Perioperative lidocaine infusion has been reported to alleviate pain intensity after colorectal surgery. However, there is no consensus on whether prolonged lidocaine infusion is more effective than short lidocaine infusion. This meta-analysis aimed to determine an appropriate duration of lidocaine infusion in patients undergoing colorectal surgery.
We searched the PubMed, EMBASE, Web of Science, and Cochrane Library databases to identify articles published before December 17, 2021. Randomized controlled trials comparing intravenous lidocaine with placebo for pain relief in patients undergoing colorectal surgery were included. The primary outcome was pain scores (visual analog scale [VAS], 0–10 cm) at 24 hours postoperatively at rest and on movement. Secondary outcomes included pain scores at 12, 48, and 72 hours postoperatively, analgesic consumption (mg), gastrointestinal function return (hour), length of hospital stay (days), and incidence of complications. According to the duration of lidocaine infusion, studies were grouped into infusion for at least 24 hours (prolonged lidocaine infusion) and less than 24 hours (short lidocaine infusion) to assess the impact of lidocaine infusion duration on the outcomes of interests. Quantitative analyses were performed using a random effects model.
Eleven studies with 548 patients were included. Five studies used prolonged lidocaine infusion, while 6 studies used short lidocaine infusion. Prolonged lidocaine infusion reduced postoperative pain scores versus placebo at 24 hours at rest (mean difference [MD], −0.91 cm; 95% confidence interval [CI], −1.54 to −0.28; P = .02) and on movement (MD, −1.69 cm; 95% CI, −2.15 to −1.22; P < .001), while short lidocaine infusion showed no benefit. Compared with placebo, prolonged lidocaine infusion reduced pain scores at 12 hours at rest and at 12 and 48 hours on movement, but short lidocaine infusion did not. However, there was no significant difference in pain scores between the prolonged and short lidocaine infusion groups at these time points. Compared with placebo, prolonged lidocaine infusion shortened the length of hospital stay (MD, −1.30 days; 95% CI, −1.72 to −0.88; P < .001) and time to first postoperative defecation (MD, −12.51 hours; 95% CI, −22.67 to −2.34; P = .02). There were no differences between groups regarding the other outcomes.
The analgesic effect of intravenous lidocaine may depend on the duration of infusion, and our results suggest that lidocaine infusion should be administered for at least 24 hours after colorectal surgery. Since overall evidence quality was low, further high-quality, large-sample trials are needed to explore an optimal lidocaine infusion strategy in patients undergoing colorectal surgery.