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目的观察 2 1d头低位卧床期间脑血流的变化及最后一周下体负压对抗的影响。方法 1 2名健康男性志愿者 ,随机分为对照组和LBNP组 ,每组 6人 ,进行头低位倾斜卧床 ( - 6°)。对照组在卧床期间不做任何处理 ,LBNP组在卧床最后一周 ,每天进行 1h、- 4.0kPa的下体负压锻炼。利用KYENG Ⅰ导纳式双侧脑血流自动检测仪测量卧床前、卧床第 3、1 0及 2 1天的脑血流量。结果对照组的左侧大脑Ⅰ相面积及流入速度在卧床期间较卧床前均显著降低 ,左侧大脑主峰高度在卧床第 3及 2 1天显著降低 ,左侧大脑阻力指数在卧床第 3及 2 1天显著升高 ;LBNP组的左侧大脑Ⅰ相面积在卧床第 3及 2 1天较卧床前均显著降低 ,左侧大脑阻力指数在卧床期间均显著升高 ,左侧大脑主峰高度及流入速度在卧床第 3及 2 1天有降低趋势 ,但未达到显著水平。两组之间比较无显著性差异。结论 2 1d头低位卧床可引起脑血管阻力增加 ,脑血流量减少 ;在 2 1d头低位卧床的最后一周进行下体负压锻炼 ,不能有效地对抗头低位卧床模拟失重引起的脑血流的变化。
Objective To observe the changes of cerebral blood flow and the effect of negative pressure confrontation in the last week of 21 days with low bed rest. Methods Twelve healthy male volunteers were randomly divided into control group and LBNP group, with 6 in each group. The control group in the bed without any treatment, LBNP group in the last week of bed, daily 1h, - 4.0kPa lower body negative pressure exercise. The cerebral blood flow on the 3rd, 10th and 21st days of bed rest and bed rest were measured by KYENG Ⅰ admittance bilateral cerebral blood flow automatic detector. Results In the control group, the area of the left brain and the inflow rate of I phase in the left ventricle were significantly lower than those in the bed before bed rest. The height of the left main brain peak was significantly reduced on the 3rd and 21st days of bed rest. The left brain resistance index was lower in the third and the second 1 day significantly increased in the LBNP group, the left brain I phase area in the bed on the 3rd and 21st days were significantly lower than before bedtime, the left brain resistance index increased significantly in bed, the left main peak height and inflow The rate of decrease was on the 3rd and 21st days of bedridden, but did not reach significant level. There was no significant difference between the two groups. Conclusions The hypothalamic bed rest may increase the cerebral vascular resistance and decrease the cerebral blood flow in the first 21 days. The lower body negative pressure exercise in the last week of 2 1d head-down bed can not effectively combat the changes of cerebral blood flow caused by simulated head-weight bed rest.