Pulmonary Venous Bed Research Articles

DISSOCIATION OF VOLUME AND OSMOLAR CONTROL OF ADH IN INFANCY.

It has been amply demonstrated that there are two physiologic stimuli which control the release of antidiuretic hormone (ADH) from the posterior pituitary. The first, delineated by the experiments of E. B. Verney (1947-1948),1involves alterations in intracellular in osmoreceptor cells which are probably in the supraoptic and paraventricular hypothalamic nuclei. The second and more recently defined stimulus appears to involve isotonic changes in some parameter (s) of the extracellular volume.2-10While the location of the volume receptors is unknown, there is evidence to suggest their locus in the left atrium and adjacent pulmonary venous bed and their communication cephalad via the vagus nerves.8,11-13 Carter et al14have reported a 40-year-old patient with inappropriate secretion of ADH and hyponatremia secondary to head trauma in whom there appeared to be a dissociation of osmolar and control stimuli. In this patient ADH secretion during the early

The anatomical and hydrostatic basis of orthopnea and of right hydrothorax in cardiac failure

When an adult of average size is recumbent, the blood flowing from the pulmonary venous bed must be lifted from 4 to 7 cm. against the force of gravity in order to fill the left ventricle; but when the body is erect, the pulmonary outflow descends from 3 to 5.5 cm. to reach the left ventricle. Thus the pulmonary venous pressure which is adequate in the erect position to maintain a given level of left ventricular filling and cardiac output is lower than that needed to maintain the same level of cardiac output, when the individual is recumbent, by the pressure represented by a column of blood 7.5 to 10 cm. high. In the same way, the pulmonary venous outflow from the right lung of an adult in the right lateral recumbent posture must be lifted 10 cm. or more to reach the left ventricle, that from the left lung, when in the left lateral position, need be lifted only 5 cm. Therefore, the average venous pressure needed to maintain the flow of blood will be much higher in the right lung than in the left, even if the individual spends equal periods lying on the two sides. In patients, like many cardiac patients, who favor the right lateral decubitus, this difference in average pressure between the venous beds in the lungs will be increased. It is suggested that these hydrostatic factors of anatomical origin are of paramount importance in causing orthopnea and the preponderance of right pleural transudation in patients with heart failure.