evaluation of the effectiveness of lidocaine infusion in reduction of postoperative pain

introduction: postoperative pain is an acute pain related to size and site of operation, patient's psychologic and physiological condition, degree of manipulation and damage of tissues. pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. administration of opioids is one of the common techniques for postoperative pain management, but complications related to opioids leads to use of other methods for pain control. in this study we evaluated the effect of low dose lidocaine infusion for postoperative pain control. methods: in this study, 30 patients were randomized in two study and control groups under similar conditions. in study group, administration of lidocaine 1% (1.5mg/kg followed by 1.5 mg/ kg /h infusion) was started 30 minutes before operation, and continued 1hour after operation. in control group, normal saline (placebo) was used. after 24hours, pain of patients and systemic analgesic consumption was assessed and analyzed. results: results showed that infusion of low dose lidocaine does not reduce postoperative pain and amount of morphine consumption 24hours after operation. conclusion: difference in results of this study and other similar investigations can result from difference in design and selected surgical procedures. also, lack of medical and research equipments such as appropriate pca (patient controlled analgesia) and measurement of blood levels of lidocaine were limitations of this study.