Nasal Airflow Resistance Research Articles

The Use of Rhinomanometry in Mouth Breathing: A Systematic Review of the Literature.

Introduction Mouth breathing generates imbalances in the musculature, in craniofacial morphofunctionality, and in the stomatognathic system. Therefore, it is essential to make a diagnosis of mouth breathing through the quantitative assessment of nasal permeability, which can be performed through rhinomanometry. Objective To investigate the effectiveness of rhinomanometry in the diagnosis of mouth breathing in pediatric patients through a systematic review of the literature. Data synthesis The guiding question was: "Is the use of rhinomanometry as an assessment tool effective in the diagnosis of mouth breathing in pediatric patients?". We conducted a search on the following databases: Latin American and Caribbean Center on Health Sciences Information (BIREME), Latin American and Caribbean Health Sciences Literature (LILACS), PubMed/Medical Literature Analysis and Retrieval System Online (MEDLINE), Scientific Electronic Library Online (SciELO), Web of Science, and Science Direct. The Health Sciences Descriptors (Descritores em Ciências da Saúde, DECS, in Portuguese) and Medical Subjects Headings (MESH) were combined with the Boolean operator AND in the search strategy: rhinomanometry AND mouth breathing AND diagnosis AND nasal pressure AND nasal airflow AND nasal resistance . Observational cohort and cross-sectional studies that addressed the effectiveness of rhinomanometry in the diagnosis of mouth breathing were included. The reviewers independently extracted the information and scored the review quality based on the Physiotherapy Evidence Database (PEDro) scale and the grading of evidence levels according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Of the 1,536 articles identified, only 3 were selected for the present review after the application of the eligibility criteria. Conclusion There is great concern regarding the assessment of nasal function. There was a lack of standardization of rhinomanometry to test the effectiveness of nasal resistance as an aid in the diagnosis of breathing mode.

Comparison of Allergen Immunotherapy Alone and in Conjunction With Turbinate Surgery for Nasal Obstruction in Perennial Allergic Rhinitis Patients.

Nasal obstruction, triggered by allergic rhinitis, often does not resolve with allergen-specific immunotherapy (AIT) alone, thus inferior turbinate reduction surgery (ITR) may be required. This study aims to investigate the impact of combined treatment on nasal obstruction, as evidence is currently limited. A retrospective cohort study of perennial allergic rhinitis patients experiencing nasal obstruction and undergoing ≥12 months AIT was conducted. Two groups were derived, those undergoing AIT-with or without an ITR. Patient reported nasal obstruction (evaluated with questionnaires) and nasal airway function (Nasal Peak Inspiratory Flow [NPIF] and Nasal Airflow Resistance [NAR]) were monitored. The change from baseline to 12 months post-treatment in each group were compared. A total of 118 patients (33.71 ± 14.43 years, 41.5% female) were recruited, 72% had AIT and 28% AIT&ITR. At baseline, the AIT&ITR group had a higher level of nasal obstruction (>moderate%; 63.6% vs 52.9%, P = .048). Post treatment, AIT&ITR group reported greater reduction in nasal obstruction (>1 category change: 75.8% vs 48.2%, P = .002). Similarly, the AIT&ITR group had greater improvement in nasal function by NPIF (-13.9 ± 110.3 L/minute vs -3.4 ± 78.1 L/minute, P = .049) and NAR (-0.120 ± 0.342 Pa/cm³/second vs -0.093 ± 0.224 Pa/cm³/second, P = .050). Allergic rhinitis patients, with moderate to severe nasal obstruction, who undergo combined AIT&ITR have greater relief of nasal obstruction and improved airflow analysis compared to AIT alone.

Overview of Nasal Airway and Nasal Breathing Evaluation.

Several methods are available for evaluating nasal breathing and nasal airflow, as this evaluation may be made from several different perspectives.Physiologic methods for nasal airway evaluation directly measure nasal airflow or nasal airway resistance, while anatomical methods measure nasal airway dimensions. Subjective methods evaluate nasal breathing through several validated patient-reported scales assessing nasal breathing. Computational fluid dynamics evaluates nasal airflow through the analysis of several physics' variables of the nasal airway.Being familiar to these methods is of utmost importance for the nasal surgeon to be able to understand data provided by the different methods and to be able to choose the combination of evaluation methods that will provide the information most relevant to each clinical situation.

Peak Nasal Inspiratory Flow (PNIF) for Nasal Breathing Evaluation.

