Management of major trauma haemorrhage: treatment priorities and controversies

Characteristics of blood clotting on thromboelastography in patients with early burns

BACKGROUND

Thromboelastography (TEG) is a viscoelastic test that may be used to evaluate the hemostatic function of whole blood, and it may be useful for burn patients with multiple hemostatic defects.

METHODS

We retrospectively recruited patients with burns between January 2019 and July 2021. Blood samples were drawn on admission and subjected to coagulation parameter assessment, including conventional coagulation tests and TEG assessment. Receiver operating characteristic (ROC) analysis was performed to predict the occurrence of complications in patients with early burns.

RESULTS

Ninety-three patients with early burns met the inclusion criteria. Patients with minor, moderate, severe, and extremely severe burns accounted for 19.4 %, 36.6 %, 16.1 %, and 27.9 % of all patients, respectively. Compared with the healthy controls, patients with early burns showed significant reductions in the R and K values, and significant elevation in the maximum amplitude (MA), coagulation index (CI), and alpha angle. Compared with minor and moderate burn patients, patients with severe and extremely severe burns had lower K values and thrombin time and higher alpha angle, CI, prothrombin time, international normalized ratio, D-dimer, and fibrin degradation products. Patients with hypercoagulation had lower R and K values, longer MA, longer CI, and greater alpha angle. After ROC analysis, the areas under the ROC curve for acute lung injury, acute kidney injury, and bleeding were 0.789, 0.802, and 0.900, respectively.

CONCLUSION

TEG provides insight into the hemostatic state of patients with early burns, and can predict complications in early burn patients when combined with conventional coagulation tests.

Predictive indicators for determining red blood cell transfusion strategies in the emergency department

BACKGROUND AND IMPORTANCE

Appropriate decision-making is critical for transfusions to prevent unnecessary adverse outcomes; however, transfusion in the emergency department (ED) can only be decided based on sparse evidence in a limited time window.

OBJECTIVES

This study aimed to identify factors associated with appropriate red blood cell (RBC) transfusion in the ED by analyzing retrospective data of patients who received transfusions at a single center.

OUTCOME MEASURES AND ANALYSIS

This study analyzed associations between transfusion appropriateness and sex, age, initial vital signs, an ED triage score [the Korean Triage and Acuity Scale (KTAS)], the length of stay, and the hemoglobin (Hb) concentration.

MAIN RESULTS

Of 10 490 transfusions, 10 109 were deemed appropriate, and 381 were considered inappropriate. A younger age ( P  < 0.001) and a KTAS level of 3-5 ( P  = 0.028) were associated with inappropriate transfusions, after adjusting for O 2 saturation and the Hb level.

CONCLUSIONS

In this single-center retrospective study, younger age and higher ED triage scores were associated with the appropriateness of RBC transfusions.

Experimental Models of Traumatic Injuries: Do They Capture the Coagulopathy and Underlying Endotheliopathy Induced by Human Trauma?

Trauma-induced coagulopathy (TIC) is a major cause of morbidity and mortality in patients with traumatic injury. It describes the spectrum of coagulation abnormalities that occur because of the trauma itself and the body's response to the trauma. These coagulation abnormalities range from hypocoagulability and hyperfibrinolysis, resulting in potentially fatal bleeding, in the early stages of trauma to hypercoagulability, leading to widespread clot formation, in the later stages. Pathological changes in the vascular endothelium and its regulation of haemostasis, a phenomenon known as the endotheliopathy of trauma (EoT), are thought to underlie TIC. Our understanding of EoT and its contribution to TIC remains in its infancy largely due to the scarcity of experimental research. This review discusses the mechanisms employed by the vascular endothelium to regulate haemostasis and their dysregulation following traumatic injury before providing an overview of the available experimental in vitro and in vivo models of trauma and their applicability for the study of the EoT and its contribution to TIC.

Blood coagulation test abnormalities in trauma patients detected by sonorheometry: a retrospective cohort study

Background

Traumatic hemorrhage guidelines include point-of-care viscoelastic tests as a standard of care. Quantra (Hemosonics) is a device based on sonic estimation of elasticity via resonance (SEER) sonorheometry to assess whole blood clot formation.

Objectives

Our study aimed to assess the ability of an early SEER evaluation to detect blood coagulation test abnormalities in trauma patients.

Methods

We conducted an observational retrospective cohort study with data collected at hospital admission of consecutive multiple trauma patients from September 2020 to February 2022 at a regional level 1 trauma center. We performed a receiving operator characteristic curve analysis to determine the ability of the SEER device to detect blood coagulation test abnormalities. Four values on the SEER device were analyzed: clot formation time, clot stiffness (CS), platelet contribution to CS, and fibrinogen contribution to CS.

Results

A total of 156 trauma patients were analyzed. The clot formation time value predicted an activated partial thromboplastin time ratio of >1.5 with an area under the curve (AUC) of 0.93 (95% CI, 0.86-0.99). The AUC of the CS value in detecting an international normalized ratio of prothrombin time of >1.5 was 0.87 (95% CI, 0.79-0.95). The AUC of fibrinogen contribution to CS to detect a fibrinogen concentration of <1.5 g/L was 0.87 (95% CI, 0.80-0.94). The AUC of platelet contribution to CS to detect a platelet concentration of <50 G/L was 0.99 (95% CI, 0.99-1.00).

