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目的 观察 2 1d头低位卧床期间颅底动脉血流动力学的变化及下体负压的对抗作用效果。 方法 12名健康男性志愿者 ,随机分为对照组和下体负压组 ,每组 6人 ,进行 2 1d头低位倾斜卧床。对照组在卧床期间不做任何处理 ,下体负压组在卧床的第 1周以及最后 1周 ,每天进行 1h- 30 mm Hg的下体负压锻炼。利用经颅超声多普勒 (TCD)测量头低位卧床 (HDT)前 (坐位 )、HDT开始时、第 1,3,7,10 ,2 1天双侧大脑前、中、后动脉的血流动力学指标。 结果 卧床期间 ,对照组右侧中动脉 (MCA)的收缩期峰值血流速度 Vs较卧床前 (pre HDT)及卧床开始时显著降低 ,左侧 MCAVs在卧床开始时较卧床前显著增加 ,卧床第 3天又较开始时显著降低。在卧床期间 ,下体负压组右侧MCA血流速度 Vs、Vd,左侧后动脉 (PCA)血流速度 Vd较卧床开始时显著降低 ,卧床第 7天右侧MCA血流速度 Vd较卧床前显著降低。 结论 2 1d头低位卧床期间双侧 MCA的 Vs显著降低 ,并有 MCA的不对称变化 ,前、后各 1周的下体负压锻炼不能改善 MCA血流速度的降低。
Objective To observe the hemodynamic changes of the skull base artery and the antagonistic effect of the lower body negative pressure during 2 1d head-down bed rest. Methods Twelve healthy male volunteers were randomly divided into control group and lower body negative pressure group, 6 in each group. The control group in the bed without any treatment, the lower body negative pressure group in the first week of bed and the last week, 1h-30 mm Hg lower body negative pressure exercise. The blood flow in the anterior, middle and posterior cerebral arteries of the bilateral brains was measured on the 1st, 3rd, 7th, 10th and 21st days at the beginning of HDT by transcranial Doppler ultrasound (TCD) Kinetic index. Results During the ambulatory period, the peak systolic blood flow velocity Vs of the right middle cerebral artery (MCA) in the control group was significantly lower than that of the pre-bedtime (pre HDT) and the beginning of bed rest. The left MCAVs were significantly increased at the beginning of bed rest compared with that before bed-ridden, 3 days significantly lower than the beginning. During the ambulation period, the blood flow velocities Vs, Vd, and PCA of the right MCA in the lower body negative pressure group were significantly lower than those at the beginning of bed rest. The right VD of the bedside MCA was Vd Significantly lower. Conclusions The Vs of bilateral MCA decreased significantly and the asymmetry of MCA during the first 2 days of low bed rest. The lower body negative pressure exercise before and after 1 week failed to improve the decrease of MCA blood flow velocity.