Abstract: Abstract Objective：To study the application value of the inhalation of ipratropium in fiberoptic bronchoscopy. Methods: 88 patients undergoing bronchoscopy were enrolled in this study, 48 patients were divided into experimental group and inholed ipratropium 1 mg before bronchoscopy, including 24 patients in the normal lung function sub-group and 24 in the non-normal sub-group; control group of 40 patients, including 20 patients in the normal lung function sub-group and 20 in the non-normal sub-group. The patients of the four sub-groups undergoing bronchoscopy after lidocaine anesthesia. Compare the changes of the airway resistance index before and after the bronchoscopy, including the total airway resistance (R5), central airway resistance (R20), surrounding elastic resistance (X5) and the resonance frequency (Fres). Results: After bronchoscopy, R5, R20, X5 and Fres of the experimental group were reduced (P < 0.01). The changes of R5, R20, X5 between the two subgroups were not significant. In control group, the variations of airway resistance in the normal sub-group were not significant, R5, R20, X5, Fres were increased in the non-normal subgroups (P <0.01), and the change quantities were greater than normal sub-group. In the normal lung function group, R5, R20, Fres of the experimental group were more improvement, X5 was also improved, but the difference was not significant. In the non-normal lung function group, R5, R20, X5 and Fres of the experimental group were significantly reduced (P <0.05). Conclusion: Premedication with an inhaled ipratropium can reduce the airway resistance of patients undergoing bronchoscopy, which can reduce the incidence of bronchospasm.

Key words: bronchoscopy, ipratropium, airway resistance, Fres, respiratory function tests, bronchial spasm