Conclusion

Our results suggest that the SEER device may be useful for the detection of blood coagulation test abnormalities at trauma admission.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A putative "chemokine switch" that regulates systemic acute inflammation in humans

Systemic inflammation is complex and likely drives clinical outcomes in critical illness such as that which ensues following severe injury. We obtained time course data on multiple inflammatory mediators in the blood of blunt trauma patients. Using dynamic network analyses, we inferred a novel control architecture for systemic inflammation: a three-way switch comprising the chemokines MCP-1/CCL2, MIG/CXCL9, and IP-10/CXCL10. To test this hypothesis, we created a logical model comprising this putative architecture. This model predicted key qualitative features of systemic inflammation in patient sub-groups, as well as the different patterns of hospital discharge of moderately vs. severely injured patients. Thus, a rational transition from data to data-driven models to mechanistic models suggests a novel, chemokine-based mechanism for control of acute inflammation in humans and points to the potential utility of this workflow in defining novel features in other complex diseases.

Assessment of endogenous fibrinolysis in clinical practice using novel tests: ready for clinical roll-out?

The occurrence of thrombotic complications, which can result in excess mortality and morbidity, represent an imbalance between the pro-thrombotic and fibrinolytic equilibrium. The mainstay treatment of these complications involves the use of antithrombotic agents but despite advances in pharmacotherapy, there remains a significant proportion of patients who continue to remain at risk. Endogenous fibrinolysis is a physiological counter-measure against lasting thrombosis and may be measured using several techniques to identify higher risk patients who may benefit from more aggressive pharmacotherapy. However, the assessment of the fibrinolytic system is not yet accepted into routine clinical practice. In this review, we will revisit the different methods of assessing endogenous fibrinolysis (factorial assays, turbidimetric lysis assays, viscoelastic and the global thrombosis tests), including the strengths, limitations, correlation to clinical outcomes of each method and how we might integrate the assessment of endogenous fibrinolysis into clinical practice in the future.

Serial Evaluation of Haemostasis Following Acute Trauma Using Rotational Thromboelastometry in Dogs

OBJECTIVE

 The aim of this study was to describe the coagulation status of traumatized dogs over the first 24 hours after admission.

STUDY DESIGN

 In 33 dogs presenting within 6 hours after trauma blood was sampled for rotational thromboelastometry (ROTEM), thrombocyte number and venous blood gas analysis at presentation and 6 and 24 hours thereafter. At each time point, dogs were defined as hypo-, normo- or hypercoagulable based on extrinsic, intrinsic and fibrinogen ROTEM profiles.

RESULTS

 Significantly more dogs (11/33) presented hypocoagulable compared with 6 hours (p = 0.046) and 24 hours (p = 0.008) thereafter and none presented hypercoagulable. Significantly more dogs were hypercoagulable (6/23, p = 0.014) and no dog was hypocoagulable at 24 hours compared with presentation. All evaluated ROTEM parameters except maximum lysis were significantly more hypocoagulable at presentation compared with 24 hours thereafter.

CONCLUSION

 Hypocoagulability is more common in acutely traumatized dogs than previously described. Dogs were hypo- or normocoagulable at presentation and the coagulation status changed to normo- or hypercoagulability over the first 24 hours. Clotting times, clot formation and clot firmness but not clot lysis were significantly altered at presentation compared with 24 hours and fibrinogen concentration or function may play an important role in the dynamic change of coagulation state over time.

Underlying Disorders, Clinical Phenotypes, and Treatment Diversity among Patients with Disseminated Intravascular Coagulation

INTRODUCTION

Clinical guidelines state that disseminated intravascular coagulation (DIC) treatment should be based on three clinical phenotypes: the marked bleeding type (e.g. leukemia, trauma, obstetric diseases, or aortic diseases); organ failure type (sepsis or pancreatitis); and asymptomatic type of DIC (solid cancer). However, among the various underlying disorders of DIC, the clinical presentations of bleeding or organ failure have not to date been well documented. The present study aimed to evaluate whether underlying disorders of DIC would affect clinical outcome including death, organ failure, and bleeding.

METHODS

Using the Japanese Diagnosis Procedure Combination inpatient database, we identified all adult patients diagnosed with DIC during hospitalization from July 1, 2010, to March 31, 2018. We collected data on patient characteristics and underlying disorders of DIC including sepsis, solid cancer, leukemia, trauma, obstetric diseases, aortic diseases, pancreatitis, and miscellaneous diseases. We counted major bleeding events and calculated an organ failure score for patients during hospitalization.

RESULTS

We identified 337,132 patients with DIC. The major disorders underlying DIC were sepsis (42%) and solid cancer (31%). The average organ failure scores of patients with aortic diseases, sepsis, and trauma were 2.8, 2.2, and 2.2, respectively. The percentages with major bleeding events among patients with aortic diseases, trauma, obstetric diseases, and solid cancer were 24%, 15%, 10%, and 10%, respectively.

CONCLUSIONS

This study suggests that the clinical presentations of bleeding and organ failure are not associated with the three existing clinical phenotypes of DIC or with the underlying disorders of DIC. Therefore, clinical presentation alone may not be sufficient for identifying the clinical phenotypes of DIC. Further research is necessary to develop new strategies for identifying the phenotypes of DIC and improving treatment strategies for individual patients.

Viscoelastic haemostatic assays and fibrinogen in paediatric acute traumatic coagulopathy: A comprehensive review

OBJECTIVE

Haemorrhage in paediatric trauma remains a significant cause of morbidity and mortality. Over recent years there has been increasing attention to the role of fibrinogen in traumatic haemorrhage and the association of low fibrinogen levels with poor patient outcomes. In addition, there has been a move towards using viscoelastic haemostatic assays (VHAs) to rapidly assess coagulation status and guide clinicians in the replacement of coagulation factors, including fibrinogen. In the paediatric population, there has been limited uptake of these principles and a paucity of data to support a change in practice. This paper summarises the available evidence in the published literature through a systematic review, presented in narrative format.

RESULTS

There is limited high-quality prospective data on the use of VHA in the management of acute traumatic coagulopathy in the paediatric population. While the use of fibrinogen early in major haemorrhage is becoming standard practice, there are currently no randomised prospective studies comparing fibrinogen concentrate to cryoprecipitate.

