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[Display omitted] The integrity of the airway epithelium is guarded by the airway basal cells that serve as progenitor cells and restore wounds in case of injury. Basal cells are a heterogenous population, and specific changes in their behavior are associated with chronic barrier disruption—mechanisms that have not been studied in detail in allergic rhinitis (AR). We aimed to study basal cell subtypes in AR and healthy controls. Single-cell RNA sequencing (scRNA-Seq) of the nasal epithelium was performed on nonallergic and house dust mite–allergic AR patients to reveal basal cell diversity and to identify allergy-related alterations. Flow cytometry, immunofluorescence staining, and in vitro experiments using primary basal cells were performed to confirm phenotypic findings at the protein level and functionally. The scRNA-Seq, flow cytometry, and immunofluorescence staining revealed that basal cells are abundantly and heterogeneously present in the nasal epithelium, suggesting specialized subtypes. The total basal cell fraction within the epithelium in AR is increased compared to controls. scRNA-Seq demonstrated that potentially beneficial basal cells are missing in AR epithelium, while an activated population of allergy-associated basal cells is more dominantly present. Furthermore, our in vitro proliferation, wound healing assay and air–liquid interface cultures show that AR-associated basal cells have altered progenitor capacity compared to nonallergic basal cells. The nasal basal cell population is abundant and diverse, and it shifts toward a diseased state in AR. The absence of potentially protective subtypes and the rise of a proinflammatory population suggest that basal cells are important players in maintaining epithelial barrier defects in AR. [ABSTRACT FROM AUTHOR]

Tracheal intubation is the gold standard for airway management in emergency medicine, but more difficult to apply for inexperienced individuals than laryngeal mask airway (LMA). The aim of our study was to investigate if inexperienced individuals are able to secure the airway with the help of LMA after a short introduction. A second aim was to evaluate Thiel-fixed specimens against unfixed ones. In a body donor model, LMA application was evaluated between medical students without previous airway experience and anesthesiologists by comparing the sealing of the larynx using a water column applied to the esophagus. LMAs were successfully applied in 46 out of 55 (83.6%) attempts by medical students and in 30 out of 39 (76.9%) attempts by anesthesiologists. Among medical students, 14.1% of all LMA applications were primarily leaky, compared with 18.8% in anesthesiologists. Esophageal sealing was better in Thiel-fixed specimens (leakage 10.9%) compared with unfixed specimens (leakage 22.9%). Our data showed no significant difference between anesthesiologists and medical students in terms of sealing of LMA. Therefore, we conclude that medical students without previous airway experience can quickly learn to apply LMA sufficiently and thus, achieve aspiration protection similar to anesthesiologists. Medical students without previous airway experience can successfully insert LMAs after a short introduction. Thiel-fixed specimens are suitable for studies as well as for training in LMA application. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnoea (OSA) and perioperative respiratory adverse events are significant risks for anaesthesia in children undergoing adenotonsillectomy. Upper airway collapse is a crucial feature of OSA that contributes to respiratory adverse events. A measure of upper airway collapsibility to identify undiagnosed OSA can help guide perioperative management. We investigated the utility of pharyngeal closing pressure (P CLOSE) for predicting OSA and respiratory adverse events. Children scheduled for elective adenotonsillectomy underwent in-laboratory polysomnography 2–12 weeks before surgery. P CLOSE measurements were obtained while the child was anaesthetised and breathing spontaneously just before surgery. Logistic regression was used to assess the predictive performance of P CLOSE for detecting OSA and perioperative respiratory adverse events after adjusting for potential covariates. In 52 children (age, mean [standard deviation] 5.7 [1.8] yr; 20 [38%] females), airway collapse during P CLOSE was observed in 42 (81%). Of these, 19 of 42 (45%) patients did not have OSA, 15 (36%) had mild OSA, and eight (19%) had moderate-to-severe OSA. All 10 children with no evidence of airway collapse during the P CLOSE measurements did not have OSA. P CLOSE predicted moderate-to-severe OSA (odds ratio [OR] 1.71; 95% confidence interval [CI]: 1.2–2.8; P =0.011). All children with moderate-to-severe OSA could be identified at a P CLOSE threshold of –4.0 cm H 2 O (100% sensitivity), and most with no or mild OSA were ruled out (64.7% specificity; receiver operating characteristic/area under the curve=0.857). However, there was no significant association between respiratory adverse events and P CLOSE (OR 1.0; 95% CI: 0.8–1.1; P =0.641). Measurement of P CLOSE after induction of anaesthesia can reliably identify moderate or severe OSA but not perioperative respiratory adverse events in children before adenotonsillectomy. ANZCTR ACTRN 12617001503314. [ABSTRACT FROM AUTHOR]

Aging is a major risk factor for obstructive sleep apnoea (OSA) and is associated with increased upper airway collapsibility, but the mechanisms are largely unknown. We hypothesized that the increase in OSA severity and upper airway collapsibility with age are partially mediated by upper airway, visceral and muscle fat infiltration. Male subjects underwent full polysomnography, upper airway collapsibility determination (Pcrit) after sleep induction with midazolam, upper airway and abdominal computed tomography. Tongue and abdominal muscle fat infiltration were assessed by the determination of muscle attenuation with computed tomography. Eighty-four males with a wide range of age (47 ± 13 years, range 22–69 years) and apnea-hypopnea index (AHI) (30 [14–60] events/h, range 1–90 events/h), were studied. Younger and older males were grouped according to the mean age. Despite similar body mass-index (BMI), older subjects had higher AHI, higher Pcrit, larger neck and waist circumference, higher visceral and upper airway fat volumes (P < 0.01) as compared to younger subjects. Age was associated with OSA severity, Pcrit, neck and waist circumference, upper airway fat volume and visceral fat (P < 0.05), but not with BMI. Older subjects had lower tongue and abdominal muscle attenuation as compared to younger subjects (P < 0.001). Age was inversely associated with tongue and abdominal muscle attenuation, indicating muscle fat infiltration. The associations between age, upper airway fat volume, visceral and muscle fat infiltration may help to explain the worsening of OSA and increased upper airway collapsibility with aging. • Aging is a major risk factor for obstructive sleep apnea, but mechanisms are unclear. • Aging is associated with higher sleep apnea severity and upper airway collapsibility. • Aging was associated with tongue and visceral fat infiltration. • Fat infiltration may partially explain age-associated worsening of OSA. [ABSTRACT FROM AUTHOR]

Accurate segmentation of the upper airway lumen and surrounding soft tissue anatomy, especially tongue fat, using magnetic resonance images is crucial for evaluating the role of anatomic risk factors in the pathogenesis of obstructive sleep apnea (OSA). We present a convolutional neural network to automatically segment and quantify upper airway structures that are known OSA risk factors from unprocessed magnetic resonance images. Four datasets (n = [31, 35, 64, 76]) with T1-weighted scans and manually delineated labels of 10 regions of interest were used for model training and validations. We investigated a modified U-Net architecture that uses multiple convolution filter sizes to achieve multi-scale feature extraction. Validations included four-fold cross-validation and leave-study-out validations to measure generalization ability of the trained models. Automatic segmentations were also used to calculate the tongue fat ratio, a biomarker of OSA. Dice coefficient, Pearson's correlation, agreement analyses, and expert-derived clinical parameters were used to evaluate segmentations and tongue fat ratio values. Cross-validated mean Dice coefficient across all regions of interests and scans was 0.70 ± 0.10 with highest mean Dice coefficient in the tongue (0.89) and mandible (0.81). The accuracy was consistent across all four folds. Also, leave-study-out validations obtained comparable accuracy across uniquely acquired datasets. Segmented volumes and the derived tongue fat ratio values showed high correlation with manual measurements, with differences that were not statistically significant (p < 0.05). High accuracy of automated segmentations indicate translational potential of the proposed method to replace time consuming manual segmentation tasks in clinical settings and large-scale research studies. [ABSTRACT FROM AUTHOR]

