A nurse anesthetist is a nurse who specializes in the administration of anesthesia. In the United States, a Certified Registered Nurse Anesthetist (CRNA) is an advanced practice registered nurse (APRN) who has acquired graduate-level education and board certification in anesthesia. The American Association of Nurse Anesthetists’ (AANA) is the national association that represents more than 92% of the 40,000 nurse anesthetists in the United States.