Airway Diameter Research Articles

Can lung anatomy predict the development of COVID-19 pneumonia in RT-PCR positive cases?

Purpose: The objective of this study was to investigate the relationship between Coronavirus disease 2019 (COVID-19) pneumonia and anatomical characteristics, including tracheobronchial and fissure variations, right/left main bronchus angle, carina angle, and large airway diameter, in patients who tested positive for the virus via reverse transcription-polymerase chain reaction (RT-PCR) at the outset of the pandemic. Materials and Methods: This cross-sectional study included 165 cases with positive RT-PCR tests who were admitted between March and June 2020 and subsequently scanned with thin-section unenhanced chest computed tomography (CT). They were divided into two groups according to the presence of pneumonia based on the chest CT images. Results: In our study, a total of 165 cases were analyzed, pneumonia was found in 35 of 76 (46.05%) female patients and 51 of 89 (57.30%) male patients. COVID-19 pneumonia was observed in older age groups. Anatomical variations and the presence of incomplete fissures were statistically higher in the pneumonia-positive group, while the difference was not statistically significant for accessory fissures. Mean tracheal area and right main bronchus angle were statistically higher in the pneumonia-positive group compared to the negative patients. The right lung was more involved than the left in terms of both zonal and total lung involvement. When the presence of comorbidity was assessed, 59 patients (35.75%) were found to have comorbidity. Hypertension, diabetes mellitus and cardiovascular disease were significantly higher among comorbidities in the pneumonia-positive group. The regression model showed that hypertension was associated with a 3.75-fold increase in COVID-19 pneumonia in test positive cases. Conclusion: Anatomical lung variations and incomplete fissures were observed more frequently in the COVID-19 pneumonia cases, independent of other comorbidities. We believe that there are anatomical variables that can be used to identify those predisposed to pneumonia in RT-PCR test positive cases.

Utilizing ultrasonography to determine the minimal transverse diameter of the subglottic airway for informed selection of reinforced cuffed endotracheal tube models in children.

We explored the use of ultrasonography in determining the minimal transverse diameter of the subglottic airway (MTDSA) for the purpose of choosing an appropriate model of reinforced cuffed endotracheal tube. A total of 110 pediatric patients who received general anesthesia and tracheal intubation for selective surgeries at the hospital from February 2019 to February 2022 were chosen. They were then randomly assigned to three groups: 39 in the MTDSA group, 35 in the age formula group, and 36 in the height formula group. We assessed how accurately the appropriate endotracheal tube model was predicted in each group and compared their predictive performance. The age range of the enrolled pediatric patients was 3-6 years old. The ultrasonic measurement method demonstrated a prediction accuracy of 87.18%, while the age formula method and height formula method exhibited lower accuracy rates of 54.29% and 47.22%, respectively. Notably, the ultrasonic measurement method outperformed the other two methods significantly (P < 0.05). In the MTDSA group, 2 patients had their catheters changed during anesthesia, and the proportion of patients who changed their catheters was 5.13%. In the MTDSA group, 6 catheters were replaced, and the frequency of catheter replacement was 15.38%. In contrast, these percentages were much higher in the age formula group, at 31.43% and 45.71%, and in the height formula group, at 36.11% and 52.78%. The latter two groups had significantly higher values than the MTDSA group (P < 0.05). Regarding complications such as hoarseness, laryngeal edema, aspiration, and laryngospasm, the MTDSA group experienced a notably lower total incidence of 7.69% compared to the 37.14% in the age formula group and 41.67% in the height formula group, demonstrating statistical significance (P < 0.05). The ultrasonic measurement technique employed in MTDSA exhibits impressive precision when it comes to forecasting the specific model of a reinforced cuffed endotracheal tube for pediatric patients. This enhanced accuracy contributes significantly to minimizing the need for tube replacements during anesthesia and the associated complications. It holds immense importance in assisting clinicians in selecting the most appropriate pediatric endotracheal tube model for anesthesia induction.

Mesenchymal Vangl1 and Vangl2 facilitate airway elongation and widening independently of the planar cell polarity complex.

Adult mammalian lungs exhibit a fractal pattern, as each successive generation of airways is a fraction of the size of the parental branch. Achieving this structure likely requires precise control of airway length and diameter, as the embryonic airways initially lack the fractal scaling observed in the adult. In monolayers and tubes, directional growth can be regulated by the planar cell polarity (PCP) complex. Here, we characterized the roles of PCP complex components in airway initiation, elongation and widening during branching morphogenesis of the lung. Using tissue-specific knockout mice, we surprisingly found that branching morphogenesis proceeds independently of PCP complex function in the lung epithelium. Instead, we found a previously unreported Celsr1-independent role for the PCP complex components Vangl1 and Vangl2 in the pulmonary mesenchyme, where they are required for branch initiation, elongation and widening. Our data thus reveal an explicit function for Vangl1 and Vangl2 that is independent of the core PCP complex, suggesting a functional diversification of PCP complex components in vertebrate development. These data also reveal an essential role for the embryonic mesenchyme in generating the fractal structure of airways in the mature lung.

