Measurement Of Nasal Resistance Research Articles

The acute impact of continuous positive airway pressure on nasal resistance: a randomized controlled comparison

Subjective nasal obstruction is common among users of continuous positive airway pressure (CPAP). The aim of this study was to measure the acute effect of CPAP on nasal resistance and nasal symptoms in awake normal subjects. Twenty-four healthy CPAP-naive adults [8 men, 16 women; mean age 30 yr (SD 14)] underwent a randomized controlled crossover study comparing nasal CPAP (8 cmH(2)O) for 6 h on one occasion and the control condition (nasal mask without CPAP) on the other. Nasal resistance measurements (posterior active rhinometry) before and after the test exposure were similar on both test days. Nasal resistance during CPAP exposure [2.04 cmH(2)O.l(-1).s (SD 0.72)] was significantly lower than that of the control [2.67 cmH(2)O.l(-1).s (SD 1.07)]: mean difference 0.66 cmH(2)O.l(-1).s, 95% confidence interval 0.19-1.13 cmH(2)O.l(-1).s. The gradient in pressure from CPAP mask to posterior naris during CPAP exposure varied from 1.6 to 2 cmH(2)O but was not significantly different between time points. Subjective nasal symptom scores and peak nasal inspiratory flow rates did not change significantly on either test day. We conclude that in awake CPAP-naive normal subjects, acute CPAP exposure is associated with a reduction in nasal resistance compared with the control condition, but it is not associated with an immediate post-CPAP change in subjective or objective nasal resistance.

Computational analysis of flow field patterns in rigid and flexible lung airway models

Computational fluid dynamic (CFD) analysis was used to model the effect of airway geometry on internal pressure in the upper airway of three children with obstructive sleep apnea syndrome (OSAS), and three controls. Model geometry was reconstructed from magnetic resonance images obtained during quiet tidal breathing, meshed with an unstructured grid, and solved at normative peak resting flow. The unsteady Reynolds-averaged Navier–Stokes equations were solved with steady flow boundary conditions in inspiration and expiration, using a two-equation low-Reynolds number turbulence model. Model results were validated using an in-vitro scale model, unsteady flow simulation, and reported nasal resistance measurements in children.Pharynx pressure drop strongly correlated to airway area restriction. Inspiratory pressure drop was primarily proportional to the square of flow, consistent with pressure losses due to convective acceleration caused by area restriction. On inspiration, in OSAS pressure drop occurred primarily between the choanae and the region where the adenoids overlap the tonsils (overlap region) due to airway narrowing, rather than in the nasal passages; in controls the majority of pressure drop was in the nasal passages. On expiration, in OSAS the majority of pressure drop occurred between the oropharynx (posterior to the tongue) and overlap region, and local minimum pressure in the overlap region was near atmospheric due to pressure recovery in the anterior nasopharynx. The results suggest that pharyngeal airway shape in children with OSAS significantly affects internal pressure distribution compared to nasal resistance. The model may also help explain regional dynamic airway narrowing during expiration.

Contemporary Rhinomanometry

By contrast with the smoked drum and other mechanical systems, modern electronic rhinomanometers provide superior sensitivity and frequency response. They enable accurate measurement of nasal airflow resistance to be made and are commercially available. In addition to a rhinomanometer, nasal airflow measurements require a face mask fitted with a flow measuring device (a pneumotach connected to an electronic differential pressure transducer) or, as an alternative to a face mask, a head-out body plethysmograph. Concurrently with nasal respiratory airflow, transnasal pressures between the nostril and pharynx are measured via nasal or oral tubing by a second differential pressure transducer. The transduced electronic analogue signals are digitized, and nasal airflow resistances are computed from the ratio between transnasal pressure and airflow. At a single sitting, a series of measurements with modern rhinomanometry can determine (1) the response to topical decongestant of the mucovascular contribution to nasal airflow resistance at the time of examination and (2) in the decongested nose, the presence, side, site, and severity of structural obstruction. Rhinomanometry is not "medically necessary" in assessment of all cases of nasal obstructive symptoms, but, in many situations, it can provide valuable objective information in compliance with the requirements of evidence-based medicine. This article includes a table listing situations in which rhinomanometry is particularly useful.