CONCLUSIONS

The early identification of hypo-fibrinogenemia and acute traumatic coagulopathy in paediatric trauma using VHA testing and subsequent early fibrinogen replacement with a concentrated off the shelf product is an attractive treatment option. However, there is currently insufficient high-level evidence to support the use of fibrinogen concentrate over cryoprecipitate in the paediatric trauma population. Pilot studies currently under way will go some way to addressing this important knowledge gap, and facilitate the design of larger definitive multi-centre randomised trials.

Association between viscoelastic tests-guided therapy with synthetic factor concentrates and allogenic blood transfusion in liver transplantation: a before-after study

Background

Perioperative bleeding and transfusion are important causes of morbidity and mortality in patients undergoing liver transplantation. The aim of this study is to assess whether viscoelastic tests-guided therapy with the use of synthetic factor concentrates impact transfusion rates of hemocomponents in adult patients undergoing liver transplantation.

Methods

This is an interventional before-after comparative study. Patients undergoing liver transplantation before the implementation of a protocol using thromboelastometry and synthetic factor concentrates were compared to patients after the implementation. Primary outcome was transfusion of any hemocomponents. Secondary outcomes included: transfusion of red blood cells (RBC), fresh frozen plasma (FFP), cryoprecipitate or platelets, clinical complications, length of stay and in-hospital mortality.

Results

A total of 183 patients were included in the control and 54 in the intervention phase. After propensity score matching, the proportion of patients receiving any transfusion of hemocomponents was lower in the intervention phase (37.0 vs 58.4%; OR, 0.42; 95% CI, 0.20–0.87; p = 0.019). Patients in the intervention phase received less RBC (30.2 vs 52.5%; OR, 0.21; 95% CI, 0.08–0.56; p = 0.002) and FFP (5.7 vs 27.3%; OR, 0.11; 95% CI, 0.03–0.43; p = 0.002). There was no difference regarding transfusion of cryoprecipitate and platelets, complications related to the procedure, hospital length of stay and mortality.

Conclusions

Use of a viscoelastic test-guided transfusion algorithm with the use of synthetic factor concentrates reduces the transfusion rates of allogenic blood in patients submitted to liver transplantation.

Trial registration

This trial was registered retrospectively on November 15th, 2018 – clinicaltrials.gov – Identifier: NCT03756948.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0664-8) contains supplementary material, which is available to authorized users.

Mortality of civilian patients with suspected traumatic haemorrhage receiving pre-hospital transfusion of packed red blood cells compared to pre-hospital crystalloid

Background

Major haemorrhage is a leading cause of mortality following major trauma. Increasingly, Helicopter Emergency Medical Services (HEMS) in the United Kingdom provide pre-hospital transfusion with blood products, although the evidence to support this is equivocal. This study compares mortality for patients with suspected traumatic haemorrhage transfused with pre-hospital packed red blood cells (PRBC) compared to crystalloid.

Methods

A single centre retrospective observational cohort study between 1 January 2010 and 1 February 2015. Patients triggering a pre-hospital Code Red activation were eligible. The primary outcome measure was all-cause mortality at 6 hours (h) and 28 days (d), including a sub-analysis of patients receiving a major and massive transfusion. Multivariable regression models predicted mortality. Multiple Imputation was employed, and logistic regression models were constructed for all imputed datasets.

Results

The crystalloid (n = 103) and PRBC (n = 92) group were comparable for demographics, Injury Severity Score (p = 0.67) and mechanism of injury (p = 0.73). Observed 6 h mortality was smaller in the PRBC group (n = 10, 10%) compared to crystalloid group (n = 19, 18%). Adjusted OR was not statistically significant (OR 0.48, CI 0.19–1.19, p = 0.11). Observed mortality at 28 days was smaller in the PRBC group (n = 21, 26%) compared to crystalloid group (n = 31, 40%), p = 0.09. Adjusted OR was not statistically significant (OR 0.66, CI 0.32–1.35, p = 0.26). A statistically significant greater proportion of the crystalloid group required a major transfusion (n = 62, 60%) compared to the PRBC group (n = 41, 40%), p = 0.02. For patients requiring a massive transfusion observed mortality was smaller in the PRBC group at 28 days (p = 0.07).

Conclusion

In a single centre UK HEMS study, in patients with suspected traumatic haemorrhage who received a PRBC transfusion there was an observed, but non-significant, reduction in mortality at 6 h and 28 days, also reflected in a massive transfusion subgroup. Patients receiving pre-hospital PRBC were significantly less likely to require an in-hospital major transfusion. Further adequately powered multi-centre prospective research is required to establish the optimum strategy for pre-hospital volume replacement in patients with traumatic haemorrhage.

The open abdomen in trauma and non-trauma patients: WSES guidelines

Damage control resuscitation may lead to postoperative intra-abdominal hypertension or abdominal compartment syndrome. These conditions may result in a vicious, self-perpetuating cycle leading to severe physiologic derangements and multiorgan failure unless interrupted by abdominal (surgical or other) decompression. Further, in some clinical situations, the abdomen cannot be closed due to the visceral edema, the inability to control the compelling source of infection or the necessity to re-explore (as a "planned second-look" laparotomy) or complete previously initiated damage control procedures or in cases of abdominal wall disruption. The open abdomen in trauma and non-trauma patients has been proposed to be effective in preventing or treating deranged physiology in patients with severe injuries or critical illness when no other perceived options exist. Its use, however, remains controversial as it is resource consuming and represents a non-anatomic situation with the potential for severe adverse effects. Its use, therefore, should only be considered in patients who would most benefit from it. Abdominal fascia-to-fascia closure should be done as soon as the patient can physiologically tolerate it. All precautions to minimize complications should be implemented.

