[THE PULMONARY HEMODYNAMICS FOLLOWING EXPERIMENTAL PULMONARY THROMBOEMBOLISM AND AFTER BLOCKADE OF THE...

In acute experiments on the anesthetized rabbits the pulmonary hemodynamics changes following pulmonary thromboembolism were studied in animals with intact circulation and isolated lungs perfusion in the control series and after the blockade of the alpha-adrenoceptors. Following pulmonary embolism in animals with intact circulation in the control group and after the blockade of alpha-adrenoceptors the pulmonary artery pressure and pulmonary vascular resistance increased, but the pulmonary artery flow decreased to the same extent. However, in control animals, the cardiac output decreased more, than the pulmonary flow; the superior vena cava flow was decreased less, than inferior vena cava flow. After the blockade of the alpha-adrenoceptors there were no any imbalance between the decreasing of the cardiac output and pulmonary flow as well as between the decreasing of superior and inferior venae cavae flows. In animals with perfused lungs after the blockade of the alpha-adrenoceptors the pulmonary artery pressure following pulmonary embolism increased to the same level as in animals with intact circulation, however, in the first case the pulmonary vascular resistance increased four times less than in the last one. Thus, we concluded, that following pulmonary thromboembolism the activation of the alpha adrenergic mechanisms could not only promote to increase the resistance of the pulmonary vessels, but these mechanisms are also involved in the changes of the capacitive function of the pulmonary vessels.