Anterior and posterior rhinomanometry

Three rhinomanometric techniques for detection of transnasal pressures were compared by computer aided plethysmographic rhinomanometry. Mean unilateral resistances were measured in the decongested nose of an experienced subject by traditional anterior (sealed anterior catheter) and posterior (perorally by mouthpiece) rhinomanometry and also by a fine catheter inserted pernasally to the nasopharynx. No significant differences in magnitude (N = 25, p = 73, mean Rn = 0.345 Pa/cm3/sec) were found. Dimensions of an #8F catheter were adequate for conduction of transnasal pressures and the catheter placed along the floor of a decongested nasal cavity was found not to increase resistance to airflow significantly. Posterior pernasal catheter measurements were less variable than either traditional posterior (peroral) or anterior rhinomanometry. In 35 consecutive patients untreated by decongestant there were no significant differences in magnitude or variation between resistances of the combined nasal cavities immediately following insertion of the catheter and those obtained 5 minutes later (initial mean Rn = 1.66 + 0.49, 5 min mean Rn = 1.70 + 0.50) and in these naive subjects posterior rhinomanometric resistances averaged 9% greater than those in whom resistances were measured pernasally.     

Dimensions and resistances of the human nose: racial differences

Dimensions of the external nose and nostrils and nasal airflow resistances were determined in healthy, young Caucasian, Oriental, and Negro adults. Statistically significant variation between racial groups was found in nasal width and the differential between dorsi-ventral and transverse nostril diameters. Corresponding differences were found also in nasal airflow resistances of combined and separate nasal cavities in both the untreated and decongested state. Caucasian noses were leptorrhine, Negro noses were platyrrhine, and Oriental noses were of intermediate dimension. Mean nasal resistances of untreated noses were 0.129 Pa/cm3/sec in Negroes (N = 17), 0.146 in Orientals (N = 20), and 0.184 in Caucasians (N = 24), and differences were more marked when noses were decongested (P less than 0.05 in all cases). Ratios between resistances of untreated and decongested noses showed no statistical differences between racial groups, suggesting a similarity in the mucovascular component of resistances.     

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.     

Resistance to respiratory airflow of the nasal passages: comparisons between different common methods of calculation

Computer assisted active posterior rhinomanometric determinations of resistance were made with four adult subjects. A face mask and pneumotach were used to measure respiratory airflow. The magnitude and variation of six different instantaneous and time averaged methods of calculation of resistance resulting from simultaneous measurements were compared. Over a resistance range of 1-6 cm H2O/l/sec (0.1-0.6 Pa/cm3/sec) time averaged results approximated those computed at 75 Pa and were 20-25% less than those at 150 Pa. Over the same range of nasal patencies, the coefficients of variation averaged 6-8% in 144 series of 10 measurements which were obtained from six modes of resistance computation in four subjects (total 1440). Time averaged results showed the least variation. A frequency range of 10-26 breaths/min increased the coefficient of variation only to 9% and a ventilation range of 7-24 l/min increased it to 11%, quantitative relationships between resistances and pattern of breathing were not evident. Mask positioning was critical, small maladjustments resulted in large resistive changes.     

Resistance to respiratory airflow of the extrapulmonary airways

Resistances to respiratory airflow of nasal, pharyngeal, laryngeal, and tracheobronchial airway segments were determined by computer processing of digitized differential pressure and flow signals in four healthy, awake, male adults seated and breathing spontaneously at rest, exclusively through decongested noses. Resistances of the nasal and pharyngeal segments in Pa/cm³ per second averaged 0.139 (SD ± 0.044) and 0.081 (SD ± 0.051), respectively, with no resistive evidence of compliance with airflow pressures. The laryngeal segment exhibited the reciprocal of compliance, expiratory resistances exceeded those of inspiration, averaging 0.125 (SD ± 0.037) and 0.035 (SD ± 0.013), respectively (.005 < P < .01). Tracheobronchial resistances during spontaneous resting breathing were too small to record reliably at the calibration used, and values augmented by voluntary hyperventilation averaged only 0.012 (SD ± 0.004). Laryngeal expiratory resistance approximated one fifth of the sum total of respiratory airflow resistances (including the pulmonary airways) and the authors suggest that, in addition to contributing to expiratory airflow braking, partial laryngeal closure induces orifice flow. This nonlaminar flow regime promotes the mucosal contact and mixing that enables greater than 30% of heat and water to be recovered from expiratory air by the human pharynx and nose.     

