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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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.
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High-intensity noninvasive positive pressure ventilation (HI-NPPV) is an effective treatment option in patients with stable hypercapnic chronic obstructive pulmonary disease (COPD). However, the effect of HI-NPPV compared with spontaneous breathing (SB) on minute ventilation (MV) in patients receiving long-term treatment remains to be determined. This study compared MV during HI-NPPV and SB. In addition, the ability of intelligent volume assured pressure support (iVAPS) to increase MV to the same extent as HI-NPPV was determined. ⋯ Long-term HI-NPPV increased MV by an average of 26% compared with SB in stable hypercapnic COPD patients. A similar increase in MV was observed during use of iVAPS.
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Whether respiratory symptoms are associated with mortality independent of lung function is unclear. The authors explored the association of the exposures i) lung function, ii) respiratory symptoms, and iii) lung function and respiratory symptoms combined, with the outcomes all-cause and cardiovascular mortality. The study included 10,491 adults who participated in the Nord-Trøndelag Health Study (HUNT) Lung Study in 1995-1997 and were followed through 2009. ⋯ Analyses of lung function and dyspnoea when walking as a combined exposure further supported this finding. Overall, associations between lung function and cardiovascular mortality were weaker, and respiratory symptoms were not associated with cardiovascular mortality. In conclusion, lung function was inversely associated with all-cause and cardiovascular mortality, and dyspnoea when walking was associated with all-cause mortality independent of lung function.
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Minimum clinically important change of 5 points in the University of California, San Diego Shortness of Breath Questionnaire (SOBQ) is established, but cutoff values between a small, a moderate, and a large change are still unknown. We used the data set of National Emphysema Treatment Trial consisting of severe and very severe chronic obstructive pulmonary disease patients, whose mean age was 64 years. Changes from baseline to post-surgical 6-month follow-up were evaluated. ⋯ In a cohort of surgically treated patients (N = 484), we propose value of 5 (range 5-6), 11 (range 9-15), and 16 (range 14-20) for the cutoff values between a meaningless and a small change (minimum clinically important difference), a small and a moderate change, and a moderate and a large change, respectively. In a cohort of medically treated patients, numbers of patients categorized according to ∆SOBQ scores were similar to those of the patients categorizes according to the ∆SGRQ (N = 480) or ∆Forced expiratory volume in 1 second (N = 425). We propose group-level cutoff values and range between a small, a moderate, and a large changes.