title: Compliance Measurements of the Upper Airway in Pediatric Down Syndrome Sleep Apnea Patients.
abstract: Compliance of soft tissue and muscle supporting the upper airway are two of several factors contributing to pharyngeal airway collapse. We present a novel, minimally invasive method of estimating regional variations in pharyngeal elasticity. Magnetic resonance images for pediatric sleep apnea patients with Down syndrome [9.5 ± 4.3 years (mean age ± standard deviation)] were analyzed to segment airways corresponding to baseline (no mask pressure) and two positive pressures. A three dimensional map was created to evaluate axial and circumferential variation in radial displacements of the airway, dilated by the positive pressures. The displacements were then normalized with respect to the appropriate transmural pressure and radius of an equivalent circle to obtain a measure of airway compliance. The resulting elasticity maps indicated the least and most compliant regions of the pharynx. Airway stiffness of the most compliant region [403 ± 204 (mean ± standard deviation) Pa] decreased with severity of obstructive sleep apnea. The non-linear response of the airway wall to continuous positive airway pressure was patient specific and varied between anatomical locations. We identified two distinct elasticity phenotypes. Patient phenotyping based on airway elasticity can potentially assist clinical practitioners in decision making on the treatments needed to improve airway patency.
authors.affiliation: Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA.
authors.forename: Dhananjay Radhakrishnan
authors.initials: DR
authors.lastname: Subramaniam
authors.affiliation: Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA.
authors.forename: Goutham
authors.initials: G
authors.lastname: Mylavarapu
authors.affiliation: Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: McConnell
authors.affiliation: Division of Pediatric Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Fleck
authors.affiliation: Department of Pediatric Otolaryngology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Sally R
authors.initials: SR
authors.lastname: Shott
authors.affiliation: Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.|Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Raouf S
authors.initials: RS
authors.lastname: Amin
authors.affiliation: Department of Aerospace Engineering and Engineering Mechanics, CEAS, University of Cincinnati, Cincinnati, OH, 45221-0070, USA. ephraim.gutmark@uc.edu.|UC Department of Otolaryngology-Head and Neck Surgery, Cincinnati, OH, USA. ephraim.gutmark@uc.edu.
authors.forename: Ephraim J
authors.initials: EJ
authors.lastname: Gutmark
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D045422:Continuous Positive Airway Pressure; D004314:Down Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010614:Pharynx / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012143:Respiratory Physiological Phenomena; D012891:Sleep Apnea Syndromes / Q000000981:diagnostic imaging / Q000503:physiopathology*
keywords: Airway elasticity; Anisotropy; CPAP; Non-linearity; Radial displacements; Sleep apnea