On a broader level, these chemicals cause inflammation, hyperalgesia, hyperglycaemia, protein catabolism, lipolysis and changes in water and electrolyte flow (Macintyre, NHMRC & ANZCA, 2010) Another significant aspect of the stress response is increased sympathetic activity, which has effects on the cardiovascular system, respiration, coagulation and the immune system (Macintyre, NHMRC & ANZCA, 2010) While pain is a necessary warning response, if severe and prolonged it becomes counterproductive and can have adverse effects on patient outcomes (Chapman et al, 2008; Pavlin et al., 2002). Chapman et al (2008) found that uncontrolled pain in a physiologically compromised patient prolongs and intensifies the stress response, which subsequently results in poorer patient outcomes and late discharge. Some of the adverse effects of unrelieved pain are cardiovascular, gastrointestinal and renal impairments such as cardiac ischemia, ileus, urinary retention and increased workload to the heart due to sympathetic activation; poor wound healing and surgical infections due to suppressed immune system; decreased mobility and related complications such as deep vein thrombosis(DVT), pulmonary embolism(PE) and pneumonia; stress; anxiety; sleep disturbances;extended hospital stay; and overall increased cost to the health system caused by these side effects (Macintyre, NHMRC & ANZCA, 2010) .

             Traditionally, analgesia in the perioperative period has largely depended on the systematic use of opioids (Chung, Ritchie, & Su, 1998). However, extensive use of opioids is associated with a variety of perioperative side effects that can delay discharge (White, 2002). Therefore, the approaches to pain relief are increasingly turning to non-opioid analgesic techniques. A number of studies have found that when inserted correctly and managed properly, epidural analgesia (EA) is a simple, safe and highly effective method of pain relief in the postoperative period, and provides superior pain relief compared to the systemic opioid technique (Weber et al.