The effect of systemic lidocaine on post-operative opioid consumption in ambulatory surgical patients: a meta-analysis of randomized controlled trials

BACKGROUND: Ambulatory surgical procedures continue to grow in relevance to perioperative medicine. Clinical studies have examined the use of systemic lidocaine as a component of multimodal analgesia in various surgeries with mixed results. A quantitative review of the opioid-sparing effects of systemic lidocaine in ambulatory surgery has not been investigated. The primary objective of this study was to systematically review the effectiveness of systemic lidocaine on postoperative analgesic outcomes in patients undergoing ambulatory surgery. METHODS: We performed a quantitative systematic review of randomized controlled trials in electronic databases (Cochrane Library, Embase, PubMed, and Google Scholar) from their inception through February 2019. Included trials investigated the effects of intraoperative systemic lidocaine on postoperative analgesic outcomes, time to hospital discharge, and adverse events. Methodological quality was evaluated using Cochrane Collaboration’s tool and the level of evidence was assessed using GRADE criteria. Data was combined in a meta-analysis using random-effects models. RESULTS: Five trials evaluating 297 patients were included in the analysis. The pooled effect of systemic lidocaine on postoperative opioid consumption at post-anesthesia care unit revealed a significant effect, weighted mean difference (95% CI) of − 4.23 (− 7.3 to 1.2, P = 0.007), and, at 24 h, weighted mean difference (95% CI) of − 1.91 (− 3.80 to − 0.03, P = 0.04) mg intravenous morphine equivalents. Postoperative pain control during both time intervals, postoperative nausea and vomiting reported at post anesthesia care unit, and time to hospital discharge were not different between groups. The incidence rate of self-limiting adverse events of the included studies is 0.007 (2/297). CONCLUSION: Our results suggest that intraoperative systemic lidocaine as treatment for postoperative pain has a moderate opioid-sparing effect in post anesthesia care unit with limited effect at 24 h after ambulatory surgery. Moreover, the opioid-sparing effect did not impact the analgesia or the presence of nausea and vomiting immediately or 24 h after surgery. Clinical trials with larger sample sizes are necessary to further confirm the short-term analgesic benefit of systemic lidocaine following ambulatory surgery. TRIAL REGISTRATION: PROSPERO (CRD42019142229) SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13741-021-00181-9.