Efficacy of continuous intravenous infusion of lidocaine on postoperative sore throat after laryngeal mask insertion: a randomized controlled trial.

Background: This randomized controlled trial was performed to explore efficacy of continuous intravenous infusion of lidocaine on postoperative sore throat after laryngeal mask insertion.

Methods: In this prospective trial one hundred and sixty general anesthesia surgery patients (20 to 60 years) using laryngeal mask airway were randomly divided into control group (Group C, saline as placebo), lidocaine gel group (Group LG, lidocaine gel applied to the surface of the laryngeal mask), single intravenous lidocaine group (Group SL, intravenous lidocaine 1.5 mg/kg at induction of anesthesia) and continuous infusion of lidocaine group (Group CL, a bolus of 1.5 mg/kg, followed by an infusion of 2 mg/kg/h until the end of the surgical). The primary outcomes were the incidence and severity of POST at the time of laryngeal mask removal (T1), 2 h (T2), 6 h (T3), and 24 h (T4) after removal. The secondary outcomes included the incidence of adverse events such as hoarseness, cough, and tongue numbness.

Result: Within 24 h after extubation, the incidence and severity of POST was significantly lower in group CL than that in group C at all time points. In contrast, compared with group C, the incidence and severity of POST in group SL was lower only at T1. The incidence of hoarseness and cough in group CL were significantly lower than that in group C at T1 and T2. In group SL, the incidence of hoarseness and cough was lower than that in the group C only at T1. In group LG, the incidence of tongue numbness was significantly higher than that in group C only at T1, and there were no significant difference in the four groups at the other time points.

Conclusion: Continuous infusion of lidocaine is effective in reducing the incidence and severity of POST after laryngeal mask ventilation, as well as reducing the incidence of adverse effects such as hoarseness and cough.

Trial registration: Chinese Clinical Trial Registry (ChiCTR2300070339,04/10/2023).