The Effect Of Low Dose Dexmedetomidine As Preanesthesia Medica Tion On The Hemodynamics In Hypertension Patients Before An D After General Anesthesia Induction

Objective Hypertension, with an increasing incidence recently,has become one of common and frequently-occurring diseases in clinic.As a result, a large number of hypertension patients in their perioperative period has mount a serious challenge for anesthesiologists.Tension and anxiety could easily happen on preoperative hypertension patients which can cause drastic change of hemodynamics, and sometimes cardio-cerebrovascular accidents occure.so the preoperative sedation is particularly important. As a new type of sedative drug, dexmedetomidine(DEX), with significant effects for sedation 、 anti-anxiety and anti-symphatin and little influence on respiration and circulation, is widely used in clinic practice,but seldom used as pre-peration medcaiton. This study aimed to observe the efficacy and safety of low dose DEX(0.3ug/kg) pumped as a preoperative sedative drug for hypertension patients in general anesthesia state. By way of early intervention in the ward, patients could reach a certain calm state before entering operating room, which could help keep the hemodynamics steady and provide a smooth transition for the operation.Forty patients with hypertension scheduled for general anesthesia, aged 46~75 years old, weighted 45~80kg, ASAⅡor Ⅲ, Mallampati airway classification ⅠorⅡ, were randomly assigned into two groups(n=20 in each group): experimental group(dexmedetomidine group:DEX group) and control group(normal saline: NS group). All patients were given no drinking for 8 hours and fasting for 12 hours, anti-hypertension drugs conventionally before operation. Enough fluid input, first-aid medicine and ECG monitoring were prescribed before pumping the preoperative. sedative drug in both groups. Preoperative sedative drug was pumped in the ward for the two groups 30 minutes before operation. Experimental group: firstly DEX was diluted to 200ug/50 ml, the dose was determined according to kg*0.3ug/kg+NS=20ml, pumping was finished in 10 minutes; vital signs were monitored closely for five minutes, if no danger happened, patients would be accompanied into operating rooms; Control group: NS 20 ml was pumped directly at the same speed and the remaining steps were as same as the experimental group.Vital signs(HR, SBP, DBP, RR, SPO2,etc) were recorded respectively at T0, T1,T2, T3, T4, T5, T6 and T7.The scores of Ramsay sedation, state-anxiety questionnaire(SAI) and visual anxiety scale(VAS) were assessed before and after pumping DEX or NS. In addition, the usage rates of the atropine, ephedrine and urapidil, and the dosage of etomidate during the induction were also recorded. MethodsResults 1. The experimental group did not show obvious respiratory depression, SPO2(%)could also remain above 95% even in the case of no oxygen, no hypoxia and carbon dioxide accumulation occurred;Compared with the NS group, RR rose slightly and SPO2(%) decline mildly, there was no statistical significance(P>0.05). 2. In the experimental group, compared with the T0, HR, SBP and DBP had an significant decline after ten minutes(T2) of pumping DEX, there was statistical significance(P< 0.05); HR, SBP and DBP increased moderately after getting into operating room(T3) and before induction(T4),which showed no statistical significance(P>0.05); HR, SBP and DBP fell obviously after induction(T5)(P<0.05); HR, SBP and DBP rose during tracheal intubation(T6), but there was no difference(P>0.05); HR, SBP and DBP gradually returned to the normal level after 2 minutes of intubation(T7)(P<0.05). Compared with the NS group, HR, SBP and DBP had no statistical significance at T0(P>0.05),while HR, SBP and DBP had obvious statistical differences at T2,T3,T5 and T6(P<0.05). 3. Compared with the T0, Ramsay score increased at T2, T3 and T4 in the DEX group, which was between 2~3 points suggesting that sedative effect was satisfactory(P<0.05);Compared with the NS group, the scores of Ramsay sedation and BIS value had statistical significance at the correspending time points(P<0.05).4. The SAI and VAS scores decreased significantly after pumping DEX in the experimental group, but there were no obvious changes in the NS group; Compared with the NS group, the SAI and VAS scores of DEX group were lower after pumping DEX, there was statistical significace(P<0.05). 5. Compared with the NS group, the dosage of etomidate decreased obviously in the DEX group, there was statistical significance(P<0.05). 6. In the ward, the usage rate of atropine ephedrine and urapidil was 0,which was of no statistical significance(P>0.05); But in the operating room,compared with the NS group,the utilization rate of atropine and ephedrine was 20% and 15% respectively, there was no difference(P>0.05); however, the utilization rate of urapidil in the DEX group dropped remarkably(10%vs50%) with statistical difference(p<0.05).Conclusions 1. When DEX was used as a preoperative sedative drug, the scores of Ramsay sedation increased, while the scores of SAI and VAS decreased. 2. As a preoperative sedation drug, low dose dexmedetomidine could reduce hemodynamics fluctuations after entering operating room and during anesthetic induction.