Measuring nasal airflow and nasal breathing has been a major goal of rhinology. Many objective methods for measuring nasal airflow or nasal airway resistance or dimensions provide valuable data but are time-consuming and require expensive equipment and trained technicians, thus making these methods less practical for clinical practice. Peak nasal inspiratory flow (PNIF) measurement is fast, unexpensive, noninvasive, and able to provide an objective evaluation of nasal airflow in real-time. Unilateral PNIF measurements allow separated evaluation of each side of the nasal airway and may prove particularly useful when clinical assessment detects significant asymmetry between both nasal cavities.PNIF measurements are most useful for assessing changes in nasal airflow achieved by any form of therapy, including surgical treatment of the nasal airway. These measurements generally correlate with other objective methods for nasal airway evaluation, but not unequivocally with patient-reported evaluation of nasal breathing. Nevertheless, as low PNIF values prevent the sensation of a suitable nasal breathing, PNIF measurement may also prove useful to optimize the decision of how to best address patients with complaints of nasal airway obstruction.

Algorithm for Nasal Breathing Impairment Evaluation.

Assessing patients with complaints of nasal obstruction has traditionally been done by evaluation of the nasal airway looking for fixed or dynamic obstructive locations that could impair nasal airflow. Not infrequently, however, symptoms of nasal obstruction do not match the clinical examination of the nasal airway. Addressing this subset of patients may be a challenge to the surgeon. Evaluation of patients with symptoms of nasal obstruction should include a combination of a patient-reported assessment of nasal breathing and at least one objective method for measuring nasal airflow or nasal airway resistance or dimensions. This will allow distinction between patients with symptoms of nasal obstruction and low airflow or high nasal airway resistance and patients with similar symptoms but whose objective evaluation demonstrates normal nasal airflow or normal airway dimensions or resistance. Patients with low nasal airflow or high nasal airway resistance will require treatment to increase nasal airflow as a necessary step to improve symptoms, whereas patients with normal nasal airflow or nasal airway resistance will require a multidimensional assessment looking for less obvious causes of impaired nasal breathing sensation.

33959 Novel nasal alar reconstruction with hyaluronic acid after Mohs micrographic surgery and repair

Mohs micrographic surgery (MMS) has become a treatment of choice for certain nonmelanoma skin cancer, especially when lesions are located on aesthetically sensitive areas of the body such as the face. Due to the unique anatomy of the nose, reconstruction of nasal defects following MMS can present a challenge. Surgery to certain nasal structures, such as the ala, columella, or tip, can result in external nasal valve collapse. Reduction in the radius of the nasal valve areas by even a small amount can cause significant effect on nasal airflow and nasal resistance. Several methods may be employed for prevention or correction of nasal defects following MMS. For example, use of cartilage grafting has shown good results in maintaining nasal ala structure and reducing the risk of alar collapse. Furthermore, various suture techniques have been described that may be used intraoperatively to try to prevent alar collapse, including a 3-point suture and a suspension suture technique. In terms of postoperative correction, conservative measures are often used first. For instance, treatment of increased flap bulk causing compression may be done with steroid injection. If this should fail, flap debulking may become necessary to correct the issue. In cases of substantial external valve collapse, batten grafting has been used to repair the defect and improve inspiratory airflow. Here we present cosmetic filler as a novel method for treatment of nasal alar collapse in patients who may not wish to undergo surgical correction.

COMPARATIVE HISTOLOGICAL ANALYSIS OF THE NASAL SEPTAL SWELL BODY AND THE POSTERIOR NASAL SEPTAL MUCOSA

Introduction: The nasal septal swell body is an area in the nasal septum located superior to the inferior turbinate, and anterior to the middle turbinate. It is closely associated with the internal nasal valve, in addition to being included among the expansile tissues of the anterior nose, which suggests that it significantly interferes with nasal airflow resistance. Objective: The present study aimed to histologically evaluate the composition of the septal mucosa in the septal body area, while comparing it with the posterior septal region, and to discover its role in nasal physiology. Methods: To perform the histological analysis, samples of the septal body mucosa and of the posterior septal mucosa of 20 patients were collected, and then the differences regarding cellular constitution, blood vessels (sinusoid and arterial) and connective tissue were outlined. Results: A larger number of venous sinusoids was noticed in the nasal septal body area, compared to the posterior septal mucosa, and less glandular-like tissue in the nasal septal body. Conclusion: The erectile tissue characteristic of the nasal septal body may play a role in the physiology of nasal obstruction, but new studies with different groups of patients are needed to define its actual role.

