General anesthetics are medicines that render a patient reversibly unconscious and unresponsive in order to allow surgeons to operate on that patient. General anesthetics are normally administered intravenously or by inhalation by a specialist doctor called an anesthetist who also monitors the patient's vital signs (breathing, heart rate, blood pressure, temperature) during the procedure. While under general anesthesia, a patient is unable to feel pain and will likely wake with some short-term amnesia (memory loss). Experts are unsure exactly how general anesthetics work.