Tranexamic Acid in Civilian Trauma Care in the California Prehospital Antifibrinolytic Therapy Study

Michael M. Neeki, DO, MS; Fanglong Dong, PhD; Jake Toy, BA; Reza Vaezazizi, MD; Joe Powell, EMT-P; David Wong, MD; Michael Mousselli, BS; Massoud Rabiei, BS; Alex Jabourian, DO; Nichole Niknafs, DO; Michelle Burgett-Moreno, BA; Richard Vara, RN, BSN; Shanna Kissel, RN, MSN; Xian Luo-Owen, MD, PhD; Karen R. O'Bosky, MD; Daniel Ludi, MD; Karl Sporer, MD; Troy Pennington, DO; Tommy Lee, MD; Rodney Borger, MD; Eugene Kwong, MD

Disclosures

Western J Emerg Med. 2018;19(6):977-986. 

In This Article

Results

A total of 362 patients were included in the TXA group (Figure 2). To eliminate the confounding effect of age, gender, ISS, and mechanism of injury, we conducted a propensity matching based on these four factors to select 362 patients as the control group. As a result, 724 patients were included in the final analysis. The median time for paramedics to administer TXA from the estimated time of injury was 33 minutes (interquartile range: 26 min, 46 min). As expected per the propensity matching process, there was no statistically significant difference in age (37.96 vs. 37.64 years for the TXA and control groups, respectively, difference=0.32 with 95% confidence interval [CI] [-2.05 to 2.69]), percentage of males (80.9% vs. 80.9% for the TXA and control groups, respectively, odds ratio [OR]=1 with 95% CI [0.69 to 1.45]), ISS (16.08 vs, 17.15 for the TXA and control groups, respectively, difference=-1.07 with 95% CI [-2.86 to 0.72]), and mechanism of injury (percentage of blunt trauma was 37.0% for both the TXA and control groups, respectively, OR=1 with 95% CI [0.74 to 1.35] (Table 1).

Figure 2.

Patient flow chart.

We compared clinical outcomes between the TXA and control groups. The results were also presented in Table 1. The TXA group had a statistically significant decrease in 28-day mortality (3.6% vs 8.3%, OR=0.41 with 95% CI [0.21 to 0.8]), fewer units of total blood products transfused (median of 1 vs. 3 units, difference=2 with 95% CI [1.14 to 2.86]), shorter hospital LOS (median of 4 vs. 8 days, difference=4 with 95% CI [2.35 to 5.64]), and shorter ICU length of stay (median of 4 vs. 5 days, difference=1 with 95% CI [0.65 to 2.25]).

Regarding the adverse events following TXA administration, no differences in the incidence of thromboembolic, myocardial infarction, or neurologic events were noted between the TXA and control groups. In the TXA group, two thromboembolic events, zero neurologic events, and zero myocardial infarction events were reported. In the control group, two thromboembolic events, zero neurologic events, and zero myocardial infarction events were reported. Additionally, two neurologic events were considered as possible adverse events in the TXA group, but after thorough review of each case, TXA as the primary etiology was deemed remote. In one case, a young male patient received TXA following a head-on, high-speed, motor vehicle accident where he sustained multiple, long bone fractures. He subsequently experienced a hemisphere ischemic stroke 40 hours after admission. Repeat computed tomography (CT) of his head revealed a new large ischemic infarct in the right middle cerebral artery distribution with moderate mass effect and midline shift. Suspecting traumatic vascular injury, a computed tomography angiography (CTA) study was ordered but not completed after his family decided to instate a do-not-resuscitate (DNR) order. A second case of ischemic stroke following TXA administration occurred in an elderly individual following a high-speed motor vehicle accident where the patient presented with altered mental status, scalp lacerations and a possible, small subdural hematoma as well as multiple, long bone fractures. Forty-eight hours after admission, the patient was diagnosed with an ischemic stroke, which neurosurgery attributed to fat emboli from long bone fractures.

We conducted a subgroup analysis to assess clinical outcomes between patients who received one dose vs. two doses of TXA (Table 2). Compared with patients who received one dose of TXA, those who received two doses of TXA required more blood transfusions (median of 0 vs. 3 units of blood product, difference=3 with 95% CI [1.34 to 4.67]).

A second subgroup analysis was conducted among patients who required transfusion (Table 3). Among patients who received <10 units of blood transfusion, the TXA group required fewer units of blood products transfused (median of 0 vs. 2 units, difference=2 with 95% CI [1.44 to 3.56]), had shorter hospital LOS (median of 4 vs. 8 days, difference=4 with 95% CI [2.28 to 5.73]), and shorter ICU LOS (median of 3 vs. 4 days, difference=1 with 95% CI [0.98 to 2.02]). Among patients who received ≥10 units of blood transfusion, the TXA group had a statistically significant decrease in mortality at 28 days (8.5% vs 23.2%, OR=0.31 with 95% CI [0.11 to 0.84]).

We conducted a third subgroup analysis based on patients' ISS score (Table 4). Among patients with ISS <16, the TXA group had lower 24-hour mortality (0% vs. 2.6%, OR=0), fewer units of blood product transfused (median of 0 vs. 2.7 units, difference=2.7 with 95% CI [2.02 to 3.64]), shorter hospital LOS (median of 3 vs. 7 days, difference=4 with 95% CI [1.66 to 6.34]), and shorter ICU LOS (median of 3 vs. 5 days, difference=2 with 95% CI [0.59 to 3.41]). Among patients with ISS >16, the TXA group had statistically significant decrease in 28-day mortality (6% vs 14.5%, OR=0.37 with 95% CI [0.17 to 0.8]).

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