Acoustic rhinometry: do we need a standardized operating procedure?

The role of sensation in subjective and objective evaluation of nasal patency

To assess if sensation of nasal mucosa affect the subjective sensation of nasal patency. This is a case control study with 50 patients, using 2% lignocaine as the active drug and normal saline as the placebo (2 groups of 25 patients each). Each subject had 2 ml of solution sprayed into the test nose. These subjects had no prior nasal symptoms, allergy or surgery. They were evaluated subjectively using Likert scale and objectively by acoustic rhinometry before and after lignocaine or normal saline. The patients in both normal saline and lignocaine groups demonstrated no significant change based upon Likert scale. The study also demonstrated the mean cross sectional area 1 (CSA1), mean cross sectional area 2 (CSA2), with mean Volume 1 and mean Volume 2, these results did not vary significantly in both groups with Acoustic Rhinometry. The analysis thus shows that the use of topical anesthetic spray on nasal mucosa produces no objective effect on nasal resistance or subjective sensation of altered nasal patency. Thus the study concludes that, tactile sensation of nasal mucosa does not play a role in the sensation of nasal obstruction.

Volumes nasais de adultos aferidos por rinometria acústica

A rinometria acústica permite aferir a geometria nasal de forma objetiva e não-invasiva. OBJETIVO: O presente estudo teve por finalidade determinar os volumes de segmentos específicos da cavidade nasal, incluindo a nasofaringe, de adultos sadios por rinometria acústica. Forma de Estudo: Clínico prospectivo. CASUÍSTICA E MÉTODO: Foram analisados 30 voluntários sem evidências de obstrução nasal com idade entre 18 e 30 anos, sendo 14 homens e 16 mulheres. Os volumes foram medidos nos segmentos correspondentes à região da válvula nasal (V1), cornetos (V2) e nasofaringe (V3), antes e após a aplicação tópica de vasoconstritor nasal. RESULTADOS: Os volumes médios aferidos em 60 cavidades, antes da vasoconstrição nasal foram os seguintes: 1,81±0,35cm³ (V1), 4,02±1,41cm³ (V2) e 17,52±4,44cm3 (V3) no grupo masculino, e, 1,58±0,25cm³ (V1), 3,94±1,03cm³ (V2) e 17,80±2,73cm³ (V3) no grupo feminino. As diferenças entre os sexos foram significantes apenas para V1 (p<0,05). Após a vasoconstrição nasal, os volumes de todos os segmentos analisados foram significantemente maiores (p<0,05), sendo as diferenças entre os sexos significantes para V1 e V2. CONCLUSÃO: Os volumes dos três segmentos da cavidade nasal determinados em adultos sem evidências de obstrução nasal podem ser utilizados como valores de referência para outros estudos.

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.

Adult nasal volumes assessed by acoustic rhinometry

Acoustic rhinometry allows an objective and non-invasive assessment of nasal geometry.

AIM

The present study aimed at determining the volumes of specific segments of the nasal cavity in healthy adults including the nasopharynx, using acoustic rhinometry.

STUDY DESIGN

A clinical prospective analysis.

CASES AND METHOD

Thirty volunteers with no evidence of nasal obstruction, aged 18 to 30 years (14 males and 16 females) were analyzed. Volumes were measured at the nasal valve region (V1), the turbinates (V2), and the nasopharynx (V3), before and after application of a topical nasal vasoconstrictor.

RESULTS

The mean volumes measured in 60 cavities before nasal decongestion, were: 1.81+/-0.35 cm(3) (V1), 4.02+/-1.41 cm(3) (V2), and 17.52+/-4.44 cm(3) (V3) for males, and 1.58+/-0.25 cm(3) (V1), 3.94+/-1.03 cm(3) (V2), and 17.80+/-2.73 cm(3) (V3) for females. Gender differences were only significant in V1 (p<0.05). After nasal decongestion, the volumes of all the analyzed segments were significantly larger (p<0.05), and the gender differences were significant for V1 and V2.

