Licorice versus ketamine gargle for postoperative sore throat due to insertion of a double-lumen endobronchial tube

Abstract

Background Postoperative sore throat (POST) is common after tracheal intubation, especially with double-lumen endobronchial tube (DLT). Licorice has many uses such as dental hygiene and in sore throat. Ketamine gargle is a newly proposed adjunct for reducing the incidence of POST in anesthesia. The aim of this study was to determine the efficacy of licorice and ketamine gargles in patients undergoing the insertion of DLT in preventing POST within 24 h. Methods This prospective, randomized, double-blind study included 90 patients undergoing thoracic surgery requiring DLT for one-lung ventilation. Patients were randomized to three groups (n=30) and were asked to gargle for 1 min to 15 min before operations. Group A received ketamine gargle (0.5 mg/kg ketamine in 30 ml of dextrose water 20%), group B received licorice gargle (500 mg licorice powder in 30 ml of dextrose water 20%), and group C (the control group) received 30 ml of dextrose water 20% gargle. Assessment of patients for the incidence and the severity of POST and any side effect was carried out in the recovery room. Sore throat (yes/no) and severity of its pain measured using visual analogue scale were recorded at baseline in the recovery room and then at 2, 4, and 24 h after operation with a specified questionnaire. Results The incidence of sore throat was significantly higher in group C at all time points in comparison with the other two groups. There was a marked decrease in the incidence of sore throat in groups A and B, with no significant difference between them. The severity of POST pain was significantly higher in group C when compared with the other two groups, with no significant difference between them and with no complications. Conclusion Ketamine and licorice gargles decrease the incidence and severity of sore throat occurring postoperatively due to DLT intubation, with no significant differences between them.