Acoustic rhinometry in nasal allergen challenge study: which dimensional measures are meaningful?

Efficacy of subcutaneous house dust mite immunotherapy in patients with moderate to severe allergic rhinitis

Aim: To evaluate the efficacy of subcutaneous immunotherapy (SCIT) for the treatment of allergy to house dust mites (HDM) in adults with moderate/severe allergic rhinitis (AR). Methods: Patients sensitized to HDM were randomized to SCIT plus rescue medication (Group A, n = 38) or rescue medication alone (Group B, n = 18), and assessed at baseline and 2, 6 and 12 months. Results: At month 12, Group A presented significant improvement with respect to baseline as evaluated by a visual analogue scale at three concentrations of antigen (0.1, 1 and 10 IR/ml; p < 0.0001). Group A presented significant decreases in symptom scores after 2 months of treatment, which were maintained after 1 year. After 12 months of treatment, Group A showed rescue medication consumption reductions (p < 0.001) and quality of life improvements (p < 0.0001). SCIT elicited a strong immunological response and was well tolerated. Conclusion: SCIT is efficacious for HDM allergy in patients with AR, generating a strong immunological response. Trial Registration Number: EUCTR2009-018155-16-ES (Cochrane Central Register of Controlled Trials).

Evaluation and Management of the Nasal Airway

Nasal airway obstruction is a very common phenomenon that can significantly decrease patients' quality of life. This review article summarizes in an evidence-based fashion the diagnosis and treatment of nasal airway obstruction. The nasal airway may be obstructed at the level of the nasal valve, septum, nasal turbinates, sinonasal mucosa, or nasopharynx. Nasal valve obstruction and septal deviations are usually treated surgically depending on the level of valve obstruction. Isolated turbinate hypertrophy is usually managed medically as part of the treatment of rhinitis, with surgery reserved for cases refractory to medical care. Sinonasal and nasopharyngeal conditions are treated according to the diagnosis.

Comparing different software packages for measuring the oropharynx and minimum cross-sectional area

INTRODUCTION

Several imaging software packages report the ability to measure the oropharynx and minimum cross-sectional area (MCA). This study aimed to compare 4 imaging software packages for measuring the oropharynx volume and MCA.

METHODS

Twenty-eight randomly selected cone-beam computed tomography scans had oropharynx volume and MCA calculated by 2 experienced operators using 4 different programs: Dolphin 3D (version 11.95.8.64; Dolphin Imaging & Management Solutions and Management Solutions, Chatsworth, Calif), InVivo Dental (version 6; Anatomage Inc, San Jose, Calif), OnDemand3D (version 1.0.10.7510; CyberMed, Seoul, South Korea), and ITK-SNAP (version 3.8.0; www.itksnap.org). The measurements were repeated after 2 weeks, and intraclass correlation coefficients were used for the reliability tests. Analysis of variance with the Tukey post-hoc test was used to compare the measurements of oropharynx and MCA with different software programs. Paired t tests were used to compare measurements of both investigators and software programs. Bland-Altman analysis was used to assess interexaminer reliability and agreement between the software programs.

RESULTS

The intraclass correlation coefficients revealed excellent repeatability for the 4 programs for both investigators. Analysis of variance showed no statistically significant difference between programs when comparing the oropharynx and MCA. There were no significant differences in software programs when measuring the airway. Bland-Altman showed the maximum difference as 4.1 cm³ for volume and 35 mm² for MCA. Those differences were below the standard deviations of 5.33 cm³ for volume and 73.75 mm² for MCA.

CONCLUSIONS

The use of 4 different software packages to measure the airway for oropharynx volume and MCA showed high intraoperator and interoperator reliability, no statistically significant difference when using analysis of variance, Tukey post-hoc, paired t tests, and variations within one standard deviation when using Bland-Altman.

Measuring Nasal Obstruction Outcomes

Methods of measuring nasal obstruction outcomes include both objective anatomic and physiologic measurements, as well as subjective patient-reported measures. Anatomic measurements include acoustic rhinometry, imaging studies, and clinician-derived examination findings. Physiologic measures include rhinomanometry, nasal peak inspiratory flow, and computational fluid dynamics. Patient-reported outcome measures (PROMs) are self-reported assessments of disease-specific quality-of-life outcomes. Several studies attempted correlation of these outcome measures; however, few show strong correlation. Expert opinion favors determining successful surgical outcomes using PROMs. This review provides a summary of current nasal obstruction outcome measures.

