Hyperfibrinolysis diagnosed by rotational thromboelastometry (ROTEM) is associated with higher mortality in patients with severe trauma

Fibrinolysis in trauma: a review

Fibrinolytic dysregulation is an important mechanism in traumatic coagulopathy. It is an incompletely understood process that consists of a spectrum ranging from excessive breakdown (hyperfibrinolysis) and the shutdown of fibrinolysis. Both hyperfibrinolysis and shutdown are associated with excess mortality and post-traumatic organ failure. The pathophysiology appears to relate to endothelial injury and hypoperfusion, with several molecular markers identified in playing a role. Although there are no universally accepted diagnostic tests, viscoelastic studies appear to offer the greatest potential for timely identification of patients presenting with fibrinolytic dysregulation. Treatment is multimodal, involving prompt hemorrhage control and resuscitation, with controversy surrounding the use of antifibrinolytic drug therapy. This review presents the current evidence on the pathophysiology, diagnostic challenges, as well as the management of this hemostatic dysfunction.

LEVEL OF EVIDENCE

Level III.

Targeted Thromboelastographic (TEG) Blood Component and Pharmacologic Hemostatic Therapy in Traumatic and Acquired Coagulopathy

Trauma-induced coagulopathy (TIC) is a recently described condition which traditionally has been diagnosed by the common coagulation tests (CCTs) such as prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), platelet count, and fibrinogen levels. The varying sensitivity and specificity of these CCTs have led trauma coagulation researchers and clinicians to use Viscoelastic Tests (VET) such as Thromboelastography (TEG) to provide Targeted Thromboelastographic Hemostatic and Adjunctive Therapy (TTHAT) in a goal directed fashion to those trauma patients in need of hemostatic resuscitation. This review describes the utility of VETs, in particular, TEG, to provide TTHAT in trauma and acquired non-trauma-induced coagulopathy.

[Extracorporeal membrane oxygenation : Principles and medical indications]

Extracorporeal membrane oxygenation (ECMO) is a special form of a miniaturized heart-lung machine with the ultimate goal to stabilize critically ill patients. Dependent on the cannulation strategy ECMO can support or replace heart and/or lung function. Medical indications and contraindications have to be evaluated thoroughly before cannulation. Moreover, before ECMO initiation a solid treatment aim has to be defined: bridge to recovery, bridge to decision, bridge to transplantation, and bridge to destination (i. e. implantation of a permanent assist device). Regarding invasiveness of the system, potential life-threatening complications, requirement of standardized monitoring of the patient and the device as well as tertiary care infrastructure, ECMO should exclusively be used in highly experienced tertiary centers.

Hyperfibrinolysis in severe isolated traumatic brain injury may occur without tissue hypoperfusion: a retrospective observational multicentre study

BACKGROUND

Hyperfibrinolysis is a critical complication in severe trauma. Hyperfibrinolysis is traditionally diagnosed via elevated D-dimer or fibrin/fibrinogen degradation product levels, and recently, using thromboelastometry. Although hyperfibrinolysis is observed in patients with severe isolated traumatic brain injury (TBI) on arrival at the emergency department (ED), it is unclear which factors induce hyperfibrinolysis. The present study aimed to investigate the factors associated with hyperfibrinolysis in patients with isolated severe TBI.

METHODS

We conducted a multicentre retrospective review of data for adult trauma patients with an injury severity score ≥ 16, and selected patients with isolated TBI (TBI group) and extra-cranial trauma (non-TBI group). The TBI group included patients with an abbreviated injury score (AIS) for the head ≥ 4 and an extra-cranial AIS < 2. The non-TBI group included patients with an extra-cranial AIS ≥ 3 and head AIS < 2. Hyperfibrinolysis was defined as a D-dimer level ≥ 38 mg/L on arrival at the ED. We evaluated the relationships between hyperfibrinolysis and injury severity/tissue injury/tissue perfusion in TBI patients by comparing them with non-TBI patients.

RESULTS

We enrolled 111 patients in the TBI group and 126 in the non-TBI group. In both groups, patients with hyperfibrinolysis had more severe injuries and received transfusion more frequently than patients without hyperfibrinolysis. Tissue injury, evaluated on the basis of lactate dehydrogenase and creatine kinase levels, was associated with hyperfibrinolysis in both groups. Among patients with TBI, the mortality rate was higher in those with hyperfibrinolysis than in those without hyperfibrinolysis. Tissue hypoperfusion, evaluated on the basis of lactate level, was associated with hyperfibrinolysis in only the non-TBI group. Although the increase in lactate level was correlated with the deterioration of coagulofibrinolytic variables (prolonged prothrombin time and activated partial thromboplastin time, decreased fibrinogen levels, and increased D-dimer levels) in the non-TBI group, no such correlation was observed in the TBI group.

CONCLUSIONS

Hyperfibrinolysis is associated with tissue injury and trauma severity in TBI and non-TBI patients. However, tissue hypoperfusion is associated with hyperfibrinolysis in non-TBI patients, but not in TBI patients. Tissue hypoperfusion may not be a prerequisite for the occurrence of hyperfibrinolysis in patients with isolated TBI.

Hemostatic Therapy Using Tranexamic Acid and Coagulation Factor Concentrates in a Model of Traumatic Liver Injury

BACKGROUND

The potential clinical benefits of targeted therapy with coagulation factor concentrates (e.g., fibrinogen) and antifibrinolytic agents (e.g., tranexamic acid [TXA]) for the treatment of trauma-induced coagulopathy are increasingly recognized. We hypothesized that human fibrinogen concentrate (FC) and prothrombin complex concentrate (PCC), administered as combined therapy with TXA, would provide additive effects for reducing blood loss in an animal trauma model.

