[Hemo- and gas dynamic effects of artificial ventilation of the lungs]

In anesthetized cats, autonomic respiration in the positive intermitting pressure mode induced a decrease of the minute blood volume under conditions of both the closed and the open chest by 24% and 43% resp. The arterial pressure in the major circulation as well as the pressure in the right heart ventricle were decreased insignificantly (by 10-15%). The mechanical respiration sharply increased the ratio: respiratory dead space volume/alveolar volume. To maintain the adequate values of the gaseous and acid-alkaline composition of arterial blood, it was necessary to set a considerably higher respiratory volume of the apparatus as compared with spontaneous breathing. Certain mechanisms of the artificial ventilation effects upon the cardiovascular and respiratory systems, are discussed.