Efficacy of Odiosoft-Rhino in Assessment of Nasal Obstruction: A Comparative Study with Acoustic Rhinometry after Treatment with Budesonide Nasal Spray in Patients with Perennial Allergic Rhinitis

Background

Odiosoft-Rhino (OR) is new software and equipment that can be used to measure changes in nasal obstruction after intranasal steroid treatment. OR is a promising method for measuring the degree of nasal obstruction. OR can precisely analyze nasal sound spectra in decibels, which is generated by nasal airflow. We studied the reliability of OR for assessing declining nasal obstruction after budesonide nasal spray treatment.

Methods

Sixty-five patients with perennial allergic rhinitis (PAR) were enrolled in the study, and 52 of these patients completed the study. Nasal endoscopic examination, acoustic rhinometry (AR), and OR were performed and symptom scores were compared before and after 3 months of treatment with intranasal budesonide. All of the patients received 7 days of placebo treatment before receiving budesonide.

Results

There was a significant difference in the visual analog scores of nasal obstruction and in the examination scores before and after the treatment for both the right and the left nasal cavities. Pretreatment AR findings and OR findings in the 2000- to 4000-Hz and 4000-to 6000-Hz intervals for both sides were significantly different from the posttreatment measurements (p = 0.000). Both AR and OR can assess the efficacy of budesonide nasal spray treatment for nasal obstruction in patients with PAR.

Conclusion

Both AR and OR are effective for assessing nasal obstruction and monitoring treatment efficacy but, as a simple and noninvasive test, OR can be used with confidence.

How to Assess, Control, and Manage Uncontrolled CRS/Nasal Polyp Patients

PURPOSE OF REVIEW

Chronic rhinosinusitis (CRS) is a multidimensional inflammatory disorder of the nose and paranasal sinuses. We reviewed the recent literature to identify improved methods to assess, control, and manage these difficult to control patients.

RECENT FINDINGS

The role of endotyping in CRS has offered a better understanding of the underlying pathophysiology and allows for more targeted treatment. The understanding of systemic disorders and their role in CRS and the importance of topical treatment reaching the sinuses has also allowed for better control of these patients. We have provided some of the commonly identified causes for uncontrolled CRS and a sensible approach to assessing these patients. We have also focused on common areas of pitfalls in the surgery and choice of patients and the role for ongoing systemic treatment. The future of managing this difficult condition includes endotyping using inflammatory markers and individualizing the treatment to the patient by using specific monoclonal antibodies.

When static meets dynamic: Comparing cone-beam computed tomography and acoustic reflection for upper airway analysis

INTRODUCTION

Upper airway measurement can be important for the diagnosis of breathing disorders. Acoustic reflection (AR) is an accepted tool for studying the airway. Our objective was to investigate the differences between cone-beam computed tomography (CBCT) and AR in calculating airway volumes and areas.

METHODS

Subjects with prescribed CBCT images as part of their records were also asked to have AR performed. A total of 59 subjects (mean age, 15 ± 3.8 years) had their upper airway (5 areas) measured from CBCT images, acoustic rhinometry, and acoustic pharyngometry. Volumes and minimal cross-sectional areas were extracted and compared with software.

RESULTS

Intraclass correlation on 20 randomly selected subjects, remeasured 2 weeks apart, showed high reliability (r >0.77). Means of total nasal volume were significantly different between the 2 methods (P = 0.035), but anterior nasal volume and minimal cross-sectional area showed no differences (P = 0.532 and P = 0.066, respectively). Pharyngeal volume showed significant differences (P = 0.01) with high correlation (r = 0.755), whereas pharyngeal minimal cross-sectional area showed no differences (P = 0.109). The pharyngeal volume difference may not be considered clinically significant, since it is 758 mm³ for measurements showing means of 11,000 ± 4000 mm³.

CONCLUSIONS

CBCT is an accurate method for measuring anterior nasal volume, nasal minimal cross-sectional area, pharyngeal volume, and pharyngeal minimal cross-sectional area.

