Anesthesia

Anesthesia, or anaesthesia (see spelling differences; from Greekαν-, an-, "without"; andαἴσθησις, aisthēsis, "sensation"), traditionally meant the condition of having sensation (including the feeling of pain) blocked or temporarily taken away. It is a pharmacologically induced and reversible state of amnesia, analgesia, loss of responsiveness, loss of skeletal muscle reflexes or decreased stress response, or all simultaneously. This allows patients to undergo surgery and other procedures without the distress and pain they would otherwise experience. An alternative definition is a "reversible lack of awareness," including a total lack of awareness (e.g. a general anesthetic) or a lack of awareness of a part of the body such as a spinal anesthetic. The word anesthesia was coined by Oliver Wendell Holmes, Sr. in 1846.