Open abdomen critical care management principles: resuscitation, fluid balance, nutrition, and ventilator management

The term "open abdomen" refers to a surgically created defect in the abdominal wall that exposes abdominal viscera. Leaving an abdominal cavity temporarily open has been well described for several indications, including damage control surgery and abdominal compartment syndrome. Although beneficial in certain patients, the act of keeping an abdominal cavity open has physiologic repercussions that must be recognized and managed during postoperative care. This review article describes these issues and provides guidelines for the critical care physician managing a patient with an open abdomen.

Importance of Endogenous Fibrinolysis in Platelet Thrombus Formation

The processes of thrombosis and coagulation are finely regulated by endogenous fibrinolysis maintaining healthy equilibrium. When the balance is altered in favour of platelet activation and/or coagulation, or if endogenous fibrinolysis becomes less efficient, pathological thrombosis can occur. Arterial thrombosis remains a major cause of morbidity and mortality in the world despite advances in medical therapies. The role endogenous fibrinolysis in the pathogenesis of arterial thrombosis has gained increasing attention in recent years as it presents novel ways to prevent and treat existing diseases. In this review article, we discuss the role of endogenous fibrinolysis in platelet thrombus formation, methods of measurement of fibrinolytic activity, its role in predicting cardiovascular diseases and clinical outcomes and future directions.

Acute traumatic coagulopathy and trauma-induced coagulopathy: an overview

Hemorrhage is the most important contributing factor of acute-phase mortality in trauma patients. Previously, traumatologists and investigators identified iatrogenic and resuscitation-associated causes of coagulopathic bleeding after traumatic injury, including hypothermia, metabolic acidosis, and dilutional coagulopathy that were recognized as primary drivers of bleeding after trauma. However, the last 10 years has seen a widespread paradigm shift in the resuscitation of critically injured patients, and there has been a dramatic evolution in our understanding of trauma-induced coagulopathy. Although there is no consensus regarding a definition or an approach to the classification and naming of trauma-associated coagulation impairment, trauma itself and/or traumatic shock-induced endogenous coagulopathy are both referred to as acute traumatic coagulopathy (ATC), and multifactorial trauma-associated coagulation impairment, including ATC and resuscitation-associated coagulopathy is recognized as trauma-induced coagulopathy. Understanding the pathophysiology of trauma-induced coagulopathy is vitally important, especially with respect to the critical issue of establishing therapeutic strategies for the management of patients with severe trauma.

Cambridge Polytrauma Pathway: Are we making appropriately guided decisions?

Addenbrooke's Hospital, the Major Trauma Centre for the East of England Trauma Network, received 1070 major trauma patients between 1st January and 31st December 2014. In order to improve care, an audit was performed of 59 patients meeting our own selection criteria for orthopaedic polytrauma between 1st January 2013 and 31st December 2013. The Cambridge Polytrauma Pathway was devised through NCEPOD guidelines, literature review, internal and external discussion. It facilitates provision of best practice Early Appropriate Care, encompassing - multidisciplinary consultant decisions around the patient in our Neurological and Trauma Critical Care Unit, early full body trauma CT scans, serial measurements of lactate and fibrinogen levels, and out-of-hours orthopaedic theatre reserved for life-and-limb threatening injuries. Re-audit was conducted of 15 patients meeting selection criteria, admitted between 1st October 2014 and 31st March 2015. Significant improvements in recording of lactate and fibrinogen were demonstrated, both on admission (lactate - p<0.000, fibrinogen - p=0.015), and preoperatively (lactate - p=0.003, fibrinogen - p=0.030). Time to trauma CT was unchanged (p=0.536) with a median time to CT of 0.53h at re-audit (IQR 0.48-0.75). The number of patients receiving definitive orthopaedic intervention out-of-hours reduced from 8 to zero (p=0.195). The approach of facilitating management decisions to be made at early daytime MDT meetings has been adopted. It is anticipated that this pathway will improve outcomes in orthopaedic polytrauma patients and it is recommended that either the GOS-E, or the EQ-5D scoring systems be introduced to assess this.

Tactical damage control resuscitation in austere military environments

BACKGROUND

Despite the early uses of tourniquets and haemostatic dressings, blood loss still accounts for the vast majority of preventable deaths on the battlefield. Over the last few years, progress has been made in the management of such injuries, especially with the use of damage control resuscitation concepts. The early application of these procedures, on the field, may constitute the best opportunity to improve survival from combat injury during remote operations.

DATA SOURCES

Currently available literature relating to trauma-induced coagulopathy treatment and far-forward transfusion was identified by searches of electronic databases. The level of evidence and methodology of the research were reviewed for each article. The appropriateness for field utilisation of each medication was then discussed to take into account the characteristics of remote military operations.

CONCLUSIONS

In tactical situations, in association with haemostatic procedures (tourniquet, suture, etc), tranexamic acid should be the first medication used according to the current guidelines. The use of fibrinogen concentrate should also be considered for patients in haemorrhagic shock, especially if point-of-care (POC) testing of haemostasis or shock severity is available. If POC evaluation is not available, it seems reasonable to still administer this treatment after clinical assessment, particularly if the evacuation is delayed. In this situation, lyophilised plasma may also be given as a resuscitation fluid while respecting permissive hypotension. Whole blood transfusion in the field deserves special attention. In addition to the aforementioned treatments, if the field care is prolonged, whole blood transfusion must be considered if it does not delay the evacuation.

Emergency red cells first: Rapid response or speed bump? The evolution of a massive transfusion protocol for trauma in a single UK centre

BACKGROUND

Death from massive haemorrhage due to traumatic injury is potentially preventable after hospital admission using haemorrhage control and improved resuscitation techniques including massive transfusion protocols. Massive transfusion protocols (MTP) are an essential element of damage control resuscitation and provide a coordinated clinical pathology response to massive haemorrhage after hospital admission. The decision to activate and de-activate a MTP is based on a number of patient and local factors. The purpose of this before-and-after study was to determine the impact of modifying a protocol to include emergency red cells. In addition, we investigated whether massive transfusion prediction models could have been used to guide on-going transfusion support.

