IV lidocaine did not reduce opioid use after minor liver surgery

Intravenous lidocaine is used for perioperative analgesia in some surgical settings, but its role in liver surgery is less established because it is metabolized by the liver. This randomized, double-blind trial assigned 124 patients undergoing minor liver surgery to lidocaine or placebo. Lidocaine was given as a 1.5 mg/kg bolus followed by an infusion of 1.5 mg/kg/h until one hour after surgery. All patients had access to opioid patient-controlled analgesia. The primary outcome was opioid consumption in the first 24 hours.

Median opioid consumption was 83 mg oral morphine equivalents (interquartile range, 50–129) with lidocaine and 97 mg (60–135) with placebo (p=0.429). The lidocaine group had lower pain scores at early postoperative time points, but not from postoperative day 1 onward. Quality-of-recovery scores and adverse events were similar between groups.

Two patients had transient plasma lidocaine concentrations above 5 µg/ml after the bolus, without clinical signs of toxicity; concentrations after liver resection and at the end of infusion were below toxic levels. The findings do not show an opioid-sparing effect in this population. They apply to minor liver surgery and do not establish efficacy or safety in more extensive liver procedures.