METHODS

Thirty-six pigs were subjected to 2 consecutive blunt liver injuries, resulting in severe hemorrhagic shock and coagulopathy. Intervention comprised saline (control group); TXA (15 mg kg, TXA group); TXA and FC (90 mg kg, TXA-FC); or TXA, FC, and PCC (20 U kg, TXA-FC-PCC). Blood loss, thromboelastometry (ROTEM), measures of thrombin generation, platelet activation, and global coagulation variables were monitored for 4 hours. Tissue sections were examined to determine the occurrence of thromboembolic events.

RESULTS

Total blood loss was similar in the TXA-FC and TXA-FC-PCC groups (mean ± SD: 1012 ± 86 mL and 1037 ± 118 mL, respectively; P = 1.000). These values were both lower (P < 0.001) than the TXA group (1579 ± 306 mL). Blood loss in all 3 intervention groups was lower (P < 0.001) than in the control group (2376 ± 478 mL). After trauma and resuscitation, but before study intervention, plasma fibrinogen levels were severely depleted (median for the whole study population: 66 mg dL; interquartile range: 51-108 mg dL) and clot strength was decreased (EXTEM whole-blood maximum clot firmness [MCF]: 53 ± 5 mm). Compared with controls, TXA inhibited fibrinolysis and stabilized MCF and clotting time. The addition of FC restored and stabilized hemostasis to a greater extent than TXA alone; the addition of PCC had no statistically significant impact on blood loss, clot strength (MCF), or clotting time, but it increased thrombin generation. There were no significant differences among the study groups regarding platelet activation. No thrombi or microthrombi were observed in any group at necropsy.

CONCLUSIONS

The early use of TXA and FC reduced blood loss and improved coagulation measurements in a porcine model of blunt liver injury and hemorrhagic shock. FC, administered in addition to TXA, was highly effective in reducing blood loss. The lack of statistically significant reduction in blood loss when PCC was added to TXA and FC may be attributable to the absence of thrombin generation impairment in this model.

Change of transfusion and treatment paradigm in major trauma patients

Trauma promotes trauma-induced coagulopathy, which requires urgent treatment with fixed-ratio transfusions of red blood cells, fresh frozen plasma and platelet concentrates, or goal-directed administration of coagulation factors based on viscoelastic testing. This retrospective observational study compared two time periods before (2005-2007) and after (2012-2014) the implementation of changes in trauma management protocols which included: use of goal-directed coagulation management; admission of patients to designated trauma centres; whole-body computed tomography scanning on admission; damage control surgery; permissive hypotension; restrictive fluid resuscitation; and administration of tranexamic acid. The incidence of massive transfusion (≥ 10 units of red blood cells from emergency department arrival until intensive care unit admission) was compared with the predicted incidence according to the trauma associated severe haemorrhage score. All adult (≥ 16 years) trauma patients primarily admitted to the University Hospital Zürich with an injury severity score ≥ 16 were included. In 2005-2007, the observed and trauma associated severe haemorrhage score that predicted the incidence of massive transfusion were identical, whereas in 2012-2014 the observed incidence was less than half that predicted (3.7% vs. 7.5%). Compared to 2005-2007, the proportion of patients transfused with red blood cells and fresh frozen plasma was significantly lower in 2012-2014 in both the emergency department (43% vs. 17%; 31% vs. 6%, respectively), and after 24 h (53% vs. 27%; 37% vs. 16%, respectively). The use of tranexamic acid and coagulation factor XIII also increased significantly in the 2012-2014 time period. Implementation of a revised trauma management strategy, which included goal-directed coagulation management, was associated with a reduced incidence of massive transfusion and a reduction in the transfusion of red blood cells and fresh frozen plasma.

Early administration of fibrinogen concentrates improves the short-term outcomes of severe pelvic fracture patients

Aim

Hemorrhage from pelvic fracture is a major cause of mortality after blunt trauma. Several studies have suggested that early fibrinogen supplementation improves outcomes of traumatic hemorrhage. Thus, we revised our massive transfusion protocol (MTP) in April 2013 to include early off‐label administration of fibrinogen concentrate. The objective of this study was to evaluate the impact of the revision on the short‐term outcomes of pelvic fracture patients.

Methods

This was a single‐center, retrospective, cohort study. A total of 224 consecutive pelvic fracture patients hospitalized in Saitama Medical Center (Saitama, Japan), 115 before the revision (Group E) and 109 after (Group L), were enrolled. Characteristics of the patients were compared between the groups. Impacts of the revision were evaluated by hazard ratios adjusted for characteristics, injury severity, and coagulation status using Cox's multivariate proportional hazard model. The impact was also evaluated by log–rank test and relative risk of 28‐day mortality between the groups.

Results

The characteristics were equivalent between the groups. The multivariate analysis revealed that the revision of MTP was significantly related to improved survival with an adjusted hazard ratio (95% confidence interval) of 0.45 (0.07–0.97). The log–rank test gave χ²‐test values of 5.2 (P = 0.022) and 6.7 (P = 0.009), and the relative risks were 0.37 (0.15–0.91) and 0.33 (0.13–0.84), in patients with all Injury Severity Scores and Injury Severity Score ≥21, respectively.

Conclusion

The revision of MTP to include aggressive off‐label treatment with fibrinogen concentrate was related to improved short‐term outcomes of severe pelvic fracture patients. However, due to the limitations of the study, the improvement could not be attributed totally to the revision.

