Kotovskaia A R, Fomin G A
Fiziol Cheloveka. 2013 Sep-Oct;39(5):25-33.
The authors intentionally present exclusively the results of their recent studies of arterial and venous hemodynamics as predictors of human orthostatic tolerance (OT) during space flight and on return to Earth. There is a sufficient demonstration of the in-flight OT predictability by arterial hemodynamic reactions to LBNP and venous hemodynamic changes in response to the lower extremities occlusion. Three levels of cerebral blood flow deficits in the course of the lower body negative pressure test (LBNP) performed in microgravity were first defined. The authors offer quantitative arguments for the dependence of cerebral flow deficit on the degree of LBNP tolerance degradation. Patterns of arterial hemodynamics during LBNP were used successfully to diagnose the actual orthostatic tolerance and also to follow its trend as flight extended, which attests to the predictability of OT change in an individual cosmonaut on space flight. Occlusion plethysmography of legs revealed three levels of response of the most informative venous parameters (capacity, distensibility and rate of filling) correlating with severity of OT degradation.
作者特意仅展示他们近期关于动脉和静脉血流动力学的研究结果，这些结果可作为人类在太空飞行期间及返回地球时体位性耐力（OT）的预测指标。有充分证据表明，通过对下体负压（LBNP）的动脉血流动力学反应以及对下肢闭塞的静脉血流动力学变化，可预测飞行中的OT。首次定义了在微重力环境下进行下体负压试验（LBNP）过程中三种程度的脑血流不足。作者提供了定量论据，证明脑血流不足与LBNP耐受能力下降程度之间的相关性。LBNP期间的动脉血流动力学模式成功用于诊断实际的体位性耐力，并跟踪其随飞行时间延长的变化趋势，这证明了个体宇航员在太空飞行中OT变化的可预测性。腿部容积描记法显示，最具信息量的静脉参数（容量、扩张性和充盈率）有三种程度的反应，与OT下降的严重程度相关。
