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: the bat principle of the nose]

All cross-sectional areas of the upper airway can be measured by an acoustic signal using the acoustic reflection technique, or acoustic rhinometry. The plane of the cross-sectional areas measured was determined in nasal models. The isotemporal layers were found to be nearly parallel to the nasal valve. The acoustically measured cross-sectional areas correlated with the cross-sectional areas of cuts from nasal models. After digitizing these cuts, a CAD software calculates cross-sectional areas in all orientations and at all distances. The difference between the measured and calculated cross-sectional areas is up to 3% in the nasal cavity and up to 17% in the nasopharynx. The hypothesis that the cross-sectional areas measured lie nearly parallel to the nasal valve was confirmed. The normal rhinometric curve shows the minimal cross-sectional area (I-notch) to lie at the nasal isthmus. The second narrowest segment of the nasal cavity lies at the head of the inferior concha and septal concha (C-notch). Characteristic examples of patients with turbinate hypertrophy, choanal atresia, enlarged adenoids, and septal deviations are presented. Acoustic rhinometric curves can only be interpreted in combination with the rhinoscopic findings because different pathological conditions can produce similar curves. Recording of reliable and reproducible data by acoustic rhinometry demands that the connection between the rhinometer and the nose does not distort the valve area. When we used two different nose pieces (1.2 and 1.5 cm outer diameter) the cross-sectional areas in the anterior third of the nose of only 28% of the patients was measured correctly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mechanical nasal alar dilators

Most studies on nasal dilators have used Breathe Right or Nozovent. Both devices dilate the nasal valves, reduce nasal resistance, and improve nasal airflow. The use of dilators improves airflow most on inspiration, as the valve is stabilised and prevented from collapse. The response varies greatly between individuals, and can be impressive. The effect of nasal dilators may be lower in non-Caucasians. During exercise, nasal dilators delay the onset of oronasal breathing, and can have only small effects on performance thereafter. Nozovent and Breathe Right can reduce snoring, and improve otherwise obstructed breathing during sleep in selected patients. It is a challenge to find those patients, and one way could be to perform polysomnography with and without nasal dilator.     

Nasal dilator strips increase maximum inspiratory flow via nasal wall stabilization.

OBJECTIVE: Inspiratory flow limitation associated with collapse of the nasal vestibular walls is a feature of nasal breathing at high ventilatory levels. We examined whether an external nasal dilator strip (ENDS) device (Breathe Right, CNS Inc., Chanhassen, MN) influences maximum inspiratory and expiratory flow rates. STUDY DESIGN: Prospective, randomized. METHODS: We studied 20 Caucasian subjects (13 female, 7 male; age range, 16-49 y) performing maximum-effort nasal flow-volume loop studies with (ENDS) and without ENDS (control) and following topical nasal decongestant (oxymetazoline hydrochloride, 0.2 mg per nostril). RESULTS: ENDS increased peak inspiratory flow from 2.55+/-0.24 L/s (mean+/-standard error [SE]) to 2.86+/-0.25 L/s and forced inspiratory flow at 50% of vital capacity from 2.23+/-0.24 L/s to 2.53+/-0.24 L/s (both, P<.0001), but had no effect on maximum expiratory flows. Nasal decongestant increased the forced expiratory volume in 1 second from 3.39+/-0.22 L/s to 3.59+/-0.22 L/s and the average forced expiratory flow over 25% to 75% of vital capacity from 3.31+/-0.31 L/s to 3.61+/-0.28 L/s (both, P< or = .008), but had no effect on maximum inspiratory flows. The combination of decongestant and ENDS increased both inspiratory and expiratory maximum flows. CONCLUSION: Since ENDS selectively increases maximum nasal inspiratory flow rates, we conclude that ENDS increases inspiratory nasal patency during maximum inspiratory efforts through the nose by supporting the lateral nasal vestibular walls and making them more resistant to collapse.     

Physiologic Effects of an External Nasal Dilator

An external nasal dilator (Breathe Right, CNS, Inc., Bloomington, MN) has become popular with athletes. The dilator is an adhesive band with a central elastic strip. When applied across the nasal valve, the device theoretically increases nasal valve area. We used acoustic rhinometry (Hood Laboratories, Pembroke, MA) to measure the cross-sectional area at the nasal valve with and without the device in 53 athletes. Thirty athletes were exercised on a cycle ergometer with and without the device while measuring physiologic parameters, including oxygen consumption (VO₂), heart rate, and respiratory rate. The study was conducted in a randomized, double-blind, placebo-controlled manner. At rest, the external nasal dilator was found to significantly increase nasal valve area in all demographic groups measured. The device was also found to significantly decrease submaximal exercise perceived exertion, heart rate, ventilation, and VO₂ when compared with placebo.     

