Author: Michael Vlessides
Clinicians searching for a safe and effective way to decrease postoperative opioid use without sacrificing analgesia after ambulatory surgery may find aid in systemic lidocaine, according to a new meta-analysis.
Researchers at Rhode Island Hospital and Brown University concluded that while systemic lidocaine had no effect on postoperative nausea and vomiting in these patients, the adjunct medication reduced opioid consumption in both the PACU and at 24 hours.
“Nevertheless, the use of systemic lidocaine hasn’t been examined in-depth with respect to outpatients,” Dr. Lovett-Carter said. “So we wanted to see what trials are out there and if we could get an answer to the question of how it affects ambulatory patients.”
The researchers searched relevant databases (through January 2019) for randomized controlled trials comparing the use of systemic lidocaine with a control group in adult patients undergoing ambulatory surgery. The primary outcome of the analysis was total 24-hour postoperative opioid consumption; secondary outcomes included pain scores at rest in the PACU and 24 hours after surgery, time to discharge, and postoperative nausea and vomiting.
Reduction in Opioids Without Increase in Pain
Presenting at the 2019 annual meeting of the Society of Critical Care Anesthesiologists (abstract C6), Dr. Lovett-Carter reported that five randomized controlled trials were included in the final analysis, comprising a total of 329 patients.
The analysis revealed that postoperative opioid consumption in the PACU was reduced by 4.23 mg IV morphine equivalents with the use of systemic lidocaine compared with controls (95% CI, –7.31 to –1.15 mg; P<0.01).
“We also found that there was no significant difference in pain scores between groups at any time point,” Dr. Lovett-Carter said in an interview with Anesthesiology News. “So even though these ambulatory patients used less opioids, their pain scores were not increased.”
Similarly, no differences were observed between groups with respect to postoperative nausea and vomiting in the PACU or at 24 hours.
Given the findings of the meta-analysis, Dr. Lovett-Carter said there is little reason for her peers not to consider using systemic lidocaine. “There are few compelling reasons to not use it,” she explained. “It’s a safe drug and it’s cost-effective.
“I think one of the reasons that clinicians might not use systemic lidocaine in ambulatory patients is that it’s simply not common practice, so we don’t think about it,” she said. “There may be concerns about using lidocaine in patients with specific cardiac conduction defects, but it is safe for the vast majority.”
Perhaps not surprisingly, Dr. Lovett-Carter now counts systemic lidocaine as a part of her regular analgesic approach in ambulatory patients. “I think it’s definitely worth considering as an adjunct for pain,” she said.
“And even if you’re not going to use it in every patient, I think it’s worth considering in patients that have chronic pain or in those who have a high opioid tolerance. You’re adding an adjunct that is going to be far more beneficial for them than it is for the average patient.”
For Maria Paz Sebastian, MBChB, a consultant anesthetist at the Royal National Orthopaedic Hospital, in Stanmore, England—author of an article that explored the perioperative use of systemic lidocaine (Pain Physician 2015;18:E442-E443)—lidocaine has a role as part of multimodal analgesia, although many questions remain.
“Regarding the study, it would be interesting to know if the authors found any different results according to the type of surgery or the regimen used, such as bolus versus infusion or intraoperative administration versus intraoperative plus postoperative administration,” Dr. Sebastian said.
“Lidocaine has shown to be effective mainly after abdominal surgery, but its effectiveness after orthopedic operations is still uncertain,” Dr. Sebastian added.