Overview of Nasal Airway and Nasal Breathing Evaluation.

Several methods are available for evaluating nasal breathing and nasal airflow, as this evaluation may be made from several different perspectives.Physiologic methods for nasal airway evaluation directly measure nasal airflow or nasal airway resistance, while anatomical methods measure nasal airway dimensions. Subjective methods evaluate nasal breathing through several validated patient-reported scales assessing nasal breathing. Computational fluid dynamics evaluates nasal airflow through the analysis of several physics' variables of the nasal airway.Being familiar to these methods is of utmost importance for the nasal surgeon to be able to understand data provided by the different methods and to be able to choose the combination of evaluation methods that will provide the information most relevant to each clinical situation.

Nasal Breathing Assessment Using Computational Fluid Dynamics: An Update from the Rhinologic Perspective.

An objective assessment of nasal breathing is currently insufficiently achievable. The application of computational fluid dynamics for this purpose is increasingly gaining attention. However, the suggested specific frameworks can differ considerably. To the best of our knowledge, there is not yet a widely accepted clinical usage of computational fluid dynamics. In this article, selected aspects are addressed that might be crucial for future development and possible implementation of computational fluid dynamics in rhinology.

Peak Nasal Inspiratory Flow (PNIF) for Nasal Breathing Evaluation.

Measuring nasal airflow and nasal breathing has been a major goal of rhinology. Many objective methods for measuring nasal airflow or nasal airway resistance or dimensions provide valuable data but are time-consuming and require expensive equipment and trained technicians, thus making these methods less practical for clinical practice. Peak nasal inspiratory flow (PNIF) measurement is fast, unexpensive, noninvasive, and able to provide an objective evaluation of nasal airflow in real-time. Unilateral PNIF measurements allow separated evaluation of each side of the nasal airway and may prove particularly useful when clinical assessment detects significant asymmetry between both nasal cavities.PNIF measurements are most useful for assessing changes in nasal airflow achieved by any form of therapy, including surgical treatment of the nasal airway. These measurements generally correlate with other objective methods for nasal airway evaluation, but not unequivocally with patient-reported evaluation of nasal breathing. Nevertheless, as low PNIF values prevent the sensation of a suitable nasal breathing, PNIF measurement may also prove useful to optimize the decision of how to best address patients with complaints of nasal airway obstruction.

Clinical Observation of the Effect of Nasal Breathing on Nonanalgesic and Sedative Gastroscopy.

This study aimed to investigate the safety, tolerance, and comfort of the subjects in gastroscopy by observing and comparing the effect of gastroscopy under two different breathing modes: nasal breathing and nasal inspiration and oral expiration. A total of 60 subjects who underwent routine gastroscopy in the hospital from January 2021 to June 2021 were selected as the research subjects. According to the willingness of the subjects, they were divided into a nasal breathing group and a nasal inspiration and oral expiration group. The differences in vital signs, adverse reactions, and visual analog scale (VAS) scores were compared between the two groups. There were no significant differences in mean arterial pressure, heart rate, and blood oxygen saturation between the two groups before, during, and after the examination (P > 0.05). The nasal breathing group had fewer adverse reactions such as nausea, cough, belching, and restlessness than the nasal inspiration and oral expiration group, and the difference was statistically significant (P < 0.01). VAS score of the nasal breathing group was lower than that of the nasal inspiration and oral expiration group, and the difference was statistically significant (P < 0.01). Subjects are more tolerant to nasal breathing mode, which causes fewer adverse reactions, less pain, and more comfort and is more worthy to be popularized in primary hospitals.

Importance of the numerical schemes in the CFD of the human nose.

Computational fluid dynamics of the air flow in the human nasal cavities, starting from patient-specific Computer Tomography (CT) scans, is an important tool for diagnostics and surgery planning. However, a complete and systematic assessment of the influence of the main modelling assumptions is still lacking. In designing such simulations, choosing the discretization scheme, which is the main subject of the present work, is an often overlooked decision of primary importance. We use a comparison framework to quantify the effects of the major design choices. The reconstructed airways of a healthy, representative adult patient are used to set up a computational study where such effects are systematically measured. It is found that the choice of the numerical scheme is the most important aspect, although all varied parameters impact the solution noticeably. For a physiologically meaningful flow rate, changes of the global pressure drop up to more than 50% are observed; locally, velocity differences can become extremely significant. Our results call for an improved standard in the description of this type of numerical studies, where way too often the order of accuracy of the numerical scheme is not mentioned.