Physiologic assessment of allergic rhinitis in mice: Role of the high-affinity IgE receptor (FcɛRI)

There have been few reports using animal models to study the development of allergic rhinitis. Characterization of such a model in mice would be advantageous given the availability of reagents and gene-manipulated strains. We sought to develop a murine model of allergic rhinitis in the absence of lower airway changes. After sensitization and challenge, both wild-type and FcepsilonRI-deficient mice were studied for their ability to develop early- and late-phase nasal responses. In the invasive approach, direct measurements of nasal airway resistance (R(NA)) were obtained; in the noninvasive approach using whole-body plethysmography, respiratory frequency and expiratory and inspiratory times were monitored. In both approaches, nasal responses were determined either acutely after challenge (early phase) or 24 hours after challenge (late phase). After challenge of sensitized mice, R(NA) significantly increased. In parallel, respiratory frequency significantly decreased and was highly correlated with the increases in R(NA). Sensitized wild-type mice had an early-phase nasal response and persistent nasal blockage (late-phase response) after allergen challenge. In contrast, sensitized and challenged FcepsilonRI alpha-chain-deficient mice did not have an early-phase nasal reaction and exhibited reduced nasal blockage and lower IL-13 levels in nasal tissue homogenates. These data indicate that FcepsilonRI is essential to development of an early-phase nasal response and contributes to the development of the late-phase nasal response. These invasive and noninvasive approaches provide new opportunities to evaluate the mechanisms underlying the development of nasal responses to allergen and to assess various therapeutic interventions.

Subjective and objective nasal obstruction assessment in children with chronic rhinitis

The present study was undertaken, to test the hypothesis that schoolchildren on long-term treatment for chronic rhinitis under-report their nasal congestion. Ninety-seven children aged 8.3-15.5 years (median 12.7) with non-purulent perennial rhinitis, for 1.4-8.5 years (median 2.8) self-graded their nasal blockage as "severe" (group-A), "moderate" (group-B), "mild" (group-C) or "absent" (group-D). An additional 48 normal children served as controls (group-E). Subsequently active anterior rhinomanometry for total nasal airway resistance (TNAR) measurement and decongestion test (>20% TNAR fall) were employed as objective means of nasal congestion. Mean pre-decongestion TNAR values did not show any significant difference between the group-A, -B and -C; significant differences were observed between group-A and -D (p=0.04) and between all groups as compared to -E. Positive decongestion test was detected in 57.1%, 53.8%, 48.3%, 32.3% and 10.4% of children in group-A, -B, -C, -D and -E, respectively (group-A, -B, -C versus -E p<0.001, group-D versus -E p=0.03). Schoolchildren on long-term treatment for perennial rhinitis frequently under-report their symptom of nasal stuffiness.

Computational fluid dynamics modeling of the upper airway of children with obstructive sleep apnea syndrome in steady flow

Computational fluid dynamic (CFD) analysis was used to model the effect of airway geometry on internal pressure in the upper airway of three children with obstructive sleep apnea syndrome (OSAS), and three controls. Model geometry was reconstructed from magnetic resonance images obtained during quiet tidal breathing, meshed with an unstructured grid, and solved at normative peak resting flow. The unsteady Reynolds-averaged Navier–Stokes equations were solved with steady flow boundary conditions in inspiration and expiration, using a two-equation low-Reynolds number turbulence model. Model results were validated using an in-vitro scale model, unsteady flow simulation, and reported nasal resistance measurements in children. Pharynx pressure drop strongly correlated to airway area restriction. Inspiratory pressure drop was primarily proportional to the square of flow, consistent with pressure losses due to convective acceleration caused by area restriction. On inspiration, in OSAS pressure drop occurred primarily between the choanae and the region where the adenoids overlap the tonsils (overlap region) due to airway narrowing, rather than in the nasal passages; in controls the majority of pressure drop was in the nasal passages. On expiration, in OSAS the majority of pressure drop occurred between the oropharynx (posterior to the tongue) and overlap region, and local minimum pressure in the overlap region was near atmospheric due to pressure recovery in the anterior nasopharynx. The results suggest that pharyngeal airway shape in children with OSAS significantly affects internal pressure distribution compared to nasal resistance. The model may also help explain regional dynamic airway narrowing during expiration.

