Tranexamic acid for trauma: filling the 'GAP' in evidence

Review article: Pre-hospital trauma guidelines and access to lifesaving interventions in Australia and Aotearoa/New Zealand

The centralisation of trauma services in western countries has led to an improvement in patient outcomes. Effective trauma systems include a pre-hospital trauma system. Delivery of high-level pre-hospital trauma care must include identification of potential major trauma patients, access and correct application of lifesaving interventions (LSIs) and timely transport to definitive care. Globally, many nations endorse nationwide pre-hospital major trauma triage guidelines, to ensure a universal approach to patient care. This paper examined clinical guidelines from all 10 EMS in Australia and Aotearoa/New Zealand. All relevant trauma guidelines were included, and key information was extracted. Authors compared major trauma triage criteria, all LSI included in guidelines, and guidelines for transport to definitive care. The identification of major trauma patients varied between all 10 EMS, with no universal criteria. The most common approach to trauma triage included a three-step assessment process: physiological criteria, identified injuries and mechanism of injury. Disparity between physiological criteria, injuries and mechanism was found when comparing guidelines. All 10 EMS had fundamental LSI included in their trauma guidelines. Fundamental LSI included haemorrhage control (arterial tourniquets, pelvic binders), non-invasive airway management (face mask ventilation, supraglottic airway devices) and pleural wall needle decompression. Variation in more advanced LSI was evident between EMS. Optimising trauma triage guidelines is an important aspect of a robust and evidence driven trauma system. The lack of consensus in trauma triage identified in the present study makes benchmarking and comparison of trauma systems difficult.

Tranexamic acid for major trauma patients in Ireland

BACKGROUND

The Clinical Randomisation of an Anti-fibrinolytic in Significant Hemorrhage-2 (CRASH-2) is the largest randomized control trial (RCT) examining circulatory resuscitation for trauma patients to date and concluded a statistically significant reduction in all-cause mortality in patients administered tranexamic acid (TXA) within 3 hours of injury. Since the publication of CRASH-2, significant geographical variance in the use of TXA for trauma patients exists. This study aims to assess TXA use for major trauma patients with hemorrhagic shock in Ireland after the publication of CRASH-2.

METHODS

A retrospective cohort study was conducted using data derived from the Trauma Audit and Research Network (TARN). All injured patients in Ireland between January 2013 and December 2018 who had evidence of hemorrhagic shock on presentation (as defined by systolic blood pressure [SBP] <100 mmHg [1 mmHg=0.133 kPa] and administration of blood products) were eligible for inclusion. Death at hospital discharge was the primary outcome.

RESULTS

During the study period, a total of 234 patients met the inclusion criteria. Among injured patients presenting with hemorrhagic shock, 133 (56.8%; 95% confidence interval [CI] 50.2%-63.3%) received TXA. Of patients that received TXA, a higher proportion of patients presented with shock index >1 (70.68% vs.57.43%) and higher Injury Severity Score (ISS >25; 49.62% vs. 23.76%). Administration of TXA was not associated with mortality at hospital discharge (odds ratio [OR] 0.86, 95% CI 0.31-2.38).

CONCLUSIONS

Among injured Irish patients presenting with hemorrhagic shock, TXA was administered to 56.8% of patients. Patients administered with TXA were on average more severely injured. However, a mortality benefit could not be demonstrated.

Use of Tranexamic Acid in Traumatic Resuscitation in a Prehospital Setting: A Case Report

This study describes the use of tranexamic acid associated with other measures in the initial approach to contain bleeding in a situation of hemorrhagic shock in a trauma patient. The case describes the care of a young man with multiple thorax punctures by a melee weapon, quickly progressing to a condition of severe shock, in addition to the action of a helicopter emergency medical team supporting the patient's transportation from a low-complexity emergency care unit to a specialized unit.

Does Liberal Prehospital and In-Hospital Tranexamic Acid Influence Outcome in Severely Injured Patients? A Prospective Cohort Study

Background

Early hemorrhage control is important in trauma-related death prevention. Tranexamic acid (TXA) has shown to be beneficial in patients in hemorrhagic shock, although widespread adoption might result in incorrect TXA administration leading to increased morbidity and mortality.

Methods

A 7-year prospective cohort study with consecutive trauma patients admitted to a Level-1 Trauma Center ICU was performed to investigate administration of both pre- and in-hospital TXA and its relation to morbidity and mortality. Indication for prehospital and in-hospital TXA administration was (suspicion of) hemorrhagic shock, and/or systolic blood pressure (SBP) ≤ 90 mmHg. Demographics, data on physiology, resuscitation and outcomes were prospectively collected.

Results

Four hundred and twenty-two patients (71% males, median ISS 29, 95% blunt injuries) were included. Even though TXA patients were more severely injured with more deranged physiology, no differences in outcome were noted. Overall, thrombo-embolic complication rate was 8%. In half the patients, hemorrhagic shock was the indication for prehospital TXA, whereas 79% of in-hospital TXA was given based on suspicion of hemorrhagic shock. Thirteen percent of patients with SBP ≤ 90 mmHg in ED received no TXA at all. Based on SBP alone, 22% of prehospital TXA and 25% of in-hospital TXA were justified.

