Abstract
Repetitive brief episodes of soft-tissue collapse within the upper airway during sleep characterize obstructive sleep apnea (OSA), an extremely common and disabling disorder. Failure to maintain the patency of the upper airway is caused by the combination of sleep-related loss of compensatory dilator muscle activity and aerodynamic forces promoting closure. The prediction of soft-tissue movement in patient-specific airway 3D mechanical models is emerging as a useful contribution to clinical understanding and decision making. Such modeling requires reliable estimations of the pharyngeal wall pressure forces. While nasal obstruction has been recognized as a risk factor for OSA, the need to include the nasal cavity in upper-airway models for OSA studies requires consideration, as it is most often omitted because of its complex shape. A quantitative analysis of the flow conditions generated by the nasal cavity and the sinuses during inspiration upstream of the pharynx is presented. Results show that adequate velocity boundary conditions and simple artificial extensions of the flow domain can reproduce the essential effects of the nasal cavity on the pharyngeal flow field. Therefore, the overall complexity and computational cost of accurate flow predictions can be reduced.






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References
Balint TS, Lucey AD (2005) Instability of a cantilevered flexible plate in viscous channel flow. J Fluid Struct 20:893–912
Breatnach E, Abbott GC, Fraser RG (1984) Dimensions of the normal human trachea. Am J Roentgenol 142:903–906
Chervin RD, Burns JW (2011) Engineering better sleep. Med Biol Eng Comput 49:623–625
Chouly F, Van Hirtum A, Lagre PY, Pelorson X, Payan Y (2009) Modelling the human pharyngeal airway: validation of numerical simulations using in vitro experiments. Med Biol Eng Comput 47:49–58
Cisonni J, Lucey AD, Walsh JH, King AJC, Elliott NSJ, Sampson DD, Eastwood PR, Hillman DR (2013) Effect of the velopharynx on intraluminal pressures in reconstructed pharynges derived from individuals with and without sleep apnea. J Biomech 46:2504–2512
Cole P (2000) Biophysics of nasal airflow: a review. Am J Rhinol 14:245–249
Croce C, Fodil R, Durand M, Sbirlea-Apiou G, Caillibotte G, Papon JF, Blondeau JR, Coste A, Isabey D, Louis B (2006) In vitro experiments and numerical simulations of airflow in realistic nasal airway geometry. Ann Biomed Eng 34:997–1007
Don GW, Kirjavainen T, Broome C, Seton C, Waters KA (2000) Site and mechanics of spontaneous, sleep-associated obstructive apnea in infants. J Appl Physiol 89:2453–2462
Doorly DJ, Taylor DJ, Schroter R (2008) Mechanics of airflow in the human nasal airways. Resp Physiol Neurobi 163:100–110
Elad D, Liebenthal R, Wenig BL, Einav S (1993) Analysis of air flow patterns in the human nose. Med Biol Eng Comput 31:585–592
Ge QJ, Inthavong K, Tu JY (2012) Local deposition fractions of ultrafine particles in a human nasal-sinus cavity CFD model. Inhalation Toxicology 24:492–505
Guilmette RA, Cheng YS, Griffith WC (1997) Characterizing the variability in adult human nasal airway dimensions. Ann Occup Hyg 41:491–496
Howell RM, Lucey AD, Carpenter PW, Pitman MW (2009) Interaction between a cantilevered-free flexible plate and ideal flow. J Fluid Struct 25:544–566
Huynh J, Kim KB, McQuilling M (2009) Pharyngeal airflow analysis in obstructive sleep apnea patients pre- and post-maxillomandibular advancement surgery. J Fluid Eng 131
Isono S (2012) Obesity and obstructive sleep apnoea: mechanisms for increased collapsibility of the passive pharyngeal airway. Respirology 17:32–42
Isono S, Remmers JE, Tanaka A, Sho Y, Sato J, Nishino T (1997) Anatomy of pharynx in patients with obstructive sleep apnea and in normal subjects. J Appl Physiol 82:1319–1326
Ito Y, Cheng GC, Shih AM, Koomullil RP, Soni BK, Sittitavornwong S, Waite PD (2011) Patient-specific geometry modeling and mesh generation for simulating obstructive sleep apnea syndrome cases by maxillomandibular advancement. Math Comput Simulat 81:1876–1891
Kelly VJ, Brown NJ, King GG, Thompson BR (2010) A method to determine in vivo, specific airway compliance, in humans. Med Biol Eng Comput 48:489–496
Kim HY, Bok KH, Dhong HJ, Chung SK (2008) The correlation between pharyngeal narrowing and the severity of sleep-disordered breathing. Otolaryng Head Neck 138:289–293
Kim S, Chung S (2009) Investigation on the respiratory airflow in human airway by PIV. J Visual 12:259–266
