Analysis Of The Effects Of Using Different Doses Of Dexmedetomidine During Endotracheal Extubation For Elderly Patients With Hypertension After General Anesthesia

Objective:To observe the effects of three different doses of dexmedetomidine(DEX)in the responses to endotracheal extubation during recovery from general anesthesia in elderly patients with hypertension.Methods:Sixty elderly patients with hypertension scheduled for elective gynecological surgery under general anesthesia, ASAⅡ-Ⅲ level,expected surgery time 2-4 h, requiring endotracheal extubation after surgery,were randomly divided into 3 groups(n=20 each):group D1 received DEX 0.2μg/kg intravenously, group D2 received DEX 0.4μg/kg intravenously,group D3 received DEX 0.6μg/kg intravenously.Dexmedetomidine 0.2, 0.4 and 0.6μg/kg(20 ml)were infused intravenously over 15 minutes,starting from 30 minutes before the end of surgery in groups D1-3, respectively. The patients were sent to postanesthesia care unit after extubation. The systolic blood pressure(SBP),diastolic blood pressure(DBP) and the heart rate(HR) were recorded before(T0) and after(T1) DEX administration, the time of extubation(T2),and 3(T3),10 minutes(T4) after extubation.Rate pressure product(RPP),defined as the product of SBP and HR were calculated at different time points.The time for surgery time,time of eye opening after surgery and time of endotracheal extubation after surgery were also recorded.At the same time,surgery blood loss, amount of infusion and urine outputs were recorded.Restlessness score(RS) at the time of excubation and Ramsay sedative score at 3 and 10 minutes after extubation were recorded.Events during extubation were also recorded.Results:(1)There were no significant differences of SBP,DBP,HR and RPP at T0 among three groups.Compared with group D1, group D2 and D3 had lower SBP, HR, RPP at the time of after DEX administration(T1),time of extubation(T2),and 3 minutes after extubation(T3). Group D3 had lower SBP、HR、RPP than group D2 at the time of extubation(T2).Compared with group D1, group D2 and D3 had lower HR,RPP at 10 minutes after extubation(T4).(2)The time of eye opening after surgery and time of endotracheal extubation after surgery were longer in group D3 as compared with those in group D1 and D2.Group D3 showed lower RS scores than those of group D1.At T3 and T4, Ramsay scores in group D2 and D3 were higher than those in group D1.(3)The incidence rate of cough in group D1 was significantly higher than that in group D3,and the incidence rate of bradycardia was remarkably lower than that in group D3.No significant difference in nausea, vomiting and shivering were found among the three groups. There was no respiratory depression in the three groups.Conclusion:Adjunctive infusion of dexmedetomidine 0.4μg/kg 30 minutes before the end of surgery was recommended as it may result in more steady hemodynamics,and would not prolong the extubation time.It would also decrease myocardial oxygen consumption and the events during extubation,for endotracheal extubation after general anesthesia for elderly patients with hypertension.