Conclusions

Despite being more severely injured, TXA patients had similar outcome compared to patients without TXA. Thrombo-embolic complication rate was low despite liberal use of both prehospital and in-hospital TXA. Caution should be exercised in selecting patients for TXA, although this might be challenging based on SBP alone in patients who do not yet show signs of deranged physiology on arrival in ED.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00268-021-06143-y.

Protocol for a multicentre prehospital randomised controlled trial investigating tranexamic acid in severe trauma: the PATCH-Trauma trial

INTRODUCTION

Haemorrhage causes most preventable prehospital trauma deaths and about a third of in-hospital trauma deaths. Tranexamic acid (TXA), administered soon after hospital arrival in certain trauma systems, is an effective therapy in preventing or managing acute traumatic coagulopathy. However, delayed administration of TXA appears to be ineffective or harmful. The effectiveness of prehospital TXA, incidence of thrombotic complications, benefit versus risk in advanced trauma systems and the mechanism of benefit remain uncertain.

METHODS AND ANALYSIS

The Pre-hospital Anti-fibrinolytics for Traumatic Coagulopathy and Haemorrhage (The PATCH-Trauma study) is comparing TXA, initiated prehospital and continued in hospital over 8 hours, with placebo in patients with severe trauma at risk of acute traumatic coagulopathy. We present the trial protocol and an overview of the statistical analysis plan. There will be 1316 patients recruited by prehospital clinicians in Australia, New Zealand and Germany. The primary outcome will be the eight-level Glasgow Outcome Scale Extended (GOSE) at 6 months after injury, dichotomised to favourable (GOSE 5-8) and unfavourable (GOSE 1-4) outcomes, analysed using an intention-to-treat (ITT) approach. Secondary outcomes will include mortality at hospital discharge and at 6 months, blood product usage, quality of life and the incidence of predefined adverse events.

ETHICS AND DISSEMINATION

The study was approved by The Alfred Hospital Research and Ethics Committee in Victoria and also approved in New South Wales, Queensland, South Australia, Tasmania and the Northern Territory. In New Zealand, Northern A Health and Disability Ethics Committee provided approval. In Germany, Witten/Herdecke University has provided ethics approval. The PATCH-Trauma study aims to provide definitive evidence of the effectiveness of prehospital TXA, when used in conjunction with current advanced trauma care, in improving outcomes after severe injury.

TRIAL REGISTRATION NUMBER

NCT02187120.

Tranexamic acid administration is associated with an increased risk of posttraumatic venous thromboembolism

BACKGROUND

Tranexamic acid (TXA) is used as a hemostatic adjunct for hemorrhage control in the injured patient and reduces early preventable death. However, the risk of venous thromboembolism (VTE) has been incompletely explored. Previous studies investigating the effect of TXA on VTE vary in their findings. We performed a propensity matched analysis to investigate the association between TXA and VTE following trauma, hypothesizing that TXA is an independent risk factor for VTE.

METHODS

This retrospective study queried trauma patients presenting to a single Level I trauma center from 2012 to 2016. Our primary outcome was composite pulmonary embolism or deep vein thrombosis. Mortality, transfusion, intensive care unit and hospital lengths of stay were secondary outcomes. Propensity matched mixed effects multivariate logistic regression was used to determine adjusted odds ratio (aOR) and 95% confidence intervals (95% CI) of TXA on outcomes of interest, adjusting for prespecified confounders. Competing risks regression assessed subdistribution hazard ratio of VTE after accounting for mortality.

RESULTS

Of 21,931 patients, 189 pairs were well matched across propensity score variables (standardized differences <0.2). Median Injury Severity Score was 19 (interquartile range, 12-27) and 14 (interquartile range, 8-22) in TXA and non-TXA groups, respectively (p = 0.19). Tranexamic acid was associated with more than threefold increase in the odds of VTE (aOR, 3.3; 95% CI, 1.3-9.1; p = 0.02). Tranexamic acid was not significantly associated with survival (aOR, 0.86; 95% CI, 0.23-3.25; p = 0.83). Risk of VTE remained elevated in the TXA cohort despite accounting for mortality (subdistribution hazard ratio, 2.42; 95% CI, 1.11-5.29; p = 0.03).

CONCLUSION

Tranexamic acid may be an independent risk factor for VTE. Future investigation is needed to identify which patients benefit most from TXA, especially given the risks of this intervention to allow a more individualized treatment approach that maximizes benefits and mitigates potential harms.

LEVEL OF EVIDENCE

Therapeutic, level III.

Validation of the COAST score for predicting acute traumatic coagulopathy: A retrospective single-centre cohort study

Purpose

Early identification of trauma patients at risk of developing acute traumatic coagulopathy is important in initiating appropriate, coagulopathy-focused treatment. A clinical acute traumatic coagulopathy prediction tool is a quick, simple method to evaluate risk. The COAST score was developed in Australia and we hypothesised that it could predict coagulopathy and bleeding-related adverse outcomes in other advanced trauma systems. We validated COAST on a single-centre cohort of trauma patients from a trauma centre in Belgium.

