Comparison of Patient Controlled & Continuous Epidural Analgesia in Thoraco-abdominal Surgeries in Cancer Patients

continuous epidural infusion at rate of 5-8 ml /hr based on maximum allowable safe dose as per body weight. The pump settings will be set at 0.1 ml per bolus with lockout interval of 20 minutes. Cross over to other group will occur after 36hours.

patient controlled epidural analgesia in form of Patient Controlled Analgesia pumps with continuous rate of 5-8ml/hour \& demand dose of 2-3 ml p.r.n with a lock out interval of 20 minutes based on maximum allowable safe dose as per body weight .The group will have a cross over at 36 hours postop.