Nasal resistance—a reliable assessment of nasal patency?

This study was undertaken to determine the distribution of nasal resistance in a healthy white population. One hundred subjects without nasal complaints were selected for the investigation. The test subjects were divided into two groups on the basis of anterior rhinoscopy. Group 1 included 60 subjects with rhinoscopically normal noses. Group 2 included 40 subjects with rhinoscopically abnormal noses. The pressure-flow data were recorded via active anterior mask rhinomanometry. The analogue pressure and flow signals were sampled and digitized by a computer system according to the time averaging method. Nasal resistance was calculated according to the recommendations of the International Committee on Standardization of Rhinomanometry. The normality of unilateral nasal resistance data distributions was assessed by the Kolmogorov-Smirnov Goodness of Fit Test at inspiratory and expiratory corresponding pressures of 50 Pa, 75 Pa, 100 Pa, and 150 Pa. The distributions of the calculated total resistance data were estimated at inspiratory and expiratory reference pressures of 75 Pa and 100 Pa. The data distributions of the two groups were compared using the Mann-Whitney U-test. Distributions for unilateral resistance were frequently found to deviate from normality. The distributions of total nasal resistance data never showed significant deviation from normality. More non-normal distributions were observed in Group 2 than in Group 1. Significant differences were determined between the two sub-groups for the non-decongested data. The entire group of subjects was homogeneous for the decongested data. The subjective assessment of nasal patency appeared not to be a sufficient criterion for the selection of subjects for normative studies in rhinomanometry. The presence of anatomical abnormalities and the influence of the nasal cycle could be responsible for the skewness of nasal resistance data in the normative studies in rhinomanometry.     

Effect of regular physical exercise on resting nasal resistance

OBJECTIVE: This study was conducted to determine (1) if long-term regular training changes resting nasal resistance in humans and (2) if the changes are related to the structural component or mucosal component of nasal resistance. METHODS: We used a case-control study to compare a group of 16 athletes to 15 sedentary people of similar age. Nasal resistance was measured by computerized head-out body plethysmograph posterior rhinometry. Physical activity was evaluated by the Baecke questionnaire. RESULTS: The p values (t-test) were very significant for the Baecke sports and total scores (p < .0001) but not for the other variables: age, untreated nasal resistances, decongested nasal resistances, and Baecke work and leisure scores. There were no significant correlations between nasal resistances and indexes of physical activity in all subjects (Pearson's correlation coefficient). The subjects with extremely low and high sports and total scores were paired and studied with the Signed test and the Wilcoxon signed rank test. No significant relationship was found between the nasal resistances and the Baecke scores. CONCLUSIONS: Resting nasal resistances in a group of endurance-trained athletes are identical to those found in a group of sedentary individuals, and this relationship stands for both the structural and mucosal components of nasal resistance. A new study of the same parameters is warranted to follow a cohort of sedentary subjects as they enroll in a physical training program.     

The effects of adenoid hypertrophy and subsequent adenoidectomy on pediatric nasal airway resistance

To investigate how adenoid hypertrophy and subsequent adenoidectomy affect pediatric airway resistance, we developed a prospective controlled study. Fifty children, aged 3 to 12 years, diagnosed with adenoid hypertrophy and selected for adenoidectomy, preoperatively had their nasal airway resistance assessed by active anterior rhinomanometry. Twenty-five of these children were subsequently followed up postoperatively, undergoing nasal resistance evaluations at 1 month, 3 months, 6 months, and 12 months. Another 25 children, without chronic upper airway obstruction symptoms, were enrolled as a control group, and their airway resistance was assessed in the same fashion. We concluded that the children selected for adenoidectomy, compared to the control group and before surgery, had mean resistance values up to two- to threefold higher, in both untreated and decongested nose states. Surgery was found to dramatically reduce airway resistance, but only in children under the age of seven. However, the postoperative values still tended to remain higher than the control subjects results. If in a significant number of children the operation failed in completely resolving their complaints, no pre-operative rhinomanometric pattern could be found to specifically relate to a complete surgical success.     

