中文摘要：

目的：探寻患儿室间隔缺损封堵术中右美托咪定（dexmedetomidine,Dex）联合氯胺酮的最佳麻醉浓度。方法：选择4～11岁拟行VSDO的室间隔缺损患儿120例,随机分为A、B、C三组（n=40）。静脉注射阿托品及氯胺酮（1.0mg·kg-1）行麻醉诱导后,输注10min右美托咪定负荷量0.5μg·kg^（-1）,然后对A、B、C三组分别静脉输注0.8、1.0、1.2μg·kg-1·h-1的右美托咪定。术中若麻醉变浅,单次追加氯胺酮0.5mg·kg-1。分别记录入室（T_0）、氯胺酮给药后1min（T_1）、5min（T_2）、输注完毕（T_3）、输注维持量15min（T_4）、术毕（T_5）、苏醒时（T_6）的BIS、BP、HR和SpO2,手术时间、苏醒时间,呼吸抑制和术后躁动等不良反应,氯胺酮总用量,氯胺酮和阿托品的追加情况。结果：与同组T_0时相比,三组在T_4和T_5的BIS值降低,三组的BP值、SpO2值在T_1～T_6无统计学差异。A组的HR在T_4、T_5无统计学差异（t=0.525,P=0.601）。三组手术时间和苏醒时间无统计学差异。B、C组的氯胺酮总用量和追加率、呼吸抑制发生率无统计学差异,均低于A组。B、C两组之间阿托品追加率有统计学差异,均高于A组。三组的苏醒期躁动发生率均为零。结论：4～11岁患儿室间隔缺损封堵术中,采用1.0mg·kg^（-1）氯胺酮行麻醉诱导,再以右美托咪定0.5μg·kg^（-1）的负荷量输注、1.0μg·kg^（-1）·h^（-1）的浓度维持,可使麻醉效果良好,且不良反应少,是最佳的联合麻醉浓度。

英文摘要：

Objective： T_o evaluate the optimum concentrations of dexmedetomidine（Dex） combined with ketamine for patients between four and eleven years old undergoing closure of ventricular septal defect. Methods： One hundred and twenty pediatric patients,aged 4 to 11 years old, with ventricular septal defect demanding ventricular septal defect occlusion（VSDO）, were randomly divided into A,B and C group（n=40 each）. Ketamine 1.0 mg·kg~（-1）and atropine 0.02 mg·kg~（-1）were used to induce anesthesia, after which administration of a loading dose of Dex 0.5 μg·kg-1was infused over 10 minutes. T_hen Dex of 0.8, 1.0 and 1.2 μg·kg-~（1）·h~（-1）were intravenously infused in A, B and C group respectively, until the operation was finished. When the patients lost their consciousness, the interventional treatment was started with femoral artery puncture. When the depth of anesthesia was insufficient, additional ketamine of 0.5 mg·kg~（1）was infused. Indicators recorded were BIS, HR, BP and SpO_2 at T_0（admission to the operating room）, T_1（1 min after ketamine administration）,T_2（5 min after ketamine administration）, T_3（the end of loading dose of Dex infusion）, T_4（15 min after the maintenance dose of Dex infusion）, T_5（the end of operation） and T_6（awaking time）. The aggregate consumption of ketamine, cases requiring additional atropine or ketamine, awaking time, operation time and cases of adverse effects such as postoperative agitation and respiratory depression were all recorded. Results： Compared with the value at T_0, BIS value declined significantly at T_4 and T_5in each group. The value of BP and Sp O_2 of the three groups had no statistical difference at T_1~T_6. HR of the group A had no statistical difference between T_4 and T_5（t=0.525,P=0.601）. No significant difference was found in the awaking time and operation time in all groups. No pediatric patients needed extra ketamine in B and C groups. The total dosage and extra rate of ketamine and respirato