.

RESULTS

A total of 1,010 patients were enrolled and 948 patients were analyzed. Median age was 38 (interquartile range (IQR) 26 to 53), 77% were male and median injury severity score was 13 (IQR 8 to 25). On admission, 7% of the patients were hypercoagulable and 8% were hypocoagulable. Altogether, 10% of patients showed hypercoagulability within the first 24 hours of trauma. Hypocoagulability, but not hypercoagulability, was associated with higher sequential organ failure assessment scores, indicating more severe MOF. Mortality in patients with hypercoagulability was 0%, compared to 7% in normocoagulable and 24% in hypocoagulable patients (P <0.001). EXTEM CT, alpha and G were predictors for occurrence of MOF and mortality.

CONCLUSIONS

The incidence of a hypercoagulable state after trauma is 10% up to 24 hours after admission, which is broadly comparable to the rate of hypocoagulability. Further work in larger studies should define the clinical consequences of identifying hypercoagulability and a possible role for very early, targeted use of anticoagulants.

Platelet aggregation following trauma: a prospective study

We aimed to elucidate platelet function in trauma patients, as it is pivotal for hemostasis yet remains scarcely investigated in this population. We conducted a prospective observational study of platelet aggregation capacity in 213 adult trauma patients on admission to an emergency department (ED). Inclusion criteria were trauma team activation and arterial cannula insertion on arrival. Blood samples were analyzed by multiple electrode aggregometry initiated by thrombin receptor agonist peptide 6 (TRAP) or collagen using a Multiplate device. Blood was sampled median 65 min after injury; median injury severity score (ISS) was 17; 14 (7%) patients received 10 or more units of red blood cells in the ED (massive transfusion); 24 (11%) patients died within 28 days of trauma: 17 due to cerebral injuries, four due to exsanguination, and three from other causes. No significant association was found between aggregation response and ISS. Higher TRAP values were associated with death due to cerebral injuries (P < 0.01, when corrected for ISS and platelet counts), whereas lower platelet counts were associated with massive transfusion (P < 0.01, when corrected for ISS and aggregation). An aggregation value of 145 IU by TRAP significantly identified death due to cerebral injury (sensitivity 71% and specificity 76%, P < 0.01) by receiver operating characteristic-curve analysis; the corresponding value of platelet counts for massive transfusion was 189 × 10/l (sensitivity 86%, specificity 75%, P < 0.01). We concluded there was no simple relationship between platelet aggregation and injury severity. Our results indicate that high platelet aggregation values are associated with fatality of cerebral injury.

How I treat patients with massive hemorrhage

Massive hemorrhage is associated with coagulopathy and high mortality. The transfusion guidelines up to 2006 recommended that resuscitation of massive hemorrhage should occur in successive steps using crystalloids, colloids, and red blood cells (RBCs) in the early phase and plasma and platelets in the late phase. With the introduction of the cell-based model of hemostasis in the mid-1990s, our understanding of the hemostatic process and of coagulopathy has improved. This has contributed to a change in resuscitation strategy and transfusion therapy of massive hemorrhage along with an acceptance of the adequacy of whole blood hemostatic tests to monitor these patients. Thus, in 2005, a strategy aiming at avoiding coagulopathy by proactive resuscitation with blood products in a balanced ratio of RBC:plasma:platelets was introduced, and this has been reported to be associated with reduced mortality in observational studies. Concurrently, whole blood viscoelastic hemostatic assays have gained acceptance by allowing a rapid and timely identification of coagulopathy along with enabling an individualized, goal-directed transfusion therapy. These strategies joined together seem beneficial for patient outcome, although final evidence on outcome from randomized controlled trials are lacking. We present how we in Copenhagen and Houston, today, manage patients with massive hemorrhage.

Effect of thromboelastography (TEG®) and rotational thromboelastometry (ROTEM®) on diagnosis of coagulopathy, transfusion guidance and mortality in trauma: descriptive systematic review

Introduction

The understanding of coagulopathies in trauma has increased interest in thromboelastography (TEG®) and thromboelastometry (ROTEM®), which promptly evaluate the entire clotting process and may guide blood product therapy. Our objective was to review the evidence for their role in diagnosing early coagulopathies, guiding blood transfusion, and reducing mortality in injured patients.

