Physiologic Studies of Pulmonary Circulation and Ductus Arteriosus of Sheep and Goat FetusesApplication of Cineangiographic Techniques

摘要

NA;A physiologic method for evaluation of fetal circulation using cinefluorography is described. The sheep and goat fetus can be exteriorized for several hours and still maintain intact fetal circulation. Circulation times through the lungs were calculated by a radiologic method and, together with main pulmonary artery size, density of pulmonary circulation and left atrial opacification, an estimate of pulmonary flow was made. The normal pulmonary circulation in the fetus showed considerable variability and possible factors relating to this are gestational age, Po2and intra‐alveolar fluid pressure. The pulmonary circulation increased significantly following administration of alpha and beta stimulators (norepinephrine and isoproterenol) and bradykinin. Effectiveness of response depends on the site of administration of the drug. Nitrogen ventilation produced a moderate increase and oxygen ventilation a marked increase in pulmonary flow. The ductus arteriosus did not exhibit any significant radiologic change in size following similarly induced pharmacologic and mechanical stimuli.