In vivo MRI and PET imaging in a translational ILD mouse model expressing non-resolving fibrosis and bronchiectasis-like pathology after repeated systemic exposure to bleomycin.

C57BL/6 mice received bleomycin (i.p. 35iU/kg) or saline as control twice per week for 4 weeks. Mice were monitored until 2 weeks after cessation of bleomycin administration (w4 + 1 and w4 + 2), referred to as the resting period. MRI scans were performed in weeks 3 and 4 and during the resting weeks. [18F]FDG-PET was performed at the last week of dosing (w4) and 2 weeks after the last dosing (w4 + 2). Lung tissue sections were stained with Masson's trichrome and evaluated by modified Ashcroft scoring. Lung volume and lesion volumes were assessed using MRI, as well as 3D mapping of the central airways. Bleomycin-challenged mice showed increased lung weights (p < 0.05), while total lung volume was unchanged (w4 and onward). Histology analysis demonstrated fibrotic lesions emanating from the distal parts of the lung. Fibrosis progression was visualized by MRI with significantly increased high signal in bleomycin-exposed lungs compared to controls (p < 0.05). In addition, a significant increase in central airway diameter (p < 0.01) was displayed in bleomycin-exposed animals compared to controls and further continued to dilate as the disease progressed, comparing the bleomycin groups over time (p < 0.05-0.001). Lung [18F]FDG uptake was significantly elevated in bleomycin-exposed mice compared to controls (p < 0.05). Non-invasive imaging displayed progressing lesions in the lungs of bleomycin-exposed mice, using two distinct MRI sequences and [18F]FDG-PET. With observed fibrosis progression emanating from distal lung areas, dilation of the central airways was evident. Taken together, this chronic bleomycin-exposure model is translationally more relevant for studying lung injury in ILD and particularly in the context of DIILD.

A pilot observation using ultrasonography and vowel articulation to investigate the influence of suspected obstructive sleep apnea on upper airway

Failure to employ suitable measures before administering full anesthesia to patients with obstructive sleep apnea (OSA) who are undergoing surgery may lead to developing complications after surgery. Therefore, it is very important to screen OSA before performing a surgery, which is currently done by subjective questionnaires such as STOP-Bang, Berlin scores. These questionnaires have 10–36% specificity in detecting sleep apnea, along with no information given on anatomy of upper airway, which is important for intubation. To address these challenges, we performed a pilot study to understand the utility of ultrasonography and vowel articulation in screening OSA. Our objective was to investigate the influence of OSA risk factors in vowel articulation through ultrasonography and acoustic features analysis. To accomplish this, we recruited 18 individuals with no risk of OSA and 13 individuals with high risk of OSA and asked them to utter vowels, such as /a/ (as in “Sah”), /e/ (as in “See”). An expert ultra-sonographer measured the parasagittal anterior–posterior (PAP) and transverse diameter of the upper airway. From the recorded vowel sounds, we extracted 106 features, including power, pitch, formant, and Mel frequency cepstral coefficients (MFCC). We analyzed the variation of the PAP diameters and vowel features from "See: /i/" to "Sah /a/" between control and OSA groups by two-way repeated measures ANOVA. We found that, there was a variation of upper airway diameter from “See” to “Sah” was significantly smaller in OSA group than control group (OSA: ∆12.8 ± 5.3 mm vs. control: ∆22.5 ± 3.9 mm OSA, p < 0.01). Moreover, we found several vowel features showed the exact same or opposite trend as PAP diameter variation, which led us to build a machine learning model to estimate PAP diameter from vowel features. We found a correlation coefficient of 0.75 between the estimated and measured PAP diameter after applying four estimation models and combining their output with a random forest model, which showed the feasibility of using acoustic features of vowel sounds to monitor upper airway diameter. Overall, this study has proven the concept that ultrasonography and vowel sounds analysis may be useful as an easily accessible imaging tool of upper airway.

