scholarly journals The complexities of nasal airflow: theory and practice

2019 ◽  
Vol 127 (5) ◽  
pp. 1215-1223 ◽  
Author(s):  
Graham O’Neill ◽  
Neil Samuel Tolley
Keyword(s):  
Theory And Practice ◽  
Poor Correlation ◽  
Airflow Rate ◽  
Nasal Resistance ◽  
Flow Limitation ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Cross Sectional ◽  
Pressure Flow ◽  
Valve Area

The objective of this study was to investigate the effects of nasal valve area, valve stiffness, and turbinate region cross-sectional area on airflow rate, nasal resistance, flow limitation, and inspiratory “hysteresis” by the use of a mathematical model of nasal airflow. The model of O’Neill and Tolley ( Clin Otolaryngol Allied Sci 13: 273–277, 1988) describing the effects of valve area and stiffness on the nasal pressure-flow relationship was improved by the incorporation of additional terms involving 1) airflow through the turbinate region, 2) the dependence of the flow coefficients for the valve and turbinate region on the Reynolds number, and 3) effects of unsteady flow. The model was found to provide a good fit for normal values for nasal resistance and for pressure-flow curves reported in the literature for both congested and decongested states. Also, by showing the relative contribution of the nasal valve and turbinate region to nasal resistance, the model sheds light in explaining the generally poor correlation between nasal resistance measurements and the results from acoustic rhinometry. Furthermore, by proposing different flow conditions for the acceleration and deceleration phases of inspiration, the model produces an inspiratory loop (commonly referred to as hysteresis) consistent with those reported in the literature. With simulation of nasal flaring, the magnitude of the loop, the nasal resistance, and flow limitation all show change similar to that observed in the experimental results. NEW & NOTEWORTHY The present model provides considerable insight into some difficult conundrums in both clinical and technical aspects of nasal airflow. Also, the description of nasal airflow mechanics based on the Hagen–Poiseuille equation and Reynolds laminar-turbulent transition in long straight tubes, which has figured prominently in medical textbooks and journal articles for many years, is shown to be seriously in error at a fundamental level.

scholarly journals Nasal resistance and flow resistive work of nasal breathing during exercise: effects of a nasal dilator strip

2000 ◽  
Vol 89 (3) ◽  
pp. 1114-1122 ◽  
Author(s):  
J. M. Gehring ◽  
S. R. Garlick ◽  
J. R. Wheatley ◽  
T. C. Amis
Keyword(s):  
Flow Curve ◽  
Cycle Ergometer ◽  
Work Rate ◽  
Nasal Resistance ◽  
Flow Limitation ◽  
Nasal Airflow ◽  
Nasal Breathing ◽  
External Work ◽  
Pressure Flow ◽  
Nasal Vestibule

Using posterior rhinomanometry, we measured nasal airflow resistance (Rn) and flow-resistive work of nasal breathing (WONB), with an external nasal dilator strip (ENDS) and without (control), in 15 healthy adults (6 men, 9 women) during exclusive nasal breathing and graded (50–230 W) exercise on a cycle ergometer. ENDS decreased resting inspiratory and/or expiratory Rn (at 0.4 l/s) by >0.5 cmH2O · l−1· s in 11 subjects (“responders”). Inspired ventilation (V˙i) increased with external work rate, but tended to be greater with ENDS. Inspiratory and expiratory Rn (at 0.4 l/s) decreased asV˙i increased but, in responders, tended to remain lower with ENDS. Inspiratory (but not expiratory) Rn at peak nasal airflow (V˙n) increased as V˙i increased but, again, was lower with ENDS. At a V˙i of ∼35 l/min, ENDS decreased flow limitation and hysteresis of the inspiratory transnasal pressure-flow curve. In responders, ENDS reduced inspiratory WONB per breath and inspiratory nasal power values during exercise. We conclude that ENDS stiffens the lateral nasal vestibule walls and, in responders, may reduce the energy required for nasal ventilation during exercise.