Methods

The COAST score was modified to suit available data; we used entrapment, blood pressure, temperature, major chest injury and abdominal injury to calculate the score. Acute traumatic coagulopathy was defined as international normalised ratio >1.5 or activated partial thromboplastin time >60 s upon arrival of the patient to the hospital. Data were extracted from the local trauma registry on patients that presented between 1 January and 31 December 2015.

Results

In all, 133 patients met the inclusion criteria (>16 years old, available COAST and outcome data) for analysis. The COAST score had an area under the receiver operating characteristics curve of 0.941 (95% CI: 0.884–0.999) and at COAST ≥3, it had 80% sensitivity and 96% specificity. The score also identified patients with higher rates of mortality, blood transfusion and emergent surgery.

Conclusion

This retrospective cohort study demonstrated the utility of the COAST score in identifying trauma patients who are likely to have bleeding-related poor outcomes. The early identification of these patients will facilitate timely, appropriate treatment for acute traumatic coagulopathy and minimise the risk of over-treatment. It can also be used to select patients with acute traumatic coagulopathy for trials involving therapeutic agents targeted at acute traumatic coagulopathy.

A Retrospective Study of Transfusion Requirements in Trauma Patients Receiving Tranexamic Acid

The Military Application of Tranexamic Acid in Trauma Emergency Resuscitation Study (MATTERs) and Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage-2 (CRASH-2) studies demonstrate that tranexamic acid (TXA) reduces mortality in patients with traumatic hemorrhage. However, their results, conducted in foreign countries and U.S. military soldiers, provoke concerns over generalizability to civilian trauma patients in the United States. We report the evaluation of patient outcomes and transfusion requirements following treatment with TXA by a civilian air medical program. We conducted a retrospective chart review of trauma patients transported by air service to a Level 1 trauma center. For the purposes of intervention evaluation, patients meeting this criterion for the 2 years (2012-2014) prior to therapy implementation were compared with patients treated during the 2-year study period (2014-2016). Goals were to evaluate morbidity, mortality, transfusion requirements, and length of stay. During the review, 52 control (non-TXA) and 43 study (TXA) patients were identified as meeting inclusion criteria. Patients in the control group were found to be less acute, which correlated with shorter hospitals stays. There was reduced mortality for patients receiving TXA in spite of their increased acuity and decreased likelihood of survival. Trauma patients from this cohort study receiving TXA demonstrate decreased mortality in spite of increased acuity. This increased acuity is associated with increased transfusion requirements. Future research should evaluate patient selection with concern for fibrinolysis and provider bias. Randomized controlled trial is needed to evaluate the role of TXA administration in the United States.

Effect of tranexamic acid by baseline risk of death in acute bleeding patients: a meta-analysis of individual patient-level data from 28 333 patients

Background

Early administration of the antifibrinolytic drug tranexamic acid reduces death from bleeding in trauma and postpartum haemorrhage. We examined how the effectiveness and safety of antifibrinolytic drugs varies by the baseline risk of death as a result of bleeding.

Methods

We performed an individual patient-level data meta-analysis of randomised trials including more than 1000 patients that assessed antifibrinolytics in acute severe bleeding. We identified trials performed between January 1, 1946 and July 5, 2018 (PROSPERO, number 42016052155).

Results

Two randomised trials were selected where 28 333 patients received tranexamic acid treatment within 3 h after the onset of acute bleeding. Baseline characteristics to estimate the risk of death as a result of bleeding were divided into four categories: Low (0–5%), intermediate (6–10%), high (11–20%), and very high (>20%). Most patients had a low baseline risk of death as a result of bleeding (23 008 [81%]). Deaths as a result of bleeding occurred in all baseline risk categories with 240 (1%), 202 (8%), 232 (14%), and 357 (30%) deaths in the low-, intermediate-, high-, and very high-risk categories, respectively. The effectiveness of tranexamic acid did not vary by baseline risk when given within 3 h after bleeding onset (P=0.51 for interaction term). There was no increased risk of vascular occlusive events with tranexamic acid and it did not vary by baseline risk categories (P=0.25).

Conclusions

Tranexamic acid appears to be safe and effective regardless of baseline risk of death. Because many deaths are in patients at low and intermediate risk, tranexamic acid use should not be restricted to the most severely injured or bleeding patients.

