Use of Intravenous Lidocaine Infusion for Postoperative Pain Control in Gynecologic Surgery

INTRODUCTION: Postoperative pain control continues to be a robust area of research with the goal of decreasing pain while simultaneously reducing reliance on opiates due to adverse effects: addiction concerns, bowel paralysis, and sedating effects. Protocols such as Enhanced Recovery After Surgery (ERAS) use multimodal analgesic approaches to achieve this goal. Lidocaine has a short half-life and favorable safety profile for intravenous (IV) administration compared to other local anesthetics. Multiple studies addressed IV use of lidocaine; however, limited studies continued the lidocaine drip into the postoperative period, especially in gynecologic surgery. Overall, these studies yield mixed results in the analgesic effect of lidocaine infusions for postoperative analgesia. To date, there are minimal studies on extended lidocaine infusions utilized for gynecologic surgeries. OBJECTIVE: The primary purpose of this project was a pilot study to evaluate logistics of performing IV lidocaine infusions during surgery and the initial postoperative days in the hospital. Given lack of definitive results in prior publications, we also planned to determine the effect of extended IV lidocaine infusion on pain control in the postoperative period following gynecologic surgery. Our hypothesis is that a postoperative IV lidocaine infusion will reduce the use of postoperative narcotic use. METHODS: This was a retrospective cohort study of patients undergoing major, benign gynecologic surgery with a planned inpatient stay at a single, academic tertiary center. The study cohort consisted of patients who received an IV lidocaine infusion, which was begun intraoperatively and continued at least one postoperative night while the control cohort did not receive IV lidocaine. Our primary outcome was morphine milligram equivalent (MME) used during admission per day. Our secondary outcomes included length of hospital stay and postoperative antiemetic use. RESULTS: There was a total of 46 patients, 10 in the lidocaine group and 36 in the control group. This was a convenience sample. There was no difference between the two groups for demographic variables such as age, race, ethnicity, or BMI. There was also no difference between clinical variables such as history of chronic pain, opiate use prior to surgery, history of mental health disorders, surgical approach, or number of incisions. There was a difference in MME usage on POD#0 with a mean difference of 11. There was less MME usage in the lidocaine group (P=0.015). There was no difference in MME usage between the two groups on the subsequent postoperative days. There was no difference in the use of antiemetics between the two groups or length of hospital stay. CONCLUSIONS: There was a reduction in MME use on POD#0 for patients who also had a lidocaine infusion as multimodal pain control without any increase in complications. Further research is needed on the utility of lidocaine infusions for pain control following gynecologic surgery.