Nasal Resistance and Nasal Valve Area

1995 ◽  
Vol 9 (5) ◽  
pp. 269-272 ◽  
Author(s):  
Saul Frenkiel ◽  
Bernard Segal ◽  
David Sinclair
Keyword(s):  
Upper Airway ◽  
Whole Body ◽  
Nasal Resistance ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Primary Flow ◽  
Geometrical Characteristics ◽  
Nasal Pathology ◽  
Whole Body Plethysmography ◽  
Valve Area

The nasal valve is considered to be the primary flow-limiting segment of the normal upper airway. We examined subjects with and without nasal pathology to determine whether nasal airway resistance, as determined by rhinomanometry, could be related to clinically measurable geometrical characteristics of the nasal valve. Data was obtained from 26 subjects, 22 with nasal airflow complaints due to valvular or septal abnormalities and four without. Nasal valve area was estimated by triangular approximation, and transnasal airflow resistance was measured using head-out whole-body plethysmography. When all subjects were considered, no clear relationship between nasal resistance and nasal valve area was apparent. However, when patients with severe septal deflection or with a prominent vasomotor response to nasal decongestion were not considered, nasal resistance was found to be significantly negatively correlated to nasal valve area. Further studies are required to relate more posterior pathology to nasal resistance.

Hypernasality and Velopharyngeal Impairment

1994 ◽  
Vol 31 (4) ◽  
pp. 257-262 ◽  
Author(s):  
Donald W. Warren ◽  
Rodger M. Dalston ◽  
Robert Mayo
Keyword(s):  
Airflow Rate ◽  
Nasal Airflow ◽  
Moderate Correlation ◽  
Interval Scale ◽  
Pressure Flow ◽  
Orifice Area ◽  
The Relationship ◽  
Nasal Resonance

Although the primary cause of hypernasality is impaired velopharyngeal (VP) function, a variety of other factors influence the outcome perceived by the listener. The purpose of the current study was to assess the relationship between oral-nasal resonance balance and (1) velopharyngeal orifice area; (2) nasal airflow rate; and (3) duration of nasal airflow. The pressure-flow technique was used to estimate VP area and measure nasal airflow rate and duration. Ratings of oral-nasal balance were made on a 6-point equal-appearing interval scale. Results Indicated a moderate correlation between hypernasality rating and VP area (0.66), nasal airflow (0.61), and nasal airflow duration (0.53). Adults tended to be perceived as more hypernasal than children for a given degree of VP impairment. Finally, when the degree of VP opening was small, perceived oral-nasal resonance balance appeared to be related to duration of the opening-closing movements.

Obstruction of the nasal valve

1996 ◽  
Vol 110 (3) ◽  
pp. 221-224 ◽  
Author(s):  
Samy Elwany ◽  
Hossam Thabet
Keyword(s):  
Surgical Procedures ◽  
Lateral Cartilage ◽  
Nasal Resistance ◽  
Nasal Airflow ◽  
Nasal Patency ◽  
Nasal Valve ◽  
Nasal Surgery ◽  
History Of ◽  
Upper Lateral Cartilage ◽  
The Mean

AbstractObstruction of the nasal valve is an important cause of chronic nasal obstruction in adults. In a series of 500 patients, obstruction at the level of the nasal valve was diagnosed in 65 of them (13 per cent). The obstruction was unilateral in 57 patients (88 per cent). Forty-seven patients (72 per cent) had history of previous nasal surgery of accidental trauma. Causes of obstruction of the nasal valve included high septal deviations, a weak or deformed upper lateral cartilage, adhesions, and alar collapse. All patients underwent corrective nasal surgery and the surgical procedures were tailored according to the existing pathology. Post-operatively, the mean nasal patency score increased from 2.9 to 8.6, the mean nasal airflow increased from 579.5 to 727 cm/sec (at 150 Pa), and the mean nasal resistance decreased from 0.31 to 0.23 Pa/cm3sec-1.

Nasal airflow in inspiration and expiration

1990 ◽  
Vol 104 (6) ◽  
pp. 473-476 ◽  
Author(s):  
Laura Viani ◽  
Andrew S. Jones ◽  
Ray Clarke
Keyword(s):  
Flow Rate ◽  
Peak Flow ◽  
Phase Relationship ◽  
Low Flow ◽  
Airflow Rate ◽  
Nasal Resistance ◽  
Nasal Airflow ◽  
Flow Rates ◽  
Induced Changes ◽  
Peak Inspiratory Flow Rate

AbstractInspiratory and expiratory airflow rates were measured in 30 subjects during quiet respiration (at a pressure gradient of 150 Pa) and at peak flow rates.For low flow rates airflow rate was greater for inspiration than for expiration. Conversely at peak flow rates flow was greatest during expiration. Thus there was a reversal in the phase relationship between inspiration and expiration as flow rate increased.It was also found that peak inspiratory flow rate correlated better with values for nasal resistance than did peak expiratory flow rate. Flow rate measured by rhinomanometry during quiet respiration was more sensitive to physiologically induced changes in nasal resistance than was peak flow rate.The findings are discussed with reference to previous work on the physiology of nasal airflow.