Iatrogenic bleeding during flexible bronchoscopy: risk factors, prophylactic measures and management

Significant iatrogenic bleeding during flexible bronchoscopy is fortunately rare and usually self-limiting. Life-threatening bleeding, however, can occur, especially after conventional or cryoprobe-assisted transbronchial biopsy. The aim of this review is to provide the practising pulmonologist with a concise overview of the incidence, severity and risk factors for bleeding, to provide sensible advice on prophylactic measures and to suggest a plan of action in the case of significant bleeding. Bronchoscopy units should have a standardised approach and plan of action in the case of life-threatening haemorrhage. Wedging the bronchoscope in the bleeding segment, turning the patient in an anti-Trendelenburg position and onto the side in order for the bleeding lung to be in the dependent position, installing vasoconstrictors and using a tamponade balloon early are the recommended first-line strategies. Involving a resuscitation team should be considered early in the case of massive bleeding, desaturation and haemodynamic instability.

Fibrinogen in traumatic haemorrhage: A narrative review

Haemorrhage in the setting of severe trauma is associated with significant morbidity and mortality. There is increasing awareness of the important role fibrinogen plays in traumatic haemorrhage. Fibrinogen levels fall precipitously in severe trauma and the resultant hypofibrinogenaemia is associated with poor outcomes. Hence, it has been postulated that early fibrinogen replacement in severe traumatic haemorrhage may improve outcomes, although, to date there is a paucity of high quality evidence to support this hypothesis. In addition there is controversy regarding the optimal method for fibrinogen supplementation. We review the current evidence regarding the role of fibrinogen in trauma, the rationale behind fibrinogen supplementation and discuss current research.

Pathophysiology of trauma-induced coagulopathy: disseminated intravascular coagulation with the fibrinolytic phenotype

In severe trauma patients, coagulopathy is frequently observed in the acute phase of trauma. Trauma-induced coagulopathy is coagulopathy caused by the trauma itself. The pathophysiology of trauma-induced coagulopathy consists of coagulation activation, hyperfibrino(geno)lysis, and consumption coagulopathy. These pathophysiological mechanisms are the characteristics to DIC with the fibrinolytic phenotype.

Dynamics of fibrinogen in acute phases of trauma

Fibrinogen is a unique precursor of fibrin and cannot be compensated for by other coagulation factors. If plasma fibrinogen concentrations are insufficient, hemostatic clots cannot be formed with the appropriate firmness. In severe trauma patients, plasma fibrinogen concentrations decrease earlier and more frequently than other coagulation factors, predicting massive bleeding and death. We review the mechanisms of plasma fibrinogen concentration decrease, which include coagulation activation-induced consumption, hyper-fibrino(geno)lysis-induced degradation, and dilution by infusion/transfusion. Understanding the mechanisms of plasma fibrinogen concentration decrease in severe trauma patients is crucial.

Pre-emptive administration of fibrinogen concentrate contributes to improved prognosis in patients with severe trauma

Background

Patients with severe trauma often present with critical coagulopathy, resulting in impaired hemostasis, massive hemorrhage, and a poor survival prognosis. The efficacy of hemostatic resuscitation in correcting coagulopathy and restoring tissue perfusion has not been studied. We assessed a novel approach of pre-emptive administration of fibrinogen concentrate to improve critical coagulopathy in patients with severe trauma.

Methods

We retrospectively compared blood transfusion volumes and survival prognosis between three groups of patients with trauma, with an Injury Severity Score (ISS) ≥26 over three consecutive periods: group A, no administration of fibrinogen concentrate; group B, administration of 3 g of fibrinogen concentrate after evaluation of trauma severity and a plasma fibrinogen level <1.5 g/L; group C, pre-emptive administration of 3 g of fibrinogen concentrate immediately on patient arrival based on prehospital information, including high-severity injury or assessed need for massive transfusion before measurement of fibrinogen.

Results

∼56% of patients with an ISS ≥26 and transfused with red blood cell concentrates ≥10 units, had hypofibrinogenemia (fibrinogen <1.5 g/L) on arrival. Patients who received fibrinogen concentrate in group C showed significantly higher fibrinogen levels after treatment with this agent than those in group B (2.41 g/L vs 1.88 g/L; p=0.01). Although no significant difference was observed in blood transfusion volumes between the groups, the 30-day survival of patients in group C (all, and those with an ISS ≥26) was significantly better than in group A (p<0.05). The 48-hour mortality rate in patients with an ISS ≥26 was significantly lower in group C than in group A (8.6% vs 22.9%; p=0.005). Further, among patients with an ISS ≥41, the overall mortality was significantly lower in group C than in group A (20% vs 50%; p=0.02).

Conclusion

Pre-emptive administration of fibrinogen concentrate for patients with trauma with critical coagulopathy may contribute to improved survival.

Level of evidence

Level IV.

The pre-hospital administration of tranexamic acid to patients with multiple injuries and its effects on rotational thrombelastometry: a prospective observational study in pre-hospital emergency medicine

Background

Hyperfibrinolysis (HF) is a major contributor to coagulopathy and mortality in trauma patients. This study investigated (i) the rate of HF during the pre-hospital management of patients with multiple injuries and (ii) the effects of pre-hospital tranexamic acid (TxA) administration on the coagulation system.

Methods

From 27 trauma patients with pre-hospital an estimated injury severity score (ISS) ≥16 points blood was obtained at the scene and on admission to the emergency department (ED). All patients received 1 g of TxA after the first blood sample was taken. Rotational thrombelastometry (ROTEM) was performed for both blood samples, and the results were compared. HF was defined as a maximum lysis (ML) >15 % in EXTEM.

