右旋美托咪啶对国人颈内动脉血流速率、血流量和平均动脉压的影响

The influence of low dose dexmedetomidine on internal carotid artery blood flow in Chinese

目的:研究右旋美托咪啶(Dexm edetom id ine,Dex)对国人颈内动脉血流量的影响。方法:选择30例年轻患者(ASA I^II)随机分为两组,各15例,Dex镇静组(D组)和对照组(C组),D组静注负荷剂量Dex 0.4μg/kg(5m in内)后以0.4μg.kg-1.h-1维持30m in,C组静输生理盐水对照。监测所有患者的MAP、HR、SpO2、PETCO2,并采用AU4型彩色多普勒仪测量颈总动脉和颈内动脉的内径、血流速率、血流量。连续记录基础值(T0),负荷剂量后即刻(T1),以及持续泵注Dex后5m in、10m in、15m in、20m in、25m in、30m in(T2~7)上述各项指标。结果:Dex负荷量输注后患者颈总动脉血流速率和血流量先分别增加19%和18%(P<0.05)后逐渐回落;持续输注25m in后患者颈内动脉血流速率、血流量比基础值降低17%~21%(P<0.05);其间患者HR和MAP与基础值相比均引起无临床意义的降低(P<0.05);颈内动脉血流速率、血流量与MAP的相关系数(r)分别为0.165和0.119,两者之间无明显相关;所有患者无明显呼吸抑制。结论:Dex(负荷剂量0.4μg/kg继以0.4μg.kg-1.h-1维持输注)减少国人颈内动脉的血流量,其变化与血压下降无相关。

Objective： To observe the influence of low dose dexmedetomidine （Dex） on internal carotid artery blood flow in Chinese. Methods： 30 young healthy patients （ ASA Ⅰ ～ Ⅱ） were randomly divided into 2 groups, Dexmedetomidine group（ Group D, n = 15） or control group（Group C, n = 15）. In Group D, intravenous 0.4μg · kg^-1 · h^-1 Dex was maintained for 30 minutes after a loading dose of 0.4μ/kg Dex given in 5 minutes, whereas in Group C, 0. 9% normal saline was given as control. The MAP, HR, SpO2, PETCO2 were monitored,and the basic diameter, blood flow velocity, blood flow of common carotid artery and internal carotid artery were measured with AU4 color Doppler. The above parameters were recorded at the time before Dex infusion（T0）, after loading dose（T1）, and at5, 10, 15, 20, 25, 30 minutes（T2-7） after continuoas infusion. Results： Demographic data of the patients in both groups were comparable. The blood flow velocity, blood flow of common carotid artery increased（P 〈0.05） firstly and then fen back to normal after the loading dose of Dex. The blood flow velocity and blood flow of the internal carotid artery decreased by 17% ～ 21% （P 〈 0.05）at T5 and T6 compare with T0. Dex infusion also produced HR and MAP decrease of 15.2% and 19.8% respectively（ P 〈 0.05 ）, however the change in HR and MAP was not clinically significant. The blood flow velocity and blood flow of the internal carotid artery have no correlated with MAP （r =0. 165 and 0. 119）. No respiratory depression was observed. Conclusion： Low dose Dex （0.4μg/kg loading dose followed by 0.4μg · kg ^-1·h^-1 continuous infusion） decrease the blood flow of internal carotid artery simultaneously and it has no correlated MAP.