Intersystem correlation of respiration and hemodynamics during postural changes

The effects of passive head-up and head-down tilting on intersystem correlation respiration and hemodynamics were investigated in anesthetized spontaneously breathing cats. Studies have shown that marked changes in circulation, functional residual capacity and compliance occur within the fist minutes of postural change. Changes in circulatory and respiratory modulation throughout postural test were opposite and linearly related to the sine of the tilt angle. This data indicate that the primarily changes in cardiorespiratory system were influenced by the blood distribution dependent from hydrostatic effect of gravity.