Results

The median (min-max) ISS was 17 points (4–50 points). Four patients (15 %) had HF diagnosed via ROTEM at the scene, and 2 patients (7.5 %) had HF diagnosed via ROTEM on admission to the ED. The median ML before TxA administration was 11 % (3–99 %) vs. 10 % after TxA administration (4–18 %; p > 0.05). TxA was administered 37 min (10–85 min) before ED arrival. The ROTEM results before and after TxA administration did not significantly differ. No adverse drug reactions were observed after TxA administration.

Discussion

HF can be present in severely injured patients during pre-hospital care. Antifibrinolytic therapy administered at the scene is a significant time saver. Even in milder trauma fibrinogen can be decreased to critically low levels. Early administration of TxA cannot reverse or entirely stop this decrease.

Conclusions

The pre-hospital use of TxA should be considered for severely injured patients to prevent the worsening of trauma-induced coagulopathy and unnecessarily high fibrinogen consumption.

Trial registration

ClinicalTrials.gov ID NCT01938768 (Registered 5 September 2013).

[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.

The utility of thromboelastography in inherited and acquired bleeding disorders

Thromboelastography (TEG) was first described by Hartert in 1948, and was designed to monitor viscoelastic clot strength in whole blood in real time. The current TEG method and Rotational Thromboelastometry (ROTEM) were subsequently developed from the original principles. Both of the modern methods provide data by measuring changes in the viscoelastic strength of a small sample of clotting blood in response to a constant rotational force. The important advantage of these techniques is to visually observe and quantify blood coagulation including the propagation, stabilization and dissolution phases of clot formation under low shear conditions. Analysis of the results provides detailed kinetic data on fibrin generation, clot strength and fibrinolysis. These TEG/ROTEM analyses therefore enable evaluation of global clotting function and the monitoring of haemostatic treatment in various clinical situations, not only in patients with genetic bleeding disorders, such as haemophilia, but also in patients undergoing cardiac surgery, liver transplantation or suffering from traumatic injury. Some evidence suggests that haemostatic management using TEG/ROTEM leads to a reduction in total transfusions of whole blood or clotting factors. Wider clinical application of this technology seems likely.

The European guideline on management of major bleeding and coagulopathy following trauma: fourth edition

BACKGROUND

Severe trauma continues to represent a global public health issue and mortality and morbidity in trauma patients remains substantial. A number of initiatives have aimed to provide guidance on the management of trauma patients. This document focuses on the management of major bleeding and coagulopathy following trauma and encourages adaptation of the guiding principles to each local situation and implementation within each institution.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004 and included representatives of six relevant European professional societies. The group used a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were reconsidered and revised based on new scientific evidence and observed shifts in clinical practice; new recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated. This guideline represents the fourth edition of a document first published in 2007 and updated in 2010 and 2013.

RESULTS

The guideline now recommends that patients be transferred directly to an appropriate trauma treatment centre and encourages use of a restricted volume replacement strategy during initial resuscitation. Best-practice use of blood products during further resuscitation continues to evolve and should be guided by a goal-directed strategy. The identification and management of patients pre-treated with anticoagulant agents continues to pose a real challenge, despite accumulating experience and awareness. The present guideline should be viewed as an educational aid to improve and standardise the care of the bleeding trauma patients across Europe and beyond. This document may also serve as a basis for local implementation. Furthermore, local quality and safety management systems need to be established to specifically assess key measures of bleeding control and outcome.

CONCLUSIONS

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. The implementation of locally adapted treatment algorithms should strive to achieve measureable improvements in patient outcome.

[Traumatic brain injury in anticoagulated patients : Hemostatic therapy for the treatment of intracranial hemorrhage]

Impaired hemostasis represents a major risk factor for increased morbidity and mortality in patients with traumatic intracranial hemorrhage. In cases of polytrauma with major bleeding, hyperfibrinolysis may develop and this may result in excessive coagulopathy. Patients receiving antithrombotic medication and suffering from intracranial hemorrhage are at particular risk for the development of neurological sequelae due to the increased tendency to bleeding. This article outlines the principles of hemostatic therapy of traumatic intracranial hemorrhage during antithrombotic treatment. The basic principles of the pathophysiology and effects of coagulation impairment in this patient population are reviewed. Furthermore, the use of specific coagulation tests and the administration of hemostatic substances are discussed.

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 and Rotational Thromboelastometry use in trauma

The appropriate resuscitation of patients in hemorrhagic shock is critical to improving survival. Current strategies for massive transfusions utilize fixed ratio protocols to rapidly deliver plasma and platelets to the patient. However, there is some concern that these larger volumes of transfusions can lead to untoward effects. Efforts are ongoing to provide patient-specific transfusion therapy in order to avoid excess transfusions. Thromboelastography (TEG) or Rotational Thromboelastometry (ROTEM) are two viscoelastic analyzers capable of providing Viscoelastic testing.

Trauma-induced coagulopathy

Coagulopathy is the inability of blood to coagulate normally; in trauma patients, it is a multifactorial and complex process. Seriously injured trauma patients experience coagulopathies during the acute injury phase. Risk factors for trauma-induced coagulopathy include hypothermia, metabolic acidosis, hypoperfusion, hemodilution, and fluid replacement. In addition to the coagulopathy induced by trauma, many patients may also be taking medications that interfere with hemostasis. Therefore, medication-induced coagulopathy also is a concern. Traditional laboratory-based methods of assessing coagulation are being supported or even replaced by point-of-care tests. The evidence-based management of trauma-induced coagulopathy should address hypothermia, fluid resuscitation, blood components administration, and, if needed, medications to reverse identified coagulation disorders.

Assessment of the relationships among coagulopathy, hyperfibrinolysis, plasma lactate, and protein C in dogs with spontaneous hemoperitoneum

OBJECTIVE

To relate coagulation and fibrinolysis derangements to shock severity as reflected by plasma lactate concentrations in dogs with spontaneous hemoperitoneum (SHP) and determine the impact on transfusions.