Tranexamic Acid for Acute Hemorrhage: A Narrative Review of Landmark Studies and a Critical Reappraisal of Its Use Over the Last Decade

The publication of the Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage-2 (CRASH-2) study and its intense dissemination prompted a renaissance for the use of the antifibrinolytic agent tranexamic acid (TXA) in acute trauma hemorrhage. Subsequent studies led to its widespread use as a therapeutic as well as prophylactic agent across different clinical scenarios involving bleeding, such as trauma, postpartum, and orthopedic surgery. However, results from the existing studies are confounded by methodological and statistical ambiguities and are open to varied interpretations. Substantial knowledge gaps remain on dosing, pharmacokinetics, mechanism of action, and clinical applications for TXA. The risk for potential thromboembolic complications with the use of TXA must be balanced against its clinical benefits. The present article aims to provide a critical reappraisal of TXA use over the last decade and a "thought exercise" in the potential downsides of TXA. A more selective and individualized use of TXA, guided by extended and functional coagulation assays, is advocated in the context of the evolving concept of precision medicine.

Geographical Variance in the Use of Tranexamic Acid for Major Trauma Patients

Background and Objectives: The CRASH-2 trial is the largest randomised control trial examining tranexamic acid (TXA) for injured patients. Since its publication, debate has arisen around whether results could be applied to mature trauma systems in developed nations, with global opinion divided. The aim of this study was to determine if, among trauma patients in or at significant risk of major haemorrhages, there is an association of geographic region with the proportion of patients that received tranexamic acid. Materials and Methods: We conducted a systematic review of the literature. Potentially eligible papers were first screened via title and abstract screening. A full copy of the remaining papers was then obtained and screened for final inclusion. The Newcastle-Ottawa Scale for non-randomised control trials was used for quality assessment of the final studies included. A meta-analysis was conducted using a random-effects model, reporting variation in use sub-grouped by geographical location. Results: There were 727 papers identified through database searching and 23 manuscripts met the criteria for final inclusion in this review. There was a statistically significant variation in the use of TXA for included patients. Europe and Oceania had higher usage rates of TXA compared to other continents. Use of TXA in Asia and Africa was significantly less than other continents and varied use was observed in North America. Conclusions: A large geographical variance in the use of TXA for trauma patients in or at significant risk of major haemorrhage currently exists. The populations in Asia and Africa, where the results of CRASH-2 could be most readily generalised to, reported low rates of use. The reason why remains unclear and further research is required to standardise the use of TXA for trauma resuscitation.

Tranexamic Acid Influences the Immune Response, but not Bacterial Clearance in a Model of Post-Traumatic Brain Injury Pneumonia

The antifibrinolytic agent, tranexamic acid (TXA), an inhibitor of plasmin formation, currently is evaluated to reduce bleeding in various conditions, including traumatic brain injury (TBI). Because plasmin is implicated in inflammation and immunity, we investigated the effects of plasmin inhibition on the immune response after TBI in the presence or absence of induced pneumonia. Wild-type mice treated with vehicle or TXA or mice deficient in plasminogen (plg^-/-) underwent TBI using the controlled cortical impact model. Mice were then subjected to Staphylococcus aureus induced pneumonia and the degree of immune competence determined. Significant baseline changes in the innate immune cell profile were seen in plg^-/- mice with increases in spleen weight and white blood cell counts, and elevation in plasma interleukin-6 levels. The plg^-/- mice subjected to TBI displayed no additional changes in these parameters at the 72 h or one week time point post-TBI. The plg^-/- mice subjected to TBI did not exhibit any further increase in susceptibility to endogenous infection. Pneumonia was induced by intratracheal instillation of S. aureus. The TBI did not worsen pneumonia symptoms or delay recovery in plg^-/- mice. Similarly, in wild type mice, treatment with TXA did not impact on the ability of mice to counteract pneumonia after TBI. Administration of TXA after TBI and subsequent pneumonia, however, altered the number and surface marker expression of several myeloid and lymphoid cell populations, consistent with enhanced immune activation at the 72 h time point. This investigation confirms the immune-modulatory properties of TXA, thereby highlighting its effects unrelated to inhibition of fibrinolysis.

Timely completion of multiple life-saving interventions for traumatic haemorrhagic shock: a retrospective cohort study

Background

Early control of haemorrhage and optimisation of physiology are guiding principles of resuscitation after injury. Improved outcomes have been previously associated with single, timely interventions. The aim of this study was to assess the association between multiple timely life-saving interventions (LSIs) and outcomes of traumatic haemorrhagic shock patients.

Methods

A retrospective cohort study was undertaken of injured patients with haemorrhagic shock who presented to Alfered Emergency & Trauma Centre between July 01, 2010 and July 31, 2014. LSIs studied included chest decompression, control of external haemorrhage, pelvic binder application, transfusion of red cells and coagulation products and surgical control of bleeding through angio-embolisation or operative intervention. The primary exposure variable was timely initiation of ≥ 50% of the indicated interventions. The association between the primary exposure variable and outcome of death at hospital discharge was adjusted for potential confounders using multivariable logistic regression analysis. The association between total pre-hospital times and pre-hospital care times (time from ambulance at scene to trauma centre), in-hospital mortality and timely initiation of ≥ 50% of the indicated interventions were assessed.

