经颅多普勒超声对绵羊体外膜肺期间脑血流动力学变化的研究  

Transcranial Doppler monitoring of cerebral blood flow velocity during extracorporeal membrane oxygenation in sheep

作　　者：张晶[1] 樊寻梅[1] 宋国维[2] 尹河华[1] 甘小庄[2] 李惠[2] 钱素云[1] 

机构地区：[1]首都医科大学附属北京儿童医院急救中心,100045 [2]首都儿科研究所

出　　处：《中华医学杂志》2003年第10期872-876,共5页National Medical Journal of China

摘　　要：目的　使用经颅多普勒超声 (TCD)探讨体外膜肺 (ECMO)期间脑血流动力学变化规律及影响因素 ,并评价体外循环时使用TCD仪进行监护的价值。方法　应用美国MedsonicsCDSTCD仪监护系统对 14只健康绵羊ECMO灌流全过程CBFV进行连续监测 ,对ECMO后 2周绵羊一般情况和CBFV进行动态观察 ,并对其中 9只绵羊行脑形态学检查。结果　 (1)麻醉对CBFV影响不大 ;结扎颈动脉后CBFV频谱形态轻度改变 ,Vs和PI下降 ,Vm ,Vd无显著变化 ,提示结扎后脑血管处于较前扩张状态 ,以维持足够的脑血流供应 ;ECMO灌流对脑血流频谱影响最大 ,呈非搏动性改变 ,且CBFV明显降低 ,主要与MABP及PaCO2 低有关 ,提示脑血流自动调节功能受损但仍对CO2 存在反应。 (2 )ECMO前及ECMO后 2周每天测定的绵羊左右两侧CBFV差值间差异均无显著意义。 (3)ECMO后 2周 ,绵羊一般情况良好 ,9只绵羊脑组织大体解剖无异常。光镜检查 :4只绵羊除有散在小片状软化灶外 ,双侧脑组织结构正常。结论　ECMO时脑血流动力学变化较大 ,脑血流自动调节功能受损但对CO2 的反应性尚存在 ,当ECMO操作顺利 ,是安全的。TCD具有适时、迅速 ,能长时间连续监测等优越性 ,TCD脑血流监测对提高体外循环操作和管理水平 ,以维持ECMO时CBFV相对稳定、减少脑损害有指导意义。Objective To investigate the hemodynamics during extracorporeal membrane oxygenation (ECMO) and the value of transcranial Doppler (TCD )monitoring. Methods ECMO was conducted on 14 sheep. TCD monitoring was conducted at different time-points to examine the bilateral cerebral blood flow velocity (CBFV), including systolic peak flow velocity (Vs), end-diastolic flow velocity (Vd), mean flow velocity (Vm), and pulse index (PI, Vs-Vd/Vm). The general condition, blood pressure, heart rate, and temperature were observed. Two weeks after, the surviving 9 sheep were killed, their brains were taken out and morphological and pathological examinations were done. Results Anesthesia showed little effect on CBFV. After the ligation of carotid artery and vein, the CBFV pattern only changed slightly, Vs and PI decreased, and Vm and Vd remained almost unchanged. During ECMO with either greater or smaller volume, especially the former, the CBFV pattern showed a non-pulse waves, Vs markedly decreased with a value hardly different from that of Vd, Vs, Vd, and Vm were 62%, 75%, and 69% of the values in normal condition. The pre-ECMO CBFV was not significantly different from those examined any day after ECMO. The differences of pH and PO 2 in femoral artery during different stages were insignificant. PaCO 2 during ECMO with great flow volume and during mechanical ventilation after ECMO was significantly lower than that before ECMO ( P <0.05). The MABP of femoral artery during ECMO with small flow volume was significantly lower than that before ECMO ( P <0.05). Vm was positively correlated with MABP and not correlated with heart rate and temperature. The gross observation of the sheep′s brain was normal. Small foci of malacia were seen in the brains of 4 sheep. Conclusion Hemodynamics changes remarkably during ECMO. TCD monitors the CBFV continuously during ECMO, thus helping maintaining the stability of CBFV and protect the brain.

关 键 词：经颅多普勒超声 体外膜肺 脑血流动力学 变化规律 影响因素 

分 类 号：R445.1[医药卫生—影像医学与核医学]