Nasal Respiration Research Articles

Air swallowing in Rett syndrome

The possible causes of excessive swallowing of air leading to bloating, which is common in Rett syndrome (RS), were investigated during feeding and at rest. Seven individuals with RS aged between 4 and 33 years (three with air bloat) underwent feeding videoflouroscopy and concurrent respiration monitoring. The results were compared with a randomly selected group of 11 individuals, aged between 2 and 16 years, with quadriplegic cerebral palsy and feeding problems, some of whom had mild air bloat. All individuals from both groups had isolated pharyngeal swallows and several mouth breathed; this may account for some air swallowing but not the severe air bloat characteristic of RS. Thirty-three individuals with RS aged between 3 and 44 years were monitored for nasal respiration, chest movements, swallowing, and vocal cord position at rest (between feeding). Twenty had air bloat, 17 of whom swallowed air during breath-holding in the same way, and three gulped air during hyperventilation. Of the 13 without air bloat, eight did not have recurrent breath-holding and five did, but without concurrent air swallowing. Several methods for reducing air swallowing in apnoea were investigated. The most successful was a dummy with an air leak, but this was poorly tolerated and could only be used for short periods of time. Apnoeas and air bloat are often worse when individuals are distressed and may in some individuals be reduced by anxiolytic medications.

Discharge properties of mitral/tufted cells in the olfactory bulb of cats

The spontaneous activity of mitral/tufted cells of the cat olfactory bulb was subjected to time-series analysis. Ninety percent of 284 cells displayed either bimodal or skewed distribution under both tracheal and nasal respiration, indicating that the spontaneous activity is characterized by burst discharge. We conclude that the source of the burst discharge originates in the olfactory bulb, rather than being induced by nasal airflow or by centrifugal inputs to the olfactory bulb.

The role of the temperature of the nasal lining in the sensation of nasal patency.

The receptors and neural pathways involved in the common symptom of nasal blockage are of great interest. Studies to date suggest that the sensation of nasal patency may be related to the temperature of the nasal passages. Sixty-two subjects were asked to assess their own nasal patency subjectively and indicate this on a visual analogue scale. The temperature of the nasal lining was continuously recorded during quiet nasal respiration using a non-contact infrared thermometer. The cooler the nasal lining, the clearer the nose felt, and the greater the drop in temperature on inspiration again the clearer the nose felt. The study supports the previously proposed hypothesis that the sensation of nasal airflow is derived from a cooling of the nasal lining on inspiration, and this is probably detected by cold thermoreceptors in the mucosa.

Gaseous dynamics of the rabbit maxillary sinus.

To better understand the mechanisms underlying maxillary sinus function, the gas composition of the sinus antrum in spontaneously breathing and tracheotomized rabbits (n = 17) was compared. The gas composition of samples (n = 117) obtained from rabbit maxillary sinuses was determined by gas chromatography. Results demonstrated significant differences (P < .005) in sinus gas composition between nasal breathing and tracheotomized animals for oxygen (02) and carbon dioxide (CO2). In tracheotomized animals O2 levels decreased while CO2 levels increased markedly to suprasystemic levels. This unexpected finding may be due to reduced sinus blood flow and the effects of nasal versus tracheal respiration. We conclude that the gaseous dynamics and perhaps the function of the maxillary sinus vary under different respiratory conditions. A better understanding of these processes may lead to earlier diagnosis and the development of improved treatments for sinus disease.

Olfaction and Multiple Chemical Sensitivity

In this paper, a description of olfactory anatomy is presented, followed by a brief review of modern procedures for testing olfactory function. Information from the sole study which has quantitatively examined olfactory function in patients with apparent multiple chemical sensitivity (MCS) is presented. In essence, this study suggests that MCS is associated with increased nasal airflow resistance, respiration rate, heart rate, and scores on the Beck Depression Inventory, but not with significant changes in odor detection threshold sensitivity to phenyl ethyl alcohol and methyl ethyl ketone, the two target stimuli evaluated. Whether MCS patients evidence hypersensitivity to other chemicals is unknown.

A study of nasal respiratory resistance andcraniofacial dimensions in white and West Indian black children

Two studies have shown that there are morphologic differences in the nasopharynx between the major racial groups. This investigation was conducted to see whether these morphologic differences affected nasal respiration. Twenty-two West Indian and 24 white children (mean age of 13 years 11 months) were studied to examine the relationship between nasorespiratory function and nasopharyngeal and dentofacial structure. The nasorespiratory function was measured in terms of nasal respiratory resistance, NRR, (Pascals/cm3 per second), both by anterior and posterior methods, with a computerized rhinomanometer. Nasopharyngeal structure was described in terms of cephalometric variables. The West Indian cephalometric profile generally conformed to its existing description in the literature including prognathic jaws and bimaxillary proclination; in addition, the West Indians were found to have a greater bony nasopharyngeal width (posterior nasal spine-basion) and shallower nasopharyngeal roof angle (posterior nasal spine-hormion-basion). All rhinomanometric measurements were significantly lower in the West Indian group, especially when posterior rhinomanometry was used. The correlation coefficients between the cephalometric and the rhinomanometric measurements were statistically significant but low. In addition, the measure of mandibular prognathism (angle SNB) was also found to be significantly correlated with the nasorespiratory resistance.

