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Background: Persistent bronchodilator response (BDR) following diagnosis of asthma is an underrecognized treatable trait, associated with worse lung function and asthma control. The forced oscillation technique (FOT) measures respiratory system impedance, and BDR cutoffs have been proposed for healthy adults; however, the relevance in asthma is unknown. We compared BDR cutoffs, using FOT and spirometry, in asthma and the relationship with asthma control.Methods: Data from patients with asthma who withheld bronchodilator medication for at least 8 h before a tertiary airway clinic visit were reviewed. All subjects performed FOT and spirometry before and after salbutamol administration, and completed the Asthma Control Test. FOT parameters examined included respiratory system resistance (R5) and reactance (X5) at 5 Hz, and area under the reactance curve (AX). BDR was defined by standard recommendations for spirometry and based on the 95th percentile of BDR in healthy adults for FOT.Results: Fifty-two subjects (18 men; mean age, 53 ± 18 years) were included. BDR was identified more frequently by FOT than spirometry (54% vs 27% of subjects). BDR assessed by X5 and AX, but not R5, was associated with spirometric BDR (χ2, P < .01) and correlated with asthma control (X5: rs = -0.36, P < .01; AX: rs = 0.34, P = .01). BDR measured by reactance parameters identified more subjects with poor asthma control than did spirometry (AX, 69% vs spirometry, 41%).Conclusions: BDR assessed by FOT can identify poor asthma control. Reactance parameters were more sensitive in identifying poor asthma control than spirometry, supporting the use of FOT to complement spirometry in the clinical management of asthma. [ABSTRACT FROM AUTHOR]

The article looks at a study indicating that the Forced Oscillation Technique (FOT), which measures day-to-day variability in respiratory system resistance (Rrs) and respiratory system reactance (Xrs) during tidal breathing, is a better tool for monitoring the severity of pediatric asthma than other lung function tests that measures peak exploratory flow (PEF) variability. It noted that children with persistent asthma showed higher day-to-day Rrs and Xrs variability rates than healthy children.

The article focuses on a randomized study which investigated the efficacy and safety of using inhaled dry powder mannitol over 12 weeks period for the symptomatic treatment of patients with non-cyctic fibrosis bronchiectasis. An overview is given on the pathophysiology and incidence of bronchiectasis and the mechanism of action of inhaled dry powder mannitol. It also examines the effect of mannitol on mucus clearance and quality of life of individuals with non-cystic fibrosis bronchiectasis.

The article presents a study which examines the contribution of emphysema and small airways disease to the severity of chronic obstructive pulmonary disease (COPD) and airflow obstruction. It says that the study used forced oscillation technique (FOT) and single-breath nitrogen washout among 26 patients with COPD. Findings reveal that both small airways disease and emphysema extent can individually predict the severity of COPD and airflow obstruction.

The article presents a study which aims to examine the association between obesity and worse asthma control. Forty-nine subjects with asthma underwent several tests, which include the methacholine challenge, fraction of exhaled nitric oxide (FENO), spirometry and asthma control questionnaire (ACQ-5). The study reveals that body mass index (BMI) is a determinant of asthma control independent of airway hyperresponsiveness (AHR), lung function and airway inflammation.

The article presents a study which determined the impact of age on the predictors of airway hyperresponsiveness (AHR). The pathophysiological predictors of AHR include ventilation heterogeneity, airway closure and inflammation. AHR is defined as a basic pathophysiologic characteristic of asthma. Among the variables that were measured are spirometry, plethysmography and ventilation heterogeneity.

Compares the airway and serum activities of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in nonasthmatic subjects, asthmatic patients and patients with asthmaticus mucus hypersecretion (AMH). Diagnosis of AMH by the presence of mucus plugging; Results of lung function test; Total white blood cell count.

Asthma and COPD are the most prevalent of lung diseases and contribute an enormous burden of morbidity in North America and globally. In both conditions, inflammation leads to airway remodeling, which contributes to airway narrowing. To date, airway remodeling has only been assessed using histological examination of airways. However, it may now be possible to assess and quantify the extent of airway remodeling in vivo using high-resolution CT (HRCT). The aim of this article is to review the use of HRCT in the investigation of airway remodeling. A number of investigators have reported techniques to make measurements of airway dimensions using CT and an increasing number of quantitative methods are being developed. Using these techniques, airway dimensions have been examined in patients with asthma and COPD. In patients with asthma, the airway wall area was increased without a decrease in luminal area, whereas in patients with COPD, the airway luminal area was decreased and airway wall area was increased. The different pattern of remodeling may reflect fundamental differences in the inflammatory processes in asthma and COPD and could influence the reversibility of the narrowing. It has also been shown that, by quantifying both the extent of emphysema and of airway remodeling, CT is useful in differentiating COPD patients who have primarily parenchymal disease from those who have primarily airway pathology. With additional advances in technology, it is likely that quantitative assessment of airway wall dimensions will ultimately provide a valuable tool for the study of airway disease. [ABSTRACT FROM AUTHOR]

An abstract of the article "Changes in Reactance with Combination Therapy (ICS/LABA) in COPD" by Sophie Timmins, Chantale Diba, Catherine Farrow, Norbert Berend, Cheryl Salome, and Gregory King is presented.