CONCLUSION

Volumes of the three segments in adults with no evidence of nasal obstruction may be used as reference values for other studies.

Acoustic Rhinometry and Paranasal Sinuses: A Systematic Study in Models, Anatomic Specimens, and In Vivo

OBJECTIVE/HYPOTHESIS

Acoustic rhinometry (AR) evaluates the cross-sectional areas (CSA) of the nasal cavity through acoustic reflections. The aim of this study was to test whether the paranasal sinuses are a cause for the measurement of increased CSA in the posterior cavum of the nose.

STUDY DESIGN

: Experimental study to evaluate the influence of paranasal sinus volume on AR measurements in two anatomic nose models, an anatomic specimen, and seven individuals.

METHODS

The paranasal sinus volume was systematically reduced by filling of the maxillary sinus with saline. The paranasal sinus ostia were enlarged in the models and the anatomic specimen by infundibulotomy and supraturbinal fenestration, with AR repeated thereafter.

RESULTS

No modification of the posterior area-distance curve was found in the models, the specimen, and the individuals after changing the volume of the maxillary sinus with unmodified anatomy of the paranasal sinus ostia. The apparent CSA measured in the posterior cavum after infundibulotomy and supraturbinate fenestration in the models and the specimen increased with the volume of the paranasal sinuses.

CONCLUSION

Regular anatomy provided, AR reveals reproducible measurements that correspond with the actual CSA up to the ostia of the paranasal sinuses. Untypical large openings to the paranasal sinuses (e.g., after paranasal sinus surgery) appear to contribute to the inaccuracy of AR by overlapping paranasal sinus CSA with the posterior part of the area distance curve.

Subclinical aspirin sensitivity in subjects with nasal polyposis

It is unclear whether subclinical airway responses to aspirin occur in subjects with nasal polyps and/or asthma without overt sensitivity. Sixty-three subjects without known aspirin sensitivity (13 controls, 17 nasal polyps alone, 15 nasal polyps and asthma and 18 asthma alone) inhaled increasing concentrations of nebulized lysine aspirin. Forced expiratory volume in 1 s (FEV1), symptoms and other potential markers of an airway response were measured. Four subjects (one polyps alone, one asthma alone, two with both) had a positive response to lysine aspirin predefined as symptoms plus a >10% fall in FEV1 from baseline. However, there was no evidence of a general subclinical response in any of the subject groups: mean (95% CI) change in FEV1; control 0.07 (-0.02,0.16) L, nasal polyps alone -0.05 (-0.16,0.05) L, nasal polyps with asthma -0.03 (-0.10,0.04) L, asthma alone -0.03 (-0.09,0.03) L. We concluded that in the absence of a suggestive clinical history, only a small proportion of patients with nasal polyposis are likely to be sensitive to aspirin. There is no evidence of general subclinical sensitivity to aspirin in subjects with nasal polyps and no relevant history.

Test-retest validity of acoustic pharyngometry measurements

BACKGROUND

Acoustic reflectometry is a relatively new technique that quantifies upper airway obstruction. The oropharyngeal airway is geometrically complex and variable; therefore establishing a standard operating protocol and understanding the possible sources of artifacts are of great importance in obtaining reliable results. This work aims at assessing the repeatability of pharyngeal cross-sectional area measurements obtained from normal and snoring individuals.

METHODS

Twenty adult normal volunteers (16 men and 4 women; mean age, 35.9 years) and 10 adult snorers (9 men and 1 woman; mean age, 36.4 years) were examined by acoustic reflectometry following the developed standard operating protocol.

RESULTS

Measurements of pharyngeal cross-sectional area are analyzed in 2 groups. In normal subjects where mean pharyngeal cross-sectional area in the first session was 3.187 cm(2), in the second session (same-day test-retest), the mean pharyngeal cross-sectional area was 3.239 cm(2), and in the third session 7 to 10 days later (day-to-day test-retest), it was 3.245 cm(2) (P > 0.4). In a second group of snoring patients where mean pharyngeal cross-sectional area in the first session was 2.244 cm(2), in the second session, mean pharyngeal cross-sectional area was 2.237 cm(2), and mean pharyngeal cross-sectional area in the third session (7 to 10 days later) was 2.238 cm(2) (P > 0.9).

