Analgesic Effects of Intravenous Lidocaine in Laparoscopic Surgery

Objectives: Recent studies have showed that intravenous lidocaine is associated with reducing postoperative pain. However, the mechanism of action of intravenous lidocaine as a part of multi-modal analgesic regimen on patients undergoing laparoscopic surgery remains unclear. The primary aim was to demonstrate the effects of intravenous lidocaine on postoperative pain score in adults undergoing laparoscopic surgery. Methods: Databases of MEDLINE, EMBASE, and CENTRAL were searched since 1947 until May 2023. Randomized clinical trials (RCT) comparing intravenous lidocaine and placebo in adults undergoing surgery were included. Results: Forty-five RCTs (n=2,599) were included. Intravenous lidocaine group was associated with significantly lower postoperative pain scores at rest (MD: -0.27, 95% CI: -0.45 to -0.08, P =0.005) at the 24-hour after surgery and during movement (MD: -0.58, 95% CI: -0.89 to -0.27, P <0.001). Intravenous lidocaine significantly decreased fentanyl consumption (MD: -14.46, 95% CI: -18.11 to -10.81, P <0.001) and morphine consumption (MD: -3.63, 95% CI: -5.12 to -2.13, P <0.001) postoperatively. It also significantly lowered the incidence of nausea and vomiting (RR: 0.66, 95% CI: 0.54 to 0.81, P <0.001) and reduced time to flatus (MD: -5.90, 95% CI: -8.18 to -3.62, P <0.001). Discussions: This systematic reinforces the potential role of adding intravenous lidocaine as part of multimodal analgesia in the reduction of postoperative pain, opioid consumption, incidence of nausea and vomiting, and the time to flatus. However, our findings should be interpreted with caution owing to low level of evidence and high degree of heterogeneity.