不同剂量右美托咪定对合并高血压开胸手术患者应激反应的影响

Effects of different doses of dexmedetomidine on stress responses of hypertensive patients undergoing thoracic surgery

目的 评价不同剂量右美托咪定对合并高血压开胸手术患者应激反应的影响，寻找其降低应激反应的适宜剂量。方法 择期合并高血压的开胸手术患者60例，性别不限，年龄45～64岁，体重65～80 kg，ASA分级Ⅰ或Ⅱ级，采用随机数字表法分为4组（n＝15）：对照组（C组）和不同剂量右美托咪定组（D1～3组）。D1组、D2组、D3组分别于麻醉诱导前15 min时静脉输注右美托咪定0.2、0.3、0.4 μg·kg－1·h－1，直至手术结束前30 min，C组静脉输注等容量生理盐水。分别于给予右美托咪定前（T0）、气管插管后1 min（T1）、切皮即刻（T2）和气管拔管即刻（T3）时采集静脉血样，采用高效液相色谱分析法测定血浆肾上腺素和去甲肾上腺素的浓度，同时测定血糖浓度。记录心动过缓、低血压及呼吸抑制等不良反应的发生情况。结果 与C组比较，D1组、D2组和D3组T1～3时血浆肾上腺素、去甲肾上腺素和血糖的浓度降低，D3组心动过缓和低血压发生率升高（P〈0.05），D1组和D2组心动过缓和低血压发生率差异无统计学意义（P〉0.05）。D1组、D2组和D3组组间各时点血浆肾上腺素、去甲肾上腺素和血糖的浓度比较差异无统计学意义（P〉0.05）。结论 右美托咪定降低合并高血压开胸手术患者应激反应的适宜输注速率为0.2和0.3 μg·kg－1·h－1。

Objective To evaluate the effects of different doses of dexmedetomidine on stress responses of the hypertensive patients undergoing thoracic surgery and find the optimal infusion rate of dexmedetomidine in decreasing stress responses.Methods Sixty hypertensive patients of both sexes, aged 45-64 yr, weighing 65-80 kg, of American Society of Anesthesiologists physical statusⅠor Ⅱ, were divided into 4 groups（n=15 each）using a random number table： control group（group C）and 3 different doses of dexmedetomidine groups（D1-3 groups）. In D1, D2 and D3 groups, dexmedetomidine 0.2, 0.3 and 0.4 μg·kg-1·h-1 were intravenously infused until 30 min before the end of surgery, respectively, starting from 15 min before induction of anesthesia.The equal volume of normal saline was given instead of dexmedetomidine in group C. Before administration of dexmedetomidine（T0）, at 1 min after endotracheal intubation（T1）, at skin incision（T2）and immediately after extubation（T3）, venous blood samples were collected for determination of epinephrine and norepinephrine concentrations in plasma（using high-performance liquid chromatography）and blood glucose concentrations.The development of adverse effects such as bradycardia, hypotension and respiratory depression was recorded.Results Compared with group C, epinephrine and norepinephrine concentrations in plasma and blood glucose concentrations were significantly decreased at T1-3 in D1, D2 and D3 groups, the incidence of bradycardia and hypotension was significantly increased in group D3（P〈0.05）, and no significant change was found in the incidence of bradycardia or hypotension in D1 and D2 groups（P〉0.05）. There were no significant differences in epinephrine and norepinephrine and concentrations in plasma and blood glucose concentrations at each time point between group D1, group D2 and group D3（P〉0.05）.Conclusion The optimal infusion rates of dexmedetomidine are 0.2 and 0.3 μg·kg-1·h-1 in decreasing stress responses of the hypertensive patients undergoing thoracic surgery.