[Hemodynamic and cerebral ventricular functions during head-down tilt at -15 degrees].

Sixteen men were exposed to head-down tilt at -15 degrees for 6 h. Cerebral circulation was examined by bipolar rheoencephalography, ventricular function by one-dimensional echoventriculometry, and blood pressure by Korotkoff's sounds. Group 1 consisting of 10 test subjects tolerated the antiorthostatic exposure well enough (they reported only blood rush to the head and moderate facial puffiness). They showed stable parameters of cerebral circulation, ventricle size, and mean blood pressure, which is indicative of adequate compensatory capabilities of their organisms. Group 2 consisting of 6 test subjects exhibited polymorphic clinical symptoms, including the syndrome of liquor hypertension (burst-like headache, autonomic dysfunction, etc). This was accompanied by decreased pulse pressure of cerebral vessels, primarily in the vertebrobasilar area, instability of the vessel tone against the background of marked dilatation of the capacitance vessels and brain ventricles.