Results

Of the 168 patients, 54 (32.1%) patients had ≥ 50% of indicated LSI completed within the specified time period. Timely delivery of LSI was independently associated with improved survival to hospital discharge (adjusted odds ratio (OR) for in-hospital death 0.17; 95% confidence interval (CI) 0.03–0.83; p = 0.028). This association was independent of patient age, pre-hospital care time, injury severity score, initial serum lactate levels and coagulopathy. Among patients with pre-hospital time of ≥ 2 h, 2 (3.6%) received timely LSIs. Pre-hospital care times of ≥ 2 h were associated with delayed LSIs and with in-hospital death (unadjusted OR 4.3; 95% CI 1.4–13.0).

Conclusions

Timely completion of LSI when indicated was completed in a small proportion of patients and reflects previous research demonstrating delayed processes and errors even in advanced trauma systems. Timely delivery of a high proportion of LSIs was associated with improved outcomes among patients presenting with haemorrhagic shock after injury. Provision of LSIs in the pre-hospital phase of trauma care has the potential to improve outcomes.

Early prediction of acute traumatic coagulopathy: a validation of the COAST score using the German Trauma Registry

BACKGROUND

Early identification of trauma patients at risk of developing acute traumatic coagulopathy (ATC) is important for initiating appropriate, coagulopathy-focused treatment. A clinical ATC prediction tool is a quick, simple method to evaluate risk. The COAST score was developed and validated in Australia but is yet to be validated on a European population. We validated the ability of the COAST score to predict coagulopathy and adverse bleeding-related outcomes on a large European trauma population.

METHODS

The COAST score was modified and applied to a retrospective cohort of trauma patients from the German Trauma Registry (TR-DGU). The primary outcome was coagulopathy defined as INR > 1.5 or aPTT > 60 s. Secondary outcomes were massive transfusion, blood product requirements, urgent surgery and mortality. The cohort included adult trauma patients with Injury Severity Score > 15 treated in Germany/Austria in 2012-2016.

RESULTS

15,370 cases were included, of which 10.9% were coagulopathic. The COAST score performed with sensitivity 21.6% and specificity 94.2% at a threshold of COAST ≥ 3. The AUROC was 0.625 (95% CI 0.61-0.64). The COAST score also identified patients who had more massive transfusions (15.3% v 1.6%), more emergency surgery (49.6% v 28.2%), and higher early (21.7% v 5.4%) and total in-hospital mortality (38.1% v 14.5%).

CONCLUSION

This large retrospective study demonstrated that the modified COAST score predicts coagulopathy with low sensitivity but high specificity. A positive COAST score identified a group of patients with bleeding-related adverse outcomes. This score appears adequate to act as an inclusion criterion for clinical trials targeting ATC.

Tranexamic acid in severe trauma patients managed in a mature trauma care system

BACKGROUND

Tranexamic acid (TXA) use in severe trauma remains controversial notably because of concerns of the applicability of the CRASH-2 study findings in mature trauma systems. The aim of our study was to evaluate the outcomes of TXA administration in severely injured trauma patients managed in a mature trauma care system.

METHODS

We performed a retrospective study of data prospectively collected in the TraumaBase registry (a regional registry collecting the prehospital and hospital data of trauma patients admitted in six Level I trauma centers in Paris Area, France). In hospital mortality was compared between patients having received TXA or not in the early phase of resuscitation among those presenting an unstable hemodynamic state. Propensity score for TXA administration was calculated and results were adjusted for this score. Hemodynamic instability was defined by the need of packed red blood cells (pRBC) transfusion and/or vasopressor administration in the emergency room (ER).

RESULTS

Among patients meeting inclusion criteria (n = 1,476), the propensity score could be calculated in 797, and survival analysis could be achieved in 684 of 797. Four hundred seventy (59%) received TXA, and 327 (41%) did not. The overall hospital mortality rate was 25.7%. There was no effect of TXA use in the whole population but mortality was lowered by the use of TXA in patients requiring pRBC transfusion in the ER (hazard ratio, 0.3; 95% confidence interval, 0.3-0.6).

CONCLUSION

The use of TXA in the management of severely injured trauma patients, in a mature trauma care system, was not associated with reduction in the hospital mortality. An independent association with a better survival was found in a selected population of patients requiring pRBC transfusion in the ER.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Evaluation of tranexamic acid in trauma patients: A retrospective quantitative analysis

INTRODUCTION

Tranexamic acid (TXA) has been shown to decrease mortality in adult trauma patients with or at significant risk of hemorrhage when administered within 3 h of injury. The use and appropriateness of TXA in adult trauma patients presenting to Royal Columbian Hospital (RCH) was investigated.

METHODS

This retrospective chart review utilized the British Columbia Trauma Registry to identify 100 consecutive trauma patients that presented to the emergency department at RCH between April 2012 to June 2015 and met the following indications for TXA: systolic blood pressure <90 mm Hg and/or heart rate >110 bpm and presentation within 8 h of injury. Primary outcomes included: percentage that met indications for TXA, received TXA according to the CRASH-2 protocol, received a pre-hospital dose, and received TXA ≤1, >1 to ≤3, or >3 h from injury.