Shape and size of the nasopharyngeal airway is controlled by muscles innervated facial, glossopharyngeal, vagal, and hypoglossal cranial nerves. Contrary to brainstem networks that drive facial, vagal and hypoglossal nerve activities (FNA, VNA, HNA) the discharge patterns and origins of glossopharyngeal nerve activity (GPNA) remain poorly investigated. Here, an in situ perfused brainstem preparation (n=19) was used for recordings of GPNA in relation to phrenic (PNA), FNA, VNA and HNA. Brainstem transections were performed (n=10/19) to explore the role of pontomedullary synaptic interactions in generating GPNA. GPNA generally mirrors FNA and HNA discharge patterns and displays pre-inspiratory activity relative to the PNA, followed by robust inspiratory discharge in coincidence with PNA. Postinspiratory (early expiratory) discharge was, contrary to VNA, generally absent in FNA, GPNA or HNA. As described previously FNA and HNA discharge was virtually eliminated after pontomedullary transection while an apneustic inspiratory motor discharge was maintained in PNA, VNA and GPNA. After brainstem transection GPNA displayed an increased tonic activity starting during mid-expiration and thus developed prolonged pre-inspiratory activity compared to control. In conclusion respiratory GPNA reflects FNA and HNA which implies similar function in controlling upper airway patency during breathing. That GPNA preserved its pre-inspiratory/inspiratory discharge pattern in relation PNA after pontomedullary transection suggest that GPNA premotor circuits may have a different anatomical distribution compared HNA and FNA and thus may therefore hold a unique role in preserving airway patency. • Efferent glossopharyngeal nerve discharge has a pre-inspiratory/inspiratory discharge pattern. • Facial, glossopharyngeal and hypoglossal nerves display similar respiratory discharge patterns. • Glossopharyngeal nerve discharge persists after pontomedullary brainstem transection. • Brainstem networks that control respiratory glossopharyngeal nerve activity is different to facial and hypoglossal. [ABSTRACT FROM AUTHOR]

Endotracheal Tubes (ETTs) maintain and secure a patent airway; however, prolonged intubation often results in unintended injury to the mucosal epithelium and inflammatory sequelae which complicate recovery. ETT design and materials used have yet to adapt to address intubation associated complications. In this study, a composite coating of electrospun polycaprolactone (PCL) fibers embedded in a four-arm polyethylene glycol acrylate matrix (4APEGA) is developed to transform the ETT from a mechanical device to a dual-purpose device capable of delivering multiple therapeutics while preserving coating integrity. Further, the composite coating system (PCL-4APEGA) is capable of sustained delivery of dexamethasone from the PCL phase and small interfering RNA (siRNA) containing polyplexes from the 4APEGA phase. The siRNA is released rapidly and targets smad3 for immediate reduction in pro-fibrotic transforming growth factor-beta 1 (TGFϐ1) signaling in the upper airway mucosa as well as suppressing long-term sequelae in inflammation from prolonged intubation. A bioreactor was used to study mucosal adhesion to the composite PCL-4APEGA coated ETTs and investigate continued mucus secretory function in ex vivo epithelial samples. The addition of the 4APEGA coating and siRNA delivery to the dexamethasone delivery was then evaluated in a swine model of intubation injury and observed to restore mechanical function of the vocal folds and maintain epithelial thickness when observed over 14 days of intubation. This study demonstrated that increase in surface lubrication paired with surface stiffness reduction significantly decreased fibrotic behavior while reducing epithelial adhesion and abrasion. [Display omitted] • Inflammation and fibrosis in upper airway prevented by multimodal local delivery. • Hydrogel coatings retained by electrospun layer support lubrication against mucosa. • Drug delivery of siRNA polyplexes from hydrogel demonstrated silencing efficacy. • Low surface stiffness prevents oral mucosal abrasion and epithelial adhesion. • Electrospun fibers allow solid diffusion and controlled corticosteroid delivery. [ABSTRACT FROM AUTHOR]

Background: Open respiratory suctioning is defined as an aerosol generating procedure (AGP). Laryngopharyngeal suctioning, used to clear secretions during anaesthesia, is widely managed as an AGP. However, it is uncertain whether upper airway suctioning should be designated as an AGP due to the lack of both aerosol and epidemiological evidence.Aim: To assess the relative risk of aerosol generation by upper airway suctioning during tracheal intubation and extubation in anaesthetized patients.Methods: This prospective environmental monitoring study was undertaken in an ultraclean operating theatre setting to assay aerosol concentrations during intubation and extubation sequences, including upper airway suctioning, for patients undergoing surgery (N=19). An optical particle sizer (particle size 0.3-10 μm) sampled aerosol 20 cm above the patient's mouth. Baseline recordings (background, tidal breathing and volitional coughs) were followed by intravenous induction of anaesthesia with neuromuscular blockade. Four periods of laryngopharyngeal suctioning were performed with a Yankauer sucker: pre-laryngoscopy, post-intubation, pre-extubation and post-extubation.Findings: Aerosol was reliably detected {median 65 [interquartile range (IQR) 39-259] particles/L} above background [median 4.8 (IQR 1-7) particles/L, P<0.0001] when sampling in close proximity to the patient's mouth during tidal breathing. Upper airway suctioning was associated with a much lower average aerosol concentration than breathing [median 6.0 (IQR 0-12) particles/L, P=0.0007], and was indistinguishable from background (P>0.99). Peak aerosol concentrations recorded during suctioning [median 45 (IQR 30-75) particles/L] were much lower than during volitional coughs [median 1520 (IQR 600-4363) particles/L, P<0.0001] and tidal breathing [median 540 (IQR 300-1826) particles/L, P<0.0001].Conclusion: Upper airway suctioning during airway management was not associated with a higher aerosol concentration compared with background, and was associated with a much lower aerosol concentration compared with breathing and coughing. Upper airway suctioning should not be designated as a high-risk AGP. [ABSTRACT FROM AUTHOR]

[Display omitted] • The air flow and powder dynamics in the inhaler-airway systems were simulated using CFD-DEM. • Effects of the airway deformation on air flow and powder dispersion were analysed. • Effects of the airway sizes on air flow and powder dispersion were analysed. • Airway deformation caused more particle deposition in the deformed region. • Deposition efficiency in the airway increases with decreasing airway size. Aerosol drug delivery in the human airway is significantly affected by the morphology and size of the airway. This work developed a CFD-DEM model to simulate and analyze air flow and powder dynamics in combined inhaler-airway systems with different degrees of airway deformation (non-deformed, 50%, and 75% deformed) and sizes (adult, 0.80, and 0.62 scaled). The airways were generated based on a regular airway constructed from the MRI images through finite element method (for deformed airways) or scaling-down (for smaller airways). The airways were connected to Turbuhaler® through a connector. The results showed that under the same flow rate, the variation in the airway geometry and size had a minimum impact on the flow field and powder deposition in the device and the connector. However, deformation caused more particle deposition in the deformed region. Notably, the airway with 50% deformation had the most particles passing through the airway with the largest particle sizes due to its lower air velocity in the deformed area. Reducing airway size resulted in more powder deposition on the airway, particularly at the pharynx and mouth regions. This was because, with the same flow rate, the flow velocity in the smaller airway was higher, causing more particle–wall collisions in the mouth and pharynx regions. More importantly, the deposition efficiency in the 0.62-scaled airway was significantly higher than the other two airways, highlighting the importance of the different administration of aerosol drugs for young children. [ABSTRACT FROM AUTHOR]

Laryngeal inhalation injury carries a significant increase in mortality rate and often indicates immediate airway evaluation. This may be difficult in the setting of clinical deterioration necessitating immediate intubation, which itself can synergistically cause mucosal damage. Prior studies do not encompass predictive factors or long-term outcomes for the laryngotracheal complex. This systemic review of PubMed, Embase, and Cochrane identified studies investigating inhalational injuries of the upper airway. Demographic data as well as presentation, physical findings, and delayed sequelae were documented. Laryngotracheal burn patients were divided into two cohorts based on timing of laryngeal injury diagnosis (before- versus after-airway intervention). 1051 papers met initial search criteria and 43 studies were ultimately included. Airway stenosis was more common in patients that were intubated immediately (50.0%, n = 18 versus 5.2%, n = 13; p = 0.57). Posterior glottic involvement was only identified in patients intubated prior to airway evaluation (71.4%, n = 15). All studies reported a closed space setting for those patients in whom airway intervention preceded laryngeal evaluation. Laryngeal inhalational injuries are a distinct subset that can have a variety of minor to severe laryngotracheal delayed sequelae, particularly for thermal injuries occurring within enclosed spaces. Given these findings, early otolaryngology referral may mitigate or treat these effects. [ABSTRACT FROM AUTHOR]