Evaluation of Nasal Function and Upper Airway Morphology After Bi-Maxillary Surgery Using Rhinomanometry and Computed Tomography.

This study was performed to evaluate changes in nasal airflow, nasal airway resistance, nasal cross-sectional area, pharyngeal horizontal area, nasopharyngeal and oropharyngeal volume following Le Fort I osteotomy (L1) impaction with sagittal split ramus osteotomy (SSRO) in classes II and III. The subjects consisted of 35 patients (6 males and 29 females, 70 sides) 17 of which were diagnosed as class II and 18 as class III who underwent L1 and SSRO. Nasal airflow and resistance were measured using the rhinomanometry system (GM NR-6 EXECUTIVE) before and at 1 and 6 months after surgery. Nasal, cross-sectional area, and volume were measured using a 3-dimensional computed tomography respectively, before and 1-year after surgery. Although a significant decrease was found in nasal volume after surgery (P = 0.0042), there was no difference between before and after surgery in the nasal airway resistance in class II.A significant decrease in nasal volume was found after surgery (P = 0.0005) and there were no postoperative changes in both nasal airflow and resistance in class III. The study suggested that L1 impaction with SSRO did not worsen nasal function such as nasal airflow and nasal airway resistance, although nasal volume significantly decreased in both groups.

Evaluation of nasal airflow resistance of operated unilateral cleft lip and palate surgery patients compared with skeletal class III individuals

ObjectiveThe purpose of this study was to measure the nasal airflow resistance of operated unilateral cleft lip and palate (UCLP) patients using the anterior rhinomanometry method compared with non-cleft skeletal class III individuals with isolated maxillary hypoplasia serving as the control group. Material&methodsSixteen UCLP patients who have undergone lip and palate reconstructions and alveolar cleft grafting but not advanced surgeries as the study group and 16 non-cleft skeletal class III participants as the control group (corresponded for age and sex to the study group) were included in this prospective study. All of the patients had class III occlusion due to isolated maxillary hypoplasia. Nasal airflow was measured with anterior rhinomanometry (in ml/sec) for each nostril separately. For evaluation of nasal side subgroups of the UCLP group for nasal resistance, the cleft sides and non-cleft sides of individuals were examined in two separate groups. The nasal side resistance of the control group was evaluated as the average of both nasal side resistances. The nasal resistances for nasal sides and total nasal resistance were measured in Pa/L/sec. The observed data were analyzed using Kolmogorov-Smirnov test used for normality, and the Student t-test and Mann Whitney U test used to determine the differences between the groups. P values of <0.05 were considered statistically significant. ResultsAs the primary outcome of this study, it was found that both the cleft sides and non-cleft sides of the UCLP individuals had statistically significantly higher nasal resistance than the healthy skeletal class III control group (p < 0.05). It was revealed that the cleft side had more nasal resistance than the non-cleft side for both inspiration and expiration, but the results were not statistically significant (p = 0.41/p = 0.28). ConclusionThe results showed that operated UCLP patients have nasal resistance and breathing problems, even when lip, palate, and alveolar cleft operations have been performed.

Does maxillary superior repositioning affect nasal airway function?

This study aimed to assess nasal airflow, nasal resistance, and the cross-sectional area of the nasal cavity in patients who have had maxillary superior repositioning (MSR). This is a cross-sectional study, and nasal airflow, nasal resistance, and the cross-sectional area of the nasal cavity were evaluated by rhinometry and acoustic rhinometry techniques in patients who had had MSR. Thirty-two patients were studied, and the mean (SD) MSR was 5.03 (1.61) (range 3-8) mm. There was a significant correlation between the mean MSR and the mean change in nasal airflow and nasal resistance (p=0.001 and p=0.005, respectively). There was also a correlation between MSR and the change in the cross-sectional area of the inferior concha (p=0.001), but there was no correlation between the mean MSR and the change in cross-sectional area of the isthmus (p=0.07). Nasal airflow increases when the mean MSR is less than 6.5mm, and when maxillary impaction is 6.5mm or more, nasal airflow decreases. It seems, therefore, that MSR of less than 6.5mm was associated with an improvement in nasal airflow. When maxillary impaction was more than 6.5mm, nasal airflow and the cross-sectional area of the nasal cavity decreased, and nasal resistance increased.

Nasal Nitric Oxide Is Correlated With Nasal Patency and Nasal Symptoms.

