[Vascular reactions of the internal organs to lower body negative pressure].
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Abdomen↗
Biomedical subjects
L Ia Andriiako
Publications and source records attributed to L Ia Andriiako.
[Dynamics of the redistribution of human blood in response to lower body negative pressure].
During exposure to LBNP of -10 to -60 mm Hg variations in the blood filling of body segments were measured, using 59Fe labelled erythrocytes. The study was performed on 10 healthy volunteers each of which was exposed to six LBNP sessions (in recumbency). The data obtained were related to changes in the blood filling of various body segments (head, thorax, abdomen, pelvis, legs) which were most pronounced at LBNP -20 to -30 mm Hg. As the LBNP level increased, the changes in the blood filling of the pelvis and legs, head and thorax decreased. In the abdominal area this parameter remained essentially unaltered. The distinct variations in the thoracic blood filling were probably dependent on the amount of blood shifted to the decompressed area which may be related not only to the venous capacity in this area but also to the venous- arterial reflexes and possibly to the specific transfer of reduced pressure in tissues.
Abdomen↗
[Characteristics of the reaction of the cardiovascular system during the immediate aftereffects of LBNP].
Circulation variations during LBNP immediate aftereffects were investigated. The test subjects with different test tolerance showed dissimilar cardiovascular responses. The lack of reflex bradycardia in the test subjects with reduced LBNP tolerance gives evidence that their regulatory mechanisms are insufficiently reactive; this is manifested during aftereffects of low LBNP (up to -40 mm Hg).
Adolescent↗
[Blood circulation under physical load in the crew members of the 1st Saliut-6 base expedition].
During the 96-day flight aboard the Salyut-6 station the crewmembers showed a satisfactory response to bicycle ergometry of moderate load. However, cardiovascular regulation during exercise declined, particularly by the end of the first and the beginning of the second month. This was mainly associated with deconditioning due to an inadequate work load. Its increase helped to restore an initial level of circulation during exercise by the end of the mission.
Blood Circulation↗
[Theoretical values for left ventricular ejection time during weightlessness].
The relationship between duration of blood ejection and cardiac cycle at rest can be well described by a linear function. This relationship is maintained in weightlessness as well. The derived formula used in calculations of the theoretical values of the ejection phase during an exposure to LBNP makes it possible to predict LBNP test tolerance in the weightless state. The level of deviation of factual values of heart rate from theoretical values may be an additional index to be used in assessing health status of crewmembers inflight.
Heart Ventricles↗
[Hemodynamics of healthy persons under various regimens of negative pressure around the lower half of the body].
Thirty male athletes kept in recumbency served as test subjects in 90 LBNP experiments. In the experiments the negative pressure level varied from 40 to 80 mm Hg. During LBNP application the heart rate, arterial pressure, cardiac output, vascular tone and other parameters of circulation were measured. Cardiac output stabilized whereas other cardiovascular parameters changed significantly. Mechanisms of compensatory reaction during LBNP application and indications of its tolerance are discussed.
Adult↗