移居高原时间对脑血流的影响及其种族差异性的研究

目的 探讨平原移居高原时间对健康青年男性脑血流动力学参数的影响及其种族差异性.方法 随机选取世居平原、从平原地区移居高原4 d、1年和5年的汉族及世居高原的藏族青年作为研究对象,均为健康男性.应用彩色双功能多普勒超声(CDDS)测量双侧椎动脉和颈内动脉的内径及平均血流速度,同步记录心率、血压、血氧饱和度,并检查血红蛋白浓度,以计算全脑血流量(TCBF)、全脑血管阻力(TCVR)及全脑供氧量(TCOS).结果 汉族移居高原后,TCVR和TCBF在刚上高原后会有一过性的变化(P<0.05),而后维持在平原水平,且后者明显高于世居藏族(P<0.05);而血压和TCOS则迅速升高(P<0.05),并在相对较长的时间内维持在一个稳定的水平,且始终高于世居藏族(P<0.05).结论 汉族移居高原后脑血流在短时间内就能发生适应性变化,并长时间保持在固定的水平,但这种适应能力始终弱于世居高原的藏族.CDDS法可无创测量脑血流量,在高原相关性脑血流动力学的研究中具有重要价值.

Abstract：

Objective To study the effects of duration of migration from sea-level to high-altitude on cerebral hemodynamic parameters and their ethnic differences.Methods This randomized comparative study recruited 5 groups of healthy male subjects which were native Hans at sea-level (NHS),Han migrants from sea-level to high-altitude (HMSH,where HMSH-a for residence duration of 4 days,HMSH-b for 1 year,and HMSH-c for 5 years),and native Tibetans at high-altitude (NTH).Color duplex Doppler sonography (CDDS) was used to measure bilateral vertebral and internal carotid arterial diameters,mean flow velocities.The heart rate,arterial blood pressure,and arterial oxygen saturation were also recorded simultaneously,and in combination,hemoglobin was measured to assess total cerebral blood flow (TCBF),total cerebrovascular resistance (TCVR),and total cerebral oxygen supply (TCOS).Results After migration to high-altitude,Hans' TCVR and TCBF maintained the level of NHS after transient changes during early stage (P<0.05),and the TCBF was markedly higher than that of NTH (P<0.05);while the blood pressure and TCOS increased abruptly (P<0.05) at the beginning and kept for a relatively long time at a constant level which were higher than those of NTH all the time (P<0.05).Conclusions Han migrants can acclimate to high-altitude by adaptive change of cerebral blood flow over a short time and maintain a constant adaptability which is always weaker than that of native Tibetans.CDDS can be used for non-invasive measurement of actual cerebral blood flow,and is of good value in the study on high-altitude-related cerebral hemodynamics.

Study on effects of duration of migration to high-altitude on cerebral hemodynamics and their ethnic differences

Objective To study the effects of duration of migration from sea-level to high-altitude on cerebral hemodynamic parameters and their ethnic differences.Methods This randomized comparative study recruited 5 groups of healthy male subjects which were native Hans at sea-level (NHS),Han migrants from sea-level to high-altitude (HMSH,where HMSH-a for residence duration of 4 days,HMSH-b for 1 year,and HMSH-c for 5 years),and native Tibetans at high-altitude (NTH).Color duplex Doppler sonography (CDDS) was used to measure bilateral vertebral and internal carotid arterial diameters,mean flow velocities.The heart rate,arterial blood pressure,and arterial oxygen saturation were also recorded simultaneously,and in combination,hemoglobin was measured to assess total cerebral blood flow (TCBF),total cerebrovascular resistance (TCVR),and total cerebral oxygen supply (TCOS).Results After migration to high-altitude,Hans' TCVR and TCBF maintained the level of NHS after transient changes during early stage (P<0.05),and the TCBF was markedly higher than that of NTH (P<0.05);while the blood pressure and TCOS increased abruptly (P<0.05) at the beginning and kept for a relatively long time at a constant level which were higher than those of NTH all the time (P<0.05).Conclusions Han migrants can acclimate to high-altitude by adaptive change of cerebral blood flow over a short time and maintain a constant adaptability which is always weaker than that of native Tibetans.CDDS can be used for non-invasive measurement of actual cerebral blood flow,and is of good value in the study on high-altitude-related cerebral hemodynamics.