PurposeNitric oxide (NO) is an important endogenous mediator in both upper and lower respiratory systems. The purpose of the present study was to extract nasal NO (nNO) normal range of Chinese adults and the internal influencing factors. The differences in nNO levels between rhinitis and asymptomatic atopic subjects, and the diagnostic value of nNO in allergic rhinitis (AR) were further investigated.MethodsOne thousand adults were recruited from the general public. Participants were divided into different subgroups according to the questionnaires and skin prick tests. In all of these subjects, nNO, fractional exhaled NO (FeNO) and nasal airflow resistance were measured. The normal ranges of nNO and FeNO, the differences between subgroups, and the correlations between NO (nNO and FeNO) and other internal factors were analyzed.ResultsBoth nNO and FeNO levels were significantly higher in AR patients than in healthy and asymptomatic atopic subjects. The nNO levels were significantly lower in asymptomatic atopic subjects than in normal adults. FeNO levels were significantly higher in non-AR patients than in the healthy and asymptomatic atopic adults. The cutoff value of nNO for the diagnosis of AR was 117.5 ppb (sensitivity, 50.9%; specificity, 63.9%). The nNO levels were correlated with FeNO levels, total nasal resistance measured at 75Pa, nasal volume within 0–7 cm from the anterior nares (V0–7cm) and nasal symptom visual analogue scale (VAS) scores, while the FeNO levels were correlated with age, height, weight, body surface area, nasal volume of V0–7cm and the nasal symptom VAS score.ConclusionsThe nNO level can be significantly different between healthy and AR patients and may be significantly correlated with nasal symptoms and nasal patency of rhinitis patients. However, the clinical value of nNO is still in the exploration stage.

Nasal Functions in Three-Dimensional Endoscopic Skull Base Surgery.

Endoscopic transnasal transsphenoidal surgery has become the standard procedure for the majority of skull base diseases, including sellar, parasellar, and clival pathologies. The aim of this study was the objective evaluation of nasal airflow resistances and olfactory function in 3-dimensional (3D) endoscopic transnasal transsphenoidal surgery. One hundred patients who underwent 3D transnasal endoscopic surgery for sellar, parasellar, and clival diseases were enrolled. Active anterior rhinomanometry and Sniffin' Sticks tests were performed before endoscopic surgery and at 3 and 6 months postoperatively. No significant difference about nasal airflow resistance and olfactory function was observed between preoperative and postoperative subjective and objective scores. In the group of patients with sellar and parasellar diseases, a worst nasal respiratory function was seen when crusting was present, and a worst olfactory function was observed in patients with synechiae. Nasal functions returned to previous levels when crusting or synechiae solved. No statistically significant correlation was observed between the evaluated nasal functions and the reconstruction with flaps. The 3D endoscopic transnasal transsphenoidal surgery represents a more and more important tool in skull base surgery. It does not determine nasal respiratory and olfactory alterations after the treatment, without an increase in nasal complaints that could worsen quality of life.

Effects of Craniofacial Morphology on Nasal Respiratory Function and Upper Airway Morphology.

Craniofacial skeletal patterns change after orthognathic surgery. The present study aimed to investigate the effects of different craniofacial patterns on nasal respiratory function and the upper airway. Forty-seven healthy subjects were selected and divided into 3 groups according to their mandibular position. Sixteen were in the skeletal Class I group, 15 were in the skeletal Class II group, and 16 were in the skeletal Class III group. Cone beam computed tomography was performed, and nasal airflow and nasal resistance were measured. Differences in nasal respiratory functions and upper airway were compared among the groups. A correlation analysis was conducted for nasal respiratory function, upper airway, and skeletal patterns. There were significant differences among the 3 groups regarding dominant-side nasal inspiratory capacity (P = 0.001), bilateral nasal inspiratory capacity (P = 0.005), nasal partitioning ratio-inspiration (P = 0.007), and velopharyngeal minimum cross-sectional area (P = 0.029). The values were significantly higher for the skeletal Class III group than the skeletal Class I and II groups. A correlation analysis showed that the nasal partitioning ratio and nasal airway resistance were mostly negatively correlated with SNA, but the upper airway volume and cross-sectional area were positively correlated with SNB and negatively correlated with ANB. The dominant-side nasal expiratory capacity was mainly negatively correlated with the mean velopharyngeal cross-sectional area (r = -0.324, P = 0.026), mean glossopharyngeal cross-sectional area (Glosso-A mean) (r = -0.293, P = 0.046), and mean total airway cross-sectional area (Total-A mean) (r = -0.307, P = 0.036). Craniofacial skeletal morphology may affect nasal respiratory function and the upper airway.