DESIGN

Prospective, observational, case-control study.

SETTING

Three veterinary teaching hospitals.

ANIMALS

Twenty-eight client-owned dogs with SHP and 28 breed- and age-matched control dogs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Blood samples for platelet counts, coagulation, and anticoagulant assays (prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin, and protein C, thromboelastography [TEG]), fibrinolysis testing (d-dimer and TEG lysis parameters with and without the addition of 50 U/mL of tissue plasminogen activator [TEG LY30 measured with the addition of 50 U/mL of tPA to the blood sample, LY3050 and TEG LY60 measured with the addition of 50 U/mL of tPA to the blood sample, LY6050 ; LY30 and LY60]), and plasma lactate as an indicator of severity of shock were collected from SHP dogs at the time of diagnosis. SHP dogs were hypocoagulable (prolonged prothrombin time and activated partial thromboplastin time, decreased TEG maximum amplitude) and hyperfibrinolytic (increased LY3050 and TEG LY6050 ) compared to controls. The severity of hypocoagulability was related to protein C activity, while the severity of hyperfibrinolysis was related to plasma lactate concentration. Among the 18 dogs discharged from the hospital, LY3050 was significantly associated with the dose of fresh frozen plasma administered, but none of the parameters were associated with the dose of red blood cells administered.

CONCLUSIONS

Dogs with SHP have evidence of hypocoagulability, protein C deficiency, and hyperfibrinolysis. Parameters of hyperfibrinolysis were related to plasma lactate concentrations and volume of plasma transfused during hospitalization. These derangements resemble those found in people with acute coagulopathy of trauma and shock, and activation of protein C may be a common feature to both syndromes.

Effect of two doses of tranexamic acid on fibrinolysis evaluated by thromboelastography during cardiac surgery: a randomised, controlled study

BACKGROUND

Tranexamic acid is used to decrease bleeding and transfusions during cardiac surgery. However, dosing based on pharmacokinetic data to optimally inhibit fibrinolysis is unknown. With increasing concerns regarding seizures associated with higher doses, lower dosing schemes may be important.

OBJECTIVE

To determine the effect of two dosing schemes compared with placebo on fibrinolysis and clinical outcomes.

DESIGN

A double-blind, randomised, controlled, pilot trial.

SETTING

Single tertiary centre.

PATIENTS

Cardiac surgery patients requiring cardiopulmonary bypass.

INTERVENTION

Patients were randomised to receive a 30 mg  kg(-1) bolus and continuous infusion of 16  mg  kg (-1) h(-1) (Group HIGH), a 5 mg  kg(-1) bolus followed by 5 mg  kg(-1)  h(-1) (Group LOW) or Sodium chloride (Placebo).

MAIN OUTCOME MEASURE

Fibrinolysis was evaluated by thromboelastography and D-dimers. Secondary endpoints were blood loss, transfusion requirement and side effects.

RESULTS

Thirty-three patients were included. Significant fibrinolysis was defined by LY30 more than 7.5% based on thromboelastography and was not observed after cardiopulmonary bypass in any groups. After protamine administration, LY30 differences between groups were 0.7 [95% confidence interval (95% CI) -0.04 to 1.4] between Groups HIGH and Placebo, -0.08 (95% CI -0.82 to 0.66) between Groups HIGH and LOW, and 0.78 (95% CI 0.02 to 1.5) between Groups LOW and Placebo. A significant increase in D-dimers was observed in the Group Placebo compared with the two treatment groups. There were no differences in bleeding or transfusion requirement.

CONCLUSION

In this dose-finding study, there were no differences in fibrinolysis or clinical outcomes among the two tranexamic acid schemes and placebo. Any difference in fibrinolytic inhibition requires a larger adequately powered study.

TRIAL REGISTRATION

EudraCT number: 2010-024104-99.

Point of care and factor concentrate-based coagulation algorithms

In the last years it has become evident that the use of blood products should be reduced whenever possible. There is increasing evidence regarding serious adverse events, including higher mortality and morbidity, related to transfusions. The use of point of care (POC) devices integrated in algorithms is one of the important mechanisms to limit blood product exposure. Any type of algorithm, especially the POC-based ones, allows goal-directed transfusions of blood products and even better targeted factor concentrate substitutions. Different types of algorithms in different surgical settings (cardiac surgery, trauma, liver surgery etc.) have been established with growing interest in their use as they offer objective therapy for management and reduction of blood product use. The use of POC devices with evidence-based algorithms is important in the bleeding patient independent of its origin (traumatic vs. surgical). The use of factor concentrates compared to the classical blood products can be cost-saving, beneficial for the patient, and in agreement with the WHO-requested standard of care. The empiric and uncontrolled use of blood products such as fresh frozen plasma, red blood cells, and platelets without POC monitoring should no longer be followed with regard to actual evidence in literature. Furthermore, the use of factor concentrates may provide better outcomes and potential for cost saving.

Coagulation profiles of unexpected DCDD donors do not indicate a role for exogenous fibrinolysis

It has been suggested that vascular stasis during cardio-circulatory arrest leads to the formation of microvascular thrombi and the viability of organs arising from donation after circulatory determination of death (DCDD) donors may be improved through the application of fibrinolytic therapy. Our aim was to comprehensively study the coagulation profiles of Maastricht category II DCDD donors in order to determine the presence of coagulation abnormalities that could benefit from fibrinolytic therapy. Whole blood from potential DCDD donors suffering out-of-hospital cardiac arrest was sampled after declaration of death in the emergency department, and rotational thromboelastomeric analysis was performed. Between July 2012 and December 2013, samples from 33 potential DCDD donors were analyzed. All patients demonstrated hyperfibrinolysis (HF), as reflected by maximum clot lysis of 98-100% in all cases, indicating that there is no role for additional fibrinolytic therapy in this setting. As well, we observed correlations between thromboelastomeric lysis parameters and maximum hepatic transaminase levels measured in potential donors and renal artery flows measured during ex situ hypothermic oxygenated machine perfusion, indicating that further studies on the utility of thromboelastometry to evaluate organ injury and perhaps even viability in unexpected DCDD may be warranted.

