As our understanding of the coagulation cascade evolves, intensivists have sought ways to manipulate the pathway to attenuate the effects of hemorrhagic shock. Tranexamic acid (TXA) is a lysine analog that binds the plasminogen molecule, inhibiting fibrinolysis. In the February issue of Archives of Surgery, Morrison et al report their experience in the use of TXA in patients with wartime injuries.

The Military Application of Tranexamic Acid in Trauma Emergency Resuscitation Study (MATTERs) was a retrospective analysis spanning two years; it compared patients who received TXA to those who did not with regards to mortality rates, as well as the influence of TXA administration on markers of postoperative coagulopathy. An additional massive transfusion cohort, which consisted of patients who received 10 or more units of packed red blood cells in a 24-hour period, was also evaluated. Multivariate regression analyses were performed to determine factors that might influence survival, such as Injury Severity Scores.

Of the 896 patients enrolled in the study, 293 (32.7%) received TXA. These patients showed a 6.5% absolute reduction in in-hospital mortality despite having statistically significantly higher Injury Severity Scores. Patients in the massive transfusion cohort who received TXA showed a 13.7% absolute reduction in in-hospital mortality (relative reduction of 49%). A statistically significant correction of coagulation markers was observed in the patients who received TXA.

As with many observational, retrospective studies, there are several inherent limitations in this study, most notably the variability in the dosage and timing of TXA. The cause and time of death also could not be determined based on the nature of the study, introducing a possible survivorship bias. The 30-day outcome was difficult to ascertain for host-nation patients because of the nature of their discharge. Finally, patients who received TXA had a statistically significantly higher rate of thromboembolic events, although the number of events was too small to make any independent risk assessments.

This study demonstrates a positive impact of TXA for blood component-resuscitated combat casualties. The administration of TXA helps to better correct trauma-associated coagulopathies and appears to improve survival, especially in those patients who require massive transfusion.

Concise Critical Appraisal is a regular feature authored by SCCM member Samuel M. Galvagno Jr., DO. Each installment highlights journal articles most relevant to the critical care practitioner.

Special thanks to Stephanie Luekel, MD, who contributed to this installment of Concise Critical Appraise. Luekel is a fellow in trauma and critical care medicine at the R Adams Cowley Shock Trauma Center at the University of Maryland School of Medicine.