General anesthesia

General anaesthesia
Intervention
Equipment used for anaesthesia in the operating theatre
MeSH	D000768
MedlinePlus	007410
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General anaesthesia or general anesthesia (see spelling differences) is a medically induced state of unconsciousness with loss of protective reflexes, resulting from the administration of one or more general anaesthetic agents. It is carried out to allow medical procedures that would otherwise be intolerably painful for the patient; or where the nature of the procedure itself precludes the patient being awake.

A variety of medications may be administered, with the overall aim of ensuring unconsciousness, amnesia, analgesia, loss of reflexes of the autonomic nervous system, and in some cases paralysis of skeletal muscles. The optimal combination of drugs for any given patient and procedure is typically selected by an anaesthetist, or another provider such as a physician assistant or nurse anaesthetist (depending on local practice), in consultation with the patient and the surgeon, dentist or other practitioner performing the operative procedure.

Attempts at producing a state of general anaesthesia can be traced throughout recorded history in the writings of the ancient Sumerians, Babylonians, Assyrians, Egyptians, Greeks, Romans, Indians, and Chinese. During the Middle Ages, scientists and other scholars made significant advances in the Eastern world, while their European counterparts also made important advances.