Efficacy and Safety of Single and Multiple Doses of Pseudoephedrine in the Treatment of Nasal Congestion associated with Common Cold

Pseudoephedrine (60 mg) is widely used as an oral decongestant taken in tablet or syrup formulations every 4-6 hours for the treatment of nasal congestion associated with common cold and allergy. However, there are relatively few studies in the literature that have used objective measures of nasal airway resistance (NAR) to assess the efficacy of pseudoephedrine, and most studies use only a single dose of medication. The present study has the aims of studying the safety and efficacy of a new pseudoephedrine formulation after single and multiple doses in patients with URTI. The study was a double-blind, randomized, parallel-group, placebo-controlled trial conducted over three study days at a single center. Patients suffering from nasal congestion associated with common cold were recruited and total NAR was measured by the technique of posterior rhinomanometry. NAR and subjective scores of nasal congestion were measured at baseline and after dosing with study medication, every hour over a four-hour period on day 1 after a single dose, and on day 3 after multiple doses of medication. Subjective scores of congestion/stuffiness were also made as a summary score at the end of each day of treatment. Two hundred and thirty-eight patients with nasal congestion associated with acute upper respiratory tract infection (URTI), mean age 20 years, were recruited to the study and received treatment. After a single dose on day 1 the pseudoephedrine group had a statistically significant lower area under the NAR curve than placebo (p = 0.006) for the primary efficacy variable area under the NAR curve from 0-3 hours (NAR AUC 0-3h), and similarly for the secondary efficacy variable NAR AUC 0-4h (p = 0.001). On day three after multiple doses, the pseudoephedrine group had a statistically significant lower NAR AUC 0-3h and AUC 0-4h than placebo (p < 0.001), On day 1, the pseudoephedrine group had significantly lower subjective scores for congestion than placebo visual analog scale (VAS) AUC 0-3h (p = 0.029) and similarly for VAS AUC 0-4h (p = 0.021). On day 3, the differences in subjective scores were not significantly different. The mean decrease from baseline of the summary score for congestion/stuffiness over the duration of the study was greater in the pseudoephedrine group compared to the placebo group (p = 0.016). On average, heart rate was between two and four beats per minute greater in the pseudoephedrine group compared to placebo. Five adverse events were reported in both treatment groups and these were deemed to be unrelated to treatment. The results demonstrate that pseudoephedrine is a safe and effective treatment for nasal congestion associated with URTI. The results from the laboratory study on day 1 demonstrate by both objective and subjective measures of nasal congestion that a single dose of 60 mg pseudoephedrine is superior to placebo treatment. Support for the decongestant efficacy of multiple doses of pseudoephedrine is provided by objective measures on day 3 and subjective measures made over three days, but not by the VAS scores on day 3.

Superoxide dismutase failed to attenuate allergen-induced nasal congestion in ragweed-sensitized dogs

We hypothesized that augmentation of antioxidant defenses with exogenous superoxide dismutase (SOD), an enzyme that provides an initial defense against oxidative injury, would attenuate allergen-induced nasal congestion in the canine model of allergic rhinitis. Nasal congestion was evaluated by the measurements of nasal resistance and the volume of the nasal passage. In five nonsensitized dogs, 30,000 U of SOD from bovine erythrocytes delivered by aerosol to the nasal passages before histamine challenge reduced the histamine-induced nasal congestion. At 30 min postchallenge, nasal resistance was 1.14 +/- 0.2 cmH2O.l(-1).min(-1) in the saline pretreatment study vs. 0.36 +/- 0.02 cmH2O.l(-1).min(-1) in the SOD pretreatment study (P < 0.05), and volume of nasal passage was 10.9 +/- 0.5 cm3 vs. 17.4 +/- 1.3 cm3 (P < 0.05), respectively. In five sensitized dogs, however, neither an analogous pretreatment with SOD nor intranasal aerosolized pretreatment with 30,000 U of SOD conjugated to polyethylene glycol attenuated ragweed-induced nasal congestion. Also, systemic application of SOD did not attenuate responses to challenges with histamine and ragweed in nonsensitized and sensitized dogs, respectively. The antioxidant-induced attenuation of nasal congestion in nonsensitized dogs confirms validity of the model and indicates the involvement of free radical-mediated damage in the genesis of the histamine-induced congestion. In sensitized dogs, the data do not support the hypothesis that oxidative stress is a clinically significant component of acute ragweed-induced nasal congestion. The data do not support the use of SOD for acute protection against allergic rhinitis.

