Bulletin européen de physiopathologie respiratoire
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Bull Eur Physiopathol Respir · May 1985
[Effect of artificial ventilation with an end-expiratory plateau on gas exchange amd hemodynamics in chronic respiratory failure].
Previous studies of pulmonary models and with animals have shown that in obstructive disease of the airways, ventilation with an end-expiratory plateau improves ventilation distribution. Paradoxically, there has been no data published on patients with obstructive disease. For this reason, we examined the effects of mechanical ventilation with an end-expiratory plateau on gas exchange and haemodynamics in 12 patients presenting acute exacerbations of chronic respiratory failure. ⋯ However, no matter which plateau is used, cardiac output decreases by more than 10% in six patients, probably due to a drop in systemic venous return. PaCO2 increase is too slight to hinder a decrease in arterial oxygen transport. The variability of these results accounts for patient diversity and restricts the indication of end-expiratory plateau to patients with severe ventilatory distribution disturbances who can benefit from close cardiorespiratory monitoring.
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Bull Eur Physiopathol Respir · Mar 1985
Interpretation of changes in spirographic and flow-volume variables after operative treatment in bilateral vocal cord paralysis.
In 13 patients, who underwent a superolateralization of a vocal cord after bilateral vocal cord paralysis, we studied pre- and postoperatively spirometric dynamic and static lung volumes and variables from maximal expiratory and maximal inspiratory flow-volume (MEFV and MIFV) curves. The effects of surgical treatment on these variables have been established by comparing the statistical significance of the changes post- versus preoperative. ⋯ Significant correlations, however, were found to exist only for the changes within the group of flow-volume indices and for those within the group of spirographic variables. This led us to the conclusion that for the diagnosis of this type of upper airway obstruction these measurements are additive, reflecting different aspects of airway mechanics.
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Bull Eur Physiopathol Respir · Mar 1985
Forced oscillation technique. Reference values for resistance and reactance over a frequency spectrum of 2-26 Hz in healthy children aged 2.3-12.5 years.
The forced pseudo-random noise oscillation technique is a method by which total respiratory resistance (Rrs) and reactance (Xrs) can be measured simultaneously at various frequencies by means of complex oscillations, superimposed at the mouth during spontaneous quiet breathing. Reference values were obtained in 255 healthy Caucasian children of Dutch descent aged 2.3-12.5 years. Rrs and Xrs vs frequency (f) curves are mainly determined by the child's sex, age, height and weight. ⋯ This suggests differences in bronchial patency of peripheral airways, boys being at a disadvantage. It is concluded that multiple frequency oscillometry is a method which is ideal for children from the age of about 3 years. The possibility of measuring Rrs as well as frequency dependence of Rrs and Xrs simultaneously is the major advantage over other oscillation devices.
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Bull Eur Physiopathol Respir · Jan 1985
Comparative Study[Measurement of the frequency response of several stethoscopes in common use. Consequences for cardiac and pulmonary auscultation].
We measured the frequency response of eight stethoscope membranes and of thirteen types of stethoscopes. Measurements were made in an anechoic chamber calculating the ratio between the intensity of a sinusoidal sound coming from a loud speaker and the intensity of the transmitted sound through the membrane of the stethoscope. ⋯ By contrast, fidelity of the measured stethoscopes was good. Discussion of the results suggests modification of stethoscope design to eliminate faults of sound transmission and to elaborate a microphone sensor allowing an electric transmission.
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Right-to-left shunting decreases the efficiency of carbon dioxide excretion and increases the alveolar dead space (physiological dead space minus anatomical dead space). The theoretical effects of shunting on alveolar dead space were studied, using a human blood nomogram, for different values of inspired oxygen fraction (FIO2), respiratory quotient (R), and arterial-venous oxygen content difference. ⋯ The conditions needed for this increase are unusual but lie within the range observed in critically ill patients. A rise in dead space of this magnitude can be clinically important in the absence of effective compensatory mechanisms.