Role of Predatory Mites in Persistent Nonoccupational Allergic Rhinitis

Mites can sensitize and induce atopic disease in predisposed individuals and are an important deteriorating factor in patients with allergic rhinitis, asthma, and atopic dermatitis. Although Pyroglyphidae mites have been extensively studied, very scarce reports are available on Cheyletidae spp. especially regarding human respiratory pathology. The main objective of the present study is to investigate the clinical role of this predator mite (Cheyletus eruditus) as a respiratory antigen in a selected sensitized human population. Fifty-two adult patients were recruited from the outpatient allergy clinic to assess their eligibility for the study. The thirty-seven subjects with persistent allergic rhinitis (PAR) who fulfilled the ARIA criteria had a positive IgE response confirmed by skin prick test (SPT) to C. eruditus. Only those individuals (37/47) with a positive SPT to C. eruditus showed a positive nasal provocation test (NPT), while 10 patients with nonallergic mild-to-moderate persistent rhinitis, control group, had a negative NPT with C. eruditus. The present paper describes a new role for the predator mite Cheyletus eruditus as a respiratory allergen in a selected subset of patients in a subtropical environment afflicted with persistent nonoccupational allergic rhinitis.

The relationship between nasal resistance to airflow and the airspace minimal cross-sectional area

The relationship between nasal resistance (R) and airspace minimal cross-sectional area (mCSA) remains unclear. After the introduction of acoustic rhinometry, many otolaryngologists believed that mCSA measurements would correlate with subjective perception of nasal airway obstruction (NAO), and thus could provide an objective measure of nasal patency to guide therapy. However, multiple studies reported a low correlation between mCSA and subjective nasal patency, and between mCSA and R. This apparent lack of correlation between nasal form and function has been a long-standing enigma in the field of rhinology. Here we propose that nasal resistance is described by the Bernoulli Obstruction Theory. This theory predicts two flow regimes. For mCSA>Acrit, the constriction is not too severe and there is not a tight coupling between R and mCSA. In contrast, when mCSAAcrit (estimated to be 0.37cm(2)), this theory suggests that airway constrictions are rarely an exclusive contributor to nasal resistance, which may explain the weak correlation between mCSA and subjective nasal patency.

Impacts of fluid dynamics simulation in study of nasal airflow physiology and pathophysiology in realistic human three-dimensional nose models

During the past decades, numerous computational fluid dynamics (CFD) studies, constructed from CT or MRI images, have simulated human nasal models. As compared to rhinomanometry and acoustic rhinometry, which provide quantitative information only of nasal airflow, resistance, and cross sectional areas, CFD enables additional measurements of airflow passing through the nasal cavity that help visualize the physiologic impact of alterations in intranasal structures. Therefore, it becomes possible to quantitatively measure, and visually appreciate, the airflow pattern (laminar or turbulent), velocity, pressure, wall shear stress, particle deposition, and temperature changes at different flow rates, in different parts of the nasal cavity. The effects of both existing anatomical factors, as well as post-operative changes, can be assessed. With recent improvements in CFD technology and computing power, there is a promising future for CFD to become a useful tool in planning, predicting, and evaluating outcomes of nasal surgery. This review discusses the possibilities and potential impacts, as well as technical limitations, of using CFD simulation to better understand nasal airflow physiology.

Subjective, anatomical, and functional nasal evaluation of patients with obstructive sleep apnea syndrome

BACKGROUND

Studies have shown a high occurrence of nasal alterations in patients with obstructive sleep apnea syndrome (OSAS), but no studies have used different methods to evaluate the nose of patients with OSAS. The objective of this study was to evaluate the nose of patients with OSAS, compare them to controls, and correlate the different methods used to evaluate the nose.

METHODS

Forty-seven patients with moderate/severe OSAS and 20 controls who were matched for gender, age, and body mass index were included. Questionnaires regarding sleep and nasal symptoms, physical examination, rhinoscopy, nasofibroscopy, nasal inspiratory peak flow (NIPF), and acoustic rhinometry (AR) measurements were performed.

RESULTS

In the OSAS group, 33 (70.2%) were male, with a mean age of 53.2 ± 9.1 years. In the control group, 13 (65%) were male, with a mean age of 53.7 ± 9.7 years. The OSAS group had a higher score on the nasal symptoms scale (p < 0.01) and a higher frequency of nasal alterations [presence of septal deviation, clinical complaints (p = 0.01) and hypertrophy of the inferior nasal turbinate (p < 0.01)]. The NIPF and AR parameters could not differentiate between the OSAS and control groups. There were no significant correlations among the different methods used to evaluate the nose. Lower NIPF values were capable of predicting higher apnea-hypopnea index scores (p = 0.007).

