Intravenous Lidocaine Useful in Reducing Postoperative Pain, Study Says

Can the use of postoperative intravenous lidocaine improve pain management and provide a safer alternative, especially in certain populations and for certain procedures? A recent investigation by a hospital in Canada identified opportunities where this technique may be helpful.

The researchers noted that intravenous lidocaine has been used perioperatively in order to reduce or eliminate the need for opioids, and that lidocaine has some anti-inflammatory properties, as well as acting on hyper pain sensitivity. But not much is known about its use after surgery, except in gastrointestinal surgery.

This retrospective study took place at a university hospital where the use of lidocaine was already in place for GI surgeries and then subsequently expanded to other surgeries. Intravenous lidocaine has been used in elective and emergency surgeries, including neurosurgery, spine, orthopedics, trauma, vascular, and other procedures.

It has also been used as a rescue analgesic for the treatment of acute pain crises in the early postoperative period, especially in patients with a history of chronic pain, opioid tolerance, and substance use disorder.

The investigators wanted to know more about assessed acute pain management in patients who received an intravenous lidocaine infusion between February 2013 and December 2017. Primary outcomes were postoperative pain scores at rest and with activity. The infusions were typically given at 1 mg/kg/h (range 0.5–2).

Pain scores at 4 hours, 24 hours, and at the end of infusion time were recorded and analyzed; clinically important differences (CIDs) in pain were determined by a raw pain score difference of ≥ 2 on a numeric rating scale of 0–10 or by a ≥ 30% change in pain intensity.

A true CID was defined as such if a CID was observed with rest and/or active pain scores at both first to second (4–24 hours) and first to final time point (4 hours to infusion end) comparisons. The average duration of infusion was 68.60 [49.52] hours.

Surgical specialties included in the study were gastrointestinal surgery (41%), orthopedics (28%), neurosurgery (15%), vascular surgery (10%), and others (6%).

In total, 544 patients received intravenous lidocaine; 394 were included in the final analysis, including 194 (49.2%) female patients and 200 (50.8%) male patients.

Overall, 56.1% experienced a CID, with reduced pain scores at rest and/or with activity. CIDs were also observed in patients with chronic pain (53.5%) and when intravenous lidocaine was used as a rescue technique (69.6%).

Within the rescue group, opioid-dependent and opioid-naïve patients saw decreases of 23.0% (~ 2.23 mg/8 h, P = .01) and 45.6% (~ 2.5 mg/8 hours, P < .001), respectively, in the amount of intravenous opioids used over 8 hours.

Some patients —37— had transient signs of mild local anesthetic toxicity, which resolved with a reduction in the infusion rate.

One serious adverse event required intervention when a patient suffered cardiac arrest caused by “inadvertent rapid lidocaine bolus.” The patient was successfully resuscitated.

The researchers said the introduction of lidocaine at the hospital was a “major advancement” in moving towards a reduction in opioid use to avoid side effects such as sedation, respiratory depression, nausea, vomiting, hyperalgesia, and prolonged hospital stay, as well as possible dependence afterwards.

Some findings need further research, they said, especially as they refer to certain populations. For example, the role of intravenous lidocaine use as a rescue analgesic in pain crises has not been previously reported, the authors said.

Reference

De Oliveira K, Eipe N. Intravenous lidocaine for acute pain: A single-institution retrospective study. Drugs Real World Outcomes. Published online July 9, 2020. doi: 10.1007/s40801-020-00205-8