Comparison of nasal obstruction symptom evaluation, peak nasal inspiratory flowmeter, and rhinomanometry in patients with nasal deformities

Nasal obstruction is the most common symptom in daily otolaryngology practice that correlates with quality of life. Nasal obstruction etiology is multifactorial and can result from mucosal or structural factors. Subjective and objective evaluation approaches are a significant challenge in its diagnosis. This study aimed to evaluate correlations among the nasal obstruction and symptom evaluation (NOSE) and peak nasal inspiratory flowmeter (PNIF) scores and active anterior rhinomanometry values for nasal obstruction diagnosis in subjects with nasal deformities including crooked nose, saddle nose, nasal valve incompetence, and deviated septum. Furthermore, the correlation of nasal obstruction with sleep-disordered breathing was evaluated. Data in this cross-sectional analytical study in 52 consecutive subjects with nasal deformities and 10 consecutive normal subjects were analyzed with the bootstrapping method. Mean nasal resistance in normal subjects and those with nasal deformities were 0.172 and 0.173 Pa/cm3/s, respectively, on 75 Pa. The NOSE score was not significantly correlated with the PNIF score or the nasal airflow resistance determined by rhinomanometry. However, there was a significant correlation between PNIF and nasal airflow resistance.

Nasal airflow resistance measured by rhinomanometry in a healthy population of China.

Although nasal congestion is among the most common symptoms in subjects suffering from nasal diseases, relatively few data on normal airflow resistance are available for reference, especially in healthy Chinese subjects. The aim of present study was therefore to objectively measure the normal airflow resistance by rhinomanometry, and calculate mean and standard reference intervals in a cohort of healthy Chinese subjects. A total of 1084 participants were recruited in Huairou region in Beijing, China from November to December 2011. All participants were required to complete 2 questionnaires and undergo nasal examination and objective assessment of nasal resistance by rhinomanometry and acoustic rhinometry. A total of 704 adults completed both questionnaires and nasal examinations; with 505 (71.73%) subjects considered "healthy" based on negative medical history, absence of nasal symptoms, and normal findings by nasal examination. The mean total nasal resistance in the congested nose was 0.168 Pa/cm3 /sec (95% CI, 0.068 to 0.268 Pa/cm3 /sec) at 75 Pa pressure and 0.243 Pa/cm3 /sec (95% CI, 0.112 to 0.374 Pa/cm3 /sec) at 150 Pa pressure. The mean total nasal resistance in males was significantly lower compared to females at 75 Pa and 150 Pa (p < 0.001). The mean unilateral nasal resistance was 0.357 Pa/cm3 /sec (95% CI, 0.034 to 0.680 Pa/cm3 /sec) at 75 Pa and 0.511 Pa/cm3 /sec (95% CI, 0.086 to 0.936 Pa/cm3 /sec) at 150 Pa, with no significant difference between males and females. Application of a vasoconstrictor decreased both total and unilateral nasal resistance, which was significant at 75 Pa. These reference values maybe useful for the Chinese clinicians in evaluating the nasal function and in choosing and assessing efficacy of therapy for nasal congestion in Chinese patients.

Residents' journal review

Residents' journal review

鼻アレルギー診断において鼻呼気一酸化窒素濃度 (nasal FeNO) は鼻腔通気抵抗とは独立した客観的指標である

鼻アレルギー診断において鼻呼気一酸化窒素濃度 (nasal FeNO) は鼻腔通気抵抗とは独立した客観的指標である

Effects on nasal airflow and resistance using two different RME appliances: a randomized controlled trial.