Inspiratory and Fixed Nasal Valve Collapse: Clinical and Rhinometric Assessment

2005 ◽  
Vol 19 (4) ◽  
pp. 370-374 ◽  
Author(s):  
Ramakrishnan Vidyasagar ◽  
Michael Friedman ◽  
Hani Ibrahim ◽  
Darius Bliznikas ◽  
Ninos J. Joseph
Keyword(s):  
Inferior Turbinate ◽  
Nasal Valve ◽  
Dual Mode ◽  
Cross Sectional ◽  
Turbinate Hypertrophy ◽  
Number Of Patients ◽  
Inferior Turbinate Hypertrophy ◽  
Nasal Valve Collapse ◽  
External Nasal Valve ◽  
Valve Area

Background Acoustic rhinometry (AR) has been used to assess nasal valve obstruction. Standard AR measurement of the cross-sectional area (CSA) of the nasal valve is done in the apneic phase, whereas collapse often occurs on inspiration. We used the ratio of the CSA obtained during active inspiration and during apnea to compute a more meaningful method of diagnosing nasal valve collapse. Methods AR was performed in 40 patients without nasal valve obstruction and 47 patients diagnosed with nasal valve obstruction. Patients with septal deflection or anterior inferior turbinate hypertrophy were excluded. The internal and external nasal valve area was observed during apnea and on active inspiration. AR measurement of the CSA of both nasal valves was performed during the apneic phase and during active inspiration and the CSA (inspiratory)/CSA (apneic) ratio was calculated. Results The CSA (inspiratory)/CSA (apneic) ratio was ≥1 in normal patients and in patients with fixed nasal valve collapse. The ratio was <1 in patients with inspiratory collapse. Data from history, physical examination, and dual-mode AR testing successfully differentiated patients into (1) normal valves, (2) fixed valve collapse, and (3) inspiratory valve collapse. A large number of patients with collapse had both internal and external valve obstruction and a large number also had a combination of inspiratory and fixed collapse. Conclusion Dual-mode AR testing is an effective tool in more precisely identifying nasal valve obstruction and is the first objective test shown to be highly diagnostic of inspiratory nasal valve collapse.

Acoustic Rhinometric Assessment of the Nasal Valve

1997 ◽  
Vol 11 (5) ◽  
pp. 379-386 ◽  
Author(s):  
Renato Roithmann ◽  
Jerry Chapnik ◽  
Noe Zamel ◽  
Sergio Menna Barreto ◽  
Philip Cole
Keyword(s):  
Cross Section ◽  
Nasal Obstruction ◽  
Cross Sectional Area ◽  
Acoustic Rhinometry ◽  
Sectional Area ◽  
Nasal Valve ◽  
Cross Sectional ◽  
Nasal Cavities ◽  
Before And After ◽  
Valve Area

The aims of this study are to assess nasal valve cross-sectional areas in healthy noses and in patients with nasal obstruction after rhinoplasty and to evaluate the effect of an external nasal dilator on both healthy and obstructive nasal valves. Subjects consisted of (i) volunteers with no nasal symptoms, nasal cavities unremarkable to rhinoscopy and normal nasal resistance and (ii) patients referred to our clinic complaining of postrhinoplasty nasal obstruction. All subjects were tested before and after topical decongestion of the nasal mucosa and with an external nasal dilator. In 79 untreated healthy nasal cavities the nasal valve area showed two constrictions: the proximal constriction averaged 0.78 cm2 cross-section and was situated 1.18 cm from the nostril, the distal constriction averaged 0.70 cm2 cross-section at 2.86 cm from the nostril. Mucosal decongestion increased cross-sectional area of the distal constriction significantly (p < 0.0001) but not the proximal. External dilation increased cross-sectional area of both constrictions significantly (p < 0.0001). In 26 post-rhinoplasty obstructed nasal cavities, only a single constriction was detected, averaging 0.34 cm2 cross-section at 2.55 cm from the nostril and 0.4 cm2 at 2.46 cm from the nostril, before and after mucosal decongestion respectively. External dilation increased the minimum cross-sectional area to 0.64 cm2 in these nasal cavities (p < 0.0001). We conclude that the nasal valve area in patients with postrhinoplasty nasal obstruction is significantly smaller than in healthy nasal cavities as shown by acoustic rhinometry. Acoustic rhinometry objectively determines the structural and mucovascular components of the nasal valve area and external dilation is an effective therapeutical approach in the management of nasal valve obstruction.

