BLOOD FLOW THROUGH EACH LUNG IN MAN DURING UNILATERAL HYPOXIA 1

Abstract

It is well established that pulmonary hypertension may be elicited in man by reducing the oxygen content of the inspired air. The mechanisms involved in this response to acute hypoxia, and the role of the individual segments of the pulmonary vascular tree in effecting this rise in pulmonary arterial pressure, are currently under investigation. In order to further analyze this phenomenon, a method has been developed for the separate measurement of blood flow through each lung in man. This method consists of a combination of (a) bronchospirometry, with each lung breathing a specifically selected oxygen mixture, (b) cardiac catheterization, and (c) arterial cannulation; this makes possible the application of the Fick principle, not only for the measurement of total blood flow, but also of blood flow through each lung. Previous attempts to partition pulmonary blood flow in man have been indirect, and have involved many assumptions (1). It is the purpose of this paper to 1) describe a method based on more direct data, and 2) present the results of studies concerning the effects of unilateral hypoxia upon the pulmonary circulation in man.