To evaluate and compare the effects of tooth-borne (TB) and tooth-bone-borne (TBB) rapid maxillary expansion (RME) on nasal airflow and resistance. Fifty-four consecutive patients who met the eligibility criteria were recruited from September 2010 to December 2015. Of these 54 subjects, 40 agreed to participate in the part of the study involving evaluation of nasal flow and resistance. The 40 subjects were allocated to either the TB group, mean age 9.7 years (SD 1.5), or the TBB group, mean age 10.2 years (SD 1.4). All subjects performed rhinomanometric registration at baseline (T0), but only 30 attended the post-expansion registration (T1), of whom 16 had been randomized to the TB group and 14 to the TBB group. The study outcomes, nasal airflow and nasal airway resistance, were evaluated with linear regression adjusted for baseline variable of the outcome to compare the study groups with complete cases strategy as well as after multiple imputation (MI). Participants were randomly allocated in blocks of different sizes, using the concealed allocation principle in a 1:1 ratio. The randomization list was computer generated to ensure homogeneity between groups. Blinding was done only for outcome assessor due to clinical limitations. The care providers at the ENT unit who conducted all the rhinomanometry examinations were blinded to which group the patients were allocated to. Complete case analysis showed significantly higher post-expansion nasal airflow values for the TBB group compared with the TB group, mean difference 51.0 cm3/s (P = 0.018). The evaluation after MI showed a similar significant mean difference, 52.7 cm3/s (P = 0.020) in favour of the TBB group when taking into account the missing values from the T1 examination. Even reduction in nasal airway resistance showed similar pattern in favour of the TBB group. Our results represent the short-term effects. A longer follow-up period would have been preferable. The TBB RME induced significantly higher nasal airway flow and lower nasal resistance values than TB RME. It might be wiser to use TBB RME in cases with constricted maxilla and upper airway obstruction. This trial was not registered in any external sites. The protocol was not published before trial commencement.

The effect of closed septorhinoplasty on nasal functions and on external and internal nasal valves: A prospective study.

Because nasal function and shape are so closely intertwined, quantitative assessments can better define their relationship and how they are affected by septorhinoplasty. The aim of this prospective study was to perform an analysis of the nasal airflow resistances and a three-dimensional (3D) evaluation of the soft-tissue changes after closed septorhinoplasty. Before surgery (T0) and 6 months after closed septorhinoplasty (T1), 30 patients underwent symptoms evaluation by means of the Italian version of the Nasal Obstruction Symptom Evaluation scale, endoscopic fiberoptic nasal examination, and visual analog scale for subjective assessment of nasal obstruction. Nasal airflow resistances were investigated with active anterior active rhinomanometry. A 3D laser scanner was used to evaluate facial soft-tissues, with specific nasal points and angles. Subjective nasal obstruction decreased. Anterior active rhinomanometry demonstrated a reduction in total inspiratory and expiratory resistances between T0 and T1 but without statistical significance. The significance was still absent after decongestion, excluding turbinate hypertrophy as a cause of failed objective amelioration of nasal resistance. Facial laser scanning showed statistically significant reduction of the superior nasal width and superior alar angle, and a weak negative correlation between the superior alar angle and nasal resistances. The absence of objective reduction of nasal airflow resistances could be the result of concurrent surgery on nasal septum and nasal valve. In particular, the ameliorating effect on nasal airflow resistances is counterbalanced by the worsening effect of the narrowing of nasal valve.

Quantification of nasal airflow resistance in English bulldogs using computed tomography and computational fluid dynamics.

Stenotic nares, edematous intranasal turbinates, mucosal swelling, and an elongated, thickened soft palate are common sources of airflow resistance for dogs with brachycephalic airway syndrome. Surgery has focused on enlarging the nasal apertures and reducing tissue of the soft palate. However, objective measures of surgical efficacy are lacking. Twenty-one English bulldogs without previous surgery were recruited for this prospective, pilot study. Computed tomography was performed using conscious sedation and without endotracheal intubation using a 128 multidetector computed tomography scanner. Raw multidetector computed tomography data were rendered to create a three-dimensional surface mesh model by automatic segmentation of the air-filled nasal passage from the nares to the caudal soft palate. Three-dimensional surface models were used to construct computational fluid dynamics models of nasal airflow resistance from the nares to the caudal aspect of the soft palate. The computational fluid dynamics models were used to simulate airflow in each dog and airway resistance varied widely with a median 36.46 (Pa/mm)/(l/s) and an interquartile range of 19.84 to 90.74 (Pa/mm)/(/s). In 19/21 dogs, the rostral third of the nasal passage exhibited a larger airflow resistance than the caudal and middle regions of the nasal passage. In addition, computational fluid dynamics data indicated that overall measures of airflow resistance may significantly underestimate the maximum local resistance. We conclude that computational fluid dynamics models derived from nasal multidetector computed tomography can quantify airway resistance in brachycephalic dogs. This methodology represents a novel approach to noninvasively quantify airflow resistance and may have utility for objectively studying effects of surgical interventions in canine brachycephalic airway syndrome.