Data for this study were obtained from the NTDB of the Committee on Trauma of the ACS, which currently houses records for more than 1.3 million trauma patients. The study population consisted of all trauma patients alive on admission with a head AIS of 3 or higher and no other body region with an AIS of 3 or higher. Data elements selected from NTDB for analysis included age, sex, mechanism of injury (blunt or penetrating), ACS trauma level designation (1 or 2), hypotension on admission (systolic blood pressure, <90 mm Hg), Glasgow Coma Score on admission (GCS), functional independence scale scores, hospital length of stay, intensive care unit (ICU) length of stay, days treated with a ventilator, and survival outcomes. Documented complications were also collected regarding occurrence of adult respiratory distress syndrome, aspiration pneumonia, bacteremia, cardiac arrest, coagulopathy, compartment syndrome, dehiscence, disseminated fungal infections, deep venous thrombosis, empyema, esophageal intubation, hypothermia, intraabdominal abscess, jaundice, myocardial infarction, pancreatitis, pneumonia, pneumothorax, progression of initial neurologic insult, pulmonary embolism, renal failure, urinary tract infection, and wound infection. The types of procedures, including intracranial pressure monitor or ventriculostomy placement, craniotomy, craniectomy, incision of brain for drainage of intracerebral hemorrhage and lobectomy, or other brain excision were also collected by procedure code.