Evaluation of sub-fascial lidocaine infusion in post-operative pain management following laparotomy

Background and One of the important problems of major abdominal surgery is post-operative pain control. There are different modalities to control the pain after surgery, such as oral, local or intravenous analgesic drugs, regional nerve block, epidural catheters and pain killer pumps with their own benefits and complications. The aim of this study was to evaluate the effect of continuous peritoneal infusion of lidocaine by a pain killer pump for post-operative pain management following laparotomy. This double blind randomized clinical trial was performed on 76 patients (38 cases and 38 controls) who underwent laparotomy with midline incision, in Imam Hospital, Sari, Iran, in 2008. Two groups were matched in age and sex. After surgery a catheter infusion pump was prepared for all patients. In case group, 2% lidocaine (20mg/kg/day) and for control, normal saline infused for 24 hours. Pain score (Visual Analog Scale), blood pressure, heart rate, respiratory rate, temperature and analgesic requirement was evaluated in 4, 10, 16 and 24 hours after surgery. Results analyzed by means of SPSS (15) software and chi-square, t test and repeated measurement. The p value less than 0.05 was considered to be significant statistically. 76 patients, 39 (51.3%) females and 37 (48.7%) males, with mean age of 47.03±15.2 years were studied. There was no significant difference in age, sex and weight between two groups. The mean of admission days was 5.03±0.6 in case and 5.29±1.3 in control, with no significant difference between them. Mean of opiod consumption was 16.05±13.05 mg and 25.39±11.4 mg in case and control respectively (P= 0.002). Mean of VAS score, blood pressure, heart rate, respiratory rate and temperature in case group was less than control group and the difference was significant statistically. Pain severity changes during 4, 10, 16 and 24 hours following surgery were significantly different in two groups, with linear correlation between time and pain reduction. Our study demonstrates that continuous infusion of 2% lidocaine by a pain killer pump can reduce pain and opioid requirements after abdominal surgeries.