Otogenic Pneumocephalus After Tegmen Bone Reconstruction: A Case Report.

Pneumocephalus is usually induced by trauma, infections, tumors of the skull base, and surgical interventions. Spontaneous pneumocephalus occurs due to a defect in the temporal bone with no obvious cause. Few cases have been reported with spontaneous otogenic pneumocephalus. However, delayed postoperative pneumocephalus is rarely reported in the literature. Here, we present a case of otogenic pneumocephalus through Eustachian tube (ET) preceded by nose blowing 10 days after surgical treatment of meningoencephalocele of the right middle ear (ME) cleft and reconstruction of tegmen and dural defects. Pneumocephalus was provoked by decreased intracranial pressure (ICP) secondary to placement of lumbar drain, which caused direct communication between unsutured dural defect and the defective posterior wall of external auditory canal skin. A revision surgery of combined transmastoid/middle cranial fossa approach was performed for intracranial decompression followed by appropriate closure by suturing the dura, obliterating the ET and ME.

Future Direction in Rhinoplasty: Functional Improvements for a Better Outcome.

The nose plays both an aesthetic and functional role in the human body. Physiologically, the nose is an important part of the upper airway. Aesthetically, it is the central focal point of the face. Thus, rhinoplasty has evolved to be both an aesthetic and functional surgery, as the manipulation of the aesthetic subunits of the nose inadvertently leads to the functional alterations of the nose. While the aesthetic goals of rhinoplasty are well described in the literature, functional outcomes from rhinoplasty have been more challenging to delineate. Rhinoplasty can have an impact on the sense of smell, sleep apnea, oxygenation, cognitive function, cardiovascular function, and voice. We have systematically reviewed the current literature in regard to functional rhinoplasty and septoplasty to summarize current surgical maneuvers and their impact on nasal function, along with physiological and perceived functional changes from rhinoplasty.

Dogs can sense weak thermal radiation.

The dog rhinarium (naked and often moist skin on the nose-tip) is prominent and richly innervated, suggesting a sensory function. Compared to nose-tips of herbivorous artio- and perissodactyla, carnivoran rhinaria are considerably colder. We hypothesized that this coldness makes the dog rhinarium particularly sensitive to radiating heat. We trained three dogs to distinguish between two distant objects based on radiating heat; the neutral object was about ambient temperature, the warm object was about the same surface temperature as a furry mammal. In addition, we employed functional magnetic resonance imaging on 13 awake dogs, comparing the responses to heat stimuli of about the same temperatures as in the behavioural experiment. The warm stimulus elicited increased neural response in the left somatosensory association cortex. Our results demonstrate a hitherto undiscovered sensory modality in a carnivoran species.

Efectos de la expansión rápida del maxilar sobre el flujo aéreo nasal en pacientes entre 6 y 14 años de edad, con compresión maxilar, medido a través de un flujómetro nasal portátil / Effects of rapid maxillary expansion on nasal airflow of patients between 6 and 14 years of age, with maxillary compression, measured with a portable nasal flowmeter

El objetivo de nuestro estudio de tipo longitudinal prospectivo simple de medidas repetidas fue determinar la variación del flujo aéreo nasal medido con un flujómetro nasal portátil, en niños entre 6 y 14 años de edad con compresión maxilar, después de la expansión rápida del maxilar (ERM). El trabajo constó de 16 niños diagnosticados con compresión maxilar y a quienes se les indicó una disyunción maxilar rápida. Los valores de la cantidad de expansión fueron registrados y la medición del flujo inspiratorio nasal máximo (FINM) se realizó antes de la ERM (T1), inmediatamente después (T2) y al cabo de 3 meses del período de retención (T3), manteniendo las mismas condiciones iniciales. El valor máximo y el promedio de las mediciones del FINM en T2 fueron significativamente mayores que en T1 (p-valor, 0,0056) y (p-valor 0,0062) respectivamente, mientras que entre T2 y T3 no existieron tales diferencias (p-valor: 0,3021) y (p-valor: 0,3315) respectivamente. Existe un aumento significativo en los valores del FINM inmediatamente después de la expansión rápida del maxilar que se mantienen en un período de tiempo de 3 meses.

