Walter J. Daly

Effects of oxygen breathing on the heart rate, blood pressure, and cardiac index of normal men--resting, with reactive hyperemia, and after atropine.

Oxygen breathing has been used extensively to treat a wide variety of clinical disorders. An understanding of its effects on the normal circulation, at rest and under conditions of increased cardiac output, is fundamental to the understanding of the efficacy of oxygen therapy in clinical situations. Furthermore, interpretation of physiologic data concerning the effects of hyperoxia on the regional circulations requires definition of any changes in cardiac output or over-all peripheral circulation that occur during oxygen breathing. This investigation was undertaken for two purposes: 1) to evaluate the effects of oxygen breathing on the heart rate, systemic blood pressure, and cardiac index of normal men, resting, after atropine, and subjected to the circulatory stress of reactive hyperemia; and 2) to study the higher ranges of oxygen-sensitive chemoreceptor activity in man.

Clinical Observations of Acute Friedländer Pneumonia

Excerpt In recent years acute Gram-negative bacterial infections of the lung, among them Friedlander pneumonia, have received renewed attention. The incidence and severity of these infections appea...

Medieval Contributions to the Search for Truth in Clinical Medicine

As these examples suggest, prescriptions used in Western Europe during the Middle Ages tended to be complex and expensive, often assembled from ingredients obtained over great distances. Although apothecaries became available in many cities toward the end of this era, often serving the dual role of compounders of medicines and purveyors of spices [3], physicians were expected to be able to compound many of their own prescriptions, and they may also have supervised the work of apothecaries. Fairly specific directions were provided in contemporary medical texts:

The Pressure-Volume Relationship of the Normal Pulmonary Capillary Bed *

In isolated lung preparations (1, 2) and in normal subjects (3, 4), acute pulmonary vascular congestion increases breath-holding diffusing capacity for carbon monoxide (DLco) by increasing the instantaneous volume of blood available for CO absorption (Vc). Conversely, in normal men, procedures that decrease pulmonary vascular pressure decrease DLco (4, 5); yet, the pulmonary capillary bed of the lung chronically subjected to increased intravascular pressure is less able to decrease its volume in response to procedures designed to decrease pulmonary vascular pressure (6). Although this may be the consequence of structural changes in the lung, this observation suggests that the curve relating DLCO to pulmonary vascular pressure may reach a plateau, beyond which changes in pulmonary vascular pressure produce no further changes on DLCO. Such a relationship does not imply a solution to the question whether increased intravascular pressure recruits a limited number of capillaries or dilates capil-laries within a limited range. In either case, a plateau of the DLco-vascular pressure curve would be anticipated. This study was undertaken to examine the behavior of the normal pulmonary capillary bed acutely subjected to increased intravascular pressure with two specific aims in mind: 1) to describe, in normal man, the effects on DLCO of graded increases in, intravascular pressure and to determine * whether a plateau does indeed exist; 2) if such a limit exists, to determine the effect of exercise on DLCo in individuals who have already experienced the maximal effect of acute passive congestion on DLCO. Methods Twenty trained normal men, ages 21 to 36, were used in this study. Their physical characteristics are summarized in Table I. They came to the laboratory from their usual work and were studied after resting 15 to 30 minutes. There was no attempt to insure a truly basal state. The basic variables measured were DLco, right atrial pressure, and oxygen consumption. These were measured in the following experimental situations: 1) In nine resting subjects, DLco and right atrial pressure were measured with the subjects supine and tilted 600 and 300

HEMODYNAMIC CONSEQUENCES OF OXYGEN BREATHING IN LEFT VENTRICULAR FAILURE.

As in normal men, oxygen breathing in patients with left ventricular failure is associated with a further reduction of cardiac index, partially the result of decreased stroke index and partially the result of decreased heart rate. The decrease in heart rate and cardiac index is associated with a decrease in left ventricular work index without impairing the delivery of oxygen to the tissues or the over-all tissue pO2. In this group of patients, oxygen breathing did not result in a decreased pulmonary vascular resistance.

Effects of breathing oxygen on atrioventricular conduction

Abstract Hyperoxic breathing slows atrioventricular conduction in patients with already prolonged A-V conduction time and decreases the ventricular response to atrial fibrillation. As in normal man, hyperoxic breathing slows the heart rate of patients with sinus rhythm who are taking digitalis and/or who have varying degrees of atrioventricular block.

The Eye Book of Master Peter of Spain – a glimpse of diagnosis and treatment of eye disease in the Middle Ages

Peter Hispanus, who became Pope John XXI, wrote a book about eye diseases and their treatment in the 13th century. De Oculis was not a scholarly treatise about eye diseases, but a manual intended for general physicians. Nevertheless, Latin copies were made into the 16th century, indicating its influence and importance. We present the first published English translation of De Oculis, based on a synthesis of the medieval Latin manuscripts and a German translation from the 19th century. The sources of Peters understanding of the causes and treatment of eye diseases were the more scholarly and complete treatises by Greek and Arab writers. Many of the diseases described then cannot be correlated precisely with ophthalmic disorders known to us today because of the limited understanding of anatomy, function and pathophysiology that existed. However, De Oculis provides us with a glimpse of the practice of medicine in the Middle Ages.

Physiological Alterations in the Pulmonary Capillary Bed at Rest and During Exercise The Effect of Body Position and Trimethaphan Camphorsulfonate

The reactivity of the pulmonary capillary bed during exercise as estimated by change in the pulmonary diffusing capacity (DLco) has been shown to be dependent upon at least two separate mechanisms. The initial (0 to 10 second) DLco rise with exercise appears to be volume-pressure dependent and may be altered by mechanisms influencing these factors in the lungs. The later elevation of DLco with exercise was demonstrated to be primarily independent of the initial rise and uninfluenced by factors affecting peripheral venous return, that is body position and ganglionic blockade.

Primary Myocardial Disease: Clinical Features and Hemodynamic Alterations.

Excerpt Thirty-two males, average age 43 years, with idiopathic cardiomegaly and signs and symptoms of heart failure were studied. Fourteen were Negroes (hospital population, 18% Negro). Twenty-one...