CONCLUSION

Clinical complaints and nasal alterations as measured by rhinoscopy and nasofibroscopy were associated with the presence of OSAS, which was not the case for the NIPF and AR parameters. The results of different evaluation methods were not correlated with each other.

Nasal cavity size, airway resistance, and subjective sensation after surgically assisted rapid maxillary expansion: a prospective longitudinal study

INTRODUCTION

The aims of this study were to measure changes in nasal minimum cross-sectional area and nasal airway resistance after surgically assisted rapid maxillary expansion and to explore a possible correlation with the subjective sensation of nasal obstruction.

METHODS

Minimum cross-sectional area and nasal airway resistance were measured in 39 consecutive patients treated with surgically assisted rapid maxillary expansion. Subjective nasal obstruction was assessed by a questionnaire at pretreatment and at 3 and 18 months postoperatively.

RESULTS

Subjective nasal obstruction had improved significantly by 3 months postoperatively. Minimum cross-sectional area increased and nasal airway resistance decreased. No correlations were found. In subjects with pretreatment subjective nasal obstruction and initially narrow anterior minimum cross-sectional area, there was a significant correlation between a moderate increase in anterior minimum cross-sectional area and improvement in perceived nasal obstruction. Eighteen months postoperatively, no changes were found from pretreatment values for subjective nasal obstruction, minimal cross-sectional area, or nasal airway resistance, and there were no correlations. Subjects with a sensation of nasal obstruction at treatment start reported a lasting significant subjective improvement.

CONCLUSIONS

The postoperative effects of surgically assisted rapid maxillary expansion did not persist in the long term. No correlation was found between objective and subjective findings. Subjects with pretreatment nasal obstruction, however, reported a lasting sensation of improved nasal function after surgically assisted rapid maxillary expansion.

A computational fluid dynamics model for drug delivery in a nasal cavity with inferior turbinate hypertrophy

BACKGROUND

Intranasal medications are commonly used in treating nasal diseases. However, technical details of the correct usage of these medications for nasal cavity with obstruction are unclear.

METHODS

A three-dimensional model of nasal cavity was constructed from MRI scans of a healthy human subject. Nasal cavities corresponding to healthy, moderate, and severe nasal obstruction (NO) were simulated by enlarging the inferior turbinate geometrically, which was documented by approximately one-third reduction of the minimum cross-sectional area for the moderate and two-thirds for the severe obstruction. The discrete phase model based on steady-state computational fluid dynamics was used to study the gas-particle flow. The results were presented with drug particle (from 7 x 10⁻⁵ to 10⁻⁷ m) deposition distribution along the lateral walls inside these three nasal cavities, and comparisons of the particle ratio escaping from the cavity were also presented and discussed.

RESULTS

Nasal patency is an essential condition that had the most impact on particle deposition of the factors studied; the particle percentage escaping the nasal cavity decreased to less than a half and one-tenth for the moderately and severely blocked noses. Decreasing of flow rate and particle diameter increased the escaping ratio; however, zero escaping percentage was detected with the absence of air flow and the effect was less noticeable when the particle diameter was very small (<10⁻⁶ m). The existence of inspiratory flow and head tilt angle helped to improve the particle escaping ratio for the healthy nose; however, such changes were not significant for the moderately and severely blocked noses.

CONCLUSION

When using an intranasal medication, it is advisable to have a moderate inspiratory air-flow rate and small size particles to improve particle escaping ratio. Various head positions suggested by clinicians do not seem to improve the drug escaping ratio significantly for the nasal cavities with inferior turbinate hypertrophy.

Mometasone Furoate Nasal Spray Provides Early, Continuing Relief of Nasal Congestion and Improves Nasal Patency in Allergic Patients

Background

Patients report nasal congestion as the most bothersome seasonal allergic rhinitis (SAR) symptom. Measurement of this symptom in previous research has largely been based on subjective patient ratings. This study was designed to measure efficacy, onset, and duration of action of the corticosteroid mometasone furoate nasal spray (MFNS) on nasal congestion using an environmental exposure chamber (EEC) and the objective assessment acoustic rhinometry (AcR).