METHODS

Sequential MTP activations over three years, before and after protocol revision, were analysed. Percentage of MTP activation, component usage and outcome data were compared. Trauma associated severe haemorrhage (TASH) and assessment of blood consumption (ABC) scores were derived and receiver operating characteristic (ROC) analysis undertaken for an outcome defined as the use of >6 red cell units.

RESULTS

52 MTP1 and 66 MTP2 activations arose from 216 and 495 major trauma cases, respectively. Protocol change significantly reduced the MTP activation rate (p=0.0006) from 24% to 13%, and the number of activations requiring >10 RCC increased from 13% to 36% (p=0.006). Average emergency red cells usage in the second cohort increased to 4 units. Survival, coagulation parameters, and time to MTP pack issue were all unaffected by the protocol revision. The TASH score showed an area under ROC (AUROC) of 0.88 ongoing transfusion requirements.

CONCLUSION

The change in protocol increased the use of emergency red cells but reduced MTP activation and use of multiple blood components. The TASH score appears to provide a useful predictive tool for ongoing transfusion support and may be of value for the trauma clinicians.

A national common massive transfusion protocol (MTP) is a feasible and advantageous option for centralized blood services and hospitals

BACKGROUND

A common national MTP was jointly implemented in 2011 by the national blood service (Blood Services Group) and seven participating acute hospitals to provide rapid access to transfusion support for massively haemorrhaging patients treated in all acute care hospitals.

METHODS

Through a systematic clinical workflow, blood components are transfused in a ratio of 1:1:1 (pRBC: whole blood-derived platelets: FFP), together with cryoprecipitate for fibrinogen replacement. The composition of components for the MTP is fixed, although operational aspects of the MTP can be adapted by individual hospitals to suit local hospital workflow. The MTP could be activated in support of any patient with critical bleeding and at risk of massive transfusion, including trauma and non-trauma general medical, surgical and obstetric patients.

RESULTS

There were 434 activations of the MTP from October 2011 to October 2013. Thirty-nine per cent were for trauma patients, and 30% were for surgical patients with heavy intra-operative bleeding, with 25% and 6% for patients with gastrointestinal bleeding and peri-partum haemorrhage, respectively. Several hospitals reported reduction in mean time between request and arrival of blood. Mean transfusion ratio achieved was one red cell unit: 0·8 FFP units: 0·8 whole blood-derived platelet units: 0·4 units of cryoprecipitate. Although cryoprecipitate usage more than doubled after introduction of MTP, there was no significant rise in overall red cells, platelet and FFP usage following implementation.

CONCLUSION

This successful collaboration shows that shared transfusion protocols are feasible and potentially advantageous for hospitals sharing a central blood provider.

Endogenous Fibrinolysis: An Important Mediator of Thrombus Formation and Cardiovascular Risk

Most acute cardiovascular events are attributable to arterial thrombosis. Plaque rupture or erosion stimulates platelet activation, aggregation, and thrombosis, whilst simultaneously activating enzymatic processes that mediate endogenous fibrinolysis to physiologically maintain vessel patency. Interplay between these pathways determines clinical outcome. If proaggregatory factors predominate, the thrombus may propagate, leading to vessel occlusion. However, if balanced by a healthy fibrinolytic system, thrombosis may not occur or cause lasting occlusion. Despite abundant evidence for the fibrinolytic system regulating thrombosis, it has been overlooked compared with platelet reactivity, partly due to a lack of techniques to measure it. We evaluate evidence for endogenous fibrinolysis in arterial thrombosis and review techniques to assess it, including biomarkers and global assays, such as thromboelastography and the Global Thrombosis Test. Global assays, simultaneously assessing proaggregatory and fibrinolytic pathways, could play a role in risk stratification and in identifying impaired fibrinolysis as a potential target for pharmacological modulation.

Analysis of risk classification for massive transfusion in severe trauma using the gray zone approach

BACKGROUND

The Traumatic Bleeding Severity Score (TBSS) was developed to predict the need for massive transfusion (MT). The aim of this study is evaluation of clinical thresholds for activation of a MT protocol using the gray zone approach based on TBSS.

METHODS

This is a single-center retrospective study of trauma patients, admitted from 2010 to 2013. The TBSS on admission was calculated, and the accuracy of predicting MT was analyzed using area under the receiver operating characteristic curve. Risk classification for MT was made using sensitivity/specificity. The gray zone (indeterminate risk) was defined from a sensitivity of 95% to a specificity of 95%, patients were separated into MT and non-MT groups, and their clinical characteristics were compared.

RESULTS

A total of 264 patients were enrolled, with an area under the TBSS curve of 0.967 (95% confidence interval, 0.94-0.99). A TBSS of 10 points or less resulted in a sensitivity of 96.5% with 146 patients in this group, and 3.4% (5/146) of them received MT. A TBSS of 17 points or higher had a specificity of 97.8%, which included 72 patients, and 94.4% (68/72) of them received MT. Forty-six patients had a TBSS from 11 to 16 points (gray zone), and 26.1% (12/46) of them received MT. Comparing the MT group (12/46) and non-MT group (34/46), coagulopathy and extravasation on computed tomographic scan were more prevalent in the MT group.

CONCLUSION

The TBSS is highly accurate in predicting the need for MT, and a risk classification for needing MT was created based on TBSS.

Effects of Fibrinogen Concentrate on Thrombin Generation, Thromboelastometry Parameters, and Laboratory Coagulation Testing in a 24-Hour Porcine Trauma Model

Introduction:

In a 24-hour porcine model of liver injury, we showed that fibrinogen supplementation does not downregulate endogenous fibrinogen synthesis. Here we report data from the same study showing the impact of fibrinogen on coagulation variables.