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.

[Thromboelastometric profile of unwashed shed blood after primary knee arthroplasty]

INTRODUCTION

Knee arthroplasty causes significant blood loss. Different blood-saving measures exist like retransfusion of unwashed salvaged blood. Some studies question the quality of this blood and in particular its ability to clot. These studies use "static" coagulation tests reflecting only partially the reality, unlike viscoelastic methods. The main objective of this study was to evaluate the salvaged blood thromboelastometric profile using ROTEM® system and to compare these results with patient venous blood.

MATERIALS AND METHODS

We performed an observational, prospective, single-center study conducted over 3 months in 2013. Agreement of local ethical committee and patient consent were obtained beforehand. All adult patients who underwent a primary total knee arthroplasty were included. A thromboelastometric profile and standard laboratory tests (hemoglobin, platelets count, PT, aPTT, fibrinogen) were performed in the same time on patient venous blood and on unwashed salvaged blood in the PACU.

RESULTS

Twenty patients were included. The median duration of surgery was 93 minutes. Thirteen patients (65%) received tranexamic acid during procedure. The median volume of shed blood was 225 mL. Two patients (10%) received a reinfusion. Analysis of shed blood showed a major deficiency of clotting factor in standard biology (PT<10%) and an absence of clot formation in thromboelastometric test (In-tem®, Ex-tem®, Fib-tem® or Ap-tem®). Compared to venous blood, shed blood had significantly lower hemoglobin levels: 8.8 vs 13.5 g/dL (P<0.0001). Allogenic transfusion concerned 5% of patients.

DISCUSSION

In this work, we confirmed that shed blood was naturally uncoagulable probably due to a multifactorial mechanism involving a major clot factor deficiency and an activation of fibrinolysis.

Viscoelastic guidance of resuscitation

PURPOSE OF REVIEW

Bleeding in trauma carries a high mortality and is increased in case of coagulopathy. Our understanding of hemostasis and coagulopathy has improved, leading to a change in the protocols for hemostatic monitoring. This review describes the current state of evidence supporting the use of viscoelastic hemostatic assays to guide trauma resuscitation.

RECENT FINDINGS

Viscoelastic hemostatic assays such as thrombelastography and rotational thrombelastometry have shown to reduce bleeding, transfusion of fresh frozen plasma and platelets, and possibly mortality in different surgical populations. In trauma care, viscoelastic hemostatic assays allows for rapid and timely identification of coagulopathy and individualized, goal-directed transfusion therapy. As part of the resuscitation concept, viscoelastic hemostatic assays seem to improve outcome also in trauma; however, there is a need for randomized clinical trials to confirm this.

SUMMARY

We are moving toward avoiding coagulopathy by individualized, goal-directed transfusion therapy, using viscoelastic hemostatic assays to guide ongoing resuscitation of actively bleeding patients in a goal-directed manner.

Prehospital coagulation monitoring of resuscitation with point-of-care devices

A variety of point-of-care monitors for the measurement of hematocrit, hemoglobin, blood gas with electrolytes, and lactate can be used also in the prehospital setting for optimizing and individualizing trauma resuscitation. Point-of-care coagulation testing with activated prothrombin test, prothrombin test, and activated coagulation/clotting time tests is available for prehospital use. Although robust, battery driven, and easy to handle, many devices lack documentation for use in prehospital care. Some of the devices correspond poorly to corresponding laboratory analyses in acute trauma coagulopathy and at lower hematocrits. In trauma, viscoelastic tests such as rotational thromboelastometry and thromboelastography can rapidly detect acute trauma coagulopathy and give an overall dynamic picture of the hemostatic system and the interaction between its different components: coagulation activation, fibrin polymerization, fibrin platelet interactions within the clot, and fibrinolysis. Rotational thromboelastometry is shock resistant and has the potential to be used outside the hospital setting to guide individualized coagulation factor and blood component therapies. Sonoclot and Rheorox are two small viscoelastic instruments with one-channel options, but with less documentation. The point-of-care market for coagulation tests is quickly expanding, and new devices are introduced all the time. Still they should be better adopted to prehospital conditions, small, robust, battery charged, and rapid and use small sample volumes and whole blood.

Strategies for the management of haemorrhage following pelvic fractures and associated trauma-induced coagulopathy

Exsanguination is the second most common cause of death in patients who suffer severe trauma. The management of haemodynamically unstable high-energy pelvic injuries remains controversial, as there are no universally accepted guidelines to direct surgeons on the ideal use of pelvic packing or early angio-embolisation. Additionally, the optimal resuscitation strategy, which prevents or halts the progression of the trauma-induced coagulopathy, remains unknown. Although early and aggressive use of blood products in these patients appears to improve survival, over-enthusiastic resuscitative measures may not be the safest strategy. This paper provides an overview of the classification of pelvic injuries and the current evidence on best-practice management of high-energy pelvic fractures, including resuscitation, transfusion of blood components, monitoring of coagulopathy, and procedural interventions including pre-peritoneal pelvic packing, external fixation and angiographic embolisation.