Methods

We considered observational studies and randomized controlled trials (MEDLINE, EMBASE, and Cochrane databases) to February 2014 that examined TEG®/ROTEM® in adult trauma patients. We extracted data on demographics, diagnosis of early coagulopathies, blood transfusion, and mortality. We assessed methodologic quality by using the Newcastle-Ottawa scale (NOS) for observational studies and QUADAS-2 tool for diagnostic accuracy studies.

Results

Fifty-five studies (12,489 patients) met inclusion criteria, including 38 prospective cohort studies, 15 retrospective cohort studies, two before-after studies, and no randomized trials. Methodologic quality was moderate (mean NOS score, 6.07; standard deviation, 0.49). With QUADAS-2, only three of 47 studies (6.4%) had a low risk of bias in all domains (patient selection, index test, reference standard and flow and timing); 37 of 47 studies (78.8%) had low concerns regarding applicability. Studies investigated TEG®/ROTEM® for diagnosis of early coagulopathies (n = 40) or for associations with blood-product transfusion (n = 25) or mortality (n = 24). Most (n = 52) were single-center studies. Techniques examined included rapid TEG® (n =12), ROTEM® (n = 18), TEG® (n = 23), or both TEG® and rapid TEG® (n = 2). Many TEG®/ROTEM® measurements were associated with early coagulopathies, including some (hypercoagulability, hyperfibrinolysis, platelet dysfunction) not assessed by routine screening coagulation tests. Standard measures of diagnostic accuracy were inconsistently reported. Many abnormalities predicted the need for massive transfusion and death, but predictive performance was not consistently superior to routine tests. One observational study suggested that a ROTEM®-based transfusion algorithm reduced blood-product transfusion, but TEG®/ROTEM®-based resuscitation was not associated with lower mortality in most studies.

Conclusions

Limited evidence from observational data suggest that TEG®/ROTEM® tests diagnose early trauma coagulopathy and may predict blood-product transfusion and mortality in trauma. Effects on blood-product transfusion, mortality, and other patient-important outcomes remain unproven in randomized trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0518-9) contains supplementary material, which is available to authorized users.

Trauma induced hypercoagulablity in pediatric patients

PURPOSE

Coagulation changes in pediatric trauma patients are not well defined. To fill this gap, we tested the hypothesis that trauma evokes a hypercoagulable response.

METHODS

A prospective observational study was conducted in hospitalized patients (age 8months to 14years) admitted for trauma or elective surgery. Informed consent was obtained from the parents and informed assent was obtained in patients 7years of age or older. Coagulation changes were evaluated on fresh whole blood using thromboelastography (TEG) and on stored plasma using assays for special clotting factors.

RESULTS

Forty three patients (22 trauma, median injury severity score =9; and 21 uninjured controls) were evaluated. For trauma vs control, prothrombin time (PT) was higher by about 10% (p<0.001), but activated partial thromboplastin time was not altered. TEG clotting time (R;p=0.005) and fibrin cross-linking were markedly accelerated (K time, alpha angle; p<0.001) relative to the control patients. d-Dimer, Prothrombin Fragment 1+2, and Plasminogen Activator Inhibitor-1 were all elevated, whereas Protein S activity was reduced (all p<0.01). Importantly, a large fraction of TEG values and clotting factor assays in the pediatric control group were outside the published reference ranges for adults.

CONCLUSION

A hypercoagulable state is associated with minor trauma in children. More work is needed to determine the functional significance of these changes and to establish normal pediatric reference ranges.

Hemostatic function and transfusion efficacy of apheresis platelet concentrates treated with gamma irradiation in use for thrombocytopenic patients

BACKGROUND

During the transfusion of blood components, the transfer of allogeneic donor white blood cells (WBCs) can mediate transfusion-associated graft-versus-host disease (TA-GVHD). To minimize the reaction, exposure of blood products to gamma irradiation is currently the standard of care. The aim of our study was to evaluate and compare hemostatic function, transfusion efficacy, and safety of gamma-irradiated single-donor apheresis platelet concentrates (PCs) and of conventional non-irradiated PCs in patients with chemotherapy-induced thrombocytopenia.

