ABSTRACT
Objective:To evaluate the effect of Parkinson′s disease factor on the sedative efficacy of dexmedetomidine.Methods:The patients of either sex, aged 45-64 yr, of American Society of Anesthesiologists Physical Status classification Ⅱor Ⅲ, with body mass index of 18.5-30.0 kg/m 2, undergoing non-intracranial space-occupying lesions in neurosurgery, were selected.Patients were divided into control group (group C) and Parkinson′s disease group (group P) according to whether they had Parkinson′s disease or not.The ED 50 of dexmedetomidine was determined by using the Dixon′s up-and-down method.The initial dose of dexmedetomidine was 0.5 μg/kg in both groups, and each time the concentration increased/decreased by 0.05 μg/kg in the next patient, which was repeated until 7th independent crossover pair (loss of consciousness) appeared, and then the test was ended.The ED 50 and 95% confidence interval of dexmedetomidine inducing loss of consciousness were calculated using the probit test in a Logistic regression model.Hypertension, hypotension, bradycardia and nausea and vomiting were recorded. Results:Compared with group C, the ED 50 of dexmedetomidine inducing loss of consciousness was significantly increased in group P ( P<0.05), and no significant change was found in the incidence of adverse reactions in group P ( P>0.05). Conclusions:Parkinson′s disease factor can decrease the sedative efficacy of dexmedetomidine.