Measurement of Central Blood Volume

paper of this series confirm the observa-tions of others that acute hypoxia frequently raises the pulmonary arterial pressure in normal man. This pressor effect cannot be solely attributed to an augmented cardiac output, nor can it be ascribed to an elevated left atrial pressure. It seems, therefore, to arise from a change in the dimensions of some portion or portions of the pulmonary vascular bed. Whether this change involves an alteration in the pulmonary blood volume has not been settled, since experiments in man and in ani-mals have yielded conflicting results.1-8 The present study was designed to investigate the relation between volume and pressure by using two dissimilar methods. The first en-tailed measuring the central blood volume before and during hypoxia; the second in-volved recording the change in the relative weights of the two ends of the body when hypoxia was induced