The principles of trauma anesthesia are the same as those for routine anesthesia but also include the added stresses of urgency, uncertainty, and reduced control. Administering an anesthetic involves the controlled, reversible poisoning of the nervous system to allow the performance of a therapeutic or diagnostic procedure without pain, anxiety, awareness, recall, movement, or cardiovascular response. Disruption of the normal homeostatic mechanisms produces adverse effects ranging from apnea and hypotension to positioning injuries and falls unless specific efforts are directed to prevent these complications. In routine anesthesia, a single organ system is disturbed by the surgery, and anesthesia is achieved in an orderly manner. In contrast, the trauma patient usually presents with multiple life-threatening insults and displays a spectrum of physiological dysfunctions. Time is of the essence. History and laboratory data are sparse. Airway establishment, ventilation, and hemorrhage control become the dominant, time-critical issues—usually under disadvantageous conditions.