Methods

In a randomized, double-blind, placebo-controlled study, ragweed-sensitive subjects were exposed to ragweed pollen (3500 ± 500 pollen grains/m3) in an EEC (day 1). Subjects rated instantaneous total nasal symptom score (TNSS), including NSS for congestion (NSS-C). Qualifying subjects received MFNS, 200 micrograms, or placebo and rated postdosing symptoms; a subset received MFNS, 200 micrograms, or placebo q.d. for 6 subsequent days, returning to EEC on day 8. Days 1 and 8 assessments included AcR, TNSS, and the Rhinoconjunctivitis Quality of Life Questionnaire developed for use in the EEC (RQOLQ-EEC).

Results

At day 1, hour 6, patients receiving MFNS (n = 155) reported significantly reduced congestion versus placebo (n = 155) per AcR and NSS-C after one dose, showing numerically superior TNSS change from baseline (p = NS). Among the subset who received 6 additional days of treatment, MFNS (n = 78) yielded significantly lower TNSS versus placebo (n = 77) before day 8 EEC entry and throughout 4-hour exposure (p < 0.05), except at 3.5 hours. AcR showed lower congestion with MFNS versus placebo before day 8 EEC exposure and at 24 and 26 hours after final dose (p < 0.05 for all). AcR and NSS-C correlated at multiple time points. Day 8 RQOLQ-EEC between-group scores were significantly different (p = 0.02) for practical problems.

Conclusion

MFNS, 200 micrograms, showed onset of nasal congestion relief at 6 hours and duration of action beyond 24 hours postdosing. Objective and subjective assessments were correlated in subjects with maximal (placebo) or minimal (MFNS treatment) congestion symptoms; both assessments were correlated with improved QOL.

Indicators for the correct usage of intranasal medications: A computational fluid dynamics study

OBJECTIVES/HYPOTHESIS

Intranasal medications are commonly used in treating nasal diseases. However, technical details of their correct administration are unclear.

METHODS

A three-dimensional model of nasal cavity was constructed from the magnetic resonance imaging scans of a healthy human subject. Nasal cavities corresponding to moderate and severe nasal obstruction were derived from the healthy nose by enlarging the inferior turbinate geometrically, which can be documented by approximately one third reduction of the minimum cross-sectional area in the moderate and two thirds in the severe obstruction. The discrete phase model based on computational fluid dynamics was used to study the gas particle flow. The percentage of discrete particles that pass through the minimum cross-sectional area in the nasal valve (NV) region is computed as the percentage of NV penetration rate.

RESULTS

The percentage of NV penetration is 10 to 20 times higher when nasal spray is accompanied by an inspiratory airflow than no flow, which can be as low as 4.69% to 8.81% in the healthy model, and 0% in moderate and severe blockage models. In the presence of inspiratory airflow, there is no significant difference in the percentage of NV penetration (80.97%-82.13%) among different head tilt angles (0 degrees -90 degrees ).

CONCLUSIONS

When using an intranasal medication, it is advisable to have an inspiratory flow to improve drug penetration. Various suggested head positions do not improve drug penetration significantly, even in the presence of uniform quiet breathing. Further studies that consider turbulence and unsteady airflow are needed to investigate the deposition distribution of discrete particles inside various nasal cavities.

Effect of an intra-oral nasal dilation appliance on 3-D nasal airway morphology in adults

To determine the effects of a nasal dilation appliance on 3-D nasopharyngeal airway patency. The sample comprised 187 adults (98 males, 89 females) with a history of sleep-disordered breathing. Acoustic rhinometry readings were taken from all patients before and after the intra-oral placement of a nasal dilation appliance (OASYS). The mean left and right nasopharyngeal airways were reconstructed in 3-D, and the data from the right and left nostrils were subjected to principal components analysis (PCA) and finite-element scaling analysis (FESA). Comparing the pre- and post-treatment 3-D mean, left nasopharyngeal airways using PCA, the first two eigenvalues accounted for 96% of the total shape change, and statistical differences were found (p < 0.01). Similarly, for the right side, significant differences were detected between the mean pre- and post-treatment 3-D nasopharyngeal airways (p < 0.01) using PCA. Using FESA to quantify and localize changes after the placement of the nasal dilation appliance, the 3-D mean, normalized, left nasopharyngeal airway was found to be 14% wider in the anterior nasal valve region and 28% wider in the distal regions, while the 3-D mean, normalized, right nasopharyngeal airway was 13% wider in the anterior nasal valve region and 27% wider further distally. The use of an intra-oral nasal dilation appliance may be useful in the management of nasopharyngeal conditions, such as snoring, upper airway resistance syndrome, sleep-disordered breathing, and obstructive sleep apnea, especially in cases where nasal obstruction is demonstrable.

