title: [Human external respiratory function and blood acid-base balance during prolonged antiorthostatic hypokinesia and during the recovery period].
abstract: The study of external respiration and acid-base equilibrium of blood of 35 test subjects exposed to 49-day head-down (-4 degrees) tilting and of 6 test subjects exposed to 182-day head-down (-4 degrees) tilting demonstrated a trend for a decrease in the respiration rate, lung ventilation, oxygen consumption, and a relative increase in the exhalation time. With respect to the arterialized blood gases, a significant decrease in PaO2, an increase in PaCO2 and in the O2 alveolar-arterial difference were seen during the 49-day head-down tilting. During the 182-day head-down tilting a further increase in the CO2 arterio-alveolar difference was noted. These changes suggest shifts of the ventilation-perfusion ration in the lungs and, probably, disturbances of central regulation of respiration induced by head-down tilting. During the recovery period the above changes diminished gradually and disappeared by the 14th and 30th day after the 49- and 182-day head-down tilting, respectively.
mesh_terms: D000136:Acid-Base Equilibrium; D000328:Adult; D001784:Blood Gas Analysis; D006801:Humans; D007103:Immobilization; D008176:Lung Volume Measurements; D008297:Male; D010101:Oxygen Consumption; D010313:Partial Pressure; D011187:Posture; D012119:Respiration; D013997:Time Factors; D014692:Ventilation-Perfusion Ratio
vernacular_title: Funktsiia vneshnego dykhaniia i kislotno-osnovnoĭ balans krovi cheloveka pri dlitel'noĭ antiortostaticheskoĭ gipokinezii i v vosstanovitel'nom periode.