Lidocaine for preventing postoperative sore throat (Review)

Background Sore throat is a common side effect of general anaesthesia and is reported by between 30% and 70% of patients after tracheal intubation. The likelihood of a sore throat varies with the type, diameter, and cuff pressure of the endotracheal tube used. If intubation is essential, it may be helpful to give drugs prophylactically to alleviate postoperative sore throat. Local anaesthetics and steroids have been used for this purpose. Objectives The objective of this review was to evaluate the effectiveness and any harms of topical and systematic lidocaine for the prevention of postoperative sore throat in adults undergoing endotracheal intubation as part of general anaesthesia. Search strategy We searched CENTRAL (The Cochrane Library 2007, Issue 3), MEDLINE (January 1966 to June 2007), and EMBASE (1980 to June 2007). We also contacted manufacturers and researchers in the field. Selection criteria We included randomized controlled trials of topical and systemic prophylactic lidocaine therapy versus control (using air or saline) that reported on the risk and severity of postoperative sore throat as an outcome. Data collection and analysis Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information, such as the risk of adverse effects. Main results We included 1232 patients from 15 studies; 672 patients received topical or systemic lidocaine therapy and 560 patients were allocated to the control group. Both the topical and systemic lidocaine therapy significantly reduced the risk of postoperative sore throat (risk ratio (RR) 0.58; 95% confidence interval (CI) 0.41 to 0.82). To evaluate the severity of sore throat on a visual analogue scale (VAS), 219 patients received topical or systemic lidocaine therapy and 152 patients were allocated to the control groups. The severity of sore throat was reduced (mean difference (MD) -11.9; 95% CI -16.44 to -7.32), an effect that neared statistical significance. The adverse effects of lidocaine were not reported in these studies. Authors' conclusions Our systematic review establishes the effectiveness of topical and systemic lidocaine for the prevention of postoperative sore throat resulting from intubation. The risk and severity of postoperative sore throat tended to be reduced. The effect size of lidocaine appeared to be affected by drug concentration and route of administration; management of cuff pressure during anaesthesia; the included population; and the type of outcome measured.