Comparison of Preoperative Topical Magnesium Sulfate Spraying and Magnesium Sulfate Gargling for the Prevention of Postoperative Sore Throat after Tracheal Intubation: A Randomized, Double-Blind, Non-Inferiority Trial

Background and Aim: Postoperative sore throat is a common complication following endotracheal intubation, which can significantly affect patient comfort and recovery. The purpose of this study is that compares the efficacy of preoperative topical magnesium sulfate spraying with that of magnesium sulfate gargling aimed at preventing postoperative sore throat.<br /> Patients and Methods: 236 Participants were randomly allocated to either the magnesium sulfate spray group (Group A) or the magnesium sulfate gargle group (Group B), with 118 patients in each group. In Group A, during intubation under direct laryngoscopy, 15 mg/kg of magnesium sulfate was sprayed using a single-use otorhinolaryngology anesthesia sprayer onto the pharyngeal mucosa and posterior pharyngeal wall near the glottis. In Group B, gargling with 20 mg/kg of magnesium sulfate for 30 seconds 15 minutes before surgery. The primary outcome measure was the total incidence of postoperative sore throat within 48 hours, with a non-inferiority margin of 0.15.<br /> Results: The upper limit of the 95% confidence interval (CI) for the difference in the total incidence of POST between Group A and Group B was below the non-inferiority margin (0.15) (non-inferiority P< 0.001). The upper limits of the 95% CI for the differences in the incidence rates of POST between Group A and Group B at time points T1- T6 were all below the non-inferiority margin (all non-inferiority P< 0.001). The total incidence of POST (P=0.046) and the incidence of POST at T2-T4 (all P< 0.001) in group A were lower than those in group B. The analysis of the individual effects between groups indicated significant differences in POST NRS scores at T1 (P=0.034) and T2-T4 (all P< 0.001).<br /> Conclusion: The local spray of magnesium sulfate on the throat before surgery to prevent postoperative sore throat is not inferior to, and may even be superior to, gargling with magnesium sulfate.