Lee JH, Na Y, Kim SK, Chung SK (2010) Unsteady flow characteristics through a human nasal airway. Resp Physiol Neurobi 172:136–146
Lofaso F, Coste A, d’Ortho MP, Zerah-Lancner F, Delclaux C, Goldenberg F, Harf A (2000) Nasal obstruction as a risk factor for sleep apnoea syndrome. Eur Respir J 16:639–643
Lucey AD, King AJC, Tetlow GA, Wang J, Armstrong JJ, Leigh MS, Paduch A, Walsh JH, Sampson DD, Eastwood PR, Hillman DR (2010) Measurement, reconstruction, and flow-field computation of the human pharynx with application to sleep apnea. IEEE Trans Biomed Eng 57:2535–2548
Mihaescu M, Murugappan S, Kalra M, Khosla S, Gutmark E (2008) Large Eddy Simulation and Reynolds-Averaged Navier-Stokes modeling of flow in a realistic pharyngeal airway model: an investigation of obstructive sleep apnea. J Biomech 41:2279–2288
Mihaescu M, Mylavarapu G, Gutmark EJ, Powell NB (2011) Large Eddy Simulation of the pharyngeal airflow associated with obstructive sleep apnea syndrome at pre and post-surgical treatment. J Biomech 44:2221–2228
Mylavarapu G, Murugappan S, Mihaescu M, Kalra M, Khosla S, Gutmark E (2009) Validation of computational fluid dynamics methodology used for human upper airway flow simulations. J Biomech 42:1553–1559
Mylavarapu G, Mihaescu M, Fuchs L, Papatziamos G, Gutmark E (2013) Planning human upper airway surgery using computational fluid dynamics. J Biomech 46:1979–1986
Open CFD Ltd (2011) OpenFOAM, the open source CFD toolbox: user guide (version 2.1.0)
Persak SC, Sin S, McDonough JM, Arens R, Wootton DM (2011) Noninvasive estimation of pharyngeal airway resistance and compliance in children based on volume-gated dynamic mri and computational fluid dynamics. J Appl Physiol 111:1819–1827
Rama AN, Tekwani SH, Kushida CA (2002) Sites of obstruction in obstructive sleep apnea. Chest 122:1139–1147
Schwab RJ, Pasirstein M, Pierson R, Mackley A, Hachadoorian R, Arens R, Maislin G, Pack AI (2003) Identification of upper airway anatomic risk factors for obstructive sleep apnea with volumetric magnetic resonance imaging. Am J Resp Crit Care 168:522–530
Segal R, Kepler G, Kimbell J (2008) Effects of differences in nasal anatomy on airflow distribution: a comparison of four individuals at rest. Ann Biomed Eng 36:1870–1882
Shepard JW, Thawley SE (1990) Localization of upper airway collapse during sleep in patients with obstructive sleep apnea. Am J Resp Crit Care 141:1350–1355
Tan J, Han D, Wang J, Liu T, Wang T, Zang H, Li Y, Wang X (2012) Numerical simulation of normal nasal cavity airflow in chinese adult: a computational flow dynamics model. Eur Arch Otorhinolaryngol 269:881–889
Van Holsbeke C, De Backer J, Vos W, Verdonck P, Van Ransbeeck P, Claessens T, Braem M, Vanderveken O, De Backer W (2011) Anatomical and functional changes in the upper airways of sleep apnea patients due to mandibular repositioning: a large scale study. J Biomech 44:442–449
Wang Y, Wang J, Liu Y, Yu S, Sun X, Li S, Shen S, Zhao W (2012) Fluid-structure interaction modeling of upper airways before and after nasal surgery for obstructive sleep apnea. Int J Numer Method Biomed Eng 28:528–546
Xiong G, Zhan J, Zuo K, Li J, Rong L, Xu G (2008) Numerical flow simulation in the post-endoscopic sinus surgery nasal cavity. Med Biol Eng Comput 46:1161–1167
Zapletal A, Chalupov J (2002) Nasal airflow and resistance measured by active anterior rhinomanometry in healthy children and adolescents. Pediatr Pulmonol 33:174–180
Zhao M, Barber T, Cistulli P, Sutherland K, Rosengarten G (2013) Computational fluid dynamics for the assessment of upper airway response to oral appliance treatment in obstructive sleep apnea. J Biomech 46:142–150
Zhu JH, Lee HP, Lim KM, Lee SJ, Teo LSL, Wang DY (2012) Passive movement of human soft palate during respiration: A simulation of 3D fluid/structure interaction. J Biomech 45:1992–2000
Acknowledgments
The authors gratefully acknowledge financial support of WA State Center of Excellence in eMedicine (Project “Airway tomography instrumentation”). The work was supported by iVEC through the use of advanced computing resources located at iVEC@Murdoch.
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Cisonni, J., Lucey, A.D., King, A.J.C. et al. Numerical simulation of pharyngeal airflow applied to obstructive sleep apnea: effect of the nasal cavity in anatomically accurate airway models. Med Biol Eng Comput 53, 1129–1139 (2015). https://doi.org/10.1007/s11517-015-1399-z
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DOI: https://doi.org/10.1007/s11517-015-1399-z