Opening the Nasal Valve with External Dilators Reduces Congestive Symptoms in Normal Subjects

2005 ◽  
Vol 19 (2) ◽  
pp. 215-219 ◽  
Author(s):  
Jenny Latte ◽  
David Taverner
Keyword(s):  
Visual Analog Scale ◽  
Nasal Congestion ◽  
Normal Subjects ◽  
Cross Sectional Area ◽  
Ordinal Scale ◽  
Sectional Area ◽  
Nasal Valve ◽  
Analog Scale ◽  
Cross Sectional ◽  
Valve Area

Background We examined whether the use of two different external nasal dilator devices influenced the size of the nasal valve area and symptoms of nasal congestion. Methods This was a randomized blind-allocation, open three-way crossover study of Breathe Right, Side Strip Nasal Dilators, and placebo. We studied 12 healthy subjects (10 female, 2 male; age range 26–56 years). Measures of total volume and total minimum cross-sectional area were collected. Subjective symptoms were collected using a visual analog scale and an ordinal scale. Results With both products, there was significant increase in the size of the minimum cross-sectional area compared to placebo, p = 0.004. This is supported by the decrease in the subjective reports of congestion; on the visual analog scale, compared to placebo p = 0.012 and the ordinal scale, compared to placebo, p = 0.004. Conclusion Both devices significantly increase the size of the nasal valve area and reduce congestion in normal subjects.

scholarly journals Nasal airflow of patient with septal deviation and allergy rhinitis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Zi Fen Lim ◽  
Parvathy Rajendran ◽  
Muhamad Yusri Musa ◽  
Chih Fang Lee
Keyword(s):  
Middle Turbinate ◽  
Three Dimensional ◽  
Septal Deviation ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Cross Sectional ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Interactive Application ◽  
Analysis System

AbstractA numerical simulation of a patient’s nasal airflow was developed via computational fluid dynamics. Accordingly, computerized tomography scans of a patient with septal deviation and allergic rhinitis were obtained. The three-dimensional (3D) nasal model was designed using InVesalius 3.0, which was then imported to (computer aided 3D interactive application) CATIA V5 for modification, and finally to analysis system (ANSYS) flow oriented logistics upgrade for enterprise networks (FLUENT) to obtain the numerical solution. The velocity contours of the cross-sectional area were analyzed on four main surfaces: the vestibule, nasal valve, middle turbinate, and nasopharynx. The pressure and velocity characteristics were assessed at both laminar and turbulent mass flow rates for both the standardized and the patient’s model nasal cavity. The developed model of the patient is approximately half the size of the standardized model; hence, its velocity was approximately two times more than that of the standardized model.

scholarly journals Effects of the nasal valve on acoustic rhinometry measurements: a model study

2003 ◽  
Vol 94 (6) ◽  
pp. 2166-2172 ◽  
Author(s):  
Mehmet Cankurtaran ◽  
Hüseyin Çelik ◽  
Ozcan Cakmak ◽  
Levent Naci Özlüoglu
Keyword(s):  
Nasal Cavity ◽  
Low Frequency ◽  
Acoustic Rhinometry ◽  
Sound Power ◽  
Nasal Valve ◽  
Cylindrical Pipe ◽  
Cross Sectional ◽  
Model Study ◽  
Valve Area

The influence of nasal valve on acoustic rhinometry (AR) measurements was evaluated by using simple nasal cavity models. Each model consisted of a cylindrical pipe with an insert simulating the nasal valve. The AR-determined cross-sectional areas beyond the insert were consistently underestimated, and the corresponding area-distance curves showed pronounced oscillations. The area underestimation was more pronounced in models with inserts of small passage area. The experimental results are discussed in terms of theoretically calculated “sound-power reflection coefficients” for the pipe models. The reason for area underestimation is reflection of most of the incident sound power from the barrier at the front junction between the pipe and the insert. It was also demonstrated that the oscillations are due to low-frequency acoustic resonances in the portion of the pipe beyond the insert. The results suggest that AR does not provide reliable information about the cross-sectional areas of the nasal cavity posterior to a significant constriction, such as pathologies narrowing the nasal valve area. When the passage area of the nasal valve is decreased, the role of AR as a diagnostic tool for the entire nasal cavity becomes limited.

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