Anesthesiology, anaesthesiology, anaesthesia or anaesthetics is the medical specialty concerned with the total perioperative care of patients before, during and after surgery. It encompasses anesthesia, intensive care medicine, critical emergency medicine, and pain medicine. A physician or dentist specialized in this field of medicine is called an anesthesiologist, anaesthesiologist or anaesthetist, depending on the country. Nurses that specialize in anesthesia are called CRNA, Certified Registered Nurse Anesthetist, or Nurse anesthetist.
The core element of the specialty is the study and use of anesthesia and anesthetics to safely support a patient’s vital functions through the perioperative period. In some countries anesthesiologists comprise the largest single cohort of doctors in hospitals, and their role can extend far beyond the traditional role of anesthesia care in the operating room, including fields such as providing pre-hospital emergency medicine, running intensive care units, transporting critically ill patients between facilities, and prehabilitation programs to optimize patients for surgery.