CONCLUSIONS

These results show that repeatability of acoustic reflection results can be achieved following the standard operating protocol.

SIGNIFICANCE

The study results add to the reliability of this technique in assessing the pharyngeal airway in patients with snoring and obstructive sleep apnea.

Applicability of a set of diagnostic tests in indoor air health research

Following recommendations from literature, 22 diagnostic tests for the most frequent complaints of indoor air health problems were selected and assessed for their applicability in epidemiological studies. The tests were applied seven times during one year to 40 volunteers who to all appearances were not affected by indoor air health problems. Most psychophysical tests (e.g., Continuous Performance Test) turned out to be suitable, but physiological tests were either heavily disturbed by technical problems (e.g., portable electrogastrography), or biased by application techniques (e.g., acoustic rhinometry), or were simply too time-consuming (e.g., PC-based voice analysis). Hence, as standardized measurements and quantitative diagnostic tests in epidemiological indoor air health research may contribute to a better understanding of cause-effect relationships and yield new approaches for preventive and therapeutic strategies, more research is urgently needed to develop and evaluate suitable physiological tests and functional measurements.

Nasal function in self-reported chemically intolerant individuals

Nasal function has not yet been investigated under controlled exposures in individuals with self-reported Multiple Chemical Sensitivity (sMCS). Therefore, anterior rhinomanometry and acoustic rhinometry were applied in 12 individuals with sMCS, and 12 age-matched controls. The sMCS individuals and controls were selected on the basis of a standardized questionnaire. Controlled 4-hr exposures to ethylbenzene and 2-butanone were performed during 4 sessions. Exposures were close to the current German threshold limit values, and they approximated odor thresholds. Subjects with sMCS had a significant decrease in the flow value in anterior rhinomanometry, independent of substance and doses, compared with controls. This result suggests somatic reactions to the exposure. The result must be confirmed in additional studies, and pathophysiological examinations must be performed. For these investigations, anterior rhinomanometry was usable, but acoustic rhinometry can be recommended only after sufficient standardization has occurred. Furthermore, biochemical parameters of nasal mucosa must be considered.

Intra- and Intersession Reliability of Acoustic Rhinometry in Measuring Nasal Cross-sectional Area

We evaluated the intrasession and intersession reliability of acoustic rhinometry in measuring nasal cross-sectional areas in 10 subjects. Subjects were measured under three conditions: with a Breathe Right nasal strip in place, with a sham strip in place, and with no strip in place. Two sets of three measurements were taken 1 week apart. The intrasession reliability both with and without the Breathe Right strip was very good (intraclass correlation coefficient [ICC] [2,1]: 0.97 and 0.98, respectively). The intersession reliability with and without the Breathe Right strip was not nearly as good (ICC [2,1]: 0.62 and 0.67). The Breathe Right strip increased the mean nasal cross-sectional area by 0.10 cm2 (17.4%). We conclude that acoustic rhinometry is a reliable way to measure nasal cross-sectional area during a single session of multiple tests, but it is not as reliable across sessions. We also determined that the Breathe Right nasal strip significantly increases nasal cross-sectional area.

Acoustic rhinometry assessment of the nasal cycle in neonates

In this study the nasal cycle in newborns was assessed using acoustic rhinometry with miniprobe (RHIN 2100). Enrolled in the study were 67 newborns aged 2 to 4 days. Each subject was assessed for 3 h, examinations taking place every 30 min. At least six measurements, three from each nostril, were taken at each examination. The miniprobe RHIN 2100 (SR Electronics ApS) was used for evaluation of nasal geometry. The minimal cross-sectional area (MCA) and the total volume of the anterior 45 mm (VOL45) were calculated and used for statistical analysis. The mean volume of MCA and VOL45 in the examined group of children was 0.08 cm3 and 1.19 cm3 respectively. Nasal cycle was assessed by constructing the plots of acoustic rhinometry parameters MCA or VOL45 for time and statistically using Pearson's correlation coefficients. Most of the examined infants (70-85%) showed no significant fluctuations in nasal patency.