Changes of airflow pattern in inferior turbinate hypertrophy: a computational fluid dynamics model

BACKGROUND

Nasal obstruction (NO) is a very common symptom, but its effect on nasal physiology has not been fully understood. We performed this study to determine the effect of severity of NO due to inferior turbinate hypertrophy on airflow pattern using the computational fluid dynamics simulations.

METHODS

A three-dimensional nasal cavity model was constructed from the MRI scans of a healthy human subject. Nasal cavities corresponding to healthy, moderate, and severe NO was simulated by enlarging the inferior turbinate geometrically, which can be documented by approximately one-third reduction of the minimum cross-sectional area (1.453 cm(2) in the healthy nose) for the moderate (0.873 cm(2)) and two-thirds (0.527 cm(2)) for the severe obstruction.

RESULTS

Total negative pressure through the nasal cavity increased during the inspiratory phase by almost twofold (-19 Pa) and threefold (-33 Pa) for moderate and severe blockage, respectively, compared with the increase of total negative pressure of -10 Pa in a healthy nose. In cases of moderate and severe blockage, a higher velocity and shear stress was observed at the nasopharynx and dorsal region of the nasal cavity. Moreover, nasal valve function will not exist in severe NO because of the changes of airflow pattern at the original nasal valve location.

CONCLUSION

Impairment of nasal airflow and physiology is evidenced in NO caused by inferior turbinate hypertrophy. Data of this study may help in predicting the aerodynamic effects of surgical correction of the inferior turbinate hypertrophy.

Potential non-immunoglobulin E-mediated food allergies: comparison of open challenge and double-blind placebo-controlled food challenge

OBJECTIVE

Comparison of open food challenge (OFC) with double-blind placebo-controlled food challenge (DBPCFC).

STUDY DESIGN

Prospective sequential randomized challenges.

METHODS

Twenty adults with chronic allergy symptoms and at least 1 positive intradermal food wheal response recorded symptoms during DBPCFC and OFC provoked using organic foods, normal portions, and normal food preparation. Acoustic Rhinometry and biochemical tests were done during DBPCFC.

RESULTS

All patients reacted to at least 1 food and to all challenges with the same food, with multiorgan symptoms in the nose, nervous system, throat, and lung. There was a correlation in the type and severity of symptoms (P = 0.015) for OFC and DBPCFC, and both were significantly (P < 0.01) more severe than placebo. Compared with DBPCFC, OFC sensitivity was 66%, and positive predictive value was 89%.

CONCLUSION

This is the first study showing both concordance of OFC and DBPCFC and also that intradermal tests can identify reactive foods that can be verified by DBPCFC. Because most tests for IgE-mediated food allergy were negative, observed reactions were probably non-IgE mediated.

