The Pulmonary Vascular Responses to Short-Term Hypoxia in Human Subjects

Using the catheter technic, the acute circulatory reactions to a brief period of hypoxia have been studied. It was found that when a normal person breathed a gas mixture containing only 10 per cent oxygen, the pulmonary arterial pressure rose but the pulmonary capillary pressure remained unchanged. This indicated pulmonary vasoconstriction, thought to be due to a direct effect on the pulmonary vascular tree. No demonstrable change in so-called pulmonary blood volume could be detected. In an additional group of patients with cardiopulmonary disease the reactions were more erratic but not significantly different in type.