Materials and Methods:

Coagulopathy was induced in 20 German land race pigs by hemodilution and blunt liver injury. Animals randomly received fibrinogen concentrate (100 mg/kg) or saline. Coagulation parameters were assessed and thromboelastometry (ROTEM) was performed.

Results:

Fibrinogen concentrate significantly reduced the prolongations of EXTEM clotting time, EXTEM clot formation time, and prothrombin time induced by hemodilution and liver injury. A decrease in clot strength was also ameliorated. Endogenous thrombin potential was significantly higher in the fibrinogen group than in the control group, 20 minutes (353 ± 24 vs 289 ± 22 nmol/L·min; P < .05) and 100 minutes (315 ± 40 vs 263 ± 38 nmol/L·min; P < .05) after the start of infusion. However, no significant between-group differences were seen in other thrombin generation parameters or in d-dimer or thrombin–antithrombin levels. Fibrinogen–platelet binding was reduced following liver injury, with no significant differences between groups. No significant between-group differences were observed in any parameter at ∼12 and ∼24 hours.

Conclusion:

This study suggests that, in trauma, fibrinogen supplementation may shorten some measurements of the speed of coagulation initiation and produce a short-lived increase in endogenous thrombin potential, potentially through increased clotting substrate availability. Approximately 12 and 24 hours after starting fibrinogen concentrate/saline infusion, all parameters measured in this study were comparable in the 2 study groups.

Early management of the severely injured major trauma patient

The major trauma team relies on an efficient, communicative team to ensure patients receive the best quality care. This requires a comprehensive handover, rapid systematic review, and early management of life- and limb-threatening injuries. These multiple injured patients often present with complex conditions in a dynamic situation. The importance of team work, communication, senior decision-making, and documentation cannot be underestimated.

Traumatic brain injury is not associated with coagulopathy out of proportion to injury in other body regions

BACKGROUND

Coagulopathy following trauma is associated with poor outcomes. Traumatic brain injury has been associated with coagulopathy out of proportion to other body regions. We hypothesized that injury severity and shock determine coagulopathy independent of body region injured.

METHODS

We performed a prospective, multicenter observational study at three Level 1 trauma centers. Conventional coagulation tests (CCTs) and rapid thrombelastography (r-TEG) were used. Admission vital signs, base deficit (BD), CCTs, and r-TEG data were collected. The Abbreviated Injury Scale (AIS) score and Injury Severity Score (ISS) were obtained. Severe injury was defined as AIS score greater than or equal to 3 for each body region. Patients were grouped according to their dominant AIS region of injury. Dominant region of injury was defined as the single region with the highest AIS score. Patients with two or more regions with the same greatest AIS score and patients without a region with an AIS score greater than or equal to 3 were excluded. Coagulation parameters were compared between the dominant AIS region. Significant hypoperfusion was defined as BD greater than or equal to 6.

RESULTS

Of the 795 patients enrolled, 462 met criteria for grouping by dominant AIS region. Patients were predominantly white (59%), were male (75%), experienced blunt trauma (71%), and had a median ISS of 25 (interquartile range, 14-29). Patients with BD greater than or equal to 6 (n = 110) were hypocoagulable by CCT and r-TEG compared with patients with BD less than 6 (n = 223). Patients grouped by dominant AIS region showed no significant differences for any r-TEG or CCT parameter. Patients with BD greater than or equal to 6 demonstrated no difference in any r-TEG or CCT parameter between dominant AIS regions.

CONCLUSION

Coagulopathy results from a combination of tissue injury and shock independent of the dominant region of injury. With the use of AIS as a measure of injury severity, traumatic brain injury was not independently associated with more profound coagulopathy.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Current concepts, which effect outcome following major hemorrhage

There are a multitude of factors, which effect outcome following major trauma. The recent conflict in the middle-east has advanced our knowledge and developed clinical practice, here within the UK. This article reviews the current and emerging concepts, which effect the outcome of patients sustaining major hemorrage in trauma.

Hypertonic saline in the traumatic hypovolemic shock: meta-analysis

BACKGROUND

A wealth of evidence from animal experiments has indicated that hypertonic saline (HS) maybe a better choice for fluid resuscitation in traumatic hypovolemic shock in comparison with conventional isotonic saline. However, the results of several clinical trials raised controversies on the superiority of fluid resuscitation with HS. This meta-analysis was performed to better understand the efficacy of HS in patients with traumatic hypovolemic shock comparing with isotonic saline.

MATERIALS AND METHODS

According to the search strategy, we searched the PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, which was completed on October 2013. After literature searching, two investigators independently performed the literature screening, assessment of quality of the included trials, and data extraction. Disagreements were resolved by consensus or by a third investigator if needed. The outcomes included mortality, blood pressure, fluid requirement, and serum sodium.

RESULTS

Six randomized controlled trials were included in the meta-analysis. The pooled risk ratio for mortality at discharge was 0.96 (95% confidence interval [CI], 0.82-1.14), whereas the pooled mean difference for the change in systolic blood pressure from baseline and the level of serum sodium after infusion was 6.47 (95% CI, 1.31-11.63) and 7.94 (95% CI, 7.38-8.51), respectively. Current data were insufficient to evaluate the effect of HS on the fluid requirement for the resuscitation.

CONCLUSIONS

The present meta-analysis was unable to demonstrate a clinically important improvement in mortality after the HS administration. Moreover, we observed HS administration maybe accompanied with significant increase in blood pressure and serum sodium.

