Estimates of nasal airflow at the nasal cycle mid-point improve the correlation between objective and subjective measures of nasal patency

Gaberino, Courtney L.; Rhee, John S.; Garcia, Guilherme J. M.

doi:10.1016/j.resp.2017.01.004

Cited by 37 publications

(46 citation statements)

References 45 publications

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“…Casey et al found strong correlations between unilateral nasal airflow and NOSE ( r = −0.55, P = 0.0016) and moderate correlations between unilateral nasal airflow and VAS ( r = −0.49, P = 0.0056). For Gaberino et al, correlations with NOSE and VAS were strong after virtual correction of the nasal cycle ( r = −0.61, P = 0.002 and r = 0.56, P = 0.04, respectively). Before virtual correction, airflow was moderately correlated with NOSE ( r = −0.41, P = 0.048) but not significantly correlated with VAS.…”

Section: Resultsmentioning

confidence: 93%

“…Before virtual correction of the nasal cycle, Gaberino et al found no correlation between CFD‐NR and NOSE or VAS. However, after virtual correction of the nasal cycle, CFD‐NR was strongly correlated with NOSE and VAS ( r = 0.55, P = 0.005 and r = −0.58, P = 0.003, respectively) . Kimbell et al found a moderate correlation between CFD‐NR and both NOSE and VAS ( r = 0.48 and r = −0.42, respectively).…”

Section: Resultsmentioning

confidence: 99%

“…Recent studies evidenced the great interest showsn in heat flux in rhinology . Heat flux could be likened to the feeling of cold felt by the patient during inspiration.…”

Section: Discussionmentioning

confidence: 99%

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Functional relevance of computational fluid dynamics in the field of nasal obstruction: A literature review

Radulesco

Meister

Bouchet

et al. 2019

Clinical Otolaryngology

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Background: Nasal airway obstruction (nasal obstruction) is a common symptom affecting the quality of life of patients. It can be estimated by patient perception or physical measurements. Computational fluid dynamics (CFD) can be used to analyse nasal ventilation modalities. There is a lack of comparative studies investigating the correlations between CFD variables and patient perception or physical measurements.Objective of the review: Our goal was to define correlations between CFD variables and patient perception and physical measurements. We also aimed to identify the most reliable CFD variable (heat flux, WSS, total pressure, temperature…) characterising nasal breathing perception.Type of review: Systematic literature review using PRISMA guidelines. Search strategy:The selected studies were obtained from the US National Library of Medicine (PubMed) online database, MEDLINE (Ovid), Google Scholar and the Cochrane Library using a combination of MeSH terms (nose, paranasal sinus, fluid dynamics, rhinology) and non-MeSH terms (CFD, nasal airway, nasal airflow, numerical, nasal symptoms). Studies that did not incorporate objective or subjective clinical assessment were excluded. Evaluation method:We compared all results obtained by authors regarding CFD variables and assessment of nasal airway obstruction (clinical or physical). Results:To compare nasal obstruction with CFD variables, most authors use CFD-calculated nasal resistances, airflow, heat flux, wall shear stress, total pressure, velocities and streamlines. We found that heat flux appears to be the CFD variable most closely correlated with patient perception. Total pressure, wall shear stress and velocities are also useful and show good correlations. Correlations between CFD-calculated nasal resistances and patient perception are stronger after correction of the nasal cycle. Conclusions:The growing number of CFD studies on the nose has led to a better understanding of nasal obstruction. The clinical interpretation of previously unknown data, such as WSS and heat flux, is opening up new horizons in the understanding of this symptom. Heat fluxes are among the best CFD values correlated with patient perception. More studies need to be performed including temperature and humidity exchanges.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

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Functional relevance of computational fluid dynamics in the field of nasal obstruction: A literature review

