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

Determination of Rate of Hearing Changes After Spinal Anesthesia

Introduction: Hearing loss after surgery is reported rarely. Its prevalence rate is different and reported to be between 3-92%. Hearing loss is often subclinical and not diagnosed without audiometry. The aim of this study was to determine rate of hearing changes after spinal anesthesia in patients undergoing surgery with spinal anesthesia. Methods: In this descriptive study, forty male patients scheduled for repair of inguinal hernia under spinal anesthesia were selected by simple sampling method. Before surgery, audiometry was performed for both the ears of the patients. Audiomatery was performed again by the audiometry specialist on day one, five, fifteen and two months after surgery. Results: Hearing loss was observed in 13 (32.5%) patients. Hearing loss in 12 patients (92%) was in low hearing frequency range and 1 patient (8%) was in mid hearing frequency. Hearing loss in 8 patients (61%) was ipsilateral and in 5 patients (39%) was bilateral. Hearing loss in 9 patients (69%) on 5th day and 2 patients (5/15%) on 15th day resolved spontaneously. Conclusion: Results of this study conformed that hearing loss after spinal anesthesia is not a serious problem and can resolve spontaneously. It seems that there is relationship between hearing loss and headache