The role of prothrombin complex concentrates in reversal of target specific anticoagulants

Over the past several years a new era for patients requiring anticoagulation has arrived. The approval of new target specific oral anticoagulants offers practitioners several advantages over traditionally used vitamin K antagonist agents including predictable pharmacokinetics, rapid onset of action, comparable efficacy and safety, all without the need for routine monitoring. Despite these benefits, hemorrhagic complicates are inevitable with any anticoagulation treatment. One of the major disadvantages of the new oral anticoagulants is lack of specific antidotes or reversal agents for patients with serious bleeding or need for urgent surgery. As use of the new target specific oral anticoagulants continues to increase, practitioners will need to understand both the pharmacodynamics and pharmacokinetic properties of the agents, as well as, the available literature with use of non-specific therapies to reverse anticoagulation. Four factor prothrombin complex concentrates have been available for several years in Europe, and recently became available in the United States with approval of Kcentra. These products have shown efficacy in reversing anticoagulation from vitamin K antagonists, however their usefulness with the new target specific oral anticoagulants is poorly understood. This article will review the properties of dabigatran, rivaroxaban and apixaban, as well as the limited literature available on the effectiveness of prothrombin complex concentrates in reversal of their anticoagulant effects. Additional studies are needed to more accurately define the role of prothrombin complex concentrates in patients with life threatening bleeding or who require emergent surgery, as current data is both limited and conflicting.

Acute coagulopathy of trauma: Mechanism, monitoring, management

Coagulopathy is a well-known consequence of trauma and is the most common cause of mortality in the young. However, its cause and management is still controversial. A new concept in the understanding of coagulopathy in trauma is the occurrence of Acute coagulopathy of trauma (ACoT). ACoT is associated with hypo perfusion and tissue trauma as seen in massive injury. The incidence of coagulopathy increases with injury scores and is associated with higher number of ventilator days, higher morbidity and mortality. The process of coagulation is better described by the cell based model with a central role for platelets rather than the older plasma based model. This shift in our understanding supports the theory that ACoT results from the endothelial release of thrombomodulin and activated protein C in the presence of hypoperfusion. This in turn leads on to a hyperfibrinolytic and hypocoagulable state. Viscoelastic hemostatic assays are replacing the older tests like prothrombin time in the assessment of coagulopathy. These tests are accurate, determine the need for transfusion and can be performed at the point of care. Damage control resuscitation includes newer concepts like permissive hypotension, increased use of plasma as a part of massive transfusion protocols and damage control surgery.

Trauma-induced coagulopathy: from biology to therapy

Trauma is a leading cause of death and disability. Hemorrhage is the major mechanism responsible for death during the first 24 hours following trauma. One quarter of severely injured patients present in the emergency room with acute coagulopathy of trauma and shock (ACOT). The drivers of ACOT are tissue hypoperfusion, inflammation, and activation of the neurohumoral system. ACOT is a result of protein C activation with cleavage of activated factor VIII and V and inhibition of plasminogen activator inhibitor-1 (PAI-1). The resuscitation-associated coagulopathy (RAC) is secondary to a combination of acidosis, hypothermia and dilution from intravenous blood and fluid therapy. RAC may further aggravate acidosis and hypoxia resulting in a vicious cycle. This review focuses on the biology of the trauma-associated coagulopathy, and reviews current therapeutic strategies.

Interchangeability of rotational elastographic instruments and reagents

BACKGROUND

Viscoelastic measurements are frequently being used in clinical and research settings for a rapid assessment of the hemostatic processes of blood clot formation and degradation. These measurements are being performed on either of two instruments (TEG and ROTEM) using their proprietary reagents. Standardization between the instruments and the reagents has been lacking but is necessary to compare results across instruments. In this study, we perform a crossover analysis between the TEG and ROTEM instruments using proprietary reagents from each manufacturer.

METHODS

We tested three sets of reagents as follows: (1) in-tem and ex-tem (Tem International GmbH); (2) kaolin and RapidTEG (Haemonetics); (3) a well-characterized control recombinant tissue factor-phospholipid reagent. Blood was drawn from six healthy donors, and each reagent was run concurrently in the TEG and ROTEM instruments. The volume of commercial reagent and calcium used was adjusted for crossover measurements to maintain the same concentration of each reagent in the blood. The outputs of clot time, rate of clot formation, and maximum firmness of the clot of the ROTEM and the TEG tracings were evaluated.

RESULTS

The in-tem and RapidTEG reagents showed no disparity between instruments for any parameter. Significant differences between the instruments were found in the α angle and maximum firmness of the clot for ex-tem and kaolin reagents as well as in the clot time and maximum firmness of the clot for the recombinant tissue factor-phospholipid reagent.

CONCLUSION

Although significant differences were observed for some parameters, the magnitudes were small compared with the differences between tests or the normal range variation in parameter values observed for these tests. These findings indicate that the instruments are more interchangeable than previously reported.

Recent advances of hemorrhage management in severe trauma

Trauma is one of the most common causes of mortality worldwide with a substantial percentage of deaths resulting secondary to haemorrhages, which are preventable and treatable when adequately managed. This paper offers a review of the current literature on how to successfully resuscitate patients with major haemorrhage.

Traumatic coagulopathy--part 2: Resuscitative strategies

OBJECTIVE

To discuss the current resuscitative strategies for trauma-induced hemorrhagic shock and acute traumatic coagulopathy (ATC).

ETIOLOGY

Hemorrhagic shock can be acutely fatal if not immediately and appropriately treated. The primary tenets of hemorrhagic shock resuscitation are to arrest hemorrhage and restore the effective circulating volume. Large volumes of isotonic crystalloids have been the resuscitative strategy of choice; however, data from experimental animal models and retrospective human analyses now recognize that large-volume fluid resuscitation in uncontrolled hemorrhage may be deleterious. The optimal resuscitative strategy has yet to be defined. In human trauma, implementing damage control resuscitation with damage control surgery for controlling ongoing hemorrhage, acidosis, and hypothermia; managing ATC; and restoring effective circulating volume is emerging as a more optimal resuscitative strategy. With hyperfibrinolysis playing an integral role in the manifestation of ATC, the use of antifibrinolytics (eg, tranexamic acid and aminocaproic acid) may also serve a beneficial role in the early posttraumatic period. Considering the sparse information regarding these resuscitative techniques in veterinary medicine, veterinarians are left with extrapolating information from human trials and experimental animal models.