Background: Identification of the obstruction site in the upper airway may help in treatment selection for patients with sleep-disordered breathing. Because of limitations of existing techniques, there is a continuous search for more feasible methods. Snoring sound parameters were hypothesized to be potential predictors of the obstruction site. Therefore, this review aims to i) investigate the association between snoring sound parameters and the obstruction sites; and ii) analyze the methodology of reported prediction models of the obstruction sites.Methods: The literature search was conducted in PubMed, Embase.com, CENTRAL, Web of Science, and Scopus in collaboration with a medical librarian. Studies were eligible if they investigated the associations between snoring sound parameters and the obstruction sites, and/or reported prediction models of the obstruction sites based on snoring sound.Results: Of the 1016 retrieved references, 28 eligible studies were included. It was found that the characteristic frequency components generated from lower-level obstructions of the upper airway were higher than those generated from upper-level obstructions. Prediction models were built mainly based on snoring sound parameters in frequency domain. The reported accuracies ranged from 60.4% to 92.2%.Conclusions: Available evidence points toward associations between the snoring sound parameters in the frequency domain and the obstruction sites in the upper airway. It is promising to build a prediction model of the obstruction sites based on snoring sound parameters and participant characteristics, but so far snoring sound analysis does not seem to be a viable diagnostic modality for treatment selection. [ABSTRACT FROM AUTHOR]

The immunoinhibitory receptor Siglec-8 on the surface of human eosinophils and mast cells binds to sialic acid–containing ligands in the local milieu, resulting in eosinophil apoptosis, inhibition of mast cell degranulation, and suppression of inflammation. Siglec-8 ligands were found on postmortem human trachea and bronchi and on upper airways in 2 compartments, cartilage and submucosal glands, but they were surprisingly absent from the epithelium. We hypothesized that Siglec-8 ligands in submucosal glands and ducts are normally transported to the airway mucus layer, which is lost during tissue preparation. Our aim was to identify the major Siglec-8 sialoglycan ligand on the mucus layer of human airways. Human upper airway mucus layer proteins were recovered during presurgical nasal lavage of patients at a sinus clinic. Proteins were resolved by gel electrophoresis and blotted, and Siglec-8 ligands detected. Ligands were purified by size exclusion and affinity chromatography, identified by proteomic mass spectrometry, and validated by electrophoretic and histochemical colocalization. The affinity of Siglec-8 binding to purified human airway ligand was determined by inhibition of glycan binding. A Siglec-8-ligand with a molecular weight of approximately 1000 kDa was found in all patient nasal lavage samples. Purification and identification revealed deleted in malignant brain tumors 1 (DMBT1) (also known by the aliases GP340 and SALSA), a large glycoprotein with multiple O-glycosylation repeats. Immunoblotting, immunohistochemistry, and enzyme treatments confirmed that Siglec-8 ligand on the human airway mucus layer is an isoform of DMBT1 carrying O-linked sialylated keratan sulfate chains (DMBT1S8). Quantitative inhibition revealed that DMBT1S8 has picomolar affinity for Siglec-8. A distinct DMBT1 isoform, DMBT1S8, is the major high-avidity ligand for Siglec-8 on human airways. [Display omitted] [ABSTRACT FROM AUTHOR]

This study delves into the dynamics of respiratory droplet dispersion in indoor settings, focusing on three pivotal aspects: the use of Respiratory Models (RM) versus Non-Respiratory Models (NRM), the influence of social distancing, and the size of exhaled droplets. Our advanced simulations reveal that RMs are essential for accurately predicting airflow and droplet trajectories, whereas NRMs tend to overestimate deposition. We further explore how variations in the distance between an infector and a susceptible individual significantly affect droplet behavior and potential transmission. Additionally, our findings highlight the critical role of droplet size in determining their travel and deposition patterns. These insights collectively provide a comprehensive understanding of aerosol transmission in indoor environments, offering valuable contributions to public health strategies aimed at controlling airborne diseases. [Display omitted] • Integrating respiratory models: boosts droplet trajectory prediction accuracy. • Simulating exhaled droplets: accounts for evaporation, heat, and mass transfer. • Analyzing social distance impact: varies droplet deposition on susceptible. • Assessing exhalation flow: crucial to determining exhaled droplets' fate. [ABSTRACT FROM AUTHOR]

[Display omitted] • The 3D model of upper respiratory tract was reconstructed based on fine CT images. • The airflow-dust transport law in the respiratory tract under turbulence was found. • The transport-deposition law of different density micron dust was obtained. • The influence mechanism of airflow volumes on dust movement-deposition was found. To address the health problems caused by the long-term intrusion of high-concentration dust generated in coal mining operations into the human respiratory tract, this study reconstructed a 3D digital model of the upper airway based on fine industrial CT scanning images, and established the micron particle migration calculation model by Euler-Lagrange method. The transport and deposition mechanisms of dust with different densities under different inspiratory intensities were simulated and analyzed. The simulated results were compared with the results of dust exposure experiments in the upper airway combined with 3D printing technology, and the relative errors obtained were in the range of 2.9% to 6.3%. The results showed that the airflow volume peaked in the nasopharynx, oropharynx, epiglottis, and larynx, leading to the airflow separation and formation of circulation that tend to cause dust deposition in these regions. As the dust density and inspiratory airflow volume increased, the deposition fraction of small dust particles (<1μm) in the upper airway slightly changed, and most of them escaped to the lung. For 7.07 μm dust particles, as the dust density increased from 1210 kg/m3 to 2750 kg/m3, the escape rate decreased from 31.43% to 0.48%, and this trend can be seen in the fitting function of escape rate and inspiratory airflow volume Y 7.07μm =(80–1.37 ν + 0.0064 ν 2) × 100%. When the dust particle diameter exceeded 20 μm, the impact of dust density was weakened by the large size of the dust, and the escape rate was close to 0% when the inspiratory airflow volume was 50–110 L/min. This study can provide theoretical support for the research and development of respiratory dust sensors and targeted dust prevention technologies. [ABSTRACT FROM AUTHOR]

Transnasal flexible laryngoscopy (TFL) is a practical and cost-effective procedure, allowing excellent evaluation of the upper airway with minimal risk of complications. The effect of obesity on endoscopic examination still remains unclear. The aim of this study was to determine if obesity has an effect on TFL. Demographic data including age and gender, and physical and endoscopic examinations including body mass index (BMI), neck circumference, and grade of the laryngeal view according to Tasli classification (TC), Mallampati classification (MC), Friedman classification, and Moore tongue base classification (MTC) scores of 200 patients were evaluated. The patients were divided into two categories as obese and nonobese, and the scores of patients were compared. Evaluation was made of 99 (50.5%) obese and 97 (49.5%) nonobese patients ranging in age from 18 to 65 years (mean age: 37.89 ± 13.55 years). Of the 196 patients in this study, 101 (51.5%) were male, and 95 (48.5%) were female. The mean BMI of the obese and nonobese patients was 33.18 ± 5.18 (min: 25, max: 45) and 22.48 ± 1.5 (min: 19, max: 24), respectively. According to cutoff points, 27 patients (27.3%) were classified as overweight, 30 (30.3%) as obese, and 42 (42.4%) as morbidly obese. According to TC, there was no statistically significant difference between the obese and nonobese groups (mean difference 0.12, P : 0.39). In Pearson correlation analysis, the scores for a correlation between TC, and MC and MTC were 0.206 (very weak) and 0.653 (strong), respectively, which were statistically significant (P < 0.05). There was no correlation between TC and BMI values (r = −0.051; P : 0.48). The results of this study demonstrated that obesity influences the scores of MC, Friedman classification, and MTC, but does not affect the laryngeal view on TFL. [ABSTRACT FROM AUTHOR]

The aims were to assess the airway morphologic changes, and to evaluate sleep respiratory function and the occurrence of obstructive sleep apnea (OSA) after mandibular setback. Fifteen prognathism patients underwent bilateral sagittal split ramus (BSSRO) with or without maxilla surgery were grouped by distance of mandibular setback as group A (≤6 mm, n = 7) and group B (>6 mm, n = 8). Morphological changes were assessed using lateral cephalometric radiography and cone-beam computed tomography (CBCT) at preoperative (T0) and 6 months after surgery (T1). Sleep respiratory functions were evaluated using polysomonography. On lateral cephalometric radiography, group B showed significant decreased at Vp (p = 0.028) and PAS-p (p = 0.017). It also significant different between groups (p = 0.011 and p = 0.009 respectively). On CBCT, airway volume and AP width of airway, except Np, decreased in both groups but not significant different between groups. Only group A showed significant different between T0 and T1, cross-sectional area of Vp (p = 0.043), AP width of Vp (p = 0.043), Hp (p = 0.042), and PAS-t (p = 0.043). In group B, apnea hypopnea index increased at T1 (p = 0.043) and REM sleep differed between groups (p = 0.04). In conclusion, mandibular setback decreased the pharyngeal airway dimensions although no OSA occurred. It might be predisposing of OSA. [ABSTRACT FROM AUTHOR]