Long-term follow-up after division of a pharyngeal flap for severe nasal obstruction.

Between 1965 and 1986, nine patients were noticed to have significant nasal airway obstruction following surgery for velopharyngeal incompetence (VPI). All had a superiorly based pharyngeal flap. Division of the flap was recommended to correct the posterior obstruction. A complete section of the flap was done in seven cases and lateral port enlargement was done in the remaining two. The interval between flap elevation and transection ranged from 5 months to 5 years. Three patients required more than one operation to fully correct the obstruction. All the patients were evaluated 2 to 14 years later to assess nasal breathing and speech and to document velopharyngeal function by nasoendoscopy and video-fluoroscopy. One patient presented major symptoms of nasal obstruction at follow-up, while other reported snoring and occasional mouth breathing, although their nasal respiration appeared subjectively adequate. Four patients had normal speech, three were mildly hyponasal, one was moderately hyponasal, and the other was severely hyponasal. Intelligibility was good in all cases but one, although three patients had some articulation errors: two with persistent errors related to early VPI and one from dental malocclusion and tongue protrusion. Videofluoroscopy and nasoendoscopy showed that despite complete transection at the base of the flap in eight cases, five still had evidence of residual tethering. In one patient, the obstruction was almost complete and repeat division of the flap was recommended. Seven patients showed increased thickness of the soft palate in the midline where the flap had been anchored.(ABSTRACT TRUNCATED AT 250 WORDS)

The nasal septum in relation to the development of the nasomaxillary complex: A study in identical twins

The influence of the nasal septum and respiration, evaluated by the total nasal resistance (TR) on the development of the nasomaxillary complex, was studied in 42 identical twins. An understanding of this influence is important for a determination of whether surgery involving the nose should be performed in children. Comparison within and between twins with different septal deformities indicated that the cartilaginous nasal septum influences the development of the nose and the anteroposterior dimensions of the maxilla. Anterior septal deformities resulted in underdeveloped cartilaginous noses and a shorter anteroposterior dimension for the maxilla. No relation was found with regard to posterior septal deformities, which may be considered as part of the development of the midface. Vertical dimensions of the face were related to TR. Increased values of TR were significantly related to a shorter maxillary height. This may not express a causal relationship but rather genetically determined shorter facial dimensions.

Sensitivity and specificity of diagnostic tests for impaired nasal respiration

Diagnostic tests are imperfect and vary in their sensitivity and specificity. The degree of imprecision may be calculated to yield probability estimates of accuracy for both the positive and negative predictions of tests under various conditions. Such information enables clinicians to decide whether to accept or reject test results or the tests themselves. Two pilot studies are reported to establish the diagnostic potential of cephalometric measurements and nasal resistance values for the identification of upper airway impairment. A linear estimate of adenoid size and an area index of adenoid encroachment in the nasopharynx were evaluated as diagnostic tests for increased nasal resistance. The sensitivity of the tests was 31.8% and 18.2%, while specificity was calculated at 83.3% and 66.6%, respectively. In the second study, nasal resistance was evaluated as a test to identify persons whose respiratory mode was equal to or less than 75% nasal airflow. At a NRz value of 5.0 cm H2O per liter per second, the sensitivity of this test was 41.2% and the specificity was 84.0%; with the critical value of NRz at 3.5 H2O per liter per second, the sensitivity was 64.7% and the specificity was reduced to 60.0%. The results suggest that these tests are too imprecise for the reliable identification of either those who might benefit from treatment or those for whom treatment is unlikely to yield benefits.

Growth of the pharynx and its physiologic implications

The bony nasopharynx increases its capacity predominantly by means of vertical development. Analogous to the facial structures is an expression of some somatotopic features that give rise to a higher and more shallow pharyngeal dimension in the dolichocephalic growth pattern. The nasopharynx's ultimate patency, however, depends on the growth and relative size of the soft tissues that line the skeletal boundaries. A decreased patency of the oropharyngeal airway can induce some postural adaptations, which secure a constant sagittal dimension at that level. However, at a certain critical point, purely nasal respiration will be turned into an oronasal breathing pattern, which in turn will elicit more compensatory mechanisms. This muscle recruitment is a possible cause of a deviant vertical craniofacial growth pattern.

