The impact of nasal adhesions on airflow and mucosal cooling – A computational fluid dynamics analysis

Senanayake, Praween; Salati, Hana; Wong, Eugene; Bradshaw, Kimberley; Shang, Yidan; Singh, Narinder; Inthavong, Kiao

doi:10.1016/j.resp.2021.103719

Cited by 16 publications

(10 citation statements)

References 52 publications

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“…50 Consistent with our single-subject pilot study, our results consolidate features of the wake region quantitatively. 43 We found that this area is characterized by reduced inspired airflow and flow recirculation, which harbors higher air temperature and higher humidity, thereby reducing these gradients, which leads to reduced mucosal cooling and reduced heat flux. In patients with NAs, the formation of wake regions with reduced heat flux and, therefore, reduced mucosal cooling is likely to be detected as reduced subjective nasal patency.…”

Section: Discussionmentioning

confidence: 79%

“…52 A recent pilot study examining the effect of NAs on airflow in a single-subject model found little to no change in overall resistance or bulk airflow through the nasal cavity and saw only local airflow changes around and, particularly, immediately downstream to the NAs. 43 In this study, we performed a novel, quantitative analysis of the wake region directly downstream of NAs and found statistically significant increased mucosal temperature, air temperature, and humidity and reduced heat flux, in multiple subject models. The reduced mucosal cooling (increased mucosal temperature) seen in the wake regions may be explained by examining air temperature and humidity.…”

Section: Discussionmentioning

confidence: 84%

“…[36][37][38][39][40][41][42] In a recent proof-of-concept single-subject study, we used CFD to examine the effect of NAs on nasal airflow in a variety of locations commonly seen following NAO surgery (ie, septoplasty and turbinate reduction). 43 The study demonstrated that for the single subject analyzed, there was significant local disruption of airflow and mucosal cooling immediately downstream of NAs in the "wake" region, particularly for anteriorly located NAs, despite negligible difference to bulk airflow. We postulated that this local impact on mucosal cooling could explain the exaggerated perception of reduced patency in patients with NAs, rather than the relatively minor reduction in crosssectional area.…”

Section: Introductionmentioning

confidence: 86%

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The Impact of Adhesions on Nasal Airflow: A Quantitative Analysis Using Computational Fluid Dynamics

Senanayake

Warfield-McAlpine

Salati

et al. 2022

Am J Rhinol�Allergy

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Background Nasal adhesions (NAs) are a known complication of nasal airway surgery. Even minor NAs can lead to significant postoperative nasal airway obstruction (NAO). Division of such NAs often provides much greater relief than anticipated. Objective We examine the impact of NAs at various anatomical sites on nasal airflow and mucosal cooling using computational fluid dynamics (CFD) and multiple test subjects. Methods CT scans of healthy adult subjects were used to construct three-dimensional nasal airway computational models. A single virtual 2.5 mm diameter NA was placed at one of five sites commonly seen following NAO surgery within each nasal cavity bilaterally, resulting in 10 NA models and 1 NA-free control for each subject. CFD analysis was performed on each NA model and compared with the subject's NA-free control model. Results 4 subjects were recruited to create 44 computational models. The NAs caused the airflow streamlines to separate, leading to a statistically significant increase in mucosal temperature immediately downstream to the NAs (wake region). Changes in the mucosal temperature in the wake region of the NAs were most prominent in anteriorly located NAs with a mean increase of 1.62 °C for the anterior inferior turbinate NAs ( P < .001) and 0.63 °C for the internal valve NAs ( P < .001). Conclusion NAs result in marked disruption to airflow patterns and reduced mucosal cooling on critical surfaces, particularly in the wake region. Reduced wake region mucosal cooling may be a contributing factor to the exaggerated perception of nasal obstruction experienced by patients with NAs.