The aim of this study was to test the reliability and validity of two software systems used to measure the pharyngeal airway space three-dimensionally. A sample of 40 cone beam computed tomography images from adult patients was taken from a database. The cone beam computed tomography images were analysed by InVivoDental and Dolphin 3D software systems by two calibrated examiners. Three nasopharynx and oropharynx prototypes were used as a reference standard to validate the software systems. The volume, minimum area and minimum area localization were the measurements tested. Measurements were compared using a paired t -test; correlated using Pearson's correlation and linear regression. Bland–Altman analysis was also used. We found significant differences in the oropharynx volume (P = 0.002) and nasopharynx minimum area localization (P = 0.009). The Dolphin 3D software presented higher-volume values than the ones found in the prototype, while the InVivoDental software presented lower values. Strong (r >0.7; P > 0.001) or very strong (r >0.9; P > 0.001) correlations were observed between the software systems. Bland–Altman analysis found good agreement between prototypes and the software systems. The measurements obtained from the Dolphin 3D and InVivoDental software systems are both reliable, strongly correlated, but should not be assumed as equal. Dolphin 3D software overestimates the nasopharynx and oropharynx volumes, while the InVivoDental software underestimates them. [ABSTRACT FROM AUTHOR]

To investigate the changes induced by surgically assisted rapid maxillary expansion (SARME) on palate and pharynx morphology as well as the correlation of these changes with the improvement of obstructive sleep apnea (OSA). The study was conducted in 16 patients, seven women and nine men, aged on average 40.23 ± 10.23 years, all of them with OSA confirmed by polysomnography (PSG) and with posterior crossbite. All participants underwent computed tomography (CT) and PSG before and after SARME. The CT scans were used to determine the dimensions of the palate and pharynx before and after surgery. Data were analyzed statistically by the paired t-test, Wilcoxon test and Pearson correlation, with the level of significance set at P < 0.05. A 56.24% reduction in apnea and hypopnea index was detected (from 33.23 ± 39.54 to 14.54 ± 19.48: P = 0.001). The total airway area increased on average by 23.99% (P = 0.016), although in a more expressive manner in its lower half (28.63%, P = 0.008). A 24% transverse bone increase was observed in the palate in the region of the first premolars and an 18% increase in the region of the first molars (from 2.42 ± 0.31 to 2.99 ± 0.26. P < 0.001, and from 3.11 ± 0.32 to 3.70 ± 0.41, P < 0.001, respectively), and a mean 15% reduction of its depth (from 1.07 ± 0.33 to 0.89 ± 0.18, P = 0.014). A moderate correlation was detected between palate depth and width and OSA severity, as well as a correlation of the reduction of palate depth and its transverse increase with the improvement of OSA, especially among patients with severe OSA. It appears that narrowing of the palate, especially in the premolar region, and its greater depth may be related to the severity of OSA. SARME promotes transverse maxillary widening and lowering of palate depth, thus reducing OSA among adults and expanding the airway, especially in its lower half. [ABSTRACT FROM AUTHOR]

To determine predictive fiberoptic findings of upper airway in children with allergic rhinitis. 129 children had fiberoptic evaluation of nasal cavity, pharynx and larynx. They were divided into allergic rhinitis group and normal group based on skin prick test results. All video recordings were randomly reviewed by three independent national board-certified otolaryngologists who were blinded to the clinical details and outcomes of the participants' allergy testing. Each physician assessed and documented 10-item questionnaire. Intra-rater, inter-rater reliability and correlation between items and allergic status was calculated. Intra-rater reliability was moderate to perfect for all physicians on all items (kappa = 0.578–0.962). Inferior turbinate hypertrophy (κ = 0.714, p = 0.02), middle turbinate hypertrophy (κ = 0.728, p = 0.01), discoloration of inferior turbinate (κ = 0.685, p = 0.01), adenoid hypertrophy (κ = 0.662, p = 0.02) had good inter-rater reliability and these findings were predictive of allergic rhinitis. Adenoid hypertrophy was less encountered in allergic rhinitis. All other endoscopic findings beyond the nasal cavity were not predictive for allergic rhinitis in children. Nasal cavity findings including inferior turbinate hypertrophy, middle turbinate hypertrophy, discoloration of inferior turbinate and adenoid tissue assessment rather than pharyngolaryngeal findings are predictive of allergic rhinitis in children. [ABSTRACT FROM AUTHOR]

• We introduced a model which simulated a normal sneezing for two cases using a healthy 30-year-old male person. • The results are consist of the variations of the velocity and pressure in the different cross sections of the airway system. • The model may help the medical system to have more data about the sneezing process. Sneezing is one of the most critical conditions that can occur in the human upper airway. As some reports confirm the injury to the human upper respiratory airway while sneezing. Therefore, the accurate study of the distribution of pressure and velocity in this case is of great importance. In the present study, using a real human upper airway model, the pressure and velocity of the airflow generated in the tract during the sneezing have been investigated. Also, considering the results from a spirometer device as a boundary condition in the simulation process, the calculations have become reliable. According to the results, during sneezing, taking into account that the average outlet flow rate from the mouth is 4.79 L/s, the velocity of outlet airflow from the mouth and nose reaches 5.3 and 8.4 m/s, respectively. These values were 11.5 and 19, respectively, when the desired maximum flow rate was 10.58 L/s. It can be concluded that the increasing of trachea flow rate, leads to higher percentage of the outlet flow rate from the nose. The highest average pressure and velocity have been occurred in the trachea. Among other salient results of this report, increased average static pressure of larynx to approximately 10 kPa can be pointed which indicates that this area is critical so that the thyroid cartilage defect is likely to occur. It is also noteworthy that the increase of speed at nasopharynx is up to 125 m/s so that the cross-section changing in this area leads the fluid acts as a jet flow. Due to the specific geometry of the nasal cavity, some streams similar to poor shocks are formed, these shocks get stronger by increasing of the flow rate. The thyroid cartilage and nasal cavity are exposed to maximum static pressure extremums, respectively. We introduced a model simulating a normal sneezing for two cases using a healthy 30-year-old male person. We believe that the model should be applied for different persons and an atlas of data could be obtained from different cases. This may help the medical system to have more data about the sneezing process. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea syndrome (OSAS) is a common form of sleep disorder. Lateral cephalograms and cone-beam computed tomography (CBCT) have been used for evaluation. However, it is lack of position comparison for these two assessments. Therefore, this study was aimed to evaluate the difference of upper airway measurements taken from lateral cephalograms in upright position and CBCT in supine position. This retrospective study enrolled patients with lateral cephalograms and CBCT images due to diagnostic necessity. The anterior-posterior distance of most constricted area in pharynx (PASmin) and the distance from mandibular plane to hyoid bone (MP-H) were identified and measured from 21 normal subjects without obstructive sleep apnea (9 males and 12 females, mean age 21.2 years). A paired data were measured from lateral cephalograms taken in upright position and lateral cephalometric images derived from CBCT taken in supine position. Both images were taken within two months. All data were analyzed statistically. No significant difference was identified in intra-examiner reliability (P > 0.05). PASmin measured from lateral cephalograms in upright position was larger than that taken from CBCT derived cephalometric images, but without statistical significant difference (P = 0.073). Significant difference of MP-H length was identified between two different image taking methods (P = 0.000), and the measurement was significantly larger in cephalograms taken from upright position. No correlations were found among the variables (Body Mass Index (BMI), age, gender) in this study. The only two variables correlated were PASmin and MP-H, and they were negatively correlated (r = −0.535). The anterior-posterior distance of most constricted area in pharynx (PASmin) and distance of mandibular plane to hyoid bone (MP-H) can be influenced due to change of body position. [ABSTRACT FROM AUTHOR]