Relationship between vertical dentofacial morphology and respiration in adolescents

The relationship between vertical dentofacial morphology and respiration has been debated and investigated from various approaches. The purpose of this study was to use contemporary respirometric techniques to compare the breathing behavior of normal and long-faced adolescents. Sixteen normal and 32 long-faced subjects 11 to 17 years of age were chosen clinically and verified by means of a discriminant function. Vertical and anteroposterior facial form was assessed from lateral cephalometric radiographs according to the following measurement criteria: six skeletal angular, eight skeletal linear, four dental linear, and three skeletal ratios. Breathing behavior was quantified according to tidal volume, minimum cross-sectional nasal area, and percent of nasal breathing as assessed by pneumotachography, measurement of differential pressures, and inductive plethysmography. The data indicated that the normal and long-faced groups were significantly different with respect to lower face form, and each group in the study was comparable to groups that had been chosen by previous investigators. Multiple regression analysis demonstrated that the normal and long-faced groups had similar tidal volumes and minimum nasal cross-sectional areas, but the long-faced subjects had significantly smaller components of nasal respiration. These results illustrate that groups without significant differences in airway impairment can have significantly different breathing modes that may be behaviorally based, rather than airway-dependent.

The effect of cleft palate speech aid prostheses on the nasopharyngeal airway and breathing

This study determined the effect of a speech aid prosthesis on resting breathing. Nasal cross-sectional area was measured during inspiration and expiration in eight cleft palate patients. The measurements were made for the unobturated defect during both phases of respiration and then repeated while the defect was obturated by a speech aid prosthesis. The results of the study revealed that the presence of a speech aid prosthesis significantly decreased the cross-sectional region of the nasal airway. In 50% of the subjects, the cross-sectional region was less than 0.40cm 2 with concomitant impairment in nasal respiration when the speech aid prosthesis was present in the oral cavity. The data suggest that the design of these prostheses should account for breathing requirements as well as for speech.

Nasorespiratory Function and Orofacial Development

The controversy over whether altered development of orofacial structures arises purely from expression of genetic potential or is influenced by environmental factors is reviewed. Resolving this controversy will determine the need for early intervention to permit nasal respiration and for orthodontic treatment.

咽頭弁が鼻咽腔機能に及ぼす影響について

Velopharyngeal competency and respiration through the nose were evaluated one year or more after the folded pharyngeal flap operation in 49 patients: 27 cleft lip and palate, six with complete cleft palate, 16 with soft or submucous cleft palate. It was confirmed that adequate velopharyngeal competency had been attained in all 49 cases on the basis of aerodynamic assessment on the utterance of the mono-syllable plosives Pa·Pi·Pu and the auditory perception of speech. Three of the 16 patients with soft or submucous cleft palate complained of nasal obstruction; nasopharyngeal resistance in the 14 with soft or submucous cleft palate was not statistically higher than normal, as measured aerodynamically. It was concluded that nasal respiration might be slightly affected by the folded pharyngeal flap operation.

片側唇裂口蓋裂例の鼻呼吸機能と鼻中隔変形

Nasal resistance was measured aerodynamically through one or both nostrils. Cleft lip nose deformity alone had a negative effect on nasal air-passages, especially on the side of the cleft. Thirty per cent of the patients with cleft lip alone complained of nasal obstruction. Patients with unilateral cleft lip and palate usually have characteristic nasal deformities, including nostril flattening, afar base ptosis and deviation of the nasal columella. In addition, deformity of the nasal cavity is also frequent. CT scans of the nasal septum were analyzed in cleft lip and palate patients. The nasal septum was deviated to the non-cleft side at and around the nostril. This anterior deviation was conspicuous in cases of alveolar cleft. Posteriorly, the nasal septum deviated to the cleft side in both horizontal and vertical planes, especially in cases of cleft hard palate. Posterior septal deviation seems to interfere with nasal respiration much less than anterior nasal deformity.

Olfactory Sensitivity, Nasal Resistance, and Autonomic Function in Patients With Multiple Chemical Sensitivities

A frequent, if not predominant, complaint of persons reporting symptoms of multiple chemical sensitivities (MCS) is that of heightened sensitivity to smells. In this study odor detection thresholds for phenyl ethyl alcohol (a major component of rose oil) and methyl ethyl ketone (a common solvent) were measured in 18 persons exhibiting symptoms of MCS and in 18 matched normal controls. In addition, nasal resistance, blood pressure, heart rate, and respiration rate were determined before and after the olfactory tests. Scores on the Beck Depression Inventory were obtained prior to testing. Although olfactory thresholds were equivalent in the two study groups, the MCS group evidenced significantly higher nasal resistances, respiration rates and Beck Depression Inventory scores. Decreases in systolic blood pressure and pulse were noted in both groups across the test sessions. These results do not support the hypothesis that MCS is associated with greater olfactory threshold sensitivity (at least to the two target chemicals), but do suggest that MCS is associated with depression, increased respiration rate, and decreased nasal airway patency.