Radulesco

Meister

Bouchet

et al. 2019

Clinical Otolaryngology

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“…In the early years of CFD simulations of nasal airflow, idealized anatomic models were sometimes used [ 36 , 37 ]. As the field progresses towards patient-specific models for surgical planning [ 12 ], it is necessary to quantify the sensitivity of CFD variables to uncertainty in the 3D reconstruction of the nasal anatomy, which can be caused by changes in nasal mucosa engorgement due to the nasal cycle [ 38 , 39 ], but can also be due to uncertainty in the airway segmentation from medical images.…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of nasal airflow variables computed via computational fluid dynamics to the computed tomography segmentation threshold

et al. 2018

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Computational fluid dynamics (CFD) allows quantitative assessment of transport phenomena in the human nasal cavity, including heat exchange, moisture transport, odorant uptake in the olfactory cleft, and regional delivery of pharmaceutical aerosols. The first step when applying CFD to investigate nasal airflow is to create a 3-dimensional reconstruction of the nasal anatomy from computed tomography (CT) scans or magnetic resonance images (MRI). However, a method to identify the exact location of the air-tissue boundary from CT scans or MRI is currently lacking. This introduces some uncertainty in the nasal cavity geometry. The radiodensity threshold for segmentation of the nasal airways has received little attention in the CFD literature. The goal of this study is to quantify how uncertainty in the segmentation threshold impacts CFD simulations of transport phenomena in the human nasal cavity. Three patients with nasal airway obstruction were included in the analysis. Pre-surgery CT scans were obtained after mucosal decongestion with oxymetazoline. For each patient, the nasal anatomy was reconstructed using three different thresholds in Hounsfield units (-800HU, -550HU, and -300HU). Our results demonstrate that some CFD variables (pressure drop, flowrate, airflow resistance) and anatomic variables (airspace cross-sectional area and volume) are strongly dependent on the segmentation threshold, while other CFD variables (intranasal flow distribution, surface area) are less sensitive to the segmentation threshold. These findings suggest that identification of an optimal threshold for segmentation of the nasal airway from CT scans will be important for good agreement between in vivo measurements and patient-specific CFD simulations of transport phenomena in the nasal cavity, particularly for processes sensitive to the transnasal pressure drop. We recommend that future CFD studies should always report the segmentation threshold used to reconstruct the nasal anatomy.

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“…In this way it permits the prediction of fluid movement during different states of nasal mucosal engorgement in the context of the NC (140)(141)(142) . Each of these methods evaluates only one aspect of the NC.…”

Section: Methods Techniquementioning

confidence: 99%

The nasal cycle: a comprehensive review

Pendolino¹,

Lund²,

Nardello³

et al. 2018

RHINOL

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Background: The nasal cycle is the spontaneous, reciprocal congestion and decongestion of the nasal mucosa during the day and it is present in almost 70-80% of healthy adults. The German physician Richard Kayser first described it in 1895. Since then, the number of papers focused on this fascinating issue has continued to flourish. Main body: Even though there are a high number of publications on this topic, the understanding of nasal cycle is still very poor. The present review tries to offer a comprehensive analysis of this issue investigating all the physiologic and pathologic conditions able to modify the nasal cycle. A section of methods used for its evaluation has been also included in this review. Conclusion: The influence of the nasal cycle on nasal airflow must be considered during any rhinologic evaluation, especially if investigating the need for septal/turbinates surgery, rather than nasal medical therapy alone. The nasal cycle is a normal phenomenon and must be recognized in order to differentiate it from the pathologic causes of nasal obstruction.

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Estimates of nasal airflow at the nasal cycle mid-point improve the correlation between objective and subjective measures of nasal patency

Cited by 37 publications

References 45 publications

Functional relevance of computational fluid dynamics in the field of nasal obstruction: A literature review

Functional relevance of computational fluid dynamics in the field of nasal obstruction: A literature review

Sensitivity of nasal airflow variables computed via computational fluid dynamics to the computed tomography segmentation threshold

The nasal cycle: a comprehensive review

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