Correlation between Acoustic Characteristics of Forced Expiratory Tracheal Noises and Lung Function Parameters in Healthy Subjects and Patients with Obstructive Lung Diseases

A Technique of Forced Expiratory Noise Time Evaluation Provides Distinguishing Human Pulmonary Ventilation Dynamics During Long-Term Head-Down and Head-Up Tilt Bed Rest Tests Simulating Micro and Lunar Gravity

“…Since significant direct correlation of expiratory bronchial resistance with FETa in the frequency band of 200–2000 Hz was found previously ( Korenbaum and Pochekutova, 2008 ; Malaeva et al, 2017 ), an elongation of the latter parameter in response to the 6 degree HDT bed rest simulating microgravity may be mechanically attributed to an increase of aerodynamic resistance of the respiratory tract that may occur due to decreasing airway lumen as a probable result of airway wall swelling.…”

“…Moreover, FETa provided reliable discrimination of HDT and HUT + HZT bed rest tests ( p = 0.018), while spirometric indices did not ( p > 0.05). Based on previously found correlations ( Korenbaum and Pochekutova, 2008 ; Malaeva et al, 2017 ), a FETa elongation in response to HDT bed rest was attributed to an increase of aerodynamic resistance of the respiratory tract. The technique seems promising to monitor human pulmonary ventilation dynamics in long-term space missions; however, new studies are welcome to verify it in real spaceflight.…”

“…Initially, it was found theoretically ( Korenbaum and Pochekutova, 2008 ). Later, it was experimentally verified by means of correlation with spirometry and body plethysmography-assessed parameters, including airway resistance ( Korenbaum et al, 2016 ; Malaeva et al, 2017 ). Therefore, FETa increase as a response to the HDT bed rest may be mechanically treated as enlarging the aerodynamic resistance in the subjects of exp_1 subgroup.…”

Human forced expiratory noise. Origin, apparatus and possible diagnostic applications

“… Malaeva et al (2017) revealed significant interrelations between band-pass acoustic durations and energies of the FE tracheal noises and biomechanical indices of lung function by means of nonparametric Spearman correlation analysis in the sample. The strongest correlation coefficients are noted between band-pass durations and measures of airway resistances (up to 0.59), reflecting primarily the function of large airways, as well as the residual volume of the lungs (up to 0.47) and its ratio to the total lung capacity (up to 0.43) that characterize the state of small airways.…”