Effect of Inflated Versus Non-inflated Endotracheal Tube on Sore Throat

Postoperative sore throat (POST) is a common morbidity following upper airway access-control with direct laryngoscopy-intubation (DLI) technique. Various reasons (size of the tracheal tube, cuff pressure, rough tube pass, and reattempts, among others) have been cited and management strategies (pharmacologic: applying lidocaine gel/EMLA cream on the cuff surface; non-pharmacologic measures: tracheal tube cuff pressure control, optimization of tracheal tube size, applying lubricating gel) have been tried, but none has been able to decrease the incidence of POST nor has been able to decrease the suffering of patients. Traditionally, intubation is performed with a deflated endotracheal tube and the cuff is later inflated to secure the tube in desired position. The striated folds present in the deflated cuff incurs additional dynamic friction that traumatizes upper airway mucosa during the procedure, causing the risk of POST. While accentuated friction burden on the posterior part of vocal cords and the tracheal mucosa has been studied recently, there has been no work on understanding the kinetic contact- friction ensued by a passing tracheal tube/cuff. We speculate that dynamic contact-friction generated at the time of passing of a cuffed tracheal tube is the major active component which has potential to cause actual tissue trauma and inflammation resulting in adverse effects (POST, hoarseness, throat pain, cough). This study aims to evaluate the effects of reducing dynamic/kinetic contact-friction by employing a pre-inflated tracheal tube cuff to pass the vocal cords at the time of orotracheal intubation.