头低位(-30°)卧床条件下不同耐力者的头颈部血流变化的特点

Changes of Cervical Blood Flow in Subjects with Different Tolerances to -30° Head-Down Bed Rest.

为探讨头低位 ( -3 0°)卧床条件下 ,不同耐力者的头颈部血流变化特点 ,被试者为40名健康男性 ,根据对头低位的耐力的好坏分为耐力良好组 (即适应组 )和耐力不良组(即不适应组 ) ,用彩色超声显像仪的多普勒技术测量了双侧颈总动脉、颈内动脉和颈内静脉的平均血流速度、血管径和血流量。结果表明 ,两组间在头颈部血流上的差别主要在于流入和流出颅内的血流量变化的不同。适应组在卧床期间 ,其流入和流出颅内的血流量与水平卧床时比较无显著差别 ,而不适应组在卧床期间 ,经颈内动脉流入颅内的血流量有增加的趋势 ,而经颈内静脉流出的血流量则明显减少。提示 :在头低位体位下 ,流入和流出颅内的血流量的变化上的差异可能与人体承受头低位体位刺激的耐受能力有关。

In order to investigate characteristics of cervical blood flow in subjects with different tolerances to head-down tilt (HDT),40 healthy men (aged 26～35 years) participated in the test of -30° HDT for 45 min. During the test, mean blood flow velocities, diameters and blood flow volume of common carotid artery(CCA),Internal caroties artery(ICA),Internal jugnlar vein(IJV) were measured with color Doppler echogram. The results showed that there have different changes of in-flow of ICA and out-flow of IJV between the adaptive subjects(n=33) and the inadaptive subjects(n=7). In the adaptive group, the cerebral blood flow volume during HDT, did not change from that during horizontal supine position. However, in the inadaptive group in-flow of ICA increased and out-flow of IJV decreased significantly during HDT as compared with those during horizontal supine position.