Tranexamic Acid: Promise or Panacea: The Impact of Air Medical Administration of Tranexamic Acid on Morbidity, Mortality, and Length of Stay

Pre-hospital administration of tranexamic acid in trauma patients: A systematic review and meta-analysis

Background

The Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage-2 (CRASH-2) trial proved that tranexamic acid (TXA) is a time-dependent drug, having a better outcome if given within 1-hour of injury. In order to test this theory, studies have been conducted to examine the effect of TXA in the pre-hospital setting. We conducted a systematic search and meta-analysis to evaluate the role of TXA administration in the civilian pre-hospital setting on patient outcomes.

Methods

Embase, Medline, CINAHL and Cochrane were searched for randomized control trials (RCTs), retrospective, and prospective studies that examined the effect of TXA on patients in the pre-hospital setting versus a control group. Outcome measures were overall mortality rate and thromboembolic events. Two authors extracted the data independently. To appraise the included studies, we used the NIH quality assessment tool for cohort and cross-sectional studies. Results are presented as Risk Ratio (RR), a random-effect model was implemented, and the I2 test was used to assess heterogeneity.

Results

The search identified 1886 papers, but only five retrospective studies met the inclusion/exclusion criteria and were selected for further analysis. A meta-analysis confirmed that TXA reduced the overall mortality rate (pooled risk ratio of 0.74 (95% CI 0.45, 1.25)) and thromboembolic events (risk ratio of 0.71 (95% CI 0.35, 1.44)).

Conclusion

The pooled effects for both outcome measures favour the administration of TXA in the pre-hospital setting, although none of the findings reported a significant effect. Our study highlights the need for additional high-quality evidence to validate the significance of these findings.

Level of evidence

Level III, therapeutic study.

Evaluating the Tactical Combat Casualty Care principles in civilian and military settings: systematic review, knowledge gap analysis and recommendations for future research

OBJECTIVES

The Tactical Combat Casualty Care (TCCC) guidelines detail resuscitation practices in prehospital and austere environments. We sought to review the content and quality of the current TCCC and civilian prehospital literature and characterize knowledge gaps to offer recommendations for future research.

METHODS

MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials were searched for studies assessing intervention techniques and devices used in civilian and military prehospital settings that could be applied to TCCC guidelines. Screening and data extraction were performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Quality appraisal was conducted using appropriate tools.

RESULTS

Ninety-two percent (n=57) of studies were observational. Most randomized trials had low risk of bias, whereas observational studies had higher risk of bias. Interventions of massive hemorrhage control (n=17) were wound dressings and tourniquets, suggesting effective hemodynamic control. Airway management interventions (n=7) had high success rates with improved outcomes. Interventions of respiratory management (n=12) reported low success with needle decompression. Studies assessing circulation (n=18) had higher quality of evidence and suggested improved outcomes with component hemostatic therapy. Hypothermia prevention interventions (n=2) were generally effective. Other studies identified assessed the use of extended focused assessment with sonography in trauma (n=3) and mixed interventions (n=2).

CONCLUSIONS

The evidence was largely non-randomized with heterogeneous populations, interventions, and outcomes, precluding robust conclusions in most subjects addressed in the review. Knowledge gaps identified included the use of blood products and concentrate of clotting factors in the prehospital setting.

LEVEL OF EVIDENCE

Systematic review, level III.

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.

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.