RESULTS

During the given time period, 117 subjects (2.7%) met indications for TXA. 67 patients (57%) received TXA in any dose, with 10 subjects (8.5%) receiving TXA according to the CRASH-2 protocol. Of the 67 patients who received any TXA, 76% did so ≤3 h. 22 patients (19%) received TXA as a pre-hospital dose.

CONCLUSIONS

<10% of adult trauma patients that met the indication for TXA received it according to the CRASH-2 protocol. Of those patients that received TXA, 76% did so within 3 h. Further inquiry to identify reasons trauma patients are not receiving TXA as well as quality improvement initiatives in trauma care are required.

LEVEL OF EVIDENCE

III STUDY TYPE: Therapeutic.

Effect of treatment delay on the effectiveness and safety of antifibrinolytics in acute severe haemorrhage: a meta-analysis of individual patient-level data from 40 138 bleeding patients

BACKGROUND

Antifibrinolytics reduce death from bleeding in trauma and post-partum haemorrhage. We examined the effect of treatment delay on the effectiveness of antifibrinolytics.

METHODS

We did an individual patient-level data meta-analysis of randomised trials done with more than 1000 patients that assessed antifibrinolytics in acute severe bleeding. We identified trials done between Jan 1, 1946, and April 7, 2017, from MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, PubMed, Popline, and the WHO International Clinical Trials Registry Platform. The primary measure of treatment benefit was absence of death from bleeding. We examined the effect of treatment delay on treatment effectiveness using logistic regression models. We investigated the effect of measurement error (misclassification) in sensitivity analyses. This study is registered with PROSPERO, number 42016052155.

FINDINGS

We obtained data for 40 138 patients from two randomised trials of tranexamic acid in acute severe bleeding (traumatic and post-partum haemorrhage). Overall, there were 3558 deaths, of which 1408 (40%) were from bleeding. Most (884 [63%] of 1408) bleeding deaths occurred within 12 h of onset. Deaths from post-partum haemorrhage peaked 2-3 h after childbirth. Tranexamic acid significantly increased overall survival from bleeding (odds ratio [OR] 1·20, 95% CI 1·08-1·33; p=0·001), with no heterogeneity by site of bleeding (interaction p=0·7243). Treatment delay reduced the treatment benefit (p<0·0001). Immediate treatment improved survival by more than 70% (OR 1·72, 95% CI 1·42-2·10; p<0·0001). Thereafter, the survival benefit decreased by 10% for every 15 min of treatment delay until 3 h, after which there was no benefit. There was no increase in vascular occlusive events with tranexamic acid, with no heterogeneity by site of bleeding (p=0·5956). Treatment delay did not modify the effect of tranexamic acid on vascular occlusive events.

INTERPRETATION

Death from bleeding occurs soon after onset and even a short delay in treatment reduces the benefit of tranexamic acid administration. Patients must be treated immediately. Further research is needed to deepen our understanding of the mechanism of action of tranexamic acid.

FUNDING

UK NIHR Health Technology Assessment programme, Pfizer, BUPA Foundation, and J P Moulton Charitable Foundation (CRASH-2 trial). London School of Hygiene & Tropical Medicine, Pfizer, UK Department of Health, Wellcome Trust, and Bill & Melinda Gates Foundation (WOMAN trial).

Tranexamic Acid Use in Prehospital Uncontrolled Hemorrhage

The use of tranexamic acid (TXA) in the treatment of trauma patients was relatively unexplored until the landmark Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage-2 (CRASH-2) trial in 2010 demonstrated a reduction in mortality with the use of TXA. Although this trial was a randomized, double-blinded, placebo-controlled study incorporating >20,000 patients, numerous limitations and weaknesses have been described. As a result, additional studies have followed, delineating the potential risks and benefits of TXA administration. A systematic review of the literature to date reveals a mortality benefit of early (ideally <1 hour and no later than 3 hours after injury) TXA administration in the treatment of severely injured trauma patients (systolic blood pressure <90 mm Hg, heart rate >110). Combined with abundant literature showing a reduction in bleeding in elective surgery, the most significant benefit may be administration of TXA before the patient goes into shock. Those trials that failed to show a mortality benefit of TXA in the treatment of hemorrhagic shock acknowledged that most patients received blood products before TXA administration, thus confounding the results. Although the use of prehospital TXA in the severely injured trauma patient will become more clear with the trauma studies currently underway, the current literature supports the use of prehospital TXA in this high-risk population. We recommend considering a 1 g TXA bolus en route to definitive care in high-risk patients and withholding subsequent doses until hyperfibrinolysis is confirmed by thromboelastography.

Tranexamic Acid Update in Trauma

Following results from the CRASH-2 trial, tranexamic acid (TXA) gained considerable interest for the treatment of hemorrhage in trauma patients. Although TXA is effective at reducing mortality in patients presenting within 3 hours of injury, optimal dosing, timing of administration, mechanism, and pharmacokinetics require further elucidation. The concept of fibrinolysis shutdown in hemorrhagic trauma patients has prompted discussion of real-time viscoelastic testing and its potential role for appropriate patient selection. The results of ongoing clinical trials will help establish high-quality evidence for optimal incorporation of TXA in mature trauma networks in the United States and abroad.

