ObjectiveTo evaluate the effect of different doses of dexmedetomidine on hemodynamics during endotracheal extubation of laparoscopic cholecystectomy in patients with hypertension. MethodsA total of 120 hypertension patients ready to undergo laparoscopic cholecystectomy under general anesthesia between December 2013 and December 2014 were chosen to be our study subjects. They were randomly divided into 4 groups with 30 patients in each:saline control group (group C), low-dose dexmedetomidine hydrochloride injection group (group D1), moderate-dose dexmedetomidine hydrochloride injection group (group D2), and high-dose dexmedetomidine hydrochloride injection group (group D3). The anesthesia methods and drugs were kept the same in each group, and 20 mL of saline, 0.25, 0.50, 1.00 μg/kg dexmedetomidine (diluted to 20 mL with saline) were given to group C, D1, D2, and D3 respectively 15 minutes before the end of surgery. Time of drug administration was set to 15 minutes. We observed and recorded each patient's mean arterial pressure (MAP) and heart rate (HR) in 5 particular moments:the time point before administration (T1), immediately after administration (T2), extubation after administration (T3), one minute after extubation (T4), and 5 minutes after extubation (T5). Surgery time, recovery time, extubation time and the number of adverse reactions were also detected. ResultsCompared at with, MAP and HR increased significantly at the times points of T3, T4, T5 compared with T1 and T2 in Group C and group D1 (P<0.05), while the correspondent difference was not statistically significant in group D2 and D3 (P>0.05). Compared with group C, MAP and HR decrease were not significantly at the time points of T3, T4, T5 in group D1 (P>0.05). However, MAP and HR decrease at times points of T3, T4, T5 in group D2 and D3 were significantly different from group C and D1 (P<0.05). After extubation, there were two cases of dysphoria in group C and two cases of somnolence in group D3, but there were no cases of dysphoria, nausea or shiver in group D1, D2, D3. ConclusionIntravenously injecting moderate dose of dexmedetomidine 15 minutes before the end of surgery can effectively reduce patients' cardiovascular stress response during laparoscopic cholecystectomy extubation for patients with hypertension, and we suggest a dose of 0.5 μg/kg of dexmedetomidine.