Nasal resistances are useful in identifying children with severe obstructive sleep apnea before polysomnography

Objective: In this study, we would like to show that anterior rhinometry measurement of nasal resistance would be a simple and useful test to identify severe obstructive sleep apnea (OSA) in a population of children affected by adenotonsillar hypertrophy. Methods: Seventy-three consecutive children (44 males; mean age 5.4±1.2 years) with adenotonsillar hypertrophy, who complained sleep-disordered breathing, were studied. All the parents completed a questionnaire concerning the children's sleeping habits and sleep complaints before consultation; each child underwent a general paediatric examination and an evaluation of craniofacial features and upper airway patency. In all 73 children polysomnography was performed and anterior rhinometry nasal patency was measured. Results: The diagnosis of OSA was confirmed in 44/73 patients (60%). Total nasal resistance showed a significant direct correlation with apnea hypopnea index, arousal index, snoring time, percentage of sleep time spent at SaO 2<90% and a significant inverse correlation with total sleep time, sleep efficiency and the mean of SaO 2% during sleep. Total nasal resistance was significantly related to snoring, mouth breathing and daytime sleepiness. The receiver operator characteristics (ROC) curve indicates that in the range of age of our sample a nasal resistance value of 0.59 Pa/cm 3/s has a sensitivity of 91% and specificity of 96% for identifying the children with adenotonsillar hypertrophy affected by OSA. Conclusions: Our study shows that in children with adenotonsillar hypertrophy nasal resistance seems to be risk factor for OSA. The anterior rhinometry appears as a useful tool in routine evaluation of sleep-disordered breathing in these patients.

Effects of beta-endorphin on nasal allergic inflammation.

Beta-endorphin is a derivative of pro-opiomelanocortin. Cells of the immune system can also synthesize and secrete beta-endorphin. Its concentration is increased during the allergic reaction and during stress. Increased reactivity during psychological stress of allergic subjects is also well known. Is beta-endorphin one physiological link between stress and an exacerbation of the allergic reaction? First, intranasal beta-endorphin challenges with subsequent lavages to determine histamine and albumin levels and measurements of nasal flow and resistance in dose-response and time course experiments were performed. Secondly, we examined whether beta-endorphin pre-treatment increased the antigen-induced release of histamine and albumin in nasal lavages and the clinical symptoms. Exogenous beta-endorphin (100 pM-10 microM/mL) induced a dose-dependent increase in nasal symptoms in asymptomatic allergic subjects with rhinitis (n = 14) as well as in non-allergic controls (n = 10), but did not release any mediators into nasal secretion. However, comparing the antigen-evoked release of mediators into nasal secretions with that of a beta-endorphin pre-treated antigen challenge we could note a significant enhancement of human serum albumin influx (P < 0.05) and histamine liberation (P < 0.05) 10 min after antigen challenge compared with the allergen challenge alone, with also a correlation with the more pronounced decrease in nasal flow (P < 0.05). These results suggest that beta-endorphin-induced increase in nasal congestion is mediated through direct neuroendocrine receptor activation independent of mast cell activation and that during the allergic reaction there is a beta-endorphin/mast cell interaction that enhances the mediator response to nasal allergen challenge.

Nasal obstruction as a risk factor for sleep apnoea syndrome.