USE OF TRANEXAMIC ACID IN TRAUMA PATIENTS: AN ANALYSIS OF COST-EFFECTIVENESS FOR USE IN BRAZIL

Introduction:

Use of tranexamic acid (TXA) in trauma has been the subject of growing interest by researchers and health professionals. However, there are still several open questions regarding its use. In some aspects medical literature is controversial. The points of disagreement among experts include questions such as: Which patients should receive TXA in trauma? Should treatment be performed in the pre-hospital environment? Is there any need for laboratory parameters before starting TXA treatment? What is the drug safety profile? The main issue on which there is still no basis in literature is: What is the indication for treatment within massive transfusion protocols?

Objective:

Answer the questions proposed based on critical evaluation of the evidence gathered so far and carry out a study of cost-effectiveness of TXA use in trauma adapted to the Brazilian reality.

Methods:

A literature review was performed through searching Pubmed.com, Embase and Cab Abstract by headings "tranexamic AND trauma", in all languages, yielding 426 articles. Manuscripts reporting on TXA utilization for elective procedures were excluded, remaining 79 articles. Fifty-five articles were selected, and critically evaluated in order to answer study questions. The evaluation of cost effectiveness was performed using CRASH-2 trial data and Brazilian official population data.

Results:

TXA is effective and efficient, and should be administered to a wide range of patients, including those with indication evaluated in research protocols and current indication criteria for TXA should be expanded. As for the cost-effectiveness, the TXA proved to be cost-effective with an average cost of R$ 61.35 (currently US$16) per year of life saved.

Conclusion:

The use of TXA in trauma setting seems to be effective, efficient and cost-effective in the various groups of polytrauma patients. Its use in massive transfusion protocols should be the subject of further investigations.

Prehospital tranexamic acid: what is the current evidence?

Many trauma systems are examining whether to implement prehospital tranexamic acid (TXA) protocols since hemorrhage remains the leading cause of potentially preventable early trauma mortality, and early in-hospital administration of TXA within 3 hours of injury is associated with reduced mortality. But robust evidence regarding the efficacy of prehospital administration of the antifibrinolytic drug TXA on trauma outcomes is lacking. This review examines the current evidence available regarding prehospital TXA efficacy in both military and civilian trauma, and updates available evidence regarding in-hospital TXA efficacy in trauma.

Advances in the understanding of trauma-induced coagulopathy

Ten percent of deaths worldwide are due to trauma, and it is the third most common cause of death in the United States. Despite a profound upregulation in procoagulant mechanisms, one-quarter of trauma patients present with laboratory-based evidence of trauma-induced coagulopathy (TIC), which is associated with poorer outcomes including increased mortality. The most common causes of death after trauma are hemorrhage and traumatic brain injury (TBI). The management of TIC has significant implications in both because many hemorrhagic deaths could be preventable, and TIC is associated with progression of intracranial injury after TBI. This review covers the most recent evidence and advances in our understanding of TIC, including the role of platelet dysfunction, endothelial activation, and fibrinolysis. Trauma induces a plethora of biochemical and physiologic changes, and despite numerous studies reporting differences in coagulation parameters between trauma patients and uninjured controls, it is unclear whether some of these differences may be "normal" after trauma. Comparisons between trauma patients with differing outcomes and use of animal studies have shed some light on this issue, but much of the data continue to be correlative with causative links lacking. In particular, there are little data linking the laboratory-based abnormalities with true clinically evident coagulopathic bleeding. For these reasons, TIC continues to be a significant diagnostic and therapeutic challenge.

Prehospital administration of tranexamic acid in trauma patients

Background

Evidence on prehospital administration of the antifibrinolytic tranexamic acid (TXA) in civilian trauma populations is scarce. The aim was to study whether prehospital TXA use in trauma patients was associated with improved outcomes.

Methods

The prehospital database of the ADAC (General German Automobile Club) Air Rescue Service was linked with the TraumaRegister of the German Trauma Society to reidentify patients documented in both registries. Primarily admitted trauma patients (2012 until 2014) who were treated with TXA during the prehospital phase were matched with patients who had not received prehospital TXA, applying propensity score-based matching.

Results

The matching yielded two identical cohorts (n = 258 in each group), since there were no significant differences in demographics or injury characteristics (mean Injury Severity Score 24 ± 14 [TXA] vs. 24 ± 16 [control]; p = 0.46). The majority had sustained blunt injury (90.3 % vs. 93.0 %; p = 0.34). There were no differences with respect to prehospital therapy, including rates of intubation, chest tube insertion or both administration of i.v. fluids and catecholamines. During ER treatment, the TXA cohort received fewer numbers of red blood cells and plasma units, but without reaching statistical significance. Incidences of organ failure, sepsis or thromboembolism showed no significant differences as well, although data were incomplete for these parameters. Early mortality was significantly lower in the TXA group (e.g., 24-h mortality 5.8 % [TXA] vs. 12.4 % [control]; p = 0.01), and mean time to death was 8.8 ± 13.4 days vs. 3.6 ± 4.9 days, respectively (p = 0.001). Overall hospital mortality was similar in both groups (14.7 % vs. 16.3 %; p = 0.72). The most pronounced mortality difference was observed in patients with a high propensity score, reflecting severe injury load.