Value of acoustic rhinometry in environmental medicine

It is a weak point of environmental medicine that health disturbances, e.g. functional affections of the upper respiratory tract, cannot be objectively judged by physicians resp. researchers. In this study, the validity of acoustic rhinometry, a method giving information on cross-sectional areas of the upper airways by means of ultrasound probing, was tested in 40 volunteers seven times during one year. Furthermore, using a simplified model of the nose the accuracy of this method to measure the minimal cross-sectional area (MCA) in the nose was tested. The measurements were extremely confounded by the mode of connection to the nose (e.g. selected adapter, direction of application) and by the MCA in the nasal cavity. Statistical analyses showed a good reproducibility of measurements repeated within minutes, but suggested an intrapersonal variability over the analyzed examination phases due to apparatus independent factors. However, this variability could not be explained by influencing and confounding factors obtained by questionnaire, medical history, and physical examination. The test model showed little to great errors (1.5 to 568.5%) between the actual and the measured MCA, depending on the diameter. It is concluded that the method of acoustic rhinometry has to be standardized before it's value for environmental medicine can finally be judged. Further studies are necessary that should focus among others on factors influencing the variability of MCA and the effect of MCA on the measurement of the area behind the MCA. So far, the use of acoustic rhinometry for the evaluation of nasal function cannot be recommended.

The subjective effects of smoking on nasal symptoms

One hundred and forty-four volunteers completed a validated questionnaire, to investigate the association between smoking, non-smoking and passive smoking status, and the degree of a range of 10 common nasal symptoms. Logistic regression showed that smokers were four times and passive smokers six times more likely to report hyposmia compared to non-smokers. No significant differences were found between the three groups for any of the other nine symptoms.

Reproducibility of acoustic rhinometry and rhinomanometry in normal subjects

The reproducibility of nasal patency measurements was assessed by acoustic rhinometry and active rhinomanometry using previously described Toronto methodologies. Six subjects with normal upper airways were tested with both procedures on six separate occasions within a 2-month period. Topical decongestant was applied to minimize the effects of mucosal variation on the nasal airway. The mean coefficients of variation (mean +/- s.d; %) over time of the measurements were 8.1 +/- 4.1 and 9.7 +/- 5.2 for minimal unilateral cross-sectional area and 4.8 +/- 1.8 and 5.5 +/- 3.5 for nasal volume (0-5 cm) of the right and left sides, respectively. For active rhinomanometry, the mean coefficients of variation (mean +/- s.d.; %) over time of the measurements were 15.9 +/- 7.3, 12.9 +/- 4.6, and 8.5 +/- 2.8 for right, left and combined nasal airflow resistance. The intraclass correlation coefficient was 0.76, 0.70, and 0.96 for right, left, and combined nasal resistance, 0.91 and 0.87 for right and left minimal cross sectional area, and 0.86 and 0.69 for right and left nasal volumes, respectively, also confirming a high level of reproducibility for both methods. In conclusion, performed by an experienced operator under controlled circumstances, the reproducibility of both methods of nasal patency assessment compared favorably with many widely accepted clinical tests.

An endoscopic photographic comparison of nasal drug delivery by aqueous spray

There is general agreement that the delivery of topical nasal medication by sprays is suboptimal. This study examines the distribution of spray to the anterior end of the middle turbinate as a guide to the distribution to the middle meatus by means of an endoscopic photographic comparison using dyed aqueous nasal spray. The technique was found to be reproducible. The effect of vigorously inhaling whilst spraying was studied by means of a randomized crossover trial and was found to have no significant effect. This technique could be used in conjunction with other means of assessing intranasal distribution when assessing improved topical nasal drug delivery systems.