The American review of respiratory disease
-
Am. Rev. Respir. Dis. · Sep 1989
ReviewChronic obstructive pulmonary disease: a definition and implications of structural determinants of airflow obstruction for epidemiology.
Chronic obstructive pulmonary disease (COPD) may be defined as a process characterized by the presence of chronic bronchitis or emphysema that may lead to the development of airways obstruction; airways obstruction need not be present at all stage of the process and may be partially reversible. The pathologic changes in the lungs due to smoking affect three regions: the bronchi, bronchioles, and parenchyma. The bronchi show enlargement of the submucosal glands with dilation of their ducts; infiltration with neutrophils and lymphocytes is present but not prominent. ⋯ The compliance of the lungs of smokers is decreased even when a emphysema and airflow limitation are mild. Standard epidemiologic tools do not differentiate emphysema from other causes of airflow obstruction. Most persons dying of COPD will have severe emphysema.
-
Although adult respiratory distress syndrome (ARDS) has been a recognized entity for over 20 years, estimates of its incidence have been very controversial. The most quoted figure is from a 1972 National Heart and Lung Institute Task Force, which estimated 150,000 cases/year in the United States, an incidence of about 75 cases/100,000 population. No experimental study, however, has adequately addressed this issue. ⋯ An average of ten patients per year, representing an incidence of 1.5 cases/100,000 population, were diagnosed as having ARDS and the mortality rate was 70%. Using a more liberal clinical criterion of PaO2 less than or equal to 75 mm Hg with FIO2 greater than or equal to 0.5, 44 more patients with ARDS, representing a total incidence of 3.5 cases/100,000 population, were identified. In conclusion, the overall incidence of ARDS was 1.5 to 3.5 cases/100,000 population, an incidence that is much lower than most previously published estimates.
-
Am. Rev. Respir. Dis. · Sep 1989
Case ReportsUnilateral lung transplantation in end-stage pulmonary emphysema.
Patients with end-stage pulmonary emphysema are usually proposed for either heart-lung or double-lung transplantation. The single-lung transplantation is reversed for patients with pulmonary fibrosis. Patients with emphysema are thought to be unsuitable for single-lung transplantation because of the ventilation-perfusion imbalance that is supposed to occur, the ventilation being preferentially distributed to the native lung when the perfusion is distributed to the transplanted lung. ⋯ Despite the persistence after transplantation of an obstructive syndrome, the clinical status was good, the blood gases were markedly improved, and ventilation-perfusion imbalance did not occur on lung scans. After discharge from the hospital, the patients could return to an almost normal life. Thus, our data support the feasibility of single-lung transplantation in patients with end-stage pulmonary emphysema, and we consider that single-lung transplantation could be the optimal form of lung transplantation in these patients.
-
Am. Rev. Respir. Dis. · Sep 1989
Expiratory glottic widening in asthmatic subjects during exercise-induced bronchoconstriction.
Glottic caliber is modulated in a way that optimizes the airway resistance and the work of breathing. The midexpiratory glottic narrowing that normally occurs during tidal breathing is enhanced during histamine- or methacholine-induced airway narrowing. Exercise is associated with increased ventilatory demand and midexpiratory glottic widening in healthy subjects. ⋯ This midexpiratory glottic widening was also associated with increased tidal flow rates. We conclude that in marked contrast to airway obstruction induced by histamine or methacholine, exercise-induced asthma is associated with midexpiratory glottic widening, which occurs concomitantly with a decrease in lower airway caliber. We suggest that modulation of glottic aperture during acute asthma is heterogeneous and depends partly on the initiating stimulus.