Human tracheal forced expiratory noises: origin and diagnostic application

Human forced exhallation is accompanied by specific respiratory noise, containing broadband and narrowband components. Acoustic considerations about the origin and characteristics of forced expiratory noises obtained in the last decade are highlighted. The acoustic-biomechanical interrelations of the forced exhallation as well as primary mechanisms and noise production zones are analyzed. The developed acoustic models and empirically revealed phenomena provided to develop a set of acoustic parameters that proved to be promising for functional diagnostics of lung ventilatory function both in general medical practice and in monitoring the human respiratory status under extreme conditions.