Objective monitoring of nasal patency and nasal physiology in rhinitis

Nasal obstruction can be monitored objectively by measurement of nasal airflow, as evaluated by nasal peak flow, or as airways resistance/conductance as evaluated by rhinomanometry. Peak flow can be measured during inspiration or expiration. Of these measurements, nasal inspiratory peak flow is the best validated technique for home monitoring in clinical trials. The equipment is portable, relatively inexpensive, and simple to use. One disadvantage, however, is that nasal inspiratory peak flow is influenced by lower airway as well as upper airway function. Rhinomanometry is a more sensitive technique that is specific for nasal measurements. The equipment, however, requires an operator, is more expensive, and is not portable. Thus, it is applicable only for clinic visit measures in clinical trials. Measurements require patient cooperation and coordination, and not all can achieve repeatable results. Thus, this objective measure is best suited to laboratory challenge studies involving smaller numbers of selected volunteers. A nonphysiological measure of nasal patency is acoustic rhinometry. This sonic echo technique measures internal nasal luminal volume and the minimum cross-sectional area. The derivation of these measures from the reflected sound waves requires complex mathematical transformation and makes several theoretical assumptions. Despite this, however, such measures correlate well with the nasal physiological measures, and the nasal volume measures have been shown to relate well to results obtained by imaging techniques such as computed tomography scanning or magnetic resonance imaging. Like rhinomanometry, acoustic rhinometry is not suitable for home monitoring and can be applied only to clinic visit measures or for laboratory nasal challenge monitoring. It has advantages in being easy to use, in requiring little patient cooperation, and in providing repeatable results. In addition to nasal obstruction, allergic rhinitis is recognized to be associated with impaired mucociliary clearance and altered nasal responsiveness. Measures exist for the monitoring of these aspects of nasal dysfunction. Although measures of mucociliary clearance are simple to perform, they have a poor record of reproducibility. Their incorporation into clinical trials is thus questionable, although positive outcomes from therapeutic intervention have been reported. Measures of nasal responsiveness are at present largely confined to research studies investigating disease mechanisms in allergic and nonallergic rhinitis. The techniques are insufficiently standardized to be applied to multicenter clinical trials but could be used in limited-center studies to gain insight into the regulatory effects of different therapeutic modalities.

Comparison of anatomic, physiological, and subjective measures of the nasal airway

BACKGROUND

Studies comparing different categories of nasal measures have reported inconsistent results. We sought to compare validated measures of the nasal airway: anatomic (acoustic rhinometry), physiological (nasal peak inspiratory flow), and subjective experience (Nasal Obstruction Symptom Evaluation Scale and a visual analog scale [VAS]).

METHODS

This prospective cross-sectional study of 290 nonrhinologic patients included upright and supine rhinometry (minimum cross sectional area [MCA] and volume) and flow (mean and maximum) measurements, as well as subjective measures. Associations between measures were evaluated with Spearman correlations and multivariate linear regression, adjusting for age, sex, race, body mass index, and smoking history.

RESULTS

Correlations between objective (rhinometry and flow) and subjective categories of nasal measures ranged from -0.16 to 0.03 (mean correlation, -0.07 +/- 0.05), with 0 significant correlations of 16 tested. Correlations between anatomic (rhinometry) and physiological (flow) categories ranged from 0.04 to 0.15 (mean correlation, 0.10 +/- 0.03), with 0 significant correlations of 16 tested. In contrast, within each category (rhinometry, flow, and subjective), all correlations were significant (13 correlations, all p < 0.001) and ranged from 0.62 to 0.99. Of 16 adjusted associations between objective and subjective measures, 14 were not significant (p > 0.05); only upright and supine MCAs were significantly associated with the VAS (both, p < 0.05).

CONCLUSION

Validated anatomic, physiological, and subjective nasal measures may assess different aspects of the nasal airway and provide complementary information. Future studies should be directed at developing a composite measure including components from all three categories of nasal measurement.

Nasal sound analysis: a new method for evaluating nasal obstruction in allergic rhinitis

OBJECTIVE

Current measurements of nasal obstruction are unreliable and may be improved with the development of new techniques. The effectiveness of odiosoft-rhino (OR) in the evaluation of nasal obstruction was investigated in a blind comparison at a referral center, institutional practice.

PATIENTS

Forty-eight patients with perennial allergic rhinitis and 52 healthy subjects were studied. Nasal endoscopic examination, acoustic rhinometry (AR), and OR were performed and symptom scores compared.

MAIN OUTCOME MEASURE

Assessment of nasal blockage with OR method was the main outcome measure.

RESULTS

Using the OR technique, significant differences were observed between the patient and control groups. OR data correlated with symptom scores and endoscopic examination. However, this was not observed with AR. A 15.5-dB cutoff point for the left side and 14.5 dB cutoff point for the right side at the 2,000 to 4,000 Hz frequency interval resulted in 93.8% sensitivity and 92.3% specificity and 72.9% sensitivity and 80.8% specificity, respectively. A 8.5-dB cutoff point for the left and right sides at the 4,000 to 6,000 Hz frequency interval resulted in 87.5% sensitivity and 80.8% specificity and 70.8% sensitivity and 78.8% specificity, respectively.

CONCLUSION

OR is a simple, noninvasive test for assessing nasal obstruction. The OR technique can detect nasal obstruction with high sensitivity and specificity, and these findings correlate with symptoms and physical examination.

