Comparing the Effects of Lidocaine Spray versus Intravenous Lidocaine Administration after Laryngeal Mask Airway (LMA) Insertion

Background and Objective: Laryngeal Mask Airway (LMA) is commonly used in short-term surgical anesthesia. Intravenous lidocaine is used for better patient tolerance after LMA insertion. Regarding the side effects of intravenous lidocaine, the aim of this study is to compare the effect of lidocaine spray versus intravenous lidocaine on blood pressure, heart rate, sore throat, cough, laryngospasm, and other side effects including nausea, vomiting, and convulsions after LMA insertion. Methods: This double-blind randomized clinical trial was conducted on 120 patients aged 18-65 years with indications for short-term elective eye surgery, in 2 equal groups of 60 people. The first group was given 1% intravenous lidocaine at the rate of 1.5 mg/kg, and the second group was administered with 5 puffs of 10% lidocaine spray in the throat. Then, blood pressure by a sphygmomanometer, heart rate by a heart rate monitoring system, sore throat intensity based on VAS criteria, and cough intensity based on mild, moderate and severe were measured and compared in the two groups. Findings: 79 men (65.8%) and 41 women (42.2%) participated in this study. Clinically, there was no significant change in blood pressure in the two groups. The mean intensity of sore throat two and three hours after waking up in lidocaine spray group (0.51±1.33 and 0.41±1.07) compared to intravenous lidocaine (1.15±2.02 and 1.9±1.08) showed a significant decrease (p<0.05). Also, there were no significant changes in heart rate, cough and laryngospasm between the two groups. In addition, no cases of nausea, vomiting and seizures were found in the two groups. Conclusion: Based on the results of this study, lidocaine spray can be suggested to reduce the severity of sore throat caused by LMA insertion