Evaluation of tranexamic acid and ε-aminocaproic acid concentrations required to inhibit fibrinolysis in plasma of dogs and humans

OBJECTIVE

To determine minimum plasma concentrations of the antifibrinolytic agents tranexamic acid (TEA) and ε-aminocaproic acid (EACA) needed to completely inhibit fibrinolysis in canine and human plasma after induction of hyperfibrinolysis.

SAMPLES

Pooled citrated plasma from 7 dogs and commercial pooled citrated human plasma.

PROCEDURES

Concentrations of EACA from 0 μg/mL to 500 μg/mL and of TEA from 0 μg/mL to 160 μg/mL were added to pooled citrated canine and human plasma. Hyperfibrinolysis was induced with 1,000 units of tissue plasminogen activator/mL, and kaolin-activated thromboelastography was performed in duplicate. The minimum concentrations required to completely inhibit fibrinolysis 30 minutes after maximum amplitude of the thromboelastography tracing occurred were determined.

RESULTS

Minimum plasma concentrations necessary for complete inhibition of fibrinolysis by EACA and TEA in pooled canine plasma were estimated as 511.7 μg/mL (95% confidence interval [CI], 433.2 to 590.3 μg/mL) and 144.7 μg/mL (95% CI, 125.2 to 164.2 μg/mL), respectively. Concentrations of EACA and TEA necessary for complete inhibition of fibrinolysis in pooled human plasma were estimated as 122.0 μg/mL (95% CI, 106.2 to 137.8 μg/mL) and 14.7 μg/mL (95% CI, 13.7 to 15.6 μg/mL), respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Results supported the concept that dogs are hyperfibrinolytic, compared with humans. Higher doses of EACA and TEA may be required to fully inhibit fibrinolysis in dogs.

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.

Rotational thromboelastometry-guided trauma resuscitation

PURPOSE OF REVIEW

Haemorrhage from major trauma is a significant cause of death worldwide. The UK Defence Medical Service (UK-DMS) has had significant experience in managing severely injured and shocked trauma casualties over the last decade. This has led to the integration of rotational thromboelastometry (ROTEM) into damage control resuscitation delivered at Camp Bastion Field Hospital in Afghanistan. This review aims to describe the rationale for its use and how its use has evolved by UK-DMS.

RECENT FINDINGS

Although there is reasonable evidence showing its benefit in cardiac and liver surgery, evidence for its use in trauma is limited. More recent studies and meta-analyses have demonstrated a reduced rate of transfusion and blood loss, but no benefit on mortality. Despite this, there is a growing body of opinion supporting ROTEM use in trauma with European guidelines supporting its use where available. Recent UK-DMS experience has shown that it is a fast, reliable and robust means of identifying transfusion requirements.

SUMMARY

ROTEM provides a means to rapidly assess coagulation in trauma casualties, allowing targeted use of blood products. It provides information on clot initiation strength and breakdown. However, its use in trauma has still to be fully evaluated.

Measurement of dabigatran in standardly used clinical assays, whole blood viscoelastic coagulation, and thrombin generation assays

Dabigatran, a direct thrombin inhibitor, is increasingly used clinically as one of the new oral anticoagulants. This review summarizes the assays available to measure its activity and includes the relative sensitivity of the different assays for this agent. In addition to plasma-based clotting tests, assays commonly used in surgical/emergency settings, such as activated clotting time and thromboelastometry/thromboelastography, are reviewed. In addition, the thrombin generation assay is discussed as an important method to determine the potential risk of thrombosis or bleeding and its relevance to the measurement of direct thrombin inhibitors.

Lysis Onset Time as Diagnostic Rotational Thromboelastometry Parameter for Fast Detection of Hyperfibrinolysis

Background:

Rotational thromboelastometry is increasingly used to detect hyperfibrinolysis, which is a predictor of unfavorable outcome in patients with coagulation disturbances. In an in vitro study, the authors investigated which thromboelastometric hemostatic parameters could be valuable for fast diagnosis of the severity of hyperfibrinolysis and confirmed their findings in a patient population with hyperfibrinolysis.

Methods:

Thromboelastometry was performed after adding increasing concentrations of tissue plasminogen activator (0 to 400 ng/ml) to citrated blood samples of 15 healthy volunteers. Lysis parameters included the clotting time, maximum clot firmness, maximum lysis, and lysis onset time (LOT). The relation of tissue plasminogen activator with the LOT was further investigated in a patient population with out-of-hospital cardiac arrest and hyperfibrinolysis.

Results:

The LOT showed a dose-dependent association with increasing tissue plasminogen activator concentrations. Late, intermediate, or fulminant hyperfibrinolysis was associated with an average LOT (mean ± SD) of 42.7 ± 13.8, 23.2 ± 8.2, and 17.5 ± 4.6 min in the in vitro study and estimated 42.2 ± 8.3, 29.1 ± 1.2, and 14.6 ± 7.7 min in patients, respectively. The authors found a moderately negative correlation between patient plasma tissue plasminogen activator levels and the LOT (r = −0.67; P = 0.01).

Conclusion:

This study shows that the LOT may be used for fast detection of severe hyperfibrinolysis, with a better resolution than the maximum lysis, and should be further evaluated for optimization of therapeutic strategies in patients with severe clot breakdown.

Effect of 6% hydroxyethyl starch 130/0.4 as a priming solution on coagulation and inflammation following complex heart surgery

PURPOSE

Prolonged duration of cardiopulmonary bypass aggravates the degree of inflammation and coagulopathy. We investigated the influence of 6% hydroxyethyl starch (HES) 130/0.4 on coagulation and inflammation compared with albumin when used for both cardiopulmonary bypass priming and perioperative fluid therapy in patients undergoing complex valvular heart surgery.

