The American review of respiratory disease
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Predictors of obstructive airways disease (OAD) have been identified, and models for estimating risk of developing OAD have been derived for the adult population of Tecumseh. Men and women 16 to 64 yr of age when first studied were reexamined after an average interval of 15 yr. Incidence rates of OAD increased with age and were higher in men than in women more than 45 yr of age. ⋯ The excess risk of obstructive airways disease associated with cigarette smoking and reduced lung function and the benefits of stopping smoking are clearly apparent. For example, the risk of developing obstructive airways disease in the next 15 years is about 1 in 200 for a 45-yr-old male nonsmoker whose Vmax50 equals to 100% of predicted, if he doesn't take up smoking. The risk for a man of the same age who smokes 40 cigarettes a day and whose Vmax50 equals 80% of predicted is 1 in 5 or 6 if he doesn't cut down on his smoking and about 1 in 15 if he stops smoking.
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Amounts and distributions of glycosaminoglycans were measured in lungs obtained from hamsters treated intratracheally 21 to 30 days previously with either saline, purified pancreatic elastase, or bleomycin. Normal hamster lungs contained 150 to 200 micrograms glycosaminoglycans per lung. ⋯ The latter was increased in emphysematous lungs when expressed as a percentage of total glycosaminoglycans. In these hamster models of lung diseases that affect the connective tissue framework of the lungs, changes in lung glycosaminoglycans accompany changes in the other connective tissue components.
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Am. Rev. Respir. Dis. · Dec 1981
Effect of positive end-expiratory pressure on lung compliance in dogs after acute alveolar injury.
We studied the effect of positive end-expiratory pressure (PEEP) on lung compliance (CL) in 17 dogs during the early phase of acute alveolar injury induced by the subcutaneous administration of N-nitroso-N-methylurethane (NNNMU). The acute phase of this injury is characterized by necrosis of the alveolar epithelium and by decreased CL, which is caused by abnormal surface forces and which correlates with decreased alveolar surfactant lipids. ⋯ Static volume-pressure curves obtained in vivo in 6 dogs showed a rightward shift of the curve without increase of hysteresis after NNNMU. these data suggest that in the surfactant-deficient lung, PEEP predominantly causes overdistention of patent alveoli rather than recruitment of closed air spaces. The physiologic response of the NNNMU-injured lung to PEEP differs from that of severely edematous lungs but is similar to that of surfactant-deficient lungs of premature lambs.
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Am. Rev. Respir. Dis. · Oct 1981
The effect of mechanical vibration physiotherapy on arterial oxygenation in acutely ill patients with atelectasis or pneumonia.
The effect of mechanical chest vibration on arterial blood gases was studied in 10 patients requiring oxygen therapy who had acute lung disease and an abnormal chest roentgenogram. Eight patients were using mechanical ventilators. For the duration of the study, patients were seated or in a high semi-Fowlers position. ⋯ This study demonstrated that external mechanical vibration of the chest is a useful therapeutic modality in the management of hypoxemia in patients with atelectasis or pneumonia. This was reflected by the increase in PO2 with no change in alveolar ventilation. We presume the better matching of ventilation to perfusion accounted for our results.
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The effect of flow of inspired gas on intrapulmonary gas distribution was examined by analysis of regional pulmonary 133Xe clearances and of total pulmonary 133Xe clearance measured at the mouth after equilibration of the lungs with 133Xe. Five awake healthy volunteers (24 to 40 yr of age) and another 5 healthy, anesthetized-paralyzed volunteers (26 to 28 yr of age) were studied while they were in the right lateral decubitus position. ⋯ Interregional differences in 133Xe clearances along the vertical axis were significantly less during anesthesia-paralysis and mechanical ventilation than during spontaneous breathing in the awake state. No differences in the regional or total pulmonary 133Xe clearances were detected at these different flows in either of the two states, i.e., the difference between the awake and anesthetized-paralyzed states persisted.