21d头低位卧床期间脑底动脉血流动力学的变化(英文)

Changes of Human Cerebral Bottom Arterial Hemodynamics during 21 d Head down Tilt(-6°) Bed-rest

目的观察 2 1d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2 4 .8± 6.1岁 ,进行了 2 1dHDT - 6°卧床试验。HDT前、HDT第 1 0天及卧床结束时进行了 3次立位耐力检查。HDT前 (坐位 )、HDT即刻 (D0 )、第 1、3、7、1 0、2 1天用经颅超声多普勒 (TCD)测量了双侧大脑前 (ACA)、中 (MCA)、后动脉 (PCA)的血流动力学指标。结果卧床第 1 0天和卧床结束时 ,受试者立位耐力比卧床前显著降低 (P <0 .0 5)。卧床第 3天和第 2 1天的右侧MCA的Vs 较卧床前显著降低 (P<0 .0 5或P <D0 .0 1 ) ,卧床第 1、3、7、1 0和第 2 1天 ,右侧MCA的Vs 显著低于D0时 (P <0 .0 5或P <0 .0 1 )。左侧MCA的Vs 在D0时较卧床前和第 3天显著增加 (P <0 .0 5或P <0 .0 1 )。右侧MCA的Vm,在第 3和第 2 1天较卧床前显著降低 (P <0 .0 5或P <0 .0 1 ) ,在第 3、1 0、2 1天较D0显著降低 (P <0 .0 5或P <0 .0 1 )。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7.0cm/s和 1 3.74% ,在第 3、1 0、和 2 1天BVD均数降为负值 ,较卧床前时显著降低 (P <0 .0 5或P <0 .0 1 ) ,AI在第 1 0和 2 1天降为负 ,较卧床前显著降低 (P <0 .0 5或P <0 .0 1 )。MCA的其余指标、ACA和PCA的各指标变化不显著。结?

Objective To investigate the change of human cerebral bottom arterial hemodynamics during 21 d simulated weightlessness.Method 21 d -6° head down tilt bed rest(HDT) were used to simulate weightlessness.6 healthy male,aged 24.8±6.1 served as subjects.Systolic blood velocity(V s),diastolic blood velocity(V d),mean blood velocity (V m),pulsatility index(PI),resistance index(RI) and other indices of middle cerebral arteries(MCA),anterior cerebral artery (ACA) and posterior cerebral artery (PCA) were measured by transcranial ultrasound Doppler before HDT and on day 0(D0),1,3,7,10,21 of HDT.HUT +75° 20 min orthostatic tolerance tests were done on day -1,10,and 21 of HDT. Result During HUT +75° 20 min orthostatic tolerance test on day 10 and 21 of HDT,the average standing time were shorter than that of the pre HDT values (P<0.05).On day 3 and 21 of HDT,V s of right MCA reduced significantly than pre HDT(P<0.05 or P<0.01).On day 1,3,7,10 and 21 of HDT,V s of right MCA were obviously lower than that on D0(P<0.05 or P<0.01).Left MCA V s on D0 increased significantly than that of pre HDT(P<0.05),and both were significantly higher than those of the 3rd day of HDT(P<0.01).Right MCA V m on the 3rd and 21st day of HDT were significantly lower than those pre HDT and D0(P<0.05 or P<0.01).On day 10 of HDT,V m of right MCA were significantly reduced than that on D0(P<0.05).Both MCA bilateral velocity difference(right V m left V m) on the 3rd,10th,21st day of HDT,and MCA inter hemispheric asymmetry index on the 10 th,21st day of HDT were significantly lower than that of pre HDT (P<0.05 or P<0.01). Conclusion 21 d HDT bed rest decreased orthostatic tolerance,V s of both side MCA,and V m of right MCA.Lower V s of both side MCA and the inter hemispheric asymmetry of MCA during HDT maybe responsible,in part,for the increased risk of orthostatic intolerance.