Highlights • Dyscoordination of dilator muscles during sleep contributes to pharyngeal collapse. • We found a sleep-dependent shift in peri-pharyngeal muscles power spectrum. • This finding suggests a state-dependent alteration in dilators motor unit activation. • We speculate that this change may lessen dilator muscles' mechanical efficiency. Abstract Introduction In addition to dyscoordination of upper airway dilator muscles activity, sleep may also alter the pattern of intra-muscular activation of single motor units (SMUs). Such changes should be identifiable by a state dependent change in EMG power spectrum, i.e., a shift in centroid frequency (ƒc) during sleep. Methods EMGs of the genioglossus and four other peri-pharyngeal muscles were recorded in OSA patients (n = 8), age-matched healthy subjects (n = 7), and 5 young healthy subjects, and ƒc was calculated for wakefulness and sleep periods. Results ƒc decreased with the onset of sleep and returned to baseline levels after arousal. ƒc of all muscles decreased similarly and significantly during sleep in the OSA and the age-matched healthy subjects, but not in the young subjects. Conclusions The pattern of decrease in ƒc is compatible with altered synchronization of SMUs during sleep. We speculate that these changes may contribute to the failure of dilator muscles to improve flow limitation during sleep in older subjects. [ABSTRACT FROM AUTHOR]

Highlights • Retropalatal luminal area is smaller than retroglossal area at end-expiration. • Retropalatal airway is more dynamically-compliant than retroglossal airway. • Negative effort dependence is associated with inspiratory retropalatal narrowing. Abstract Objectives We hypothesized that preferential retropalatal as compared to retroglossal collapse in patients with obstructive sleep apnea was due to a narrower retropalatal area and a higher retropalatal compliance. Patients with a greater retropalatal compliance would exhibit a recognizable increase in negative effort dependence (NED). Methods Fourteen patients underwent upper airway endoscopy with simultaneous recordings of airflow and pharyngeal pressure during natural sleep. Airway areas were obtained by manually outlining the lumen. Compliance was calculated by the change of airway area from end-expiration to a pressure swing of −5 cm H 2 O. NED was quantified for each breath as [peak inspiratory flow minus flow at −5 cm H 2 O]/[peak flow] × 100. Results Compared to the retroglossal airway, the retropalatal airway was smaller at end-expiration (p < 0.001), and had greater absolute and relative compliances (p < 0.001). NED was positively associated with retropalatal relative area change (r = 0.47; p < 0.001). Conclusions Retropalatal airway is narrower and more collapsible than retroglossal airway. Retropalatal compliance is reflected in the clinically-available NED value. [ABSTRACT FROM AUTHOR]

We aim to determine average volumes of the upper airway, adenoids and tonsils in preterm and term infants and assess for the differences according to weight, sex and ethnicity. The volumes of the upper airways, tonsils and adenoids were measured from brain MR images in 96 (49 preterm and 47 term) infants and compared using a two-tailed t -test (significant at p < 0.05). The average volumes are reported for both groups. Term infants showed larger naso- and oropharyngeal volumes (independent of weight, sex, and ethnicity). No differences in hypopharyngeal, adenoidal or tonsillar volumes were found. [ABSTRACT FROM AUTHOR]

Human respiratory syncytial virus (RSV) is the leading cause of lower airway disease in infants worldwide and repeatedly infects immunocompetent individuals throughout life. Severe lower airway RSV infection during infancy can be life-threatening, but is also associated with important sequelae including development of asthma and recurrent wheezing in later childhood. The basis for the inadequate, short-lived adaptive immune response to RSV infection is poorly understood, but it is widely recognized that RSV actively antagonizes Type I interferon (IFN) production. In addition to the induction of the anti-viral state, IFN production during viral infection is critical for downstream development of robust, long-lived immunity. Based on the hypothesis that a vaccine that induced robust IFN production would be protective, we previously constructed a Newcastle disease virus-vectored vaccine that expresses the F glycoprotein of RSV (NDV-F) and demonstrated that vaccinated mice had reduced lung viral loads and an enhanced IFN-γ response after RSV challenge. Here we show that vaccination also protected cotton rats from RSV challenge and induced long-lived neutralizing antibody production, even in RSV immune animals. Finally, pulmonary eosinophilia induced by RSV infection of unvaccinated cotton rats was prevented by vaccination. Overall, these data demonstrate enhanced protective immunity to RSV F when this protein is presented in the context of an abortive NDV infection. [ABSTRACT FROM AUTHOR]

Objective To evaluate whether and when Drug-Induced Sleep Endoscopy (DISE) changes diagnosis and treatment plan in pediatric Obstructive Sleep Apnoea Syndrome (OSAS) with the aim to identify specific subgroups of patients for whom DISE should be especially considered. Methods A case-control study of DISE in 150 children with OSAS. Pre-operative OSA were assessed through detailed history, Chervin questionnaire, physical examination and overnight polysomnography. The group of study was divided into three subgroups according to clinical and polysomnographyc criteria: conventional OSAS, disproportional OSAS and persistent OSAS. Endoscopic evaluation of the upper airway during DISE was scored using Chan classification. Surgical treatment was tailored individually upon the basis of sleep endoscopy findings: performance of any surgery other than tonsillectomy and adenoidectomy (T&A) was considered as a change of the treatment plan. Cases and controls were compared considering presence and absence of DISE-directed extra surgery, respectively. Results 150 patients with mean age (SD) 56.09 (23.94) months and mean apnoea-hypopnea index (AHI) of 5.79 (6.52) underwent DISE. The conventional subgroup represented the 58.67% of the sample (n = 88), while the disproportional one counted for the 26.67% (n = 40), and the persistent one for 14.66% (n = 22) of the population. Sleep endoscopy changed the surgical plan in 4.5% of conventional OSAS, 17.5% of disproportional OSAS and 72.7% of persistent OSAS (p < 0.005). Overall, a change of the treatment plan operated by DISE was associated with a non-conventional OSAS status (OR = 6; 95% CI = 1.6–26.4). Conclusions DISE is a safe procedure in children suffering from OSAS, and, despite being unnecessary in conventional cases of OSA, DISE should be considered not only in syndromic children, as previously demonstrated, but also in the general non-syndromic pediatric population, in the case of non-conventional OSA patients, and in children with persistent OSAS. [ABSTRACT FROM AUTHOR]

Background Context: The occipito-C2 angle (O-C2a) influences the oropharyngeal space. However, O-C2a has several limitations. There is no normal value of O-C2a because of the wide individual variations, and O-C2a does not reflect translation of the cranium to the axis, another factor influencing the oropharyngeal space in patients with atlantoaxial subluxation.Purpose: The objective of this study was to propose a novel parameter that accounts for craniocervical junction alignment (CJA) and the oropharyngeal space.Study Design: This is a post hoc analysis of craniocervical radiological parameters from another study.Patient Sample: Forty healthy volunteers were included in the study.Outcome Measures: Craniocervical measurement parameters included the occipital and external acoustic meatus to axis angle (O-EAa), the C2 tilting angle (C2Ta), O-C2a, and the anterior-posterior distance of the narrowest oropharyngeal airway space (nPAS).Materials and Methods: We collected 40 healthy volunteers' lateral cervical radiographs in neutral, flexion, extension, protrusion, and retraction positions. We measured O-C2a, C2Ta (formed by the inferior end plate of C2 and a line connecting the external acoustic meatus and the midpoint of the inferior end plate of C2 [EA-line]), O-EAa (formed by the McGregor line and the EA-line), and nPAS. We evaluated the inter-rater and intrarater reliability of O-EAa and C2Ta, and the associations between each of the measured parameters.Results: The inter-rater and intrarater reliabilities of measuring O-EAa and C2Ta were excellent. The neutral position O-EAa values remained in a narrower range (mean±standard deviation, 90.0°±5.0°) than O-C2a (15.6°±6.7°) (Levene test of equality of variances, p=.044). In the linear mixed-effects models, sex, O-C2a, C2Ta, and O-EAa were significantly associated with nPAS. The marginal R2 values for the mixed-effect models, which express the variance explained by fixed effects, were 0.605 and 0.632 for the O-C2a and O-EAa models, respectively. In all models, the subaxial alignment (C2-C6a) had no significant association with nPAS.Conclusions: The O-EAa may be a useful parameter of CJA with several advantages over O-C2a, including less individual variation, easier visual recognition during surgery, and improved prediction of postoperative nPAS after occipitocervical fusion. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of counterclockwise (CCW) rotation and maxillomandibular advancement (MMA) on the upper airway space using three-dimensional images. An electronic search was performed in the PubMed, Cochrane Library, Scopus, Virtual Health Library, Web of Science, and OpenGrey databases (end date July 2016); a hand-search of primary study reference lists was also conducted. The inclusion criteria encompassed computed tomography evaluations of the upper airway spaces of adult patients undergoing orthognathic surgery with CCW rotation and MMA. The articles were evaluated for risk of bias with a tool for before-and-after studies. A meta-analysis was performed with the mean differences using a random-effects model. Heterogeneity was assessed with the Q -test and the I 2 index. The meta-analysis revealed significant ( P < 0.001) increases in both the total airway volume (effect size of 6832 mm 3 and confidence interval of 5554–8109 mm 3 ) and the minimum axial area (effect size of 92 mm 2 and confidence interval of 70–113 mm 2 ). The heterogeneity was low in both comparisons ( I 2 = 38% and 7%, respectively). The technique of mandibular advancement with CCW rotation produced significant increases in the volumes and areas of the upper airway spaces. [ABSTRACT FROM AUTHOR]

