Effect of Intravenous Lidocaine, Dexamethasone, and Their Combination on Postoperative Sore Throat: A Randomized Controlled Trial.

Background: Postoperative sore throat (POST), hoarseness, and cough after tracheal intubation are not uncommon. Although both lidocaine and dexamethasone have been used independently to reduce these events, there is no study assessing the combined effects of lidocaine and dexamethasone.

Methods: This prospective, double-blind, randomized controlled study enrolled 180 patients requiring general anesthesia with endotracheal intubation for >90 minutes. They received 1 of the 4 intravenous agents just before induction of anesthesia: lidocaine (1.5 mg/kg) in group L, dexamethasone (8 mg) in group D, lidocaine (1.5 mg/kg) with dexamethasone (8 mg) in group DL, and placebo as normal saline in group NS. Standard anesthesia protocol was followed. Incidence and severity of a sore throat, cough, and hoarseness of voice were assessed up to 24 hours postoperatively. The primary outcome was the incidence of POST, and the main effects of dexamethasone and lidocaine were the primary interest.

Results: Data of 45 patients in D, 44 in L, 44 in DL, and 43 in NS groups were analyzed. The incidence of a sore throat was 36%, 43%, 25%, and 56% in group D, L, DL, and NS, respectively (P = .02). Dexamethasone with or without lidocaine reduced the incidence of the POST (odds ratio, 0.44; 95% confidence interval, 0.24-0.82; P < .01). However, lidocaine was not effective in reducing POST (odds ratio, 0.62; 95% confidence interval, 0.33-1.14; P = .12). No difference was observed in the severity of a sore throat, incidence and severity of a cough, and hoarseness among the groups.

Conclusions: Dexamethasone, with or without lidocaine, was effective in reducing the incidence of POST in patients requiring prolonged tracheal intubation.