METHODS

20 double-dose single-donor leukoreduced PCs were split in two identical units; one was gamma-irradiated with 25 Gy (study arm A) and the other remains non-irradiated (study arm B). Both units were stored under equal conditions. Hematologic patients were randomly assigned to receive gamma-irradiated or conventional non-irradiated PCs. Hemostatic function was evaluated by thrombelastography (TEG). TEG measurements were taken pre transfusion and 1 and 24 h post transfusion. TEG profiles were measured, noting the time to initiate clotting (R), the angle of clot formation (α), and the maximum amplitude (clot strength (MA)). Whole blood samples were collected from these thrombocytopenic patients at 1 and 24 h for PLT count increments (CIs) and corrected count increments (CCIs) with assessments of transfusion efficacy. Time to next PLT transfusion, transfusion requirement of RBCs, active bleeding, and adverse events (AEs), were analyzed.

RESULTS

No differences could be found in hemostatic function parameters (MA, R, and α) between study arms A and B (all p values > 0.096) pre transfusion as well as 1 and 24 h post transfusion. No differences between study arms A and B were observed for mean (± standard deviation (SD)) 1-hour CCI (12.83 ± 6.33 vs. 11.59 ± 5.97) and 24-hour CCI (6.56 ± 4.10 vs. 5.76 ± 4.05). Mean 1-hour CI and 24-hour CI were not significantly different in both study arms (p = 0.254 and p = 0.242 respectively). Median time to the next PC transfusion after study PC was not significantly different between groups: (2.4 vs. 2.2 days, p = 0.767). No differences could be found in transfusion requirement of red blood cells (p = 0.744) between both study arms. There were also no regarding bleeding, adverse events, and acute transfusion reaction(s).

CONCLUSIONS

This study confirms safety of gamma-irradiated PCs for treatment thrombocytopenia. Hemostatic function, transfusion efficacy, bleeding, and safety of single-donor apheresis PCs treated with gamma irradiation versus untreated control PCs are comparable.

Adenosine, lidocaine, and Mg2+ (ALM™) increases survival and corrects coagulopathy after eight-minute asphyxial cardiac arrest in the rat

INTRODUCTION

No drug therapy has demonstrated improved survival following cardiac arrest (CA) of cardiac or noncardiac origin. In an effort to translate the cardiorescue properties of Adenocaine (adenosine and lidocaine) and magnesium sulfate (ALM) from cardiac surgery and hemorrhagic shock to resuscitation, we examined the effect of ALM on hemodynamic rescue and coagulopathy following asphyxial-induced CA in the rat.

METHODS

Nonheparinized animals (400-500 g, n = 39) were randomly assigned to 0.9% saline (n = 12) and 0.9% saline ALM (n = 10) groups. After baseline data were acquired, the animal was surface cooled (33°C-34°C) and the ventilator line clamped for 8 min inducing CA; 0.5 mL of solution was injected intravenously followed by 60-s chest compressions (300/min), and rats were rewarmed. Return of spontaneous circulation (ROSC), mean arterial pressure, heart rate, and rectal temperature were recorded for 2 h. Additional rats were randomized for rotation thromboelastometry measurements (n = 17).

RESULTS

Rats treated with ALM had a significant survival benefit (100% ALM vs. 67% controls achieved ROSC) and generated a higher mean arterial pressure than did controls after 75 min (81 vs. 72 mmHg at 120 min, P < 0.05). In all rats, rotation thromboelastometry lysis index decreased during CA, implying hyperfibrinolysis. Control ROSC survivors displayed hypocoagulopathy (prolonged EXTEM/INTEM clotting time, clot formation time, prothrombin time, activated partial thromboplastin time), decreased maximal clot firmness, lowered elasticity, and lowered clot amplitudes but no change in lysis index. These coagulation abnormalities were corrected by ALM at 120 min after ROSC.

CONCLUSIONS

Small bolus of 0.9% NaCl ALM improved survival and hemodynamics following nonhemorrhagic, asphyxial CA and corrected prolonged clot times and clot retraction compared with controls.

Fibrin patch in a pig model with blunt liver injury under severe hypothermia

BACKGROUND

Rapid control of hemorrhage is one of the key aspects in trauma handling. To cope with bleeding, local hemostatic approaches are useful, along with surgical and systemic homostatic therapy. In this experimental study, we investigated the efficacy of a fibrinogen/thrombin containing collagen patch (TachoSil) in a coagulopathic pig model with blunt liver trauma under severe hypothermia.

METHODS

Eighteen anesthetized pigs underwent hemodilution by exchanging 70% of the blood volume with Ringer Lactate solution and hydroxyethyl starch 130/0.4 (1:1). Ten minutes after induction of a grade III blunt liver trauma, the animals randomly received treatment with TachoSil (FT-patch, n = 9) or a collagen patch (Tachotop, control group, n = 9). Blood loss, hemodynamics, and coagulation parameters were observed for 2 h. To confirm the consistency of liver trauma, pathologic examination of the liver tissue was performed.