We tested the functional effects of hypoglossal (CNXII) stimulation in the anesthetized rabbit before and after injections of saline into the tongue base to obstruct the airway. Data (n = 6) show little or no effect of CN XII trunk stimulation; however, medial branch stimulation (20–100 Hz; 50–500 μs pulse width, and incremental increases from 10 μA) reduced upper airway resistance. Medial branch stimulation was less effective in reducing resistance than anterior advancement of the hyoid. Endoscopic viewing (n-3) of the retropalate showed this region as the narrowest and dynamically changed by anterior hyoid displacement, with less evident effects than CNXII stimulation. We conclude that under these conditions CNXII medial branch stimulation reduces airway resistance, especially after induced obstruction. [ABSTRACT FROM AUTHOR]

Up to 14% of the U.S. population is estimated to have obstructive sleep apnea (OSA), while the outcomes of the treatments have variable results. In the current study, a three-dimensional fluid-structure interaction modeling was applied to simulate the upper airway to identify the precise location, severity, and characteristic of airway collapse. This was accomplished using Simpleware ® and ANSYS ® software applied to a 3-D rendering of the airway in a real patient with severe OSA. During this simulation, areas which are prone to collapse and precipitate apneic episodes were identified at the tip of the soft palate and the base of the tongue, with intrathoracic pressure as low as −1370 Pa. These results are consistent with anatomical structures currently indicated and targeted in the treatment of OSA. This improved FSI modeling simulation, which is the first to completely model the whole upper airway without consideration of the nasal cavity in OSA, and can allow virtual modification of the airway prior to actual treatment by doctors. [ABSTRACT FROM AUTHOR]

In obstructive sleep apnea patients, contraction of lingual muscles protects the pharyngeal airway from collapse. Hypoglossal (XII) motoneurons innervate the muscles of the tongue and are themselves under wake-related excitatory drives, including that mediated by serotonin (5-HT). Estimates of endogenous 5-HT activation vary among different studies. We tested whether endogenous drive mediated by 5-HT is present in rat XII motoneurons when measured during the active period of the circadian cycle. We monitored sleep-wake states and lingual and nuchal electromyograms (EMGs) while perfusing the XII nucleus with a vehicle or a 5-HT 2 receptor antagonist (mianserin, 0.2 mM) at the active period onset. EMG levels were measured during each behavioral state and normalized by the mean EMG activity during wakefulness at 4–7am. Wake-related lingual EMG was significantly lower during mianserin perfusion than with the vehicle (53.0 ± 9.7% vs. 84.5 ± 8.7%; p = 0.002). Mianserin had no effect on nuchal EMG or sleep-wake behavior. Thus, rat XII motoneurons receive endogenous serotonergic activation during wakefulness when measured during the dark period. This indicates that XII motoneuronal activity is enhanced by 5-HT output during the active period of the circadian cycle. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnoea syndrome (OSAS) is a breathing disorder with a multifactorial etiology. The respiratory epithelium is lined with a thin layer of airway surface liquid preventing interactions between the airflow and epithelium. The effect of the liquid lining in OSAS pathogenesis remains poorly understood despite clinical research. Previous studies have shown that the physical properties of the airway surface liquid or altered stimulation of the airway mechanoreceptors could alleviate or intensify OSAS; however, these studies do not provide a clear physical interpretation. To study the forces transmitted from the airflow to the liquid-lined compliant wall and to discuss the effects of the airway surface liquid properties on the stimulation of the mechanoreceptors, a novel and simplified experimental system mimicking the upper airway fundamental characteristics (i.e., liquid-lined compliant wall and complex unsteady airflow features) was constructed. The fluctuating force on the compliant wall was reduced through a damping mechanism when the liquid film thickness and/or the viscosity were increased. Conversely, the liquid film damping was reduced when the surface tension decreased. Based on the experimental data, empirical correlations were developed to predict the damping potential of the liquid film. In the future, this will enable us to extend the existing computational fluid–structure interaction simulations of airflow in the human upper airway by incorporating the airway surface liquid effect without adopting two-phase flow interface tracking methods. Furthermore, the experimental system developed in this study could be used to investigate the fundamental principles of the complex once/twice-coupled physical phenomena. [ABSTRACT FROM AUTHOR]

Objectives: To establish normative data of upper airway structure in Chinese Han infants and preschool children.Methods: Magnetic resonance imaging (MRI) scans of 521 Chinese Han infants and preschool children (225 girls, 296 boys) aged from 1 day to 72 months were selected from the children who underwent head MRI at the Capital Institute of Pediatrics Affiliated Children Hospital, Beijing, China. No subjects had sleep-disordered breathing or associated conditions that may have affected the upper airway anatomy. The upper airway dimensions and surrounding soft tissue sizes were measured along the mid-sagittal and axial images.Results: On images from the mid-sagittal image, the normative values of the following were obtained for all age group: thickness of the adenoid and nasopharyngeal area, length and thickness of the soft palate, length and height of the tongue, length of upper airway, distance between the mental spine and clivus, and the adenoid oblique width, soft palate oblique width, and tongue oblique width along the mental spine-clivus line. Normative values of the mean tonsillar width and intertonsillar space on the axial images were also obtained. There were no differences in any measurements between boys and girls in either infants or preschool children. Older children had larger airway dimensions, as expected.Conclusion: Normative values for upper airway structure in Chinese Han infants and preschool children assessed by MRI were established. The upper airway dimension and surrounding soft tissues size, including soft palate, adenoid, tongue, and tonsils, were increased with age. There were no gender differences during the first six years of life. These data may prove useful when studying airway disease in Chinese Han children. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnoea (OSA) is highly prevalent in people with tetraplegia. Nasal congestion, a risk factor for OSA, is common in people with tetraplegia. The purpose of this study was to quantify objective and perceived nasal resistance and its stability over four separate days in people with tetraplegia and OSA (n = 8) compared to able-bodied controls (n = 6). Awake nasal resistance was quantified using gold standard choanal pressure recordings (days 1 and 4) and anterior rhinomanometry (all visits). Nasal resistance (choanal pressure) was higher in people with tetraplegia versus controls (5.3[6.5] vs. 2.1[2.4] cmH 2 O/L/s, p = 0.02) yet perceived nasal congestion (modified Borg score) was similar (0.5[1.8] vs. 0.5[2.0], p = 0.8). Nasal resistance was stable over time in both groups (CV = 0.23 ± 0.09 vs. 0.16 ± 0.08, p = 0.2). These findings are consistent with autonomic dysfunction in tetraplegia and adaptation of perception to high nasal resistance. Nasal resistance may be an important therapeutic target for OSA in this population but self-assessment cannot reliably identify those most at risk. [ABSTRACT FROM AUTHOR]

Identifying the deposition pattern of inhaled pharmaceutical aerosols in the human respiratory system and understanding the effective parameters in this process is vital for more efficient drug delivery to this region. This study investigated aerosol deposition in a patient-specific upper respiratory airway and determined the deposition fraction (DF) and pressure drop across the airway. An experimental setup was developed to measure the pressure drop in the same realistic geometry printed from the patient-specific geometry. The unsteady simulations were performed with a flow rate of 15 L/min and different particle diameters ranging from 2 to 30 µm. The results revealed significant flow circulation after the nasal valve in the upper and oropharynx regions, and a maximum local velocity observed in the nasopharynx. Transient cumulative deposition fraction showed that after 2 s of the simulation, all particles deposit or escape the computational domain. About 30 % of the injected large particles (d p ≥ 20 µm) deposited in the first 1 cm away from the nostril and more than 95 % deposited in the nasal airway before entering the oropharynx region. While almost 94 % deposition in trachea was composed of particles smaller than 5 µm. Approximately 20 % of inhaled fine particles (2–5 µm) deposited in the upper airway and the rest deposited in oropharynx, larynx and trachea. • Transient simulation of particle deposition. • Inhalation and exhalation breathing phases were considered. • Experimental measurements were performed to compare CFD pressure drop. • Dominant deposition were found in the oropharynx, larynx and trachea. [ABSTRACT FROM AUTHOR]

