COPD
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COPD is often regarded as a smoker's disease. In fact, up to 50% of COPD could be attributable to other causes. Relatively little is known about COPD among nonsmokers, and this group is usually excluded from studies of COPD. ⋯ Asthma is a very common cause of COPD among nonsmokers. Radiological bronchiectasis is common in COPD; the clinical significance of this finding is unclear.
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Oxidative stress is implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). Analysis of the expired breath condensate (EBC) has been suggested to provide non-invasive inflammatory markers that reflect oxidative stress in the airways. ⋯ These findings suggest that oxidative stress is involved in the pathogenesis of asthma and COPD and that the H2O2 levels in EBC might reflect the health status in COPD.
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Tidal expiratory flow limitation (EFL) is a step of paramount importance in the functional decline in COPD. Among mechanisms contributing to EFL, loss of airway-parenchymal interdependence could mostly be involved. ⋯ In COPD EFL in sitting position is highly dependent by the severity of airflow obstruction. In contrast, the occurrence of EFL in supine position is associated with worse DLCO and KCO and greater chronic dyspnea, reflecting a prevalent emphysematous phenotype in moderate-to-severe COPD patients.