[Metabolic shifts and gas exchange during the working of artificial heart ventricles]

Complete cardiac bypass has been performed in the experiments on 21 random-bred dogs under thiopental-ketamine anesthesia using artificial heart ventricles (AHV), "Kedr" type. In 9 dogs 15 hours after AHV insertion their output was increased by half, as compared to baseline cardiac output values; in the rest of animals AHV worked in the regimen of normal perfusion. The study of acid-base balance parameters has revealed that AHV functioning in the regimen of normal perfusion for 2.5 hours leads to the development of moderate decompensated metabolic acidosis, the degree of which depends on the duration of AHV functioning. Changes in arterial and venous blood pO2 in long-term AHV functioning is indicative of blood flow activation in arteriovenous shunts. Blood flow increase during the first 15-20 min is accompanied by the improvement of blood oxygenation and stabilization of the acid-base balance parameters. AHV functioning in hyperperfusion regimen for 1 hour leads to deterioration of ventilation-perfusion pulmonary ratio and the onset of hypoxemia.