Experimental models for the evaluation of treatment of allergic rhinitis

OBJECTIVE

To review the experimental models used for the clinical evaluation of treatments for allergic rhinitis.

DATA SOURCES

Peer-reviewed clinical studies and review articles were selected from the PubMed database using the following relevant keywords: allergic rhinitis in combination with efficacy, wheal and flare, nasal challenge, park, cat room, or exposure unit. Regulatory guidance documents on allergic rhinitis were also included.

STUDY SELECTION

The authors' knowledge of the field was used to limit references with emphasis on recent randomized and controlled studies. References of historical significance were also included.

RESULTS

Traditional outpatient studies are universally accepted in the evaluation of treatment for allergic rhinitis. Experimental models provide ancillary information on efficacy at different stages of treatment development. Skin histamine and allergen challenge, as well as direct nasal challenge with histamine and allergen, are often used as early steps in assessing drug efficacy. Exposure units, park settings, and cat rooms better approximate real life by drawing on the natural mode of allergen exposure and delivering the sensitizing allergen to allergic individuals in the ambient air. Park studies make use of allergens in the outdoors, whereas cat rooms and exposure units present the sensitizing allergens indoors, with the latter providing consistent predetermined allergen levels. Exposure unit and park studies are acknowledged for the determination of onset of action and are also suited to the measurement of duration of effect and other measures of efficacy. Onset and duration of effect are 2 important pharmacodynamic properties of antihistamines and nasal corticosteroids as determined by the Allergic Rhinitis and Its Impact on Asthma and the European Academy of Allergology and Clinical Immunology workshop group.

CONCLUSIONS

All challenge models serve as important instruments in the evaluation of antiallergic medications and provide additional information to complement traditional studies.

Acoustic rhinometry: should we be using it?

PURPOSE OF THE REVIEW

The purpose of this review is to examine the role of acoustic rhinometry in clinical practice. Although acoustic rhinometry was first described for clinical use in 1989, it is not in common use today. Should we be using it? Yes. I think we should be using it more often. This review provides an update of the new standard for interpretation and expanded clinical uses.

RECENT FINDINGS

The most significant advances in the past year in this area have been the publication of standards for its clinical use. In addition, the repertoire of clinical problems that can be analyzed objectively with acoustic rhinometry has expanded to include turbinoplasty, sleep disorders, more types of cosmetic/reconstructive procedures, sinus surgery, vasomotor rhinitis, maxillofacial expansion procedures, and aspirin and methacholine challenge. (Its ability for pediatric disorders, such as adenoidectomy, has been reaffirmed.) Some case examples are included to demonstrate the utility of acoustic rhinometry for 'mixed' pathology.

SUMMARY

Acoustic rhinometry is a rapid, objective, painless, noninvasive technique for assessing nasal airway obstruction. Recently, standards have been developed that aid its expansion for clinical use. Expanded clinical applications include sleep disorders, cosmetic/reconstructive and maxillofacial disorders, sinus and turbinate procedures, and pediatrics. Acoustic rhinometry should be utilized to improve our ability to practice evidence-based medicine in rhinology.

Mite allergens

There is an increasing awareness of the health implications of mite sensitivity, as it is closely related to asthma. Mite allergy constitutes a complex worldwide problem, with sanitary and economical implications. Not only are mite species present in house dust, producing potent allergens, but other, less studied species are also responsible for significant allergic reactions in occupational settings. In this review, we focus on the growing number of mite species that are implicated in allergic cutaneous and respiratory diseases in humans. Mite allergy is not restricted only to the human "indoor" environment, because numerous reports clearly demonstrate that many species that can induce sensitization and symptoms are encountered in occupational settings. An important component of allergy research is the evaluation of the allergenic cross-reactivity to verify to what extent different mite species have unique, species-specific, or cross-reactive allergens. The results of these investigations have important clinical consequences for the diagnosis and treatment of allergic diseases. Internationally standardized mite extracts are needed to compare sensitization rates around the world and clearly establish risk factors associated with sensitization and asthma. In spite of recent controversial results, a significant reduction in the exposure to mite allergens continues to be an important challenge and one of the main goals in the treatment of mite-induced respiratory symptoms. In many cases, this reduction must be achieved in the workplace as well as in the home environment.