DIAGNOSIS

Viscoelastic tests integrated with predictive scoring systems may prove to be the most reliable methods for early detection of ATC as well as for guiding transfusion requirements.

SUMMARY

Hemorrhage accounts for up to 40% of human trauma-related deaths and remains the leading cause of preventable death in human trauma. The exact proportion of trauma-related deaths due to exsanguinations in veterinary patients remains uncertain. Survivability depends upon achieving rapid definitive hemostasis, early attenuation of posttraumatic coagulopathy, and timely restoration of effective circulating volume. Early institution of damage control resuscitation in severely injured patients with uncontrolled hemorrhage has the ability to curtail posttraumatic coagulopathy and the exacerbation of metabolic acidosis and hypothermia and improve survival until definitive hemostasis is achieved.

Traumatic coagulopathy--part 1: Pathophysiology and diagnosis

OBJECTIVE

To review the current literature in reference to the pathophysiology and diagnostic modalities available for acute traumatic coagulopathy (ATC) in relationship to traumatic hemorrhagic shock.

ETIOLOGY

Posttraumatic hemorrhage is responsible for one of the leading causes of preventable human deaths worldwide. Acute traumatic coagulopathy is an endogenous hypocoagulable condition that has been observed during the immediate (< 1 hour) posttraumatic period. Phenotypically, ATC manifests as a state of systemic hypocoagulability and hyperfibrinolysis. Although different functional mechanisms have been proposed for causing ATC, it is universally thought to be a manifestation of severe tissue injury, shock-induced hypoperfusion, systemic inflammation, and endothelial damage. Excessive activation of the thrombin-thrombomodulin activated Protein C pathway, catecholamine-induced endothelial damage as well as disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype are all hypotheses that have been proposed in attempts to explain the functional mechanism of ATC.

DIAGNOSIS

An accurate and reliable test remains to be validated for ATC. Traditional coagulation assays (activated partial thromboplastin times and prothrombin times) along with platelet count and fibrinogen concentrations have been used more commonly. Viscoelastic tests (thromboelastography and rotational thromboelastometry) are currently being investigated as a more predictive modality for identifying and guiding therapy for ATC.

THERAPY

Damage control resuscitation and hemostatic resuscitation are gaining favor as the optimal resuscitative strategies for hemorrhagic shock and ATC. Antifibrinolytics may also play a role when hyperfibrinolysis is present.

PROGNOSIS

Massive hemorrhage accounts for 30-56% of prehospital posttraumatic deaths in people, with coagulopathic hemorrhage remaining one of the major causes of preventable deaths within the first 24 hours posttrauma. Ten to twenty-five percent of human trauma patients experience ATC, which has been shown to prolong hemorrhage, deter resuscitative efforts, promote sepsis, and increase mortality by at least 4-fold. Prognosis in veterinary patients is not currently known.

The Pathophysiology and Management of Acute Traumatic Coagulopathy

Acute traumatic coagulopathy (ATC) is commonly seen among patients with severe injury and will lead to uncontrolled bleeding diathesis, which is an important contributor to trauma death. During the past 10 years, the understanding of the mechanism causing ATC has changed rapidly. The mechanisms for ATC are complicated. To date, the possible mechanisms include activation of protein C, shedding of endothelial glycocalyx, catecholamine release, platelet dysfunction, primary, and secondary fibrinolysis, with tissue injury and hypoperfusion as the triggers. Classic factors such as dilution, acidosis, and hypothermia can further aggravate the coagulopathy. Inflammation may have a potential effect on the onset and prognosis of ATC. With the aid of diagnostic device, the outcome can be improved through early and customized treatment. Antifibrinolytics such as tranexamic acid has some benefits in patients with bleeding trauma, especially in the early time. This review presents the current understanding of ATC mechanisms and management.

Fibrinogen depletion after plasma-dilution: impairment of proteolytic resistance and reversal via clotting factor concentrates

In trauma patients, resuscitation treatment of intravascular volume may cause haemodilution including blood cell- and plasma-dilution. After plasma-dilution, fibrinogen is the first factor that decreases to critically low concentrations. Fibrin formed in lowered levels is susceptible to fibrinolysis, a natural forerunner for bleeding. To assess whether a fibrinogen concentrate or a factor XIII (FXIII) concentrate can reverse the impairment of fibrin properties after plasma dilution, different laboratory methods were used to determine thrombin generation and fibrin quantity/quality in a normal plasma sample diluted in vitro. Coagulation and clot lysis by plasmin were triggered with tissue factor and rt-PA, respectively.We found that while the endogenous thrombin potential (ETP) was unaffected after plasma-dilution due to postponement of thrombin decay, levels of fibrinogen and hence fibrin were decreased in dilution degree-dependency. The imbalance between influence of the dilution on thrombin activity and fibrin formation brought unexpected outcomes of fibrin properties: the formed clots favoured the degradation by plasminbut the fibrin networks remained tighter/less permeable. This proteolytic tendency was partly overturned by the fibrinogen concentrate added (total fibrinogen ≥ 2 g/l), and much more affected if used in combination with tranexamic acid (a fibrinolysis inhibitor) at small doses. No reversal effect resulted from the FXIII concentrate added. We conclude that plasma-dilution did reduce the proteolytic resistance of formed clots. The fibrinogen concentrate, better together with small doses of tranexamic acid, may reverse the impairment of fibrin property.The FXIII concentrate is not effective in this regard in our in vitro model using platelet-poor plasma.