Anesthesiology provides care for patients during operation theaters by helping them under go certain procedures and operations without pain and distress. This specialty also provides relief from chronic pain. Anaestheisa basically is a "reversible lack of awareness," whether this is 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 or another nerve block would cause. Anesthesia is a pharmacologically induced reversible state of amnesia, analgesia, loss of responsiveness, loss of skeletal muscle reflexes and decreased stress response.