Inhalation of salt aerosol particles—i. Estimation of the temperature and relative humidity of the air in the human upper airways

In order to estimate the growth and deposition of hygroscopic aerosol particles during respiration the relative humidity (RH) of the air in the airways must be known. The RH has been calculated with a transport theory for the heat and water vapour in a tube using a numerical method, Cartesian coordinates, and nasal respiration [Ferron et al., J. Aerosol Sci. (1983) 14, 196; Ferron et al., Bull. math. Biol. (1985) 47, 565]. A similar theory is described here to calculate the transport for cylindrical coordinates, both for nasal and oral respiration. The method has the advantage of a reduced computational time compared with the method used before. Calculations are carried out both for nasal and oral inhalation and exhalation. The values of several parameters of the theory, the thickness of the boundary layer, the additional diffusivity by airflow instabilities, the profiles for the temperature and RH at the airway wall, are chosen to fit experimental data on the mean air temperature and RH in the human airways. Since the experimental data are scattered, maximum and minimum curves for the experimental data are derived. It was found mathematically that the RH of the air is more strongly dependent on the RH at the airway wall and less on its temperature. However due to the large uncertainties of the experimental data on the RH no firm conclusion can be drawn.

Effects of nasal obstruction on facial development

The relationship between nasal obstruction and facial growth is controversial. Much of the controversy relates to the lack of sophistication in quantifying nasal versus oral respiration and the lack of longitudinal data. Nevertheless, a number of studies in laboratory animals, nonhuman primates, and humans have shown a relationship between nasal airway obstruction and aberrant facial growth. In monkeys, occlusion of the nares with silicon plugs triggered deviant muscle function and altered morphogenesis. In general, the nasally obstructed animals had longer faces and unusual dental malocclusions. In human studies allergic, mouth-breathing children have longer, narrower faces and retrognathic jaws, compared with control subjects. Medical intervention has not been shown to influence the pattern of facial growth in children with allergies. Surgical therapy to relieve nasal airway obstruction in children (whether adenoidectomy or turbinectomy) has not been shown to predictably affect ultimate facial form. Therefore, although an increasing body of literature demonstrates a relationship between nasal airway obstruction and facial growth, the clinician should be cautious in prescribing aggressive therapy or in promising dramatic results.

Alterations in nasal respiration and nasal airway size following superior repositioning of the maxilla

Twenty patients who underwent superior repositioning of the maxilla via Le Fort I down fracture had their respiratory mode and nasal cross-sectional area determined prior to and 6 months following surgery. Inductive plethysmography and nasal air flow techniques were used in the determination of these parameters. Prior to surgery, five patients were nasal breathers, five were predominantly nasal breathers, six were oral-nasal breathers, and four were predominantly oral breathers. Nine patients had inadequate nasal airways. Six months following surgery, 14 patients were nasal breathers and six were predominantly nasal breathers. Sixteen patients had adequate nasal airways, three had borderline nasal airways and one had an inadequate nasal airway postsurgically. These findings suggest that superior repositioning of the maxilla by Le Fort I down fracture does not adversely affect nasal respiration. Nasal function actually improved in 17 of the 20 subjects studied.

Respiration characteristics in subjects diagnosed as having nasal obstruction

The purpose of this study was to determine the respective oral and nasal contributions to total respiration in patients scheduled for surgical corrections of nasal obstruction. The effect of anterior nares expansion and/or nasal decongestant administration on the nasal component of breathing was also examined in these patients. Although variability among subjects was demonstrated in the ratio of nasal respiration to total respiration, 25% of the “nasally-obstructed” patients were 100% nasal brethers and no patient had a nasal component less than 18% of total respiration. Great variability existed among the patients in their response to nares expansion and/or decongestant administration. Collectively, they demonstrated no significant mean increase in nasal respiration with nares expansion alone. The patients demonstrated an increase with administration of the decongestant and with decongestant combined with nares expansion. The latter condition resulted in an increase that was greater than with decongestant alone. The implication of this study is that the traditional diagnostic terms “mouth breathing” or “nasal obstruction” are not useful. They do not describe the type, location, or severity of an obstruction or the relative contribution of the nose and mouth to respiration. Many patients who experience symptoms or have signs of nasal obstruction can functionally compensate to maintain 100% nasal breathing.