Nasal obstruction has frequently been mentioned as a possible risk factor in obstructive sleep apnoea syndrome (OSAS). Over a 2-yr period, 541 unselected consecutive snorers referred for suspected breathing disorders during sleep were included to undergo posterior rhinomanometry. In addition cephalometric landmarks and body mass index (BMI) were obtained. Polysomnography was used to determine the number of abnormal respiratory events that occurred during sleep. OSAS was defined as 15 episodes, or more, of apnoea or hypopnoea per hour of sleep (AHI). Of the 541 consecutive snorers 528 underwent nasal resistance measurement by posterior rhinomanometry (failure rate: 2.4%). Patients with OSAS (259 patients) had higher nasal resistance than patients without OSAS (2.6+/-1.6 hPa x L x s(-1) versus 2.2+/-1.0 hPa x L x s(-1), respectively, p<0.005). A stepwise multiple regression analysis showed that BMI, male sex, nasal resistance, and cephalometric parameters were contributing factors to the AHI. The r2-value of the multiple regression analysis was 0.183. Nasal resistance contributed 2.3% of the variance (p<0.0001), whereas mandibular plane-hyoid distance, BMI, male sex and age contributed 6.2%, 4.6%, 3% and 1.3% of the variance, respectively. To conclude, daytime nasal obstruction is an independent risk factor for OSAS.

Effect on nasal resistance of an external nasal splint and isotonic exercise.

OBJECTIVES: The now commonplace wearing of external nasal splints by sportsmen and athletes has never been scientifically evaluated. The present study looks into the effect of isotonic exercise on nasal...

Nasal airflow resistance measurement: forced oscillation technique versus posterior rhinomanometry

This study was designed to determine whether nasal airflow resistance (Rn) which is nonlinear during tidal breathing, can be assessed by the forced oscillation (FO) technique. Rn values obtained by the FO technique and extrapolated to 0 Hz (Rn,FO) were compared to those assessed by posterior rhinomanometry at maximal tidal inspiratory flow (Rn,m), at a 0.5 L x s(-1) flow (Rn,F), and at a 1 hPa transnasal pressure (Rn,P). All Rn estimates were derived from the same inspiratory and expiratory nasal flow and transnasal pressure signals obtained during tidal nasal breathing whilst a forced flow was applied at the nose via a rigid nasal mask in 23 healthy volunteers, of whom 14 had additional measurements after vasoconstrictor treatment. In the basal state, no significant difference, and significant correlations (p<0.0001) were found between Rn,FO and the other Rn estimates. Only the regression line of Rn,FO versus Rn,m was not significantly different from the identity line. After nasal decongestion, Rn,P became significantly higher than the other Rn estimates (p<0.005). The regression line of Rn,FO versus Rn,m remained nonsignificantly different from the identity line. Similar results were observed regarding the percentage values of the different Rn estimates after decongestant treatment. This study shows that, despite its nonlinearity, Rn can be assessed by the FO technique, and that Rn,FO and Rn,m could be indifferently used as physiological indices of nasal patency. As the FO technique is more difficult to implement than the conventional rhinomanometry, its interest in rhinology appears not to be obvious.

Evaluation of nasal obstruction with acoustic rhinometry: a simulated study with a nasal model

The measurement of nasal resistance is important for understanding the pathophysiology of nasal obstruction. However, it is difficult to define the normal range of nasal resistance because of various physiological factors. Several authors have reported that nasal resistance is not correlated with the sensation of nasal obstruction. On the other hand, acoustic rhinometry was introduced by Hilberg et. al. (1989) to determine the geometry of the nasal cavity. The method based on sound reflection analysis provides an estimate of the cross-sectinal area of the nasal cavity as a function of the distance from the nostril. Recently, the measurement by acoustic rhinometry is becoming popular also in our country. However, the assessment by acoustic rhinometry may be different from that by measuring nasal resistance because the cross-sectional area is measured without studying the air flow. The aim of this study was to investigate the benefit of acoustic rhinometry using a nasal model. First, 4 pieces of nasal model LM005 (KOKEN, Co., Japan) made of silicone were coated with resinous putty. Then, the changes in the area-distance curve were measured with an acoustic rhinometer RHIN 2100 (SRE, Co., Denmark) in which this putty was scraped off gradually from anterior to posterior. In the next study, the quality of coated putty was increased at three points of the nasal area: anterior part, middle part, and posterior part. Thereafter the changes in the area-distance curve were observed in the same way. As a result, neither a decrease or an increase in the putty changed the area-distance curve at the posterior part. Therefore, it is suitable that the degree of the changing of nasal mucosa is defined as the change in the nasal volume between the top the I-notch and the end of the C-notch. In conclusion, acoustic rhinometry is useful to investigate nasal obstruction, especially the change in the nasal mucosa. Therefore, further clinical study is required for the different purpose of measuring nasal resistance.