A functional anatomic study of the relationship of the nasal cartilages and muscles to the nasal valve area

The functioning of the nasal valve area is largely determined by the stability and the mobility of the lateral nasal wall. To gain insight into the kinematics of the lateral nasal wall, we studied the functional anatomy of the nasal muscles and the intercartilaginous and osseous-cartilaginous junctions. We performed gross and microscopic nasal dissection and serial sectioning in 15 human cadaveric noses. In addition, two noses were used for three-dimensional reconstruction of the nasal cartilages. We conclude that the lateral nasal wall can be seen as made up of three parts. At the level of the osseous-cartilaginous chain of bone, lateral nasal cartilage, and lateral crus, the lateral nasal wall is relatively stable, limited mobility being allowed by translation and rotation in the intercartilaginous joint and a coupled distortion of the cartilages. At the level of the hinge area the lateral nasal wall is supported by one or more accessory cartilages, embedded in soft tissue, and therefore much more compliant. The alar part of the nasalis muscle, which originates from the maxilla and inserts on these cartilages, may dilate the valve area by drawing this hinge area laterally. The third and most compliant part of the lateral nasal wall is the part that is not supported by cartilage, the ala. The dilatator naris muscle largely occupies the ala and is attached to the lateral crus; it opens the vestibule and nostril. The third nasal muscle that influences the lateral nasal wall is the transverse part of the nasalis muscle. It overlies the nose but is not attached to it. This muscle stabilizes the lateral nasal wall, in particular, the lateral nasal cartilage, the intercartilaginous junction, and the hinge area, by moving the nasal skin.     

The use of acoustic rhinometry in predicting outcomes after sinonasal surgery

Today's healthcare environment demands objective assessment of surgical outcomes. The recent otolaryngologic literature has established acoustic rhinometry (AR) as a valid instrument to objectively document nasal patency. The purpose of this article is to evaluate the utility of AR in predicting outcomes after sinonasal surgery. All patients scheduled for sinonasal surgery at the Tulane University and University of Mainz Departments of Otolaryngology between 10/1/98 and 12/15/98 were enrolled. All subjects underwent AR and completed a sinonasal outcome survey (SNOT-20) one day before and two months after their surgical procedure. Thirty-one patients were enrolled. The SNOT-20 raw scores improved from a mean of 7.93 (+/- 3.78) preoperatively to 3.35 (+/- 2.33) postoperatively (p < 0.05). The I-notch revealed no significant change postoperatively. The mean bilateral predecongestion C-notch increased from 1.257 cm2 to 1.451 cm2 (p < 0.05). Patients with a bilateral C-notch > 1 cm2 were 1.96 times more likely to have a five-point improvement in the SNOT-20 raw score (95% CI = 1.17, 3.27). The mean value of the C-notch is significantly altered (increased) as a result of sinonasal surgery. Patients with a preoperative cross-sectional area < 1 cm2 are less likely to report large postoperative subjective improvement. These results indicate that patients with poor geometry at the area of the C-notch do not fare as well surgically as those with better preoperative measurements.     

Opening the nasal valve with external dilators reduces congestive symptoms in normal subjects

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.     

The distribution of thermoreceptors within the nasal cavity

The distribution of thermoreceptors within the nasal vestibule (that part of the nasal cavities lined with skin) and nasal cavum (that part of the nasal cavities lined with respiratory epithelium) was studied in 20 subjects. The distribution was compared with that of the malar skin adjacent to the nose. No thermoreceptors were located in the nasal cavum but the nasal vestibule contained a dense distribution of cold receptors (3.5 receptors per cm2) and warm receptors (3.2 receptors per cm2). The corresponding density of receptors in the malar skin was 2.7 receptors per cm2 and 2.6 receptors per cm2. The difference in distribution density between the nasal vestibule and the malar skin was significant (P less than 0.05). The implications of these findings are discussed.     

