Background: Chemical warfare victims with pulmonary injuries require frequent bronchoscopy, and most of these diagnostic procedures are performed using deep sedation and local anesthetic "spray as you go" technique. The aim of the study was to compare spray as you go and trans-cricothyroid membrane injection. Methods: In this clinical trial, all candidates for diagnostic bronchoscopy were divided to 2 groups. In group 1, after intravenous injection of 1 mg midazolam and 50 mcg fentanyl and intravenous injection of 20mg propofol, 3 cc of 4% lidocaine was injected into the trans-cricothyroid membrane. In group 2, after passing the bronchoscope through the nose, the clinicians proceeded to spray 6 cc of 2% lidocaine (spray as you go technique) with bolus doses of propofol, intravenously. The total dose of propofol, the convenience of the physicians, and cough episodes were recorded. The patients were monitored in terms of vital signs before and during bronchoscopy. Moreover, according to the discharge criteria, the time of discharge from the recovery room and side effects were recorded. Using SPSS-21, the data were analyzed and P values of < 0.05 were considered as significant. Results: In the present study, 80 patients (2 groups of 40) were evaluated. The patients in both groups were not significantly different regarding age, gender, and duration of bronchoscopy. In group 1, the rate of satisfaction of the physician was significantly higher than that of group 2. In group 2, the average cough episodes, mean dose of anesthetic, and the average time of recovery were higher than that of group1. Both groups were comparable with respect to hemodynamic stability. No side-effects, i.e. hematoma, lung inflation or subcutaneous emphysema, were observed. Conclusions: Trans-cricothyroid injection anesthesia is a safe method for anesthesia of the respiratory mucosa, tolerable for patients without major side-effects.