RESUMEN
Objective To determine ED50 and ED9 5 of etomidate for combined remifentanil used in elderly patients in gastroscope.Methods Twenty-three patients were scheduled to receive gastros-copy aged 65-78 years old including males 13 and females 10,weighting 45-76 kg and ASA Ⅰ-Ⅲ. They were slowly injected remifentanil 0.3 μg/kg,and then etomidate 0.20 mg/kg,gastroscopy was performed after their eyelash reflex disappeared.The dosage of etomidate were determined by modified up-and-down methods,0.20 mg/kg was initial dosage.During the gastroscope,restlessness, frowning,swallowing,choking cough could be seen.The adjacent experimental interval dosage was 0.05 mg/kg,the trial was ended when there was the seventh cross-sectional,and determined the ED50 and ED9 5 of etomidate and (95%confidence interval)of them for gastroscope with probability a-nalysis methods.Results The ED50 of etomidate was 0.1 7 mg/kg and 95%CI 0.14-0.21 mg/kg,and the ED9 5 was 0.23 mg/kg,95%CI 0.20-0.42 mg/kg respectively.Conclusion The ED50 and ED9 5 of etomidate combined with remifentanil used for elderly patients for gastroscope respectively are 0.1 7 mg/kg and 0.23 mg/kg.