Abstract:Objective To evaluate the safety and efficacy of Alfentanil combined with Remimazolam for moderate and deep sedation in fiberoptic bronchoscopy, and calculate its median effective dose (ED50) and 95% effective dose (ED95).Methods 50 patients were selected for fiberoptic bronchoscopy and treatment. Sedation was performed with the test dose of Alfentanil and Remimazolam. After the eyelash reflex disappeared and the MOAA/S score <1, the patients were examined or treated by fiberoptic bronchoscopy. The dose of Alfentanil given to the first patient was 6.000 μg/kg, while the dose of Alfentanil used in the other patients was calculated according to the sequential test method. The results of the sequential test and and adverse reactions were recorded.Results All the 50 patients successfully completed the fiberoptic bronchoscopy examination and treatment. According to the results of the sequential test, the Logarithmic regression equation of Alfentanil dose was Y = 8.9286X - 7.6429, and the ED50 for moderate and deep sedation of Alfentanil in fiberoptic bronchoscopy was 7.286 μg/kg (95%CI: 6.566 ~ 8.084) and ED95 was 10.154 μg/kg (95%CI: 8.753 ~ 22.323).Conclusion The ED50 of Alfentanil for moderate and deep sedation in fiberoptic bronchoscopy was 7.286 μg/kg and ED95 was 10.154 μg/kg. The moderate and deep sedation strategy based on Alfentanil and Remimazolam can be safely and effectively used in the examination and treatment during fiberoptic bronchoscopy.