RESULTS

Hypothermia (33.5°C ± 0.5°C) and hemodilution led to severe coagulopathy as measured by thromboelastometry and coagulation parameters. After trauma and patch application, thromboelastometry and coagulation parameters in the control group showed further deterioration compared with the stable parameters in the FT-patch group. The total blood loss was significantly reduced in the FT-patch group (FT-patch: 1195 mL; control group: 2495 mL; P < 0.001). Concordantly, the control animals were hemodynamically jeopardized to a higher degree. Microscopy confirmed a similar degree of liver injury.

CONCLUSIONS

Despite severe hypothermia and coagulopathy, TachoSil provided effective hemorrhage control in pigs with blunt liver injury. Therefore, TachoSil demonstrated usefulness as an additional early therapy in cases of uncontrolled bleeding following severe trauma.

Admission rapid thrombelastography delivers real-time "actionable" data in pediatric trauma

PURPOSE

Admission rapid thrombelastography (rTEG) is a "real-time" clinical tool used to evaluate trauma-induced coagulopathy and direct hemostatic resuscitation. The relationship of rTEG to conventional coagulation tests (CCT) and early lifesaving interventions (LSI) in pediatric trauma is unknown.

METHODS

Severely injured patients (age ≤ 14 years) with an rTEG were retrospectively reviewed (8/1/2009-8/31/2011). Demographic and clinical information was collected. Spearman's correlation and regression models were used to evaluate rTEG with respect to CCT, early transfusion, LSI, and mortality.

RESULTS

Eighty-six patients were identified. The median age was 8 years, and the median injury severity score (ISS) was 21. Activated clotting time (r=0.68), k-time (r=0.77), and α-angle (r=-0.75) showed strong correlation to PTT, and maximum amplitude (MA) (r=0.46) showed good correlation to platelet count (all p<0.001). When controlling for age, gender, and ISS, regression analysis showed that ACT, r-value, k-time, α-angle, and MA predicted red blood cell and plasma transfusion within 6h. MA (OR 0.82, 95% CI 0.70-0.96; p=0.018) was predictive of LSI. All rTEG values, except for LY30, predicted mortality.

CONCLUSION

Admission rTEG correlates with CCT and predicts early transfusion, early LSI, and outcome in pediatric trauma. rTEG provides valuable data for goal-directed hemostatic resuscitation of critically injured children.

Low hemorrhage-related mortality in trauma patients in a Level I trauma center employing transfusion packages and early thromboelastography-directed hemostatic resuscitation with plasma and platelets

BACKGROUND

Hemorrhage accounts for most preventable trauma deaths, but still the optimal strategy for hemostatic resuscitation remains debated.

STUDY DESIGN AND METHODS

This was a prospective study of adult trauma patients admitted to a Level I trauma center. Demography, Injury Severity Score (ISS), transfusion therapy, and mortality were registered. Hemostatic resuscitation was based on a massive transfusion protocol encompassing transfusion packages and thromboelastography (TEG)-guided therapy.

RESULTS

A total of 182 patients were included (75% males, median age 43 years, ISS of 17, 92% with blunt trauma). Overall 28-day mortality was 12% with causes of death being exsanguinations (14%), traumatic brain injury (72%, two-thirds expiring within 24 hr), and other (14%). One-fourth, 16 and 15% of the patients, received red blood cells (RBCs), plasma, or platelets (PLTs) within 2 hours from admission and 68, 71, and 75%, respectively, of patients transfused within 24 hours received the respective blood products within the first 2 hours. In patients transfused within 24 hours, the median number of blood products at 2 hours was 5 units of RBCs, 5 units of plasma, and 2 units of PLT concentrates. Nonsurvivors had lower clot strength by kaolin-activated TEG and TEG functional fibrinogen and lower kaolin-tissue factor-activated TEG α-angle and lysis after 30 minutes compared to survivors. None of the TEG variables were independent predictors of massive transfusion or mortality.

CONCLUSION

Three-fourths of the patients transfused with plasma or PLTs within 24 hours received these in the first 2 hours. Hemorrhage caused 14% of the deaths. We introduced transfusion packages and early TEG-directed hemostatic resuscitation at our hospital 10 years ago and this may have contributed to reducing hemorrhagic trauma deaths.