Dynamic components of interrelation among the parameters of heart preload, venous return and central venous pressure

In acute experiments on cats, in applying of original methodical approach--control of systemic circulation by the aid of computerized negative feedback loop changing the volume of circulating blood (method of biological feedback)--first were experimentally measured and analyzed the dynamic characteristics of relationship between central venous pressure and venous return of blood to the right heart. The following positions are offered and validated in the work. (1) It is shown that the passive component (mechanical compliance) is more important than active one (active myogenic component) in the small circle of circulation being compared to large one. (2) Venous return plays the leading role in forming the shifts of central venous pressure directly during developing of the transition processes of systemic circulation caused by the norepinephrine injection and the linear type of this link is proved directly during the development of the cardiovascular shift. (3) The dynamic characteristics of relationship between venous return and central venous pressure during the geodynamical reaction caused by the shifts of intravascular blood volume are experimentally measured and mathematically analyzed. It is revealed that dynamic summands of this link may overbalance the static ones known before in influence on the total shifts in developing of the systemic reaction of circulation and this influence increases when the velocity of changes in studied parameters of circulation becomes more.