Conclusions

This is the first civilian study, to our knowledge, in which the effect of prehospital TXA use in trauma patients has been examined. TXA was associated with prolonged time to death and significantly improved early survival. Until further evidence emerges, the results of this study support the use of TXA during prehospital treatment of severely injured patients.

Exploring redundant research into the effect of tranexamic acid on surgical bleeding: further analysis of a systematic review of randomised controlled trials

OBJECTIVES

We examined whether apparent redundancy in a cumulative meta-analysis of trials is justified by concern about bias, random error or generalisability of the results.

DESIGN

Cumulative meta-analysis, risk of bias assessment, trial sequential analysis, description of study participants over time and a review of rationales for conducting trials.

DATA SOURCE

126 randomised trials included in a systematic review assessing of tranexamic acid on blood transfusion in surgery.

RESULTS

The cumulative meta-analysis including all trials shows that the pooled estimate first reached statistical significance after the second trial in 1993. When the analysis was limited to the 38 high-quality trials and adjusted to account for potential systematic and random errors, the uncertainty was resolved after the 22nd trial in 2008. When the analysis was restricted to the two high-quality, prospectively registered trials, the cumulative z-curve crossed p=0.05 but not the monitoring boundary, suggesting an early potentially spurious statistically significant result. As precision of the pooled estimate increased, the number of trials initiated increased, although trial activity appeared to move to other surgery types. Most (62%) reports cited at least one systematic review. Of 118 reports examined, concern about generalisability was the reason for initiating the trial in 60%. Other reasons were to address a question other than the effect on bleeding (26%) and to confirm previously observed results (4%). Unawareness of previous research was apparent in 4% trials, while the rationale was unclear in 3%.

CONCLUSIONS

Our results indicate that poor quality is a more important cause of redundant research than the failure to review existing evidence. Concerns about generalisability of results is the main motivation for new trials. Contrary to previous claims, our results suggest that systematic reviews showing treatment effects can stimulate an increase in trial activity rather than reduce it.

Rural trauma patients cannot wait: tranexamic Acid administration by helicopter emergency medical services

OBJECTIVE

Tranexamic acid (TXA) administration has been shown to reduce mortality in bleeding trauma patients if given in the hospital within 3 hours of injury. Its use has been theorized to be of benefit in the prehospital environment. This study evaluates the timing of TXA administration in a critical care helicopter emergency medical service (HEMS) versus that of the destination trauma hospital.

METHODS

We performed a retrospective chart review of consecutive trauma patients who were given TXA during HEMS transfer. The time of injury to HEMS arrival, TXA administration, and hospital arrival was collected.

RESULTS

Twenty complete records were identified in which TXA was administered by HEMS: 11 scene calls and 9 interfacility transfers. The median time in minutes from the time of injury to HEMS arrival, TXA administration, and receiving hospital arrival was 90, 114, and 171, respectively, for scene calls and 134, 173, and 224, respectively, for interfacility transfers.

CONCLUSION

TXA must be administered before arrival at a trauma hospital to meet the recommendation of administration within 3 hours of injury for all patients transferred between facilities and for many patients transported from a trauma scene.

Red blood cell storage duration and trauma

Numerous retrospective clinical studies suggest that transfusion of longer stored red blood cells (RBCs) is associated with an independent risk of poorer outcomes for certain groups of patients, including trauma, intensive care, and cardiac surgery patients. Large multicenter randomized controlled trials are currently underway to address the concern about RBC storage duration. However, none of these randomized controlled trials focus specifically on trauma patients with hemorrhage. Major trauma, particularly due to road accidents, is the leading cause of critical injury in the younger-than-40-year-old age group. Severe bleeding associated with major trauma induces hemodynamic dysregulation that increases the risk of hypoxia, coagulopathy, and potentially multiorgan failure, which can be fatal. In major trauma, a multitude of stress-associated changes occur to the patient's RBCs, including morphological changes that increase cell rigidity and thereby alter blood flow hemodynamics, particularly in the microvascular vessels, and reduce RBC survival. Initial inflammatory responses induce deleterious cellular interactions, including endothelial activation, RBC adhesion, and erythrophagocytosis that are quickly followed by profound immunosuppressive responses. Stored RBCs exhibit similar biophysical characteristics to those of trauma-stressed RBCs. Whether transfusion of RBCs that exhibit storage lesion changes exacerbates the hemodynamic perturbations already active in the trauma patient is not known. This article reviews findings from several recent nonrandomized studies examining RBC storage duration and clinical outcomes in trauma patients. The rationale for further research on RBC storage duration in the trauma setting is provided.