Refinements in techniques, equipment, and mechanistic understanding have improved the ability of anesthesiologists to induce and manage general anesthesia and conscious sedation. The recognition that anesthesia is a receptor mediated phenomenon has led to the concept that immobility and unconsciousness are mediated at different sites and should be addressed separately during anesthetic care. New, processed electroencephalogram monitors allow anesthesiologists to assess consciousness separately from movement or autonomic control. The novel anesthetic dexmedetomidine, which offers sedation with less depression of respiratory or cognitive function, may provide further flexibility. Advances in anesthesia ventilator technology and specialty gases, such as heliox and nitric oxide, have widened the range of patients that may be cared for safely in the intraoperative setting. These improvements have enhanced the range of procedures that can be performed and the types of patients able to tolerate anesthesia.