模拟失重对门静脉血流动力学影响的彩色多普勒超声研究

目的探讨模拟失重环境下门静脉血流动力学的变化规律。方法研究对象为16位健康男性志愿者,平均年龄(20.38±2.00)岁,身高(174.75±3.85)cm。受试者取-6°头低足高位,连续卧床21d。受检者空腹8h以上,取仰卧位或左侧卧位,采用GEVivid7彩色多普勒超声显像仪,安静状态下检测门静脉的血流变化。结果模拟失重后门静脉左右径和前后径均有增加趋势,但与模拟失重前1d相比,组间差异无统计学意义(P0.05)。模拟失重后1d门静脉最大流速即显著下降,由模拟失重前1d的(19.8±7.7)ml/s下降为(17.1±6.8)ml/s。模拟失重后3d、7d、14d和21d门静脉最大流速继续逐步下降,与模拟失重前1d相比,组间差异有统计学意义(P0.05,P0.01)。模拟失重直立后,门静脉最大流速逐渐上升,至直立后7d上升为(18.7±7.4)ml/s,与模拟失重前1d相比,组间差异无统计学意义(P0.05)。模拟失重前1d门静脉的血流量为(1028.27±237.14)ml/min,模拟失重后1d门静脉血流量即下降为(906.23±209.89)ml/min,此后的3d、7d、14d和21d,其血流量持续下降,与模拟失重前1d相比,组间差异有统计学意义(P0.05,P0.01)。模拟失重直立后1d,门静脉血流量即上升为(934.29±217.13)ml/min,至直立后7d上升为(980.48±227.41)ml/min,与模拟失重前1d门静脉的血流量基本持平。结论模拟失重后,肝门静脉血流量呈逐渐下降的趋势,其变化类型为不适应型。临床应加强肝脏对抗失重环境的防护措施研究,以确保航天员的航天训练和太空飞行安全。

Color Doppler ultrasound study with simulated weightlessness on the effects of portal vein hemodynamics

Objective To exptore the effect of simulated weightless on portal hemodynamics. Methods The subjects were 16 healthy male volunteers. The average age was （20.38 ±2.00） years, and the height was （ 174.75 ± 3.85） cm. The subjects took positions of heads - 6° down to foot for 21 days. Af- ter fasting for more than 8 h, the subjects laid on the left decubitus or supine position, blood flow variation of portal vein were detected in a resting state with GE Vivid 7 color Doppler ultrasound imaging device. Results There was an increasing trend in left-right diameter and the anteroposterior diameter of simulated weightlessness portal vein, while no significant difference （P 〉 0.05） was shown compared with simulated weightlessness groups 1 day before. The maximum velocities of portal vein were significantly decreased 1 day after simulated weightlessness from （ 19.8 ± 7.7 ） ml/s and 1 day before the simulated weightlessness down to （ 17.1 ± 6.8） ml/s. The maximum velocity of portal vein was continued to gradually decrease for 3, 7, 14 and 21 days after simulated weightlessness. The significant （P 〈0.05, or P 〈0.01 ） difference was shown between the groups and simulated weightlessness compared and the values 1 day before. The maximum velocity of portal vein was gradually increased to （18.7±7.4） ml/s after 7-day simulated weightlessness upright without significant difference between groups. The values of 1 day before simulated weightlessness were compared（P 〉0.05 ）. The portal vein blood flow was （1028.27± 237.14） ml/min 1 day before simulated weightlessness, and the portal vein blood flow were decreased to （906.23 ±209.89） ml/min 1 day after simulated weightlessness. The blood flow were continued to reduce in the following 3, 7, 14 and 21 days.The significant difference （ P 〈 0. 05 ） or extremely significant （ P 〈 0. 01 ） were shown between the two groups compared with those 1 day before simulated weightlessness. Portal blood flow was increased to （934.29 ±217.13） ml/min 1 day after simulated weightlessness uptight and （980.48 ±227.41 ） ml/min 7 days after simulated weightlessness uptight. Portal blood flow had no chance compared with simulated weightlessness 1 day before simulated weightlessness （P 〉 0.05）. Conclusion A gradual reduction was shown as simulated weightlessness with hepatic portal vein blood flow. The astronauts space flight training and space flight safety, liver research were designed to protect the measures of weightless environment.