Unilateral and bilateral nasal resistances

Plethysmographic rhinomanometric resistance measurements of combined and separate nasal cavities were made at a transnasal differential pressure of 100 Pa. The coefficients of variation over time of 40 consecutive total resistance values obtained at 1 min intervals from untreated noses of five healthy subjects averaged 11.0% measured directly and 11.8% calculated by application of Ohm's Law for parallel resistors. Measurements at 5 min intervals between sides increased variation of calculated total resistances markedly. The coefficients decreased to 4.7% and 5.1% respectively when the noses were decongested and by contrast with untreated noses these resistances varied independently from each other. Facial masking increased the coefficient of variation of resistance in the decongested nose (p less than 0.001) to as much as 11.0% and the magnitude of averaged resistances was moderately increased also (p less than 0.035). Measured values plotted against calculated values for total nasal resistance of 45 consecutive patients produced a regression differing insignificantly (p = 0.94) from the line of identity in the decongested nose but diverging from it (intercept 0.03 Pa/cm3/sec and slope 0.83, p less than 0.03) when the nose was untreated. Resistive variations associated with mucovascular instability and with use of a face-mask contribute substantially to differences between the results of anterior and posterior rhinomanometric assessments of total nasal resistance.     

Septal cartilage graft for nasal valve incompetence associated with deviated septum

BACKGROUND: The nasal valve is one of the major factors contributing to nasal airflow obstruction. Physiologically, the nasal valve offers the greatest resistance to nasal airflow and generally functions as an inflow device controlling nasal airflow and resistance. Many patients who have complaints of breathing impairment are affected by alterations of the nasal septum, the turbinates, the columellar base, the vestibule floor, or the lateral wall of the nose but may have associated incompetence of the nasal valve, which is too often undervalued by nasal surgeons. The aim of this study was to propose a relatively easy surgical technique to correct most nasal valve impairments associated with nasal septum deviation whether or not there also is inferior turbinate hypertrophy. METHODS: Between May 2004 and September 2006, 68 patients (26 women and 42 men; mean age, 37 years; range, 16-71 years) underwent primary or secondary functional nasal surgery, because of a nasal respiratory obstruction caused by nasal septal deviation eventually associated with inferior turbinates hypertrophy, and also demonstrated nasal valvular incompetence. A septal cartilage graft was used to correct the valvular incompetence. RESULTS: On postoperative visits almost all of the patients (with one exception) showed a remarkable improvement in the stiffening of the valvular region and had only minimal depression of the nostril during deep inspiration. CONCLUSION: This study indicated that septal grafts were useful in the surgical management of nasal respiratory impairment because of nasal valve incompetence, where there had been flaccid mobile collapse of the ala of the nose associated with septal alterations.     

The relationship between nasal index and nasal airway resistance, and response to a topical decongestant

The differences in the shape and size of the nose have been proposed to be an adaptation to climate with broad noses (platyrrhine) evolving in a warm humid environment where there was little need for air conditioning and narrow noses (leptorrhine) evolving in colder climates where the air needed more warming. The main aim of this research was to determine if there was any relationship between the shape of the nose as expressed in terms of nasal height and width (nasal index) and total nasal airway resistance (NAR), as one would predict that the narrower leptorrhine noses would have a greater resistance to air flow than the broader platyrrhine noses. It was also proposed that the narrow leptorrhine nose would have better developed vascular tissue than the broad platyrrhine nose in order to condition cold air, and would exhibit a greater response to nasal decongestion. No correlation was found between nasal index and NAR (r = -0.09) and similarly no correlation was found between nasal index and response to a topical nasal decongestant (r = 0.02). The absence of any physiological differences between the different nose types may be due to acclimatisation of participants to the area of recruitment.     

Acoustic rhinometry of the oriental nose

Most studies have established normal values for acoustic rhinometric (AR) analysis of the nasal passage based on a primarily caucasian or mixed population. Because consistent anatomic differences do occur in anthropomorphic measurements of the nose of different races, AR analysis was performed on an Asian population to determine whether differences occurred in the minimum cross-sectional area (MCA). AR with expanded testing was performed on a non-Asian control group and an Asian study population containing 28 subjects, with 56 half-cavities (F: 20; M: 8; age range 21-58), including 16 Vietnamese, 8 Korean, 4 Thai, all of whom had physically typical mesorrhine noses. In the Asian population, the mean MCA of each half-cavity was 0.56 +/- 0.16 cm2, and 39.3% of subjects had significant asymmetry between their two half-cavities. The mean MCA increased to 0.67 +/- 0.12 cm2 after the placement of a Breathe Right Strip Dilator (BRSD) over the nasal bridge, which was a significant increase in 32% of subjects, and to 0.68 +/- 0.14 cm2 after the application of 1% Neosinephrine, a significant increase in 34% of those tested compared to the resting state. The combination of BRSD and Neosinephrine produced an MCA of 0.72 +/- 0.11 cm2, which was a statistically significant increase in 24 half-cavities (43%). Compared to our non-Asian population, the Asian group had fewer subjects with significant asymmetry (39% versus 59%) before expanded testing and fewer responders to BRSD (48% versus 79%).     

