Intravenous Lidocaine Infusion Reduce Post-operative Pain and Length of Hospital in Elderly Patients Undergoing Surgery: Meta-analysis of Randomized Controlled Trials

Objective. It is debated wheter intravenous (IV) lidocaine improves post-operative pain and has other potential benefits in elderly patients. This systematic review and meta-analysis aimed to estimate the effect of perioperative continuous IV lidocaine in elderly patients undergoing surgery. Method. PubMed/Medline, Web of Science, Embase, and CENTRAL databases (through OVID SP) were searched independently until October 10, 2020 by two authors. We included all randomized controlled trials that compared the effect of continuous IV lidocaine and any placebo or no treatment in elderly patients after surgery. Primary outcomes were length of hospital stay and post-operative pain score. Results. Eighteen studies (988 patients) were included. Meta-analysis suggested that IV lidocaine reduced the post-operative pain scores 2 hours (standardized mean difference [SMD]: -1.58, 95% confidence interval [CI]: -2.03 to -1.13), 4 hours (SMD:-1.20, 95% CI: -2.02 to -.39), 8 hours (SMD:-.82, 95% CI: -1.51 to -.13), 12 hours (SMD:-.66, 95% CI: -1.28 to -.04), and 24 hours (SMD:-.42, 95% CI: -.72 to -.12) post-operatively. Moreover, those patients given IV lidocaine had a shorter length of hospital stay (MD: -.24, 95% CI: -.71 to -.23) and required fewer opioid drugs (SMD: -.31, 95% CI: -.31 to -.01). Conclusion. The evidence suggested that IV lidocaine significantly reduced post-operative pain intensity and opioid consumption and shortened the length of hospital stay in elderly patients. IV lidocaine decreased the incidence of post-operative nausea while it could not reduce the incidence of post-operative vomiting and accelerate the recovery of gastrointestinal function.