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Impulse oscillometry may be of value in detecting early manifestations of COPD.

Impulse oscillometry may be of value in detecting early manifestations of COPD.

Respir Med. 2012 May 19;

Authors: Frantz S, Nihlén U, Dencker M, Engström G, Löfdahl CG, Wollmer P

Abstract
BACKGROUND: Spirometry is used to diagnose chronic obstructive pulmonary disease (COPD). The Impulse oscillometry system (IOS) allows determination of respiratory impedance indices, which might be of potential value in early COPD, although previous experience is limited. We examined pulmonary resistance and reactance measured by IOS in subjects with or without self-reported chronic bronchitis or emphysema or COPD (Q+ or Q-) and subjects with or without COPD diagnosed according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (G+ or G-). METHODS: From a previous population-based study 450 subjects were examined with spirometry and IOS and answered a questionnaire on respiratory symptoms and diseases. RESULTS: Seventy-seven subjects were Q+, of whom 34 also were G+. Q+/G- subjects (n = 43) reported respiratory symptoms more frequently (35-40% vs 8-14%) but had higher FEV(1) (100% vs 87%) than Q-/G+ subjects (n = 90), p < 0.05 for both comparisons. Q+ subjects had higher pulmonary resistance and lower pulmonary reactance than Q- subjects (p < 0.01 for all comparisons). The same pattern was seen both in G+ subjects ((Q+/Q-) R5 0.39/0.32, R5-R20 0.10/0.07, X5 0.13/0.09, AX 0.55/0.27, p < 0.05 for all) and G- subjects ((Q+/Q-) R5 0.35/0.29, R5-R20 0.08/0.06, X5 0.10/0.08, AX 0.31/0.19 p < 0.05 for all) except for R20 (adjusted for gender and age). CONCLUSIONS: Self-reported chronic bronchitis or emphysema or COPD was associated with higher pulmonary resistance and lower pulmonary reactance measured by IOS, both among subjects with and without COPD according to GOLD criteria. IOS may have the potential to detect pathology associated with COPD earlier than spirometry.

PMID: 22613172 [PubMed - as supplied by publisher]

Clinical Audit on Diagnostic Accuracy and Management of Respiratory Failure in COPD.

The aim of study was to evaluate the adequacy of diagnosis and management of respiratory failure (RF) in COPD.

METHODS: Retrospective analysis of the Hospital Discharge Forms of COPD patients hospitalised for RF from January 2007 to June 2008. Using the clinical audit tool, the primary end-point was the accuracy of RF diagnosis. The secondary end-points were mortality, re-hospitalisation rate, length of hospital stay, accuracy of long-term oxygen therapy (LTOT) prescription, agreement of the treatments with the GOLD 2008 guidelines. Statistical analysis used Pearson and Spearman correlation test and Cohen's kappa for degree of agreement. Differences in demographics and clinical parameters were analyzed with χ²-test, t-test or Fisher?s test, as appropriate.

RESULTS: 130 patients were studied, 80 males (62%), mean age 76.6 ± 9.1 (SD) years. Arterial blood gas analysis (ABG) was performed in 118 patients (90.8%) and in 77 (81%) a PaO₂ < 60 mmHg was found at admission. Of these, 42 cases (54.5%) had no diagnosis of RF despite a PaO₂ < 60 mmHg. In 18 (19%) PaO₂ was > 60 mmHg; of these, 6 cases (33.3%) received an incorrect RF diagnosis.

Improved correlation between CT emphysema quantification and pulmonary function test by density correction of volumetric CT data based on air and aortic density.

To determine the improvement of emphysema quantification with density correction and to determine the optimal site to use for air density correction on volumetric computed tomography (CT).

METHODS: Seventy-eight CT scans of COPD patients (GOLD II-IV, smoking history 39.2±25.3 pack-years) were obtained from several single-vendor 16-MDCT scanners. After density measurement of aorta, tracheal- and external air, volumetric CT density correction was conducted (two reference values: air, -1000HU/blood, +50HU). Using in-house software, emphysema index (EI) and mean lung density (MLD) were calculated. Differences in air densities, MLD and EI prior to and after density correction were evaluated (paired t-test). Correlation between those parameters and FEV(1) and FEV(1)/FVC were compared (age- and sex adjusted partial correlation analysis).

RESULTS: Measured densities (HU) of tracheal- and external air differed significantly (-990±14, -1016±9, P<0.001). MLD and EI on original CT data, after density correction using tracheal- and external air also differed significantly (MLD: -874.9±27.6 vs. -882.3±24.9 vs. -860.5±26.6; EI: 16.8±13.4 vs. 21.1±14.5 vs. 9.7±10.5, respectively, P<0.001). The correlation coefficients between CT quantification indices and FEV(1), and FEV(1)/FVC increased after density correction. The tracheal air correction showed better results than the external air correction.

CONCLUSION: Density correction of volumetric CT data can improve correlations of emphysema quantification and PFT.

Effects of tiotropium on sympathetic activation during exercise in stable chronic obstructive pulmonary disease patients.

Tiotropium partially relieves exertional dyspnea and reduces the risk of congestive heart failure in chronic obstructive pulmonary disease (COPD) patients. However, its effect on the sympathetic activation response to exercise is unknown.

AIMS: This study aimed to determine whether tiotropium use results in a sustained reduction in sympathetic activation during exercise.

METHODS: We conducted a 12-week, open-label (treatments: tiotropium 18 μg or oxitropium 0.2 mg × 3 mg), crossover study in 17 COPD patients. Treatment order was randomized across subjects. The subjects underwent a pulmonary function test and two modes of cardiopulmonary exercise (constant work rate and incremental exercise) testing using a cycle ergometer, with measurement of arterial catecholamines after each treatment period.

RESULTS: Forced expiratory volume in 1 second and forced vital capacity were significantly larger in the tiotropium treatment group. In constant exercise testing, exercise endurance time was longer, with improvement in dyspnea during exercise and reduction in dynamic hyperinflation in the tiotropium treatment group. Similarly, in incremental exercise testing, exercise time, carbon dioxide production, and minute ventilation at peak exercise were significantly higher in the tiotropium treatment group. Plasma norepinephrine concentrations and dyspnea intensity were also lower during submaximal isotime exercise and throughout the incremental workload exercise in the tiotropium treatment group.

CONCLUSION: Tiotropium suppressed the increase of sympathetic activation during exercise at the end of the 6-week treatment, as compared with the effect of oxipropium. This effect might be attributed to improvement in lung function and exercise capacity and reduction in exertional dyspnea, which were associated with decreases in respiratory frequency and heart rate and reduced progression of arterial acidosis.

Abnormal Lung Aging in Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis.

Aging is a natural process characterized by progressive functional impairment and reduced capacity to respond appropriately to environmental stimuli and injury.

The incidence of two common chronic respiratory diseases (chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF)) increases with advanced age. It is plausible, therefore, that abnormal regulation of the mechanisms of normal aging may contribute to the pathobiology of both COPD and IPF.

This review discusses the available evidence supporting a number of aging mechanisms, including oxidative stress, telomere length regulation, cellular and immunosenescense, as well as changes in a number of anti-aging molecules and the extra-cellular matrix are abnormal in COPD and/or IPF.

A better understanding of these abnormalities may help the design of novel and better therapeutic interventions for these patients.

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