title: Acoustic simulation of a patient's obstructed airway.
abstract: This research focuses on the numerical simulation of stridor; a high pitched, abnormal noise, resulting from turbulent airflow and vibrating tissue through a partially obstructed airway. Characteristics of stridor noise are used by medical doctors as indication for location and size of the obstruction. The relation between type of stridor and the various diseases associated with airway obstruction is unclear; therefore, simply listening to stridor is an unreliable diagnostic tool. The overall aim of the study is to better understand the relationship between characteristics of stridor noise and localization and size of the obstruction. Acoustic analysis of stridor may then in future simplify the diagnostic process, and reduce the need for more invasive procedures such as laryngoscopy under general anesthesia. In this paper, the feasibility of a coupled flow, acoustic and structural model is investigated to predict the noise generated by the obstruction as well as the propagation of the noise through the airways, taking into account a one-way coupled fluid, structure, and acoustic interaction components. The flow and acoustic solver are validated on a diaphragm and a simplified airway model. A realistic airway model of a patient suffering from a subglottic stenosis, derived from a real computed tomography scan, is further analyzed. Near the mouth, the broadband noise levels at higher frequencies increased with approximately 15-20 dB comparing the stridorous model with the healthy model, indicating stridorous sound.
authors.affiliation: a Department of Aerodynamics , Faculty of Aerospace Engineering, Delft University of Technology , Kluyverweg 2, 2629 HT Delft , The Netherlands.
authors.forename: W C P
authors.initials: WC
authors.lastname: van der Velden
authors.affiliation: a Department of Aerodynamics , Faculty of Aerospace Engineering, Delft University of Technology , Kluyverweg 2, 2629 HT Delft , The Netherlands.
authors.forename: A H
authors.initials: AH
authors.lastname: van Zuijlen
authors.affiliation: a Department of Aerodynamics , Faculty of Aerospace Engineering, Delft University of Technology , Kluyverweg 2, 2629 HT Delft , The Netherlands.
authors.forename: A T
authors.initials: AT
authors.lastname: de Jong
authors.affiliation: a Department of Aerodynamics , Faculty of Aerospace Engineering, Delft University of Technology , Kluyverweg 2, 2629 HT Delft , The Netherlands.
authors.forename: C T
authors.initials: CT
authors.lastname: Lynch
authors.affiliation: b Department of Pediatric Otorhinolaryngology , Erasmus Medical Center, Sophia Children's Hospital , Dr. Molewaterplein 60, 3015 GJ Rotterdam , The Netherlands.
authors.forename: L J
authors.initials: LJ
authors.lastname: Hoeve
authors.affiliation: a Department of Aerodynamics , Faculty of Aerospace Engineering, Delft University of Technology , Kluyverweg 2, 2629 HT Delft , The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Bijl
mesh_terms: D000162:Acoustics; D000402:Airway Obstruction / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D011312:Pressure; D012212:Rheology; D013016:Sound; D014057:Tomography, X-Ray Computed; D014732:Vibration
keywords: Ffowcs-Williams and Hawkings analogy; fluid-structure-acoustic interaction; human airway; large eddy simulation; stridor