Fig. 1. Incidence of head trauma during the study period and distribution of traumatic brain injury necessitating neurosurgical intervention. Patients who received total intravenous anesthesia (TIVA) versus volatile gas anesthesia (VGA) with complete data were evaluated for mortality and good neurologic outcome (Glasgow Outcome Score [GOS] 4–5). DOW = died of wounds (patients surviving to combat support hospital but died after receiving some medical interventions; interventions include expectant management in patients with severe injuries); ICP = intracranial pressure; KIA = killed in action (died before reaching the combat support hospital); OR = operating room.