MATERIALS AND METHODS

Fifty four patients were randomly allocated into albumin-HES, albumin-nonHES, and HES-HES groups. The cardiopulmonary bypass circuit was primed with 5% albumin in the albumin-HES and albumin-nonHES group, and with HES in the HES-HES group. As perioperative fluid, only plasmalyte was used in the albumin-nonHES group whereas HES was used up to 20 mL/kg in the albumin-HES and albumin-HES group. Serial assessments of coagulation profiles using the rotational thromboelastometry and inflammatory markers (tissue necrosis factor-α, interleukin-6, and interleukin-8) were performed.

RESULTS

Patients' characteristics and the duration of cardiopulmonary bypass (albumin-HES; 137±34 min, HES-HES; 136±47 min, albumin-nonHES; 132±39 min) were all similar among the groups. Postoperative coagulation profiles demonstrated sporadic increases in clot formation time and coagulation time, without any differences in the actual amount of perioperative bleeding and transfusion requirements among the groups. Also, inflammatory markers showed significant activation after cardiopulmonary bypass without any differences among the groups.

CONCLUSION

Even in the presence of prolonged duration of cardiopulmonary bypass, HES seemed to yield similar influence on the ensuing coagulopathy and inflammatory response when used for priming and perioperative fluid therapy following complex valvular heart surgery compared with conventional fluid regimen including albumin and plasmalyte.

Tranexamic acid corrects fibrinolysis in the presence of acidemia in a swine model of severe ischemic reperfusion

BACKGROUND

Tranexamic acid (TXA) is an antifibrinolytic with anti-inflammatory properties associated with improved outcomes when administered to trauma patients at risk for bleeding; however, its efficacy is unknown in acidemia. We evaluated the efficacy of TXA on hyperfibrinolysis using an established porcine traumatic hemorrhage ischemic shock model.

METHODS

Ten Yorkshire swine underwent a controlled hemorrhage followed by supraceliac aortic cross-clamping. During standard resuscitation, control animals received recombinant tissue plasminogen activator (rtPA) after cross-clamp removal, and experimental animals received rtPA followed by TXA. Rotational thromboelastometry analysis was performed at baseline, 5 minutes and 15 minutes after rtPA dosing, and 4 hours after cross-clamp removal.

RESULTS

Control and experimental animals had similar hemodynamics and routine laboratory values at baseline and throughout resuscitation. At the time of TXA administration, average pH was 7.2. Clot formation time was prolonged from baseline and all resuscitation time points in both groups, with no difference at any time point. Maximum clot firmness decreased from baseline at all resuscitation time points in both groups. Maximum lysis increased from baseline (9% control vs. 9% TXA) after tissue plasminogen activator administration in both groups (100% control vs. 99% TXA). In experimental animals, maximum lysis returned to baseline 10 minutes after TXA administration (92% vs. 9%, p < 0.001).

CONCLUSION

TXA rapidly and fully reverses hyperfibrinolysis despite severe acidemia in a porcine trauma model. TXA is a promising adjunct to trauma resuscitation that is easily administered in austere or prehospital settings.

The efficacy of antifibrinolytic drugs in children undergoing noncardiac surgery: a systematic review of the literature

Children undergoing major surgery are frequently exposed to a high risk of blood loss often requiring transfusion. Although the risks associated with blood product transfusion have considerably decreased over the last decade, transfusion is still associated with significant morbidity and mortality. Thus, rigorous efforts should be made to decrease surgical bleeding and the need for blood product transfusion. Antifibrinolytic drugs have been shown to be effective when used in both adult and pediatric surgical patients. While there are data in adults to support safety, data remain limited for pediatric patients. Since the restriction of aprotinin use in 2008, the most commonly used antifibrinolytic drugs have been the lysine analogs, tranexamic acid (TXA), and ε-aminocaproic acid, which inhibit the conversion of plasminogen to plasmin and decrease the degree of fibrinolysis. We performed a systematic review of the literature pertaining to the efficacy of antifibrinolytic drugs in children undergoing noncardiac surgery. During spine surgery, both TXA and ε-aminocaproic acid decrease blood loss and transfusion requirements; however, this information comes from small, mainly retrospective trials. Two prospective, randomized, controlled trials have tested the efficacy of TXA in children undergoing craniofacial surgery and have reported that TXA decreases transfusion requirements. Two pharmacokinetic trials were also recently published and are summarized in this review. No data have been published regarding the efficacy of TXA administration in the pediatric trauma population. Further data are still needed in this field of study, and we discuss some perspectives for future research.

Management of hemorrhage in trauma

Hemorrhage remains one of the leading causes of trauma-related deaths. Uncontrolled diffuse microvascular bleeding in the course of initial care is common, potentially resulting in exsanguination. Early and aggressive hemostatic intervention increases survival and reduces the incidence of massive transfusion. Thus, timely diagnosis of the underlying coagulation disorders is mandatory. It has been shown that standard coagulation tests do not sufficiently characterize trauma-induced coagulopathy (TIC). This has led to increasing interest in alternatives, such as the viscoelastic test, to diagnose TIC and to provide the basis for a goal-directed hemostatic therapy. The concept of damage control resuscitation (DCR) has been introduced widely in trauma patients with severe bleeding. This strategy addresses important confounders of the coagulation process such as hemodilution, hypothermia, and acidosis; DCR is based on a damage control surgical approach, permissive hypotension, and improvement of hemostatic competence. Many studies have shown benefit in mortality when using high ratios of fresh frozen plasma (FFP) to red blood cells (RBC) as early treatment. However, there is increased awareness that coagulation factor concentrate could be beneficial in the treatment of trauma-induced coagulopathy.