Breathe Right nasal strips and the respiratory disturbance index in sleep related breathing disorders

This investigation assesses the effects of Breathe Right nasal strips on the respiratory disturbance index (RDI) measured by polysomnography in patients suffering from obstructive sleep apnea and snoring. The positive effect of these strips on nasal ventilation was shown in earlier studies. Twenty-six patients with an RDI higher than 10 in an initial measurement underwent a second preoperative polysomnography with Breathe Right nasal strips in place. Nineteen of these 26 patients showed reduction of RDI during the second night of polysomnography using the nasal strips, indicating that nasal obstruction seems to be a predominant factor in the etiology of snoring and apnea in these individuals. Demographic data, medical history, rhinoscopy, clinical assessment of pharyngeal obstruction (Mueller's maneuver), as well as anterior rhinomanometry and acoustic rhinometry were used to identify typical findings correlating with a positive effect of the Breathe Right nasal strips on the RDI: 1. Hyperplasia or hypertrophy of the lower turbinates, septal deviation, and/or allergic rhinitis. 2. None or only minor pharyngeal obstruction. 3. Age less than 55 years. If a positive effect is seen during polysomnography with the strips in place, patients will most likely profit from an improvement of nasal ventilation. This may help to target more effectively septal or turbinate surgery if applicable. In other cases, if a significant RDI reduction is obtained by the use of the nasal strips, they could also offer a noninvasive modality of treatment, especially since the high degree of co-morbidity in this group of patients can sometimes make a surgical approach less favorable.     

The site and function of the nasal valve

Previous observers have suggested that the main site of respiratory airflow resistance is localized to the vestibular region of the nose. This resistive segment of the airway was investigated using a “head-out” body plethysmograph in subjects with anatomically normal noses (a) untreated, (b) congested and (c) decongested. In all three conditions, 2/3 of the total nasal airflow resistance was found within the bony cavum in the vicinity of the pyriform aperture and about 1/3, in the cartilaginous vestibule. As might be expected, caval resistance changed proportionately with the degree of mucosal congestion; but, more surprisingly, vestibular resistance changed similarly. This was due in part to the observed forward expansion of the anterior ends of the inferior turbinates with congestion. EMG recordings in subjects breathing through both nostrils demonstrated a gradation of inspiratory alar dilator muscle activity with increased minute ventilation and with mucosal congestion, and there was no evidence of inspiratory alar collapse. But with elevated ventilation through one nostril only, or when the alar muscles were paralyzed by lidocaine block of the VIIth nerve, alar collapse occurred. These findings are of importance in the management of the congested but anatomically normal nose and in surgery of the nasal tip.     

鼻内镜辅助下外鼻整形同期鼻中隔偏曲矫正术

目的 总结33例外鼻畸形伴鼻中隔偏曲患者施行内镜辅助下鼻整形术同期鼻中隔偏曲矫正术的临床资料,分析手术方法和术后疗效。 方法 患者均在全麻下经鼻小柱鼻前庭做切口,骨膜下暴露鼻骨及上颌骨额突,在内镜辅助下进行截骨整复并矫正鼻中隔,酌情将取出的自体鼻中隔骨质及软骨条修整后填于塌陷处或支撑鼻小柱、修整鼻尖等。术中可同期行下鼻甲成形术。随访3个月以上。 结果 全部患者术后均取得满意的整形效果,鼻腔通气良好。 结论 鼻内镜辅助下鼻整形术同期行鼻中隔偏曲矫正术效果好,无排异反应,不仅能改善鼻部外观,而且能改善鼻腔通气效果。     

Evaluation of nasal cavity by acoustic rhinometry in Chinese, Malay and Indian ethnic groups.