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.     

Unilateral and bilateral nasal resistances: a supplement

Three hundred and thirty-four measurements of bilateral and unilateral nasal resistance (at delta P 1.0 cm H2O and by time averaging) in 233 adults were carried out by posterior rhinomanometry with a head-out body plethysmograph. Total nasal resistances, calculated by the equation of Ohm's Law for parallel resistors from measured unilateral resistances, were compared with measured total nasal resistances. The time averaged total nasal resistances calculated by use of Ohm's Law for parallel resistors were closer to direct measurements than resistances at delta P 1.0 cm H2O calculated from the same equation. We attempted to fit calculated total nasal resistance with direct measurements by modification of the equation of Ohm's Law for parallel resistors to T = 0.96[R x L/(R + L)]0.92 in the time averaged nasal resistance and T = 1.07[R x L/(R + L)]0.77 in resistance at delta P 1.0 cm H2O (T: total nasal resistance, R: nasal resistance on the right side, L: nasal resistance on the left side). Calculated total nasal resistances from the above equations agreed closely with direct measurements.     

Nasal resistance to respiratory airflow: a plethysmographic alternative to the face mask

Nasal airflow resistances were measured simultaneously by face mask and "head-out" body plethysmograph and compared. Computer averaging of transnasal pressure and flow signals digitized at 50Hz during 5 breath sequences was employed to determine a ratio of pressure to flow as an index of nasal resistance to breathing. The mean value of ten plethysmograph measurements differed by only 2.0% from that of ten face mask measurements which were made simultaneously. Coefficients of variation of plethysmograph resistance measurements averaged less than 6% in twenty subjects (ten measurements/subject) aged 7-68 years over an intersubject resistance range of 1 to 7 cms H2O/l/sec (0.1-0.7 Pa/cm3/sec). Voluntarily altered minute ventilations from 8-28 l/min in a subject at rest increased this variation to 10%. The "head-out" body plethysmograph is a versatile and reliable instrument for assessment of nasal respiratory airflow resistance.     

Rhinomanometry: do the anterior and posterior methods give equivalent results?

Nasal resistance to airflow was measured by both anterior and posterior rhinomanometry in 15 healthy volunteers. It was found that the posterior method gave values on average 16% higher than the anterior method. This difference was statistically significant. We propose that this is due to posterior rhinomanometry measuring the resistance of the nasopharynx as well as the resistance of the nose. In the past a discrepancy between the 2 methods has been claimed to be due to an error in the standard form of the parallel resistance equation. This hypothesis was tested by measuring total nasal resistance by posterior rhinomanometry and comparing this with a total nasal resistance value derived from posterior rhinomanometric measurements of the resistance of the individual nasal cavities. The standard form of the parallel resistance formula was used to derive the total nasal resistance. There was no significant difference between the 2 values for total nasal resistance. We conclude that if measurements are made at the same pressure gradient then the use of this equation is valid.     

Nasal airway volume and resistance to airflow

BACKGROUND: In modern rhinological practice and research, rhinomanometry and acoustic rhinometry are widely used. The goal of this study was to determine whether there is correlation between rhinomanometrically derived nasal airflow resistances and acoustic rhinometrically derived nasal airway volumes. METHODS: To achieve the goal, a prospective cross-sectional study of a total of 316 patients complaining of nasal obstruction was performed. Resulting data were compared by means of Spearman rank correlations of the total number of patients and of subgroups. RESULTS: The total number of patients, and most subgroups, in both their untreated and decongested states showed significant negative correlation unilaterally between nasal airflow resistances and nasal volumes. CONCLUSION: Rhinomanometric nasal airflow resistances and concurrent acoustic rhinometric nasal airway volumes are closely correlated. The combination of the two objective methods provides insight into nasal airflow physiology and nasal airway anatomy.     

