Effect of Intraoperative Low-Dose Lidocaine Administration on the Consumption of Mivacurium During Gynecological Laparoscopic Surgery: A Prospective Clinical Study

Background: Recent literatures have shown that lidocaine obviously shortened the onset time and reduced the maintenance dose of vecuronium. However, there have been no reports on the use of mivacurium. This study aimed to investigate the effects of lidocaine on the requirement and onset time of mivacurium administration during gynecological laparoscopic surgery. Methods: 66 patients scheduled for elective gynecological laparoscopic surgery were randomly assigned to receive an intravenous bolus of 1.5 mg·kg − 1 lidocaine followed by a continuous infusion of 2 mg·kg − 1 ·h − 1 or an equivalent volume of placebo. Neuromuscular block was induced with 0.2 mg·kg − 1 followed by an infusion of 0.2 mg·kg − 1 ·h − 1 mivacurium. The primary outcome was the onset time of mivacurium. Consumption of mivacurium, extubation time, and postoperative numeric rating scale (NRS) score for pain were recorded. Results: The onset time of mivacurium was significantly shorter in the lidocaine group than in the control group (mean difference − 25.0 s, 95% CI − 47.8 to − 2.3, P =0.032). Hourly consumption of mivacurium was lower in the lidocaine group than in the control group (median difference, − 0.04 mg·kg − 1 ·h − 1 ; 95% CI, − 0.08 to − 0.01; P =0.017). The extubation time was also significantly shorter in the lidocaine group than in the control group ( P =0.006). The NRS pain score at 6 h and 12 h after surgery was lower in the lidocaine group than in the control group. Conclusion: Intravenously administered lidocaine significantly decreased the requirement of mivacurium, shortened the onset time, accelerated the extubation time, and alleviated pain intensity at 6 h and 12 h after surgery, without increasing adverse events in patients with a low risk of airway difficulty undergoing gynecological laparoscopic surgery. Given the small sample size from a single centre, our result requires further verification. Keywords: lidocaine, mivacurium, muscle relaxation, neuromuscular block, neuromuscular monitoring, tracheal intubating conditions, gynecological laparoscopic surgery