The forced oscillation technique (FOT) can measure respiratory mechanics and has attracted attention in chronic obstructive pulmonary disease (COPD). We aimed to evaluate the effects of only indacaterol and tiotropium monotherapies on airflow limitation and respiratory impedance. Pulmonary function tests, COPD assessment test (CAT), and multifrequency FOT with MostGraph-01 were performed at the...

OBJECTIVE Nasal airflow resistance, as measured by rhinomanometry, is frequently impaired in allergic rhinitis (AR). However, rhinomanometry is scarcely available. The aim of this study was to verify the suitability of the use of visual analog scales (VAS) as a surrogate for rhinomanometry in quantifying nasal obstruction in patients with persistent allergic rhinitis. STUDY DESIGN Prospective...

An imaging-based computational framework for simulation of airflow in subject specific breathing human lungs is established. The three-dimensional (3D) airways of up to 9 generations and lobes are segmented and reconstructed from computed tomography (CT) images. Beyond the CT-resolved 3D airways, a volume filling method is applied to generate the one-dimensional (1D) conducting airway tree that...

Many patients undergo long-term artificial ventilation and their respiratory system mechanics should be monitored to detect changes in the patient's state and to optimize ventilator settings. In this work the most popular algorithms for tracking variations of respiratory resistance (R(rs)) and elastance (E(rs)) over a ventilatory cycle were analysed in terms of systematic and random errors. Add...

A new device for measuring airway resistance following brief airflow interruption (Microlab 4000; Micromedical Ltd, UK) was evaluated in 25 asthmatic school children in comparison with well-established methods. Airway resistance was measured during brief airflow interruption (Rint), before and after administration of salbutamol 200 micrograms by metered-dose inhaler, and in the spirometric para...

It is not clear how airway pathology relates to the severity of airflow obstruction and increased bronchial responsiveness in cystic fibrosis (CF) patients. The aim of this study was to measure the airway dimensions of CF patients and to estimate the importance of these dimensions to airway resistance using a computational model. Airway dimensions were measured in lungs obtained from CF patient...

We examined oronasal flow partitioning in 27 volunteers with normal or slightly increased nasal resistance (mean +/- SD, 0.24 +/- 0.19 kPa/l/s). Mean percentage of inspiratory nasal flow contribution was measured during spontaneous oronasal breathing. The averaged nasal admixture of airflow differed considerably within and between all subjects (mean +/- SD, 20.9% +/- 16.5%; range 1%-70%), showi...

Chronic obstructive pulmonary disease (COPD) is a chronic airway disease with increased airway resistance. This study investigated the common characteristics of electrocardiographic (ECG) and nostril airflow signals in COPD patients using cross-spectral analysis. Heart rate variability (HRV) measures and cross-spectral (cs) measures of ECG and nostril airflow were compared in COPD patients and ...