TCD对模拟失重下脑动脉血流的检测(1)
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【摘要】 目的观察21 d头低位卧床期间脑底动脉血流动力学的变化。方法6名健康男性志愿者，年龄(24.8±6.1)岁，进行了21 d头低位倾斜(HDT)-6°卧床试验。HDT前、HDT第10天及卧床结束时进行了3次立位耐力检查。HDT前(坐位)、HDT开始时、第1、3、7、10、21天用经颅超声多普勒(TCD)测量了双侧大脑前(ACA)、中(MCA)、后(PCA)动脉的血流动力学指标。结果卧床第10天和卧床结束时，受试者立位耐力比卧床前显著降低(P<0.05)。卧床第3天和第21天的右侧MCA的Vs较卧床前显著降低(P<0.05或P<0.01)，卧床第1、3、7、10和第21天，右侧MCA的Vs显著低于开始时(P<0.05或P<0.01)。左侧MCA的Vs在开始时较卧床前和第3天显著增加(P<0.05或P<0.01)。右侧MCA的Vm，在第3和第21天较卧床前显著降低(P<0.05或P<0.01)，在第3、10、21天较开始时显著降低(P<0.05或P<0.01)。在卧床前，MCA右左两侧流速差BVD和右左两侧非对称指数(AI)的均数分别为7.0 cm/s和13.74%，在第3、10、和21天BVD均数降为负值，较卧床前时显著降低(P<0.05或P<0.01)，AI在第10天和21天降为负，较卧床前显著降低(P<0.05或P<0.01)。MCA的其余指标、ACA和PCA的各个指标变化不显著。结论21 d头低位卧床使立位耐力、双侧MCA的Vs和右侧MCA的Vm显著降低；HDT卧床期间，MCA血流速度降低和不对称变化，可能是导致立位耐力降低的原因之一。
【关键词】失重模拟脑底动脉；血流动力学；经颅多普勒；立位耐力
【Abstract】 Objective To investigate the changes of human cerebral bottom artery hemodynamics during 21-day simulated weightlessness. Methods 21-day-6°head-down tilt bed test (HDT) were used to simulate weightlessness. Subjects were 6 healthy male volunteers, aged 24.8±6.1 years old. The Vs,Vm,Vd,RI, PI and other indexes of MCA, ACA and PCA were measured by transcranial Doppler before HDT and on day 0,1,3,7,10 ,21 of HDT. HUT +75°20 min orthostatic tolerance tests were down on day -1, 10,and
21 of HDT.Results During HUT +75°20 min orthostatic tolerance test on D10 and 21 after HDT, the average standing time were lower than those before HDT (P<0.05). On D3 and 21 after HDT Vs of right MCA were reduced significantly comparing with those before HDT (P<0.05 or P<0.01). On D1, 3, 7, 10 and 21 after HDT Vs of right MCA were obviously decreased comparing with those on D0 (P<0.05 or P<0.01). Left MCA Vs on D0 were increased significantly comparing with those before HDT (P<0.05), and also increased significantly comparing with those on D3 after HDT (P<0.01). Right MCA Vm on D3 and D21 after HDT were significant lower than those before HDT and D0 after HDT (P<0 ......
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