The objective of our simple prospective longitudinal type study of repeated measures, was to determine the variation of nasal airflow measured with a portable nasal flow meter, in children between 6 and 14 years of age with maxillary compression, after rapid maxillary expansion (RME). The study consisted of 16 children diagnosed with maxillary compression and those who were identified with a rapid maxillary disjunction. The values of the amount of expansion were recorded and the measurement of the peak nasal inspiratory flow (PNIF) was performed before the ERM (T1), immediately after (T2) and after 3 months of retention period (T3), maintaining the same initial conditions. Results: the value maximum and average measurements of FINM in T2 were greater than in T1 (p-value, 0.0056) and (p-value 0.0062) respectively, while between T2 and T3 there were no differences (p value: 0.3021) and (p value: 0.3315) respectively. There is a significant increase in PNIF values immediately after rapid maxillary expansion that is in a period of 3 months.

Nasal Reconstruction Using the Integra Dermal Regeneration Template.

The reconstruction of nasal defects following oncologic resection has traditionally involved the use of locoregional flaps or full-thickness skin grafts. However, these options are not always feasible because of limitations in donor tissues, defect size or shape, oncologic issues, or patient preference. Reconstruction in this setting has been limited and unsatisfactory. In this report, the authors present their experience in reconstruction of nasal defects using the dermal regeneration template Integra. In most cases, reconstruction with Integra enabled a single-stage, satisfactory reconstruction. The authors present a simple, standardized technique for application and postoperative care, which has resulted in good aesthetic outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, IV.

Correction of the Over-resected Nose.

Overzealous reduction during rhinoplasty may result in manifold functional as well as aesthetic injuries to the nose and is a prevailing antecedent of revision rhinoplasty. Although challenges for the revision rhinoplasty surgeon abound, careful assessment of the anatomic deficiencies of the nose, accurate evaluation and management of a patient's expectations, and precise planning and execution of surgical technique serve to facilitate a successful result. Contemporary techniques for correction of the over-resected nose are discussed, with special attention directed toward costal cartilage grafting and diced cartilage fascia techniques.

Discriminant analysis followed by unsupervised cluster analysis including exosomal cystatins predict presence of chronic rhinosinusitis, phenotype, and disease severity.

BACKGROUND: Cystatins are epithelial protease inhibitors that participate in sinonasal immunity and inflammation. Nasal mucus-derived exosomes (NMDEs) are small vesicles secreted by epithelial cells that carry protein cargo reflective of their host cell. NMDEs have been used as a noninvasive biomarker source to study chronic rhinosinusitis with nasal polyps (CRSwNP) proteomics with superior sensitivity to whole mucus. The purpose of this study was to noninvasively quantify exosomal cystatins in a heterogenous population to determine their utility in predicting phenotype and disease severity. METHODS: This was an Institutional Review Board-approved study in which NMDEs were purified from 105 patients undergoing sinonasal surgery by ultracentrifugation. Demographic and clinical variables were collected and phenotypes were assigned a priori. Linear discriminant analysis was executed based on normalized Cystatin values as phenotype predictor variables. Unsupervised cluster analysis was performed using Ward's linkage followed by Duda/Hart Je(2)/Je(1) index cluster stopping rules. Analysis of variance (ANOVA), Welch's test, and Fisher's exact tests were used for continuous and categorical variables. RESULTS: NMDE Cystatin-2 expression segregated by phenotype (mean ± standard error [SEM]): control (23.4 ± 4.2 pg/µg, n = 32); CRS without NP (CRSsNP) (56.6 ± 8.3 pg/µg, n = 33); and CRSwNP (130.5 ± 16.7 pg/µg, n = 40) (p < 0.0001). Seven clusters were identified among patients where the highest NMDE Cystatin-2 levels clustered with asthma, tissue eosinophilia, and aspirin-exacerbated respiratory disease (AERD). CONCLUSION: Cystatin levels in NMDEs predict CRS phenotype and disease severity. As a "liquid biopsy," noninvasive NMDE collection offers a promising opportunity to study disease pathophysiology, discriminate disease states, and potentially reveal novel therapeutic targets.

Correlation between olfactory function, trigeminal sensitivity, and nasal anatomy in healthy subjects.

