Showing papers on "Hypoventilation published in 1967"

Effect of Oxygen Breathing on Distribution of Pulmonary Blood Flow in Chronic Obstructive Lung Disease1, 2

Abstract: In chronic obstructive lung disease, a major functional disturbance lies in maldistribution of ventilation of the lungs. It has been postulated that, at least in some patients, compensatory regional pulmonary vasoconstriction may occur in the poorly ventilated portions of such lungs, thus reducing the range of ventilation-perfusion ratios and improving arterial oxygen tension. The evidence for this lies largely in the reduction of arterial oxygen tension or saturation that may follow the administration of pulmonary vasodilator drugs, such as tolazoline (1, 2) and aminophylline (3-5). It has been suggested that these drugs reverse pre-existing vasoconstriction in poorly ventilated regions of the lungs and that this leads to a worsening of ventilation-perfusion ratio distribution and a fall in arterial oxygen tension. Oxygen is a powerful, nonspecific, pulmonary vasodilator agent. Pain, Read, and Read (6) showed that in a group of patients with chronic lung disease oxygen breathing was sometimes associated with an increase of arterial carbon dioxide tension (Pac02 ) greater than that to be expected from any hypoventilation produced by the oxygen. It was suggested that these increases of Pa002, not due to diminished ventilation of the lungs, were also due to worsening of ventilationperfusion ratio distribution in the lungs. Analysis of the factors involved indicated that this, in turn, must reflect an increased blood flow through poorly ventilated regions of the lungs associated with oxygen breathing; that is, there was reversal of pre-existing regional compensatory vasoconstriction in some of these patients. These conclusions were based on comparisons of ventilation and Pa002 that were made when the subject was breathing air and after breathing oxygen for ten minutes. Some of the conclusions

Controlled ventilation with intermittent positive-pressure breathing in the management of acute ventilatory failure associated with chronic obstructive pulmonary disease.

Abstract: Excerpt Controlled mechanical ventilation may be employed for ventilatory support in patients with respiratory failure when assisted ventilation fails. The purpose of controlled ventilation is to r...

Mechanisms leading to hypoventilation in extrapyramidal disorders, with special reference to Parkinson's disease.

Abstract: In extrapyramidal disorders a variety of clinical manifestations appear as a consequence of the neurologic dysfunction. These become apparent whenever the clinical approach is replaced by analysis of the physiologic abnormalities which lend themselves to accurate measurement. The relationship between these two is not always evident, particularly to those who are actively engaged in the everyday problems of caring for the sick. Furthermore, use is seldom made of laboratory studies which provide the information necessary for diagnosing the complications of the disease or following a therapeutic program. Clinical signs of respiratory distress in patients with Parkinson’s disease first attracted the attention of Maty over a century ago (1). It has been only during the last few years that pulmonary abnormalities have emerged as a part of the parkinsonian syndrome. The tardiness in recognizing these alterations was probably due to the limitations inherent in clinical observation and in certain pulmonary function tests. The manifestations of hypoventilation may be at times ill-defined. Some patients with disordered function of the ventilatory mechanism have rather nonspecific complaints which do not suffice to establish the correct diagnosis on clinical grounds alone. Furthermore, the clinical signs of hyperventilation may closely resemble those described as a component of the parliinsonian syndrome. The physician then becomes dependent upon a variety of complex laboratory determinations to support his tenuous impressions. Occasionally the laboratory tests furnish suggestive but hardly unequivocal support for the diagnosis. Normal standards show a wide variation. Thus it is impossible to know whether a measurement of pulmonary function which falls within these wide normal limits represents a true alteration from the pre-disease state. The physician then may revert to more careful clinical observation of the patient or to elaborate procedures designed to reveal abnormal responses to a variety of physical exercises. But a definite diagnosis may still elude him if, due to the neuromuscular derangement, the patient is unable to carry out physical exercise to the point of dyspnea or if he cannot perform the tests. Diagnostic difficulties are numerous despite the increased acuity of the present-day examiner, who frequently suspects alterations of respiratory function in the course of neurologic disorders. Although physiologic knowledge is sterile without clinical application and

Errors in Management of Patients Dying of Chronic Obstructive Lung Disease

Abstract: Recent advances in the understanding of chronic obstructive lung disease have led to the general acceptance of several principles of therapy. The primary aim of management is the maintenance of adequate alveolar ventilation. To this end, satisfactory therapy requires the prompt treatment of pulmonary infection and the avoidance of respiratory-depressant drugs. Severe hypoxemia must be alleviated by oxygen, and life threatening hypoventilation corrected by mechanical ventilation. The measures alone often are effective in relieving heart failure secondary to the primary lung disease. The extent to which adherence to the above therapeutic principles contributes to patient survival has not been objectively evaluated. This report analyzes the medical management of a group of patients dying of chronic obstructive disease in the medical wards of two teaching hospitals. The findings provide the basis for revising management of these patients. Materials and Methods Selection of Patients.— The records of all patients dying with diagnosed