Evaluation of active anterior and posterior rhinomanometry in normal subjects

In this study active anterior (AAR) and active posterior (APR) rhinomanometry were performed by 100 normal subjects with a Mercury rhinomanometer according to the recommendations of the International Standardization Committee. There was no significant difference between total nasal airway resistance (Rna) values obtained with APR by direct measurement and those calculated from AAR. Mean total Rna was 0.31 Pa/cm³/s (range 0.13-0.84) at a reference pressure of 75 Pa. Measurements by AAR were more reproducible than those by APR, mean intrasubject coefficients of variation were 12 and 16% respectively. This reproducibility was similar to that of lower airways’ resistance measurements. Rna values from this population did not conform to a normal Gaussian distribution. Rna was higher during expiration than inspiration and values were higher in women than in men.     

Evaluation of active anterior and posterior rhinomanometry in normal subjects.

In this study active anterior (AAR) and active posterior (APR) rhinomanometry were performed by 100 normal subjects with a Mercury rhinomanometer according to the recommendations of the International Standardization Committee. There was no significant difference between total nasal airway resistance (Rna) values obtained with APR by direct measurement and those calculated from AAR. Mean total Rna was 0.31 Pa/cm3/s (range 0.13-0.84) at a reference pressure of 75 Pa. Measurements by AAR were more reproducible than those by APR, mean intrasubject coefficients of variation were 12 and 16% respectively. This reproducibility was similar to that of lower airways' resistance measurements. Rna values from this population did not conform to a normal Gaussian distribution. Rna was higher during expiration than inspiration and values were higher in women than in men.     

Current advances in rhinomanometry

Current advances in rhinomanometry were reviewed in this paper. Active posterior rhinomanometry with a “head-out” body plethysmograph may be the least invasive method currently available for measuring nasal patency. In general, active anterior rhinomanometry with a face mask or a nasal nozzle has been employed in various studies throughout the world. Nasal resistance as calculated from the equationR = 0.78 (ΔP/V)^1.33 at any points on a pressure/flow curve, or averaged nasal resistance may be the most suitable expression for nasal patency. Values for nasal resistance at ΔP 100 Pa in Japanese patients or ΔP 150 Pa in Caucasians have been widely employed as standard objective data for nasal obstruction, although rhinomanometric results sometimes do not agree with subjective evaluation of nasal obstruction. Nasal airflow acceleration or peak flow index during nasal breathing at rest can be applied as warranted to confirm an objective diagnosis of symptomatic nasal obstruction. Further, nationality and anthropological characteristics can be related to the severity and type of stuffiness.     

上海市崇明地区成年人鼻阻力和鼻声反射的初步研究

目的 通过对上海市崇明地区健康成年人鼻通气功能的客观测定,建立崇明地区健康成年人鼻阻力(RM)、鼻声反射(AR)等参数的正常参考值范围,并初步分析两者相关性.方法 采用NR6鼻阻力计采集受试者经鼻压差为150Pa下前端测量的单侧鼻腔吸气阻力(Ri)、呼气阻力(Re)等数据,通过计算机软件计算后得出单侧总阻力(RI)、双...     

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.     

Variations in nasal resistance in man: a rhinomanometric study of the nasal cycle in 50 human subjects

The alternating congestion and decongestion of the nasal mucosa, termed the "nasal cycle", was investigated with current mask (posterior) active rhinomanometric techniques. This communication reports variations in nasal resistance in 50 human subjects, each studied for about 7 hours. Approximately 600 resistance values (cm H2O/liter per second) were obtained from each subject. The nasal cycle defined in rhinomanometric terms was that alternating congestion and decongestion of the nasal turbinates which produced a change in pressure and airflow values calculated as resistance (comparing one side with the other) of 20% or greater for two consecutive observations (at least 15 minutes). The data demonstrated that 36 of 50 subjects (12 of 18 males and 24 of 32 females) had at least one nasal cycle during the period of observation.     

Phase variation in nasal airways resistance assessed by active anterior rhinomanometry

Measurements of nasal airways resistance in normal subjects have shown a significant difference between values obtained in the two respiratory phases. Higher overall values are found during expiration in both the unprepared and decongested nose but these differences fail to maintain statistical significance after application of a decongestant. This indicates that the phase of respiration in which measurement is made must be routinely recorded especially when measurement is made without decongestant, and comparisons of data made only with recordings from equivalent parts of the nasal cycle.