PURPOSE: Few studies have investigated the correlation between chemosensory function (trigeminal and olfactory) and nasal volume in humans, even though nasal anatomy is crucial for the sense of smell. Aim of this study was to evaluate these correlations in normosmic subjects. METHODS: Two hundred and fifty-six healthy volunteers (age range 19-69 years) participated. Olfactory function was investigated for (the rose-like) phenylethyl alcohol odor threshold and odor identification (OI) using the Sniffin' Sticks test, while nasal structure was evaluated by acoustic rhinometry (AR); trigeminal sensitivity was assessed in terms of detection "thresholds" for the odorless carbon dioxide (CO2). RESULTS: There were negative correlations between olfactory sensitivity at threshold level and minimum cross-sectional area (MCSA) in both nostrils. No significant correlations were found between OI and nasal anatomy. Similar to olfactory sensitivity, with regard to the trigeminal stimulus CO2 for the right nostril subjects were the more sensitive the smaller the MCSA. CONCLUSIONS: The current results emphasize the significance of nasal anatomy for trigeminal/olfactory threshold perception. Interestingly, correlations were not found between suprathreshold odor identification and nasal anatomy. Other than odor identification, odor thresholds appear to depend on subtle differences in nasal anatomy.

[Schirmer test for determining the moisture status of the nasal mucosa]. / Schirmer-Test zur Bestimmung des Feuchtezustands der nasalen Mukosa.

BACKGROUND: There is no established method to objectively measure the moisture status of nasal mucosa. In a pilot study it was shown that a nasal Schirmer test is a possible method. The aim of the current study was to check whether the nasal Schirmer test is suitable to define moisture status in cases with an expected pathological secretion. MATERIALS AND METHODS: Initially, 154 subjects participated, of whom n = 112 were included (healthy n = 65, deviated septum n = 47, ♂ 60, ♀ 52, median age 33 years). After evaluation of various test strips, the most suitable one was placed on both sides of the mucosa of the anterior septum. Secretion running distance (SRD) was measured in mm after 10 min. In addition, rhinomanometry (AAR) and acoustic rhinometry (AR) were performed. Healthy volunteers and subjects with septum deviation were compared, and subjects were also compared in terms of smoking behavior and age (<60 and ≥60 years). RESULTS: The total median SRD was 12 mm. SRDs between 9 and 14 mm were considered physiological. In non-smokers, SRD was significantly higher in all groups compared to smokers (p > 0.05). Nasal side, age, and deviated septum had no significant influence on SRD (p < 0.05). There were no correlations between SRD and AAR or AR. CONCLUSION: Our results confirm that a statement about moisture of the nasal mucosa is possible based on a nasal Schirmer test. Standard values of SRD are relevantly influenced by the respective test strip. Smoking is associated with a drier mucosa. Further investigations on the nasal Schirmer test in patients with expected atrophy of the nose, e. g., Sjogren's or empty nose syndrome, should be performed.

The Nasal Musculature as a Control Panel for Singing-Why Classical Singers Use a Special Facial Expression?

OBJECTIVES: This study aimed to explain the possible reason why classical singers seem to spread their nostrils and raise their cheeks before starting to sing. STUDY DESIGN: This is an experimental study. METHODS: Five subjects (three classical singers, two nonsingers) were investigated with nasofiberoscopy holding their breath after inhalation. The subjects were instructed to have a neutral expression first and then to take the singers' expression characterized by nostril flaring. In case of nonsingers, the special expression was rehearsed beforehand, guided by a classical singer. The following measurements were made: (1) height of soft palate, (2) area of the hypopharynx, (3) area of the epilaryngeal tube inlet (Aditus laryngis), and (4) dimensions of the (visible) glottis (length, width, and length-to-width ratio). RESULTS: All subjects raised the palate and widened the pharyngeal inlet, epilaryngeal inlet, and the glottis during "singer's expression." CONCLUSIONS: The results suggest that classical singers may take advantage of breathing- and smelling-related connections between nasal and facial muscles and the larynx to avoid a hard glottal attack and pressed phonation and possibly also to assist the production of mixed register (head voice), characterized by a relatively low adduction between the vocal folds.

Correlation of high flow nasal cannula outlet area with gas clearance and pressure in adult upper airway replicas.

