Acidosis, a part of the lethal trauma triad, occurs frequently after major combat trauma. Tris-hydroxymethyl aminomethane (THAM) has been used to effectively treat acidosis in injured casualties. No research has been conducted assessing the safety of THAM in the military combat setting. We sought to describe the US military experience with THAM administration to battlefield injury subjects.

We conducted a retrospective descriptive cohort study reviewing the trauma data from the Department of Defense Trauma Registry. US military personnel with an injury severity score greater than 15, between September 2001 and December 2014, were analyzed. Our primary outcome was the 30-day all-cause mortality among cohort treated with THAM versus those who were not. Differences between the cohort were examined using a student t-test (continuous variables), Wilcoxon Rank Sum test (ordinal variables), and chi-squared test (nominal variables).

4558 subjects met the inclusion criteria. 69 received THAM and 4489 did not. Casualties receiving THAM had higher mean ISS scores (33 vs. 27, p < 0.001), and required significantly higher amounts of packed red blood cells (RBCs, 37 vs. 10, p < 0.001). THAM cohort had longer ventilator and intensive care unit (ICU) days with an overall lower survival to hospital discharge. On univariable analysis, THAM was associated with lower odds of survival (OR 0.18, 95% CI 0.11–0.31) but on multivariable analysis, when controlling for confounders, THAM use was not associated with a worse odds of survival (OR 0.83, 95% CI 0.21–3.24).

Within our combat trauma population, we were unable to detect worse 30 day mortality associated with THAM administration. Prospective investigations are needed to validate its use in critically injured combat casualties.