Herbert O. Sieker

Pulmonary lymphangiomyomatosis responsive to progesterone.

PULMONARY lymphangiomyomatosis occurs almost exclusively in women of reproductive age.1 The principal manifestation is a proliferation of immature smooth muscle throughout the peribronchial, periva...

Reflex Venomotor Activity in Normal Persons and in Patients with Postural Hypotension

Reflex venomotor activity has been observed and measured in normal subjects by means of the pressures developed within isolated segments of superficial veins. Strong contractions are caused by the Valsalva maneuver, tilting, cold, exercise, and hyperventilation. After the Valsalva and after tilting there is a brief elevation of central venous pressure. Pulmonary vascular pressures are also increased after the Valsalva. This is taken to indicate a widespread venoconstriction with central shifting of blood. Persons with postural hypotension show little or no segment or central venous pressure response to these stimuli, indicating impaired reflex venomotor activity.

Cardiovascular and blood gas responses to hyperbaric oxygenation

Abstract Ten normal subjects were studied while they breathed air and 100% oxygen at 1 and 3.04 atmospheres. Oxygen inhalation at 3.04 atmospheres was associated with a significant increase in arterial and venous pO 2 and O 2 content. Hemoglobin in the venous circulation was completely saturated in 8 of 10 subjects. Oxygen inhalation at 3.04 atmospheres produced a small but significant increase in venous pCO 2 , presumably due to the loss of the buffering effect of reduced hemoglobin. Heart rate and cardiac output fell significantly with little change in stroke volume during oxygen inhalation at 3.04 atmospheres, indicating that the decrease in cardiac output was rate-dependent. There was little change in mean arterial pressure but an increase in calculated peripheral resistance during oxygen inhalation at 3.04 atmospheres. Two subjects who demonstrated signs of acute oxygen intoxication did not differ significantly from the group as a whole either in terms of blood gas values or patterns of hemodynamic response.

Correlation of Clinical and Physiologic Manifestations of Sustained Hyperventilation

THE hyperventilation syndrome, as seen in anxious, tense persons, is characterized by paresthesia of the extremities and circumoral area, sensations of lightheadedness and altered consciousness and...

Reversible Cardiopulmonary Syndrome with Extreme Obesity

A syndrome consisting of obesity, somnolence, cyanosis, periodic breathing, and polycythemia, with congestive heart failure has been observed in 6 patients. The effect of weight reduction and the mechanisms responsible for the symptoms and signs are discussed.

Normal and Impaired Retinal Vascular Reactivity

Normal retinal arteries and veins will constrict when the arterial blood oxygen tension is increased and dilate when it is lowered. A technic, employing fundus photography, is described for measuring this reaction. The amount of constriction on breathing oxygen, and its trend with age, have been measured in normal subjects. The arteries of persons with well-established hypertension and diabetes usually show marked impairment of this constrictor reaction, presumably because of sclerotic changes. It is suggested that measurements of this reaction may prove to be a useful, quantitative extension of present retinal vascular grading technics.

Cardiac receptors and fluid volume control.

Summary o 1. Evidence is presented that volume is regulated as an independent parameter. Thus, expansion of the blood volume by a small blood transfusion leads to diuresis, its contraction to oliguria. 2. A consideration of the anatomy and physiology of the circulation, including the relative elasticities of the arterial tree and the low-pressure system, suggests the highly distensible great veins and atria as the most appropriate location for “volume” receptors. 3. Negative pressure breathing and oscillation ventilation technics induce diuresis and implicate the thoracic viscera. Further experiments have pinpointed the left atrium as one sensitive area concerned with antidiuretic hormone release. The right atrium appears to be involved in aldosterone secretion. 4. Afferent impulses from the atria travel to the central nervous system by the vagus nerves, entering the medulla by their rostral rootlets. They relay in a restricted area in the region of the vagal sensory nuclei. There is some indirect evidence that they affect aldosterone secretion by impulses relayed to the “midbrain-limbic” region, and antidiuretic hormone secretion by influencing the supraoptic region of the hypothalamus. They may also modify kidney function by changing the brainstem sympathetic nervous outflow. 5. This growing evidence of nervous connections between mechanical events in the heart and the central adjustment of water and mineral excretion promises to throw light on the puzzling metabolic changes in congestive heart failure and a number of other cardiovascular disturbances.

Effect of Aminophylline on Respiratory-Center Sensitivity in Cheyne-Stokes Respiration and in Pulmonary Emphysema

ALTHOUGH aminophylline has been known for many years to abolish Cheyne-Stokes respiration and restore a normal breathing pattern, the mechanism of this phenomenon is poorly understood. This agent a...

The Continuous Recording of Central Venous Pressure Changes from an Arm Vein

With the subject in the right lateral decubitus position, changes of central venous pressure can be recorded accurately and conveniently from a vein in the antecubital fossa of the dependent arm. Theoretically the hydrostatic, pressure transforms the venous bed between the heart and the site of puncture into uninterrupted wide channels with relatively low distensibility. Simultaneous recordings of pressure by the method described and by catheterization of the central veins showed that induced changes of central venous pressure were identically recorded from both sites. The mean pressure gradient between the peripheral and central veins was 35 mm. of water.

Hemodynamic Effects of Continuous Positive and Negative Pressure Breathing in Normal Man

Alterations in cardiac output, central blood volume, and arterial and central venous pressures were studied in 36 young men subjected to continuous negative or continuous positive pressure breathing. Negative pressure breathing increased cardiac output, stroke volume, and, to a lesser extent, central blood volume. Positive pressure, without overbreathing, decreased both cardiac output and central blood volume, but hyperventilation reversed these effects. On the basis of these observations, it is concluded that decreased intrathoracic pressure is important in maintaining or increasing the blood available to the heart in man, particularly during circulatory stress.