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Section: Discussionmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 86%

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The Impact of Adhesions on Nasal Airflow: A Quantitative Analysis Using Computational Fluid Dynamics

Senanayake

Warfield-McAlpine

Salati

et al. 2022

Am J Rhinol�Allergy

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“…The conduction heat transfer is governed by:

\overset{q}{true} goodbreak= k \frac{normalΔ T}{δ} goodbreak= \frac{normalΔ T}{normalΔ R_{eff}}

where,

R_{eff} goodbreak= \frac{δ_{rep}}{k_{rep}}

where R eff is the effective thermal resistance. During preliminary testing a R eff = 0.006 K/W m 2 was the most suitable value, based on conductivity and thickness parameters suggested in Na et al 30 who reviewed anatomic information on the respiratory mucosa from Beule, 31 and later in Senanayake et al 32 . The k rep is a representative conductivity for the solid region defined such that the desired effective thermal resistance, R eff , per unit area (K/W m 2 ) was achieved.…”

Section: Methodsmentioning

confidence: 99%

“…During preliminary testing a R eff = 0.006 K/W m 2 was the most suitable value, based on conductivity and thickness parameters suggested in Na et al 30 who reviewed anatomic information on the respiratory mucosa from Beule, 31 and later in Senanayake et al. 32 The k rep is a representative conductivity for the solid region defined such that the desired effective thermal resistance, R eff , per unit area (K/W m 2 ) was achieved. For example, in the pipe geometry, we set k rep = 0.1667 W/mK for a δ rep = 0.001 m, giving R eff = 0.006 K/W m 2 .…”

Section: Methodsmentioning

confidence: 99%

Wet surface wall model for latent heat exchange during evaporation

Inthavong

Fletcher

Kamooshi

et al. 2022

Numer Methods Biomed Eng

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Air conditioning is a dual heat and mass transfer process, and the human nasal cavity achieves this through the mucosal wall surface, which is supplied with an energy source through the sub-epithelial network of capillaries. Computational studies of air conditioning in the nasal cavity have included temperature and humidity, but most studies solved these flow parameters separately, and in some cases, a constant mucosal surface temperature was used. Recent developments demonstrated that both heat and mass transfer need to be modeled. This work expands on existing modeling efforts in accounting for the nasal cavity's dual heat and mass transfer process by introducing a new subwall model, given in the Supplementary Materials. The model was applied to a pipe geometry, and a human nasal cavity was recreated from CT-scans, and six inhalation conditions were studied. The results showed that when the energy transfer from the latent heat of evaporation is included, there is a cooling effect on the mucosal surface temperature.

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Correlation of Nasal Mucosal Temperature and Nasal Patency—A Computational Fluid Dynamics Study

et al. 2022

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Objectives Recent evidence suggests that detection of nasal mucosal temperature, rather than direct airflow detection, is the primary determinant of subjective nasal patency. This study examines the role of nasal mucosal temperature in the perception of nasal patency using in vivo and computational fluid dynamics (CFD) measurements. Methods Healthy adult participants completed Nasal Obstruction Symptom Evaluation (NOSE) and Visual Analogue Scale (VAS) questionnaires. A temperature probe measured nasal mucosal temperature at the vestibule, inferior turbinate, middle turbinate, and nasopharynx bilaterally. Participants underwent a CT scan, used to create a 3D nasal anatomy model to perform CFD analysis of nasal mucosal and inspired air temperature and heat flux along with mucosal surface area where heat flux >50 W/m2 (SAHF50). Results Eleven participants with a median age of 27 (IQR 24; 48) were recruited. Probe‐measured temperature values correlated strongly with CFD‐derived values (r = 0.87, p < 0.05). Correlations were seen anteriorly in the vestibule and inferior turbinate regions between nasal mucosal temperature and unilateral VAS (r = 0.42–0.46; p < 0.05), between SAHF50 and unilateral VAS (r = −0.31 to −0.36; p < 0.05) and between nasal mucosal temperature and SAHF50 (r = −0.37 to −0.41; p < 0.05). Subjects with high patency (VAS ≤10) had increased heat flux anteriorly compared with lower patency subjects (VAS >10; p < 0.05). Conclusion Lower nasal mucosal temperature and higher heat flux within the anterior nasal cavity correlates with a perception of improved unilateral nasal patency in healthy individuals. Level of Evidence 4 Laryngoscope, 133:1328–1335, 2023

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The impact of nasal adhesions on airflow and mucosal cooling – A computational fluid dynamics analysis

Cited by 16 publications

References 52 publications

The Impact of Adhesions on Nasal Airflow: A Quantitative Analysis Using Computational Fluid Dynamics

The Impact of Adhesions on Nasal Airflow: A Quantitative Analysis Using Computational Fluid Dynamics

Wet surface wall model for latent heat exchange during evaporation

Correlation of Nasal Mucosal Temperature and Nasal Patency—A Computational Fluid Dynamics Study

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