Anesthesia can be defined as a state of reduced consciousness or reduced sensitivity in order to render uncomfortable procedures tolerable, safe and technically feasible. Anesthesia can also be defined as the practice of employing techniques to induce such a state. Most commonly, this is achieved by administering medications that reduce perception and attenuate reactions to stimuli. The practitioner that provides anesthesia also monitors and attends to vital physiologic functions as they are altered during the anesthetic state and are affected by the surgical procedure.
Providers of anesthesia in the United States include anesthesiologists, nurse anesthetists, and anesthesia assistants. Anesthesiologists are specialized physicians who, after acquiring a medical degree, complete residency training of at least four years. Nurse anesthetists have achieved certification through additional schooling and training following acquisition of an initial nursing degree and practice of nursing in a critical care setting for at least one year. Anesthesia assistants attend school and undergo training to provide anesthesia under the direction of a physician anesthesiologist. Nurse anesthetists, depending upon the jurisdiction, may provide anesthesia with or without the direction of a physician anesthesiologist.