Acoustic rhinometry (AR) evaluates the geometry of the nasal cavity by measuring the minimum cross-sectional area (MCA) and nasal volume (V) by means of acoustic reflection. Understanding the normal and pathologic conditions of the internal nasal cavity using AR is important in the diagnosis of structural abnormalities in patients. The aim of this study was to investigate the normal range of AR parameters in healthy volunteers from three ethnic groups in Singapore: Chinese, Malay and Indian. We also attempted to evaluate the role of these measurements in the documentation of structural abnormalities in the nose. A total of 189 Singaporeans, aged > or = 18 years, were recruited from a nationwide survey study. They comprised 83 Chinese, 35 Malays and 71 Indians. Eighty-nine subjects had a rhinoscopically normal nose (Group 1), 77 had significant septal deviation (Group 2) and 23 had inferior turbinate hypertrophy (Group 3). AR was performed to measure the MCA at the anterior 1-5 cm from the nostril and the volume (V) between points at the nostril and 5 cm into the nose. A mean MCA (mMCA; equal to (L + R)/2) and a total volume (Vt; equal to L + R) were then calculated for each subject, where L and R refer to the measurements made for the left and right nostrils, respectively. The results showed that there was no statistically significant difference in mMCA (p = 0.80) and Vt (p = 0.60) among the three ethnic subgroups of Group 1. Statistically significant differences were found only between Groups 1 and 3 (p < 0.001 for both mMCA and Vt) and between Groups 2 and 3 (p = 0.001 for mMCA and p = 0.013 for Vt). Although there was no significant difference between Groups 1 and 2, significant differences in MCA (p = 0.001) and V (p = 0.040) were found between the narrower sides (smaller volume) and the wider sides in Group 2, indicating volume compensation between the nasal cavities. In conclusion, our study demonstrates that there is no significant difference in the normal range of AR measurements among Chinese, Malay and Indian ethnic groups. AR is able to determine the structural abnormality of the internal nasal cavity caused by septal deviation and inferior turbinate hypertrophy.     

Pleomorphic adenoma of nasal septum

The pleomorphic adenoma is the most common benign tumour of the major and minor salivary glands. We report a 40-year-old female patient, who presented with progressive swelling and deformity of the left side of her nose for last 2 years. On a lateral rhinotomy a mass (4 cm X3 cm in size) was found to be arising from the cartilaginous part of the nasal septum. The mass was emicleated from its capsule and the walls excised. The histopathological examination revealed it to be pleomorphic adenoma.     

Temperature profile in the nasal cavity

OBJECTIVES/HYPOTHESIS: Inspired air is heated and moistened as it passes the nasal cavity. The temperature increase should be similar to a heated tube model, depending on the airflow. STUDY DESIGN: Intranasal temperature values of 50 volunteers were measured after inspiration at different locations: nasal vestibule, nasal valve area, anterior to the head of the middle turbinate, and the nasopharynx. Temperature values were related to nasal airway resistance data. METHODS: Intranasal temperature measurements were made with a miniaturized thermocouple. Nasal airway resistance was detected by active anterior rhinomanometry. RESULTS: A logarithmic increase of air temperature from the anterior segment of the nose to the posterior part was noted. In the nasopharynx temperature was approximately 34 degrees C. The highest increase in temperature was observed in the nasal valve area. CONCLUSIONS: The temperature increase of ambient air in the nasal airways can be compared with a logarithmic curve of the heating of air passing a heated tube. As the heating of air is important for water transport, the space between the nasal valve and the middle turbinate is of special functional importance. No correlation to the results of rhinomanometry was found.     

The obstructive nasal septum. Effect of simulated deviations on nasal airflow resistance

Effects of simulated septal deviations on nasal airflow resistances were assessed by rhinomanometry in healthy human adults. Obstructions 5 x 15 mm protruding 1 to 5 mm into the nasal lumen were applied to the septum in untreated and decongested nasal cavities. The most resistive septal site was located opposite the caudal edge of the upper lateral cartilage where a 3-mm deviation increased resistance substantially in untreated noses, but produced no resistive effect when the mucosa was decongested, whereas a 4-mm deviation increased resistance severely at this site in untreated and decongested noses. Deviations at the caudal end of the septum that overlapped the upper lateral cartilage were markedly resistive also, while near the cavum they were less resistive. Decongestion reduced resistance and length of this anterior-resistive nasal segment. By contrast, within the cavum neither deviations of 5 mm nor mucosal status affected resistance. It is concluded that airflow resistance of the nasal cavum is unresponsive to septal deviations and mucosal status, but the anterior part of the nose is most susceptible and differences of 1 mm in lumen can be critical.