An anesthesiologist, also "anaesthesiologist," is a medical doctor trained to administer anesthesia and manage the medical care of patients before, during, and after surgery. According to Mosby's Medical Dictionary, 8th edition, 2009, anesthetist is a general term used to describe a health care professional trained to administer anesthesia to their patients. In addition, the source defines an anesthesiologist as a physician who completes an accredited residency program in anesthesiology. A nurse anesthetist is a nurse who is trained in the administration of anesthesia after undergoing special training, and generally under supervision of a physician. Anesthesiologists may administer anesthesia directly or as part of an anesthesia team consisting of nurse anesthetists or anesthesiologist's assistants.