Evaluation of Nasal Patency: Comparison of Patient and Clinician Assessments with Rhinomanometry

The correlation between the objective measurement of nasal resistance and nasal airflow sensation is usually regarded as poor. The aim of the study was to assess the relation between objective indices of nasal patency, as assessed by the occlusion method (RN) and the Youlten peak nasal inspiratory flow meter (PNIF), with subjective sensations of nasal blockade by either the patient or the clinician in groups of patients with rhinitis, asthma, rhinitis and asthma, nasal septal deformity and in normal controls. We studied nasal airway patency in 254 subjects (37 women, 217 men), mean age 21 years (range 14-78) by RN and PNIF. Nasal resistance was also measured by the application of Ohm's law for parallel resistors (NRO) by estimating the unilateral resistance separately. Subjective sensation of nasal blockade was assessed either by the patient on a 10-point Borg scale (SUB), or the clinician (CLN) on a 6-point scale (3 for each side of the nose). The latter was done in a controlled fashion with the aid of reference sensations. Adjusting for age, height, smoking status and airway calibre, we found good correlation between RN and CLN (r=0.57, p=10

A prospective study using rhinomanometry and patient clinical satisfaction to determine if objective measurements of nasal airway resistance can improve the quality of septoplasty.

In the ENT Department of University Central Hospital, Turku, the waiting list for elective septoplasty grew to 4 to 5 years in the late 1980s. Therefore, a prospective clinical project was initiated during which all patients waiting for septal surgery were re-examined and nasal airway function was measured with rhinomanometry. Patients with high nasal resistance or other specific indications for nasal obstruction were selected for surgery (n = 432). The remaining patients were excluded from surgery and followed up (n = 284). Results showed that if patients were referred for septal surgery without rhinomanometric study, about 10% became symptom-free within 3 to 5 years. Patients operated on after defining a high preoperative intranasal resistance had a higher postoperative satisfaction level (85%) than those operated on with normal nasal resistances but other indications for correcting the nasal septum (69%). After 3 years, the majority of patients not treated surgically were satisfied with their conservative treatments, although certain patients still required some form of nasal surgery to relieve recurring nasal and/or sinus complaints.

Effect of septal perforations on measures of nasal resistance.

The purpose of this investigation was to determine the effect of septal perforations on posterior and anterior rhinomanometric measures of nasal resistance in an analog model. The data were analyzed using a repeated-measures ANOVA. Nasal resistance was the dependent variable, while type of rhinomanometry, septal perforation size, and position of resistance (proximal vs. distal) were nominal scale independent variables. The analog model used in this study was similar to that described by Warren and Devereux (1966), except that the nasal cavities of the model were modified to create septal perforations. The main dependent measure was nasal resistance. An Important finding of this investigation was that septal perforations resulted in large differences (> 3 cm H2O/L/sec) between posterior and anterior nasal resistance values in the bilateral proximal resistor condition. Anterior rhinomanometry may underestimate true nasal resistance when a septal perforation is present, because the septal perforation prevents accurate measurement of nasopharyngeal pressure. Posterior rhinomanometric measures should accurately reflect nasal resistance despite septal perforations, because the perforation does not invalidate the estimate of nasopharyngeal pressure.

