Ketamine Lubrication of Endotracheal Tubes for Attenuating Postoperative Sore Throat: a Randomized, Double-Blind Study

Abstract

Background: Postoperative sore throat (POST) is a common complaint after tracheal intubation for general anaesthesia, with an incidence of 32.6-57.5%. This study was designed to determine the efficacy of ketamine lubrication on the endotracheal tube cuff to reduce the incidence and severity of POST in patients undergoing general anaesthesia with endotracheal tube (ETT). Methods: This study was a prospective, randomized, double-blind study. We enrolled 40 patients who were classified as ASA I-III scheduled for surgery under general anaesthesia in this study. The participants were randomly assigned into two groups. Before induction of anaesthesia, the ETT cuff was lubricated with 1 ml (50 mg) of ketamine or 1 ml of normal saline as a control. POST was evaluated at 0, 6 and 24 h after extubation using a direct question survey with a four-point scale (0-3). Results: Data from 18 patients in the ketamine group and 18 patients in the control group were analysed. The overall incidence of POST was comparable between the ketamine group and the normal saline group (P=0.324). There was no significant difference in the incidence and severity of POST between both groups across the three intervals. No patients developed adverse effects related to ketamine administration. Conclusion: This study did not demonstrate the effect of ketamine lubrication on the ETT cuff on recuction in the incidence or severity of POST. The route of administration of ketamine may be crucial to its effectiveness in attenuating the incidence and severity of POST.