[The effect of high-frequency ventilation of the lungs on the pulmonary and systemic circulations]

By means of ultrasonic method used in acute experiments on cats with open chest under nembutal narcosis the authors studied the linear and volumetric blood flow velocity in the ascending aorta and conus of the pulmonary artery, the balance between the cardiac output of right and left ventricles, as well as blood pressure (BP) in pulmonary and femoral arteries, the pulmonary microvascular bed under conversion from traditional to the high frequency jet ventilation (HFJV). It was shown that under HFJV there were decreases in pulmonary BP and pulmonary vascular resistance, a reduction of right ventricular output, redistribution of blood to the general circulation. At the same time, in most experiments the linear blood velocity in the aorta and in the pulmonary artery, systemic BP, the general vessel resistance remained stable. HFJV, unlike conventional artificial lung ventilation did not cause any deformation of the pulmonary microvascular bed. There was an insignificant decrease of the capillary perfusion index. The change of such parameters as cardiac output, stroke volume, stroke index, cardiac in index in the central circulatory hemodynamics occurred 5 minutes following the same and unidirectional changes in the lesser circulation. The stabilisation of fundamental hemodynamic parameters took place from 10 to 20 minutes after conversion to HFJV.