The human upper respiratory tract is the first site of contact for inhaled respiratory viruses and elaborates an array of innate immune responses. Seasonal variation in respiratory viral infections and the importance of ambient temperature in modulating immune responses to infections have been well recognized; however, the underlying biological mechanisms remain understudied. We investigated the role of nasal epithelium-derived extracellular vesicles (EVs) in innate Toll-like receptor 3 (TLR3)-dependent antiviral immunity. We evaluated the secretion and composition of nasal epithelial EVs after TLR3 stimulation in human autologous cells and fresh human nasal mucosal surgical specimens. We also explored the antiviral activity and mechanisms of TLR3-stimulated EVs against respiratory viruses as well as the effect of cool ambient temperature on TLR3-dependent antiviral immunity. We found that polyinosinic:polycytidylic acid, aka poly(I:C), exposure induced a swarm-like increase in the secretion of nasal epithelial EVs via the TLR3 signaling. EVs participated in TLR3-dependent antiviral immunity, protecting the host from viral infections through both EV-mediated functional delivery of miR-17 and direct virion neutralization after binding to virus ligands via surface receptors, including LDLR and ICAM-1. These potent antiviral immune defense functions mediated by TLR3-stimulated EVs were impaired by cold exposure via a decrease in total EV secretion as well as diminished microRNA packaging and antiviral binding affinity of individual EV. TLR3-dependent nasal epithelial EVs exhibit multiple innate antiviral mechanisms to suppress respiratory viral infections. Furthermore, our study provides a direct quantitative mechanistic explanation for seasonal variation in upper respiratory tract infection prevalence. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: The aim of this study is to investigate the prevalence of central sleep apneas syndrome (CSAS) in children with obstructive sleep apnea syndrome (OSAS) and the effect of adenotonsillectomy (A)TE on CSAS.Methods: Retrospective analysis of polysomnographic data in children diagnosed with OSAS and without comorbidity. A central apnea index (CAI) ≥1/h is considered abnormal and central sleep apnea syndrome (CSAS) is diagnosed at a CAI >5/h. Data are presented as median (25-75 percentile).Results: Data were available for 90 children, 35 girls and 55 boys, age 3.7 years (1.8-5.4), BMI-z score 0.20 (-0.85-0.90), oAHI 10.9/h (5.8-19.1). Sixty-four percent had an abnormal CAI and the prevalence of CSAS was 7.8%. There was a significant correlation between CAI and MinSat (r = -0.48, p = 0.01) and between CAI and age (r = -0.45, p = 0.01). Pre-postop PSG data were available for 41 children with a CAI ≥ 1/h. Central apnea index decreased from 2.2/h (1.7-3.8) to 1.3/h (0.8-2.6) (p < 0.001) following (A)TE along with an improvement in oAHI from 10.9/h (5.9-22.2) to 1.2/h (0.6-2.7) (p < 0.001). No patient had postoperative CSAS and a reduction in the CAI <1/h was observed in 11 patients (26,9%).Conclusion: A central apnea index ≥1/h is common in children with OSAS but CSAS (CAI >5) is rare. We observed a significant decrease in the CAI and a resolution of CSAS after (adeno)tonsillectomy. [ABSTRACT FROM AUTHOR]

Objective: To describe the pattern of upper airway (UA) obstruction in surgically naive children with Down syndrome and obstructive sleep apnea (OSA), and to evaluate the outcome of drug-induced sedation endoscopy (DISE)-directed treatment.Methods: A prospective study of DISE in surgically naive children with Down syndrome and OSA was performed. Treatment was individually tailored based on the DISE findings and was evaluated by control polysomnography (PGS). Results are presented as median (lower-upper quartile) unless otherwise stated.Results: In 41 children, aged 4.2 years (range, 2.8-6.0) with a body mass z score of 1.04 (-0.55 to 1.82) and obstructive apnea-hypopnea index (oAHI) of 10.1/h (range, 6.3-23.0), DISE was performed. Adeno-/tonsillar obstruction was found in 75.6% of the patients, and these patients subsequently underwent UA surgery. Seven patients were non-surgically treated, and three received a combined treatment. A multilevel collapse was present in 85.4%. Tongue base obstruction was present in ten patients (24.4%) and epiglottic collapse in 48.8%. Pre- and postoperative PSG data were available for 25 children (adenotonsillectomy, n = 16; tonsillectomy, n = 7; adenoidectomy, n = 2). A significant improvement in oAHI from 11.4/h (range, 7.7-27.0) to 5.5/h (range, 2.1-7.6) was found. Persistent OSA was present in 52% of the children. No significant association between different DISE findings and persistent OSA could be found.Conclusion: Most patients with Down syndrome and OSA present with multilevel collapse on DISE. Adenotonsillectomy results in a significant improvement of the oAHI; however more than half of the patients had persistent OSA, probably due to multilevel collapse. Upper airway evaluation may provide more insights into the pattern of UA obstruction in patients with persistent OSA. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the correlation between upper airway dimensions and hyoid bone position in Chinese adolescents based on cone beam computed tomography (CBCT) images. CBCT images from a total of 254 study subjects were included. The upper airway and hyoid bone parameters were measured by Materialism's interactive medical image control system (MIMICS) v.16.01 (Materialise, Leuven, Belgium). The airway dimensions were evaluated in terms of volume, cross-sectional area (CSA), mean CSA, length, anteroposterior dimension of the cross-section (AP), lateral dimension of the cross-section (LAT), and LAT/AP ratio. The hyoid bone position was evaluated using eight linear parameters and two angular parameters. Facial characteristics were evaluated using three linear parameters and three angular parameters. Most hyoid bone position parameters (especially the distance between the hyoid bone and hard palate) were significantly associated with most airway dimension parameters. Significant correlations were also observed between the different facial characteristic parameters and hyoid bone position parameters. Most airway dimension parameters showed significant correlations with linear facial parameters, but they displayed significant correlations with only a few angular facial parameters. These findings provide an understanding of the static relationship between the hyoid bone position and airway dimensions, which may serve as a reference for surgeons before orthodontic or orthognathic surgery. [ABSTRACT FROM AUTHOR]

Duchenne muscular dystrophy (DMD) is a genetic disease characterised by deficiency in the protein dystrophin. The respiratory system is weakened and patients suffer from sleep disordered breathing and hypoventilation culminating in periods of hypoxaemia. We examined the effects of an acute (6 h) hypoxic stress on sternohyoid muscle function (representative pharyngeal dilator). 8 week old male, wild-type (WT; C57BL/10ScSnJ; n = 18) and mdx (C57BL/10ScSn-Dmd mdx /J; n = 16) mice were exposed to sustained hypoxia (F I O 2 = 0.10) or normoxia. Muscle functional properties were examined ex vivo . Additional WT ( n = 5) and mdx ( n = 5) sternohyoid muscle was exposed to an anoxic challenge . Sternohyoid dysfunction was observed in mdx mice with significant reductions in force and power. Following exposure to the acute in vivo hypoxic stress, WT sternohyoid muscle showed evidence of functional impairment (reduced force, work and power). Conversely, mdx sternohyoid showed an apparent tolerance to the acute hypoxic stress. This tolerance was not maintained for mdx following a severe hypoxic stress . A dysfunctional upper airway muscle phenotype is present at 8 weeks of age in the mdx mouse, which may have implications for the control of airway patency in DMD. Hypoxic tolerance in mdx respiratory muscle is suggestive of adaptation to chronic hypoxia, which could be present due to respiratory morbidity. We speculate a role for hypoxia in mdx respiratory muscle morbidity. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnoea syndrome (OSAS) is a common respiratory disorder with devastating consequences for integrative body systems. A picture is emerging to illustrate wide-ranging deleterious consequences of disordered breathing during sleep for major homeostatic control systems, with considerable interest in cardiorespiratory and autonomic morbidity underpinning the development of hypertension. The vista is bleak when one also considers the link between OSAS and a host of other maladies. Exposure to chronic intermittent hypoxia (CIH), resulting from repeated obstructions of the pharyngeal airway, is a hallmark feature of OSAS that appears, in animal models, to drive the development and maintenance of several key morbidities. A growing body of evidence now points to aberrant respiratory plasticity at multiple levels following exposure to CIH. Herein, we review the experimental data revealing that CIH causes: respiratory muscle weakness and fatigue; impaired motor control of the upper airway; and, discordant respiratory rhythm and pattern generation. This multifaceted conspiracy creates the perfect storm with the potential to exacerbate OSAS—serving to establish an inescapable cycle of respiratory morbidity. Several pharmacological interventions in animal models appear wholly effective in preventing the calamitous consequences of CIH and may have application as adjunctive therapies in the treatment of OSAS. [ABSTRACT FROM AUTHOR]

