The Effect of Intravenous Infusion of Lidocaine to Control Postoperative Pain After Gynecologic Laparoscopic Surgery: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Background: Pain after laparoscopy may still be moderate to severe due to stretching of the intraabdominal cavity and peritoneal inflammation. Systemic Lidocaine with anti-inflammatory properties may reduce this pain. Objectives: The aim of this study was to evaluate the effect of perioperative intravenous infusion of Lidocaine on postoperative pain relief after the gynecologic laparoscopic procedure. Methods: A double-blind, randomized clinical trial study was conducted in Iran, during the years 2014 and 2015. A sample of 60 females with American anesthesiology association (ASA) physical class I or II, who were scheduled for gynecologic laparoscopy were selected through consecutive sampling and were randomly assigned to receive either intravenous Lidocaine or Normal saline, as placebo, prior to induction of anesthesia and until the end of surgery. The severity of postoperative pain was evaluated starting at the recovery unit until 24-hours postoperatively for a total of 8 times using the visual analogue scale (VAS) scoring system. Time to first analgesic request, total analgesic dose used in the first 24-hours, and any probable postoperative complications were recorded. Risk ratio (RR) and number needed to treat (NNT) were used to analyze the data along with the generalized linear model for multivariate analysis of repeated measurements over time. Results: The VAS at recovery was lower at recovery with a mean score of 2.8 in the Lidocaine group versus 3.9 in the control group (P = 0.02). Results of generalized linear modeling revealed that pain intensity decreased over time in both groups (P = 0.02), and the groups had different trend slopes in pain intensity over repeated measurements at various time points up to 24 hours after laparoscopy, while controlling for the baseline VAS at recovery and ASA PS (P = 0.016). However, when controlling for use of the painkillers, the trends were not found to be different. Patients in the Lidocaine group were 3.8 times more likely not to need postoperative analgesic (95% CI:1.4 to 9.9). Mean total analgesic dose was 1.3 mg in the Lidocaine group versus 38.2 mg in the control group differing significantly between the 2 groups (P < 0.01). Use of Lidocaine was associated with lower postoperative nausea and agitation. Conclusions: Systemic perioperative Lidocaine could improve the pain pattern and severity as well as nausea and agitation after gynecologic laparoscopy. Although no significant side effects were detected in this study, the benefits of the intervention should be weighed against its safety.