Effect of Septal Perforations on Measures of Nasal Resistance

The purpose of this investigation was to determine the effect of septal perforations on posterior and anterior rhinomanometric measures of nasal resistance in an analog model.The data were analyzed using a repeated-measures ANOVA. Nasal resistance was the dependent variable, while type of rhinomanometry, septal perforation size, and position of resistance (proximal vs. distal) were nominal scale independent variables.The analog model used in this study was similar to that described by Warren and Devereux (1966), except that the nasal cavities of the model were modified to create septal perforations.The main dependent measure was nasal resistance.An Important finding of this investigation was that septal perforations resulted in large differences (> 3 cm H2O/L/sec) between posterior and anterior nasal resistance values in the bilateral proximal resistor condition.Anterior rhinomanometry may underestimate true nasal resistance when a septal perforation is present, because the septal perforation prevents accurate measurement of nasopharyngeal pressure. Posterior rhinomanometric measures should accurately reflect nasal resistance despite septal perforations, because the perforation does not invalidate the estimate of nasopharyngeal pressure.

Objective and subjective nasal airflow

Purpose: This study was designed to assess whether a correlation exists between the rhinomanometric measurement of nasal resistance, nasal airflow, and the subjective sensation of airflow. Materials and Methods: Sixteen patients with recurrent maxillary sinusitis were examined before and after uncinectomy during functional endoscopic sinus surgery. Subjective nasal sensation of airflow was assessed by means of a visual scale before and after uncinectomy. Rhinomanometry was performed three times for every patient: before anesthesia, and before and after uncinectomy. The subjective nasal sensation of airflow was compared with the nasal airflow and resistance to flow as measured by rhinomanometry. Results: Rhinomanometric measurements were almost the same before and after uncinectomy, with no significant difference, whereas patients reported a significant improvement in nasal airflow. Conclusion: Rhinomanometric measurements of nasal airflow and resistance often have no correlation to the patient's sensation of airflow. However, because it is the patients' ultimate concern to breathe more comfortably, the rhinomanometer has little clinical value.

The long-term effects of open cosmetic septorhinoplasty on nasal air flow.

To determine if elective cosmetic septorhinoplasty impacts on nasal air flow resistance over the long-term. Case series. Mean postoperative follow-up period was 41.5 months (range, 16 to 77 months). A consecutive sample of 200 patients having undergone cosmetic open septorhinoplasty by one of us (P.A.A.) before July 1992 were contacted by telephone; 50 agreed to participate, and 27 actually participated in the study. Open cosmetic septorhinoplasty performed by one of us (P.A.A.). Comparison of preoperative and postoperative nasal resistance values by headout body displacement plethysmography; correlation of preoperative and postoperative nasal valve anatomy with nasal resistance values; and correlation of postoperative nasal resistance values with subjective evaluation of nasal air flow as reported on a 10-point analogue scale. Of the 27 patients, 10 had normal preoperative nasal resistance values and 17 had elevated resistance values. Preoperative Normal Group: Four of the 10 patients' mean resistance values exceeded normal limits postoperatively. One of these four patients reported subjective nasal obstruction. Preoperative Abnormal Group: Of the 17 patients, surgery resulted in normal resistance values postoperatively in six, decreased but still above normal resistance values in eight, and no decrease in postoperative resistance values in three. (1) Patients with normal nasal resistance values may suffer long-term, asymptomatic increase in nasal resistance values after cosmetic open septorhinoplasty, often with no quantifiable change at the nasal valve. (2) Patients with elevated nasal resistance measurements generally improve with open septorhinoplasty. Patients with isolated septal deformities improve with septoplasty. Patients with upper lateral cartilage collapse improve with spreader grafts. The lasting objective improvement on the nasal valve using spreader grafts is reported herein for the first time. (3) Subjective estimations of nasal patency do not correlate well with objective measures of patency, namely nasal resistance measurements. (4) Cosmetic septorhinoplasty can alter nasal patency. Continued care must be exercised when manipulating the nasal framework for cosmetic purposes, as slight changes to the nasal valve may result in significant alterations in nasal air flow resistance.