BACKGROUND: Primary benefits of high flow nasal cannula therapy include washout of carbon dioxide rich exhaled gas and increased airway pressures during tidal breathing. This work reports on the influence of high flow nasal cannula outlet area on upper airways gas clearance and tracheal pressures using measurements in five realistic adult nose-throat airway replicas. METHODS: Two commercial high flow nasal cannulas and one generic nasal cannula of varying size were compared. 100% oxygen was supplied via cannulas at flow rates ranging from 30 to 90l/min to replicas originally filled with air, and oxygen concentrations at the larynx and trachea were compared over time. Additionally, and separately, replicas were connected to a mechanical lung simulator to simulate tidal breathing while undergoing high flow nasal cannula therapy, with tracheal pressure-time waveforms recorded. FINDINGS: Faster gas clearance corresponded with higher flow rates (P<0.001), and with smaller cannula outlet area (P<0.001). Observed pressures were in approximate agreement with limited available in-vivo data in the literature. Between 0 and 60L/min cannula flow rates, tracheal positive end expiratory pressures increase was greater with the smallest cannula (∆PPEEP=785SD(185) Pa) compared to the largest cannula (∆PPEEP=380SD(120)Pa). Regression analysis indicates that positive end expiratory pressure is proportional to the square of flow velocities exiting the cannula and nares (R2=0.906). INTERPRETATION: Since increased pressure and clearance rate have been associated with improved clinical outcomes in previous studies, our results suggest that smaller cannula outlet area may be preferable.

Novel mandibular advancement bite block with supplemental oxygen to both nasal and oral cavity improves oxygenation during esophagogastroduodenoscopy: a bench comparison.

Drug-induced respiratory depression is a major cause of serious adverse events. Adequate oxygenation is very important during sedated esophagogastroduodenoscopy (EGD). Nasal breathing often shifts to oral breathing during open mouth EGD. A mandibular advancement bite block was developed for EGD using computer-assisted design and three-dimensional printing techniques. The mandible is advanced when using this bite block to facilitate airway opening. The device is composed of an oxygen inlet with one opening directed towards the nostril and another opening directed towards the oral cavity. The aim of this bench study was to compare the inspired oxygen concentration (FiO2) provided by the different nasal cannulas, masks, and bite blocks commonly used in sedated EGD. A manikin head was connected to one side of a two-compartment lung model by a 7.0 mm endotracheal tube with its opening in the nasopharyngeal position. The other compartment was driven by a ventilator to mimic "patient" inspiratory effort. Using this spontaneously breathing lung model, we evaluated five nasal cannulas, two face masks, and four new oral bite blocks at different oxygen flow rates and different mouth opening sizes. The respiratory rate was set at 12/min with a tidal volume of 500 mL and 8/min with a tidal volume of 300 mL. Several Pneuflo resistors of different sizes were used in the mouth of the manikin head to generate different degrees of mouth opening. FiO2 was evaluated continuously via the endotracheal tube. All parameters were evaluated using a Datex anesthesia monitoring system. The mandibular advancement bite block provided the highest FiO2 under the same supplemental oxygen flow. The FiO2 was higher for devices with oxygen flow provided via an oral bite block than that provided via the nasal route. Under the same supplemental oxygen flow, the tidal volume and respiratory rate also played an important role in the FiO2. A low respiratory rate with a smaller tidal volume has a relative high FiO2. The ratio of nasal to oral breathing played an important role in the FiO2 under hypoventilation but less role under normal ventilation. Bite blocks deliver a higher FiO2 during EGD. The ratio of nasal to oral breathing, supplemental oxygen flow, tidal volume, and respiratory rate influenced the FiO2 in most of the supplemental oxygen devices tested, which are often used for conscious sedation in patients undergoing EGD and colonoscopy.

Nasal Functions in Three-Dimensional Endoscopic Skull Base Surgery.

OBJECTIVES: Endoscopic transnasal transsphenoidal surgery has become the standard procedure for the majority of skull base diseases, including sellar, parasellar, and clival pathologies. The aim of this study was the objective evaluation of nasal airflow resistances and olfactory function in 3-dimensional (3D) endoscopic transnasal transsphenoidal surgery. METHODS: One hundred patients who underwent 3D transnasal endoscopic surgery for sellar, parasellar, and clival diseases were enrolled. Active anterior rhinomanometry and Sniffin' Sticks tests were performed before endoscopic surgery and at 3 and 6 months postoperatively. RESULTS: No significant difference about nasal airflow resistance and olfactory function was observed between preoperative and postoperative subjective and objective scores. In the group of patients with sellar and parasellar diseases, a worst nasal respiratory function was seen when crusting was present, and a worst olfactory function was observed in patients with synechiae. Nasal functions returned to previous levels when crusting or synechiae solved. No statistically significant correlation was observed between the evaluated nasal functions and the reconstruction with flaps. CONCLUSIONS: The 3D endoscopic transnasal transsphenoidal surgery represents a more and more important tool in skull base surgery. It does not determine nasal respiratory and olfactory alterations after the treatment, without an increase in nasal complaints that could worsen quality of life.