Objective: Adrenergic receptors (ARs) include four general types (α1, α2, β1 and β2), which are found in different target tissues. α-AR agonists are commonly used for decongestant therapy of upper airway diseases. In order to clarify the roles of AR subtypes in the upper airways, we investigated the localization of these receptors by immunohistochemistry.Methods: Human turbinates were obtained after turbinectomy from 12 patients with nasal obstruction refractory to medical therapy. The specific cells expressing α- and β-AR proteins were identified by immunostaining using an anti-human AR subtype-specific antibodies (α1A-, α1D-, α2C- and β2-ARs) antibody.Results: Immunohistochemical analysis revealed that immunoreactivities for α1D- and β2-ARs were densely distributed in submucosal glands. In contrast, immunoreactivities for α1A- and 2C-ARs were densely distributed in vascular smooth muscle.Conclusion: Our results suggested that adrenergic receptor (AR) subtypes had different roles in upper airway diseases, such as allergic rhinitis and nonallergic rhinitis. [ABSTRACT FROM AUTHOR]

Introduction: The pathogenesis of upper airway collapse in people with obstructive sleep apnea (OSA) is not fully understood. The aim of this study was to systematically review the literature in order to assess the most relevant anatomical characteristics of the upper airway related to the pathogenesis of OSA by analyzing the three-dimensional upper airway anatomy.Method: A PICO (population/patient, intervention, comparison, outcome) search strategy, focusing on the upper airway anatomy of people with OSA, was conducted using the following databases: MEDLINE (PubMed), Excerpta Medica database (EMBASE), Web of Science, and Cochrane Library. The studies in which three-dimensional images were made from the participants who were awake and in the supine position during quiet breathing were selected in this systematic review.Results: Of the 758 unique retrieved studies, eight fulfilled the criteria for this systematic review. The minimum cross-sectional area of the upper airways of people with OSA, which is influenced by many factors such as hard and soft tissues surrounding the upper airway, was significantly smaller than that of those without OSA.Conclusion: Within the limitation of the selected studies, this systematic review suggested that a small minimum cross-sectional area is the most relevant anatomical characteristic of the upper airway related to the pathogenesis of OSA. [ABSTRACT FROM AUTHOR]

Elastic ducts with time-varying geometry are a recurrent issue in many engineering and physiological flow or sound production problems. In this study, we present and characterize a setup to study aero-acoustic phenomena through a deformable duct with time-varying geometry. The setup is designed in such a way that experimental control parameters relate directly to input parameters of a quasi-analytical geometrical model (Van Hirtum, 2015). We focus on low Mach number and moderate Reynolds number applications pertinent to physiological problems for which geometrical model input parameters can be related to well defined physiological quantities. Therefore, data gathered using the presented setup allow to study underlying physical phenomena and in addition favor comparison with high performance computational simulations as well as with analytical models for which a limited number of physiological meaningful input parameters are essential. Typical measurements illustrate the impact of geometrical control parameters on the acoustic pressure field in absence and in presence of flow, respectively. [ABSTRACT FROM AUTHOR]

The Nasal Obstruction Symptom Evaluation (NOSE) scale is a reliable and valid instrument used widely in otorhinolaryngology to evaluate nasal obstruction symptoms in patients with nasal disorders. The purpose of this study was to assess nasal obstruction symptoms prospectively in patients undergoing surgically assisted rapid maxillary expansion (SARME) using the NOSE scale. Sixteen patients were studied (mean age 31 ± 7.7 years), 10 women and six men, all with a transverse maxillary deficiency and an indication for SARME. Hyrax type devices were placed preoperatively and SARME was performed using Kraut's technique. The NOSE scale was applied prospectively to assess nasal obstruction symptoms. The results were recorded for each score on a scale ranging from 0 to 4, and these scores were multiplied by 5, generating a balanced scale from 0 to 100. Data were stratified according to NOSE scores, and nasal obstruction was categorized as mild (0–25), moderate (26–50), or severe (>50). The questionnaire was administered twice, first preoperatively and then at 6 months after surgery, and the results compared. Data were analyzed statistically using SAS statistical package software and showed that patients experienced a subjective improvement or did not have a worsening of nasal obstruction symptoms after SARME. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnoea syndrome (OSAS) is a breathing disorder in sleep developed as a consequence of upper airway anatomical characteristics and sleep-related muscle relaxation. Fluid-structure interaction (FSI) simulation was adopted to explain the mechanism of pharyngeal collapse and snoring. The focus was put on the velopharyngeal region where the greatest level of upper airway compliance was estimated to occur. The velopharyngeal tissue was considered in a way that ensures proper boundary conditions, at the regions where the tissue adheres to the bone structures. The soft palate with uvula was not cut out from the surrounding tissue and considered as an isolated structure. Both, soft palate flutter as well as airway narrowing have been obtained by 3D FSI simulations which can be considered as a step forward to explain snoring and eventual occlusion. It was found out that during the inspiratory phase of breathing, at given elastic properties of the tissue and without taking gravity into consideration, velopharyngeal narrowing due to negative suction pressure occurs. Furthermore, soft palate flutter as the main attribute of snoring was predicted during the expiratory phase of breathing. The evaluated flutter frequency of 17.8 Hz is in close correlation with the frequency of explosive peaks of sound that are produced in palatal snoring in inspiratory phase, as reported in literature. [ABSTRACT FROM AUTHOR]

Purpose The goal of this retrospective study was to examine the radiological changes in the pharyngeal airway following mandibular distraction osteogenesis (DO) and bilateral sagittal split osteotomy (BSSO). Material and methods Between 2005 and 2009, a total of 41 nonsyndromic patients underwent a mandibular osteotomy (n DO = 23; n BSSO = 18). Digital volume tomography images were created for preoperative and postoperative evaluations of both groups. The Dolphin 3D program was used for comparative analysis of the pharyngeal airways. Results After DO, the airway volumes (VOL) improved by 6.8 mL. In comparison, an improvement of 5.9 mL was observed as result of BSSO. The minimum axial areas (AREA) of the enlargements increased by 109.1 mm 2 with DO and 103.1 mm 2 with BSSO. The airway areas (SA) increased by 193.8 mm 2 with DO and 185.2 mm 2 with BSSO. There were no significant differences between two surgical procedures in terms of the parameters describe above (p VOL = 0.358; p AREA = 0.752; p SA = 0.777). However, the initial preoperative values (p VOL = 0.020; p AREA = 0.005) and the patients' ages (p AREA = 0.042; p SA = 0.007) did have significant effects on the postoperative values. Conclusion Both DO and BSSO expanded the pharyngeal airways of all nonsyndromic patients. [ABSTRACT FROM AUTHOR]

Objective Swallowing statuses in patients with advanced cancers that require reconstruction have not been studied well. The relationship between topography of the reconstructed upper airway and swallowing status was evaluated. Material and methods Subjects comprised 19 cases of tongue cancer and 10 cases of mandibular cancer who underwent resection of the primary lesion and reconstructive surgery with the vascularized free flap. CT image data preoperatively and postoperatively were utilized to evaluate morphological airway changes. Videofluorographic swallowing study (VFSS) was performed postoperatively. Aspiration and laryngeal penetration were noted and compared with morphological airway changes. Results Regarding postoperative airway morphology, no significant differences in postoperative airway changes were apparent between tongue and mandibular cancers. In postoperative VFSS, aspiration and/or laryngeal penetration was seen in 32% of the tongue cancer cases and 20% of the mandibular cancer cases. Conclusion Cases with aspiration and/or laryngeal penetration revealed less reduction of postoperative cross-sectional area compared to other cases. [ABSTRACT FROM AUTHOR]