may effect patient outcome. There are a number of potential adverse physiologic sequelae of surgical trauma and unrelieved pain, including (1) cardiovascular stress, (2) autonomic hyperactivity, (3) tissue breakdown ( production of a catabolic state with suppression of anabolic hormones), (4) increased metabolic rate, (5) pulmonary dysfunction ( most significant after upper abdominal and thoracic surgery), (6) increased blood clotting (hyperoagulability), (7) fluid retention, (8) dysfunction of the immune system, (9) delayed return of bowel function ( ileus), and (10) development of chronic pain syndromes after certain surgeries ( phantom limb pain after amputation, post- thoracotomy…