Study on the rationality of small diameter metallic airway stent in treatment of tracheal stenosis in injured rabbits

BackgroundTo observe the occurrence of related complications after self-expandable metallic (SEM) airway stents implantation with different diameters at different time points, and to provide theoretical basis for the optimal chioce of existing airway stents in clinical practice.MethodsHealthy New Zealand white rabbits were used to establish benign tracheal stenosis models after chest CT examination. Forty-fivemodel rabbits with more than 50% of airway stenosis were divided into two groups. Small-diameter SEM stents (The ratio of stent diameter to airway diameter is nearly 1.0) were implanted in Group A in 21 rabbits, and large-diameter tracheal stents (The ratio of stent diameter to airway diameter is more than 1.2) were implanted in Group B in 24 rabbits. Stent-related complications were observed after stent implantation in 2nd,4th,8th, and 12th week by bronchoscopygross anatomy, pathological and the expressions of IL-1RA, IL-8 and MMP9 in involved tracheal.ResultsThe incidence rate of tracheomalacia of stent was significantly higher in group B (24/24 100%) than that in group A (1 /21,4.8%) (P < 0.05). The incidence rate of scar contracture at both ends of stent was significantly higher than in group B (11 / 24,45.8%) that in group A (2 /21, 9.5%) (P < 0.05). The pathological results of both A and B showed that the columnar epithelium of bronchial mucosa began to damage and detach, inflammatory cells infiltrated after 2nd and 4th week of stenting, The epithelium was repaired, the lamina propria glands almost disappeared, collagen fiber proliferation was obvious, and scars were formed after 8th and 12th week of stenting. ELISA results revealed that the expressions of IL-1RA, IL-8, and MMP9 were increased in the stent group than in model rabbit with benign tracheal stenosis. IL-1RA and MMP9 increased at different periods in group B, but the expression of IL-1RA and MMP9 showed a tread of increasing in the early stage and then decreasing in group A.ConclusionMetal stents can cause different degrees of stent-related complications in rabbits with benign tracheal stenosis. The incidence of stent-induced tracheomalacia and scar contracture were higher in Group B than that in Group A. IL-1RA, IL-8 and MMP9 may be involved in the development of complications after stentimplantation and peak value of group B movered backward. ing.

Comparison of airway collapsibility following single induction dose ketamine with propofol versus propofol sedation in children undergoing magnetic resonance imaging: A randomised controlled study.

Adequate sedation is essential for children undergoing magnetic resonance imaging (MRI) console. Propofol is commonly used for sedation, but it has the drawback of upper airway collapse at higher doses, which may be overcome by ketamine. This study was designed to evaluate the beneficial effect of ketamine on propofol in preventing airway collapse. Fifty-eight children undergoing MRI were randomised to Group P (propofol bolus dose followed by infusion or Group KP (bolus dose of ketamine and propofol followed by propofol infusion). The primary aim is to compare the upper airway cross-sectional area (CSA) and diameters (transverse diameter [TD] and anteroposterior diameter [APD]) obtained from MRI during inspiration and expiration. Upper airway collapse as measured by delta CSA in mean (SD) [95% confidence interval] was statistically more significant between the two groups [at the soft palate level, 16.9 mm2 (19.8) [9.3-24.4] versus 9.0 mm2 (5.50) [6.9-11.1] (P = 0.043); at the base of the tongue level, 15.4 mm2 (11.03) [11.2-19.6] versus 7.48 mm2 (4.83) [5.64-9.32] (P < 0.001); at the epiglottis level, 23.9 (26.05) [14.0-33.8] versus 10.9 mm2 (9.47) [7.35-14.5] (P = 0.014)]. A significant difference was obtained for TD at all levels and for APD at the soft palate and base of tongue level. Adding a single dose of ketamine to propofol reduced the upper airway collapse significantly, as evidenced by the MRI-based measurements of upper airway dimensions, compared to propofol alone.

Validated respiratory drug deposition predictions from 2D and 3D medical images with statistical shape models and convolutional neural networks.

For the one billion sufferers of respiratory disease, managing their disease with inhalers crucially influences their quality of life. Generic treatment plans could be improved with the aid of computational models that account for patient-specific features such as breathing pattern, lung pathology and morphology. Therefore, we aim to develop and validate an automated computational framework for patient-specific deposition modelling. To that end, an image processing approach is proposed that could produce 3D patient respiratory geometries from 2D chest X-rays and 3D CT images. We evaluated the airway and lung morphology produced by our image processing framework, and assessed deposition compared to in vivo data. The 2D-to-3D image processing reproduces airway diameter to 9% median error compared to ground truth segmentations, but is sensitive to outliers of up to 33% due to lung outline noise. Predicted regional deposition gave 5% median error compared to in vivo measurements. The proposed framework is capable of providing patient-specific deposition measurements for varying treatments, to determine which treatment would best satisfy the needs imposed by each patient (such as disease and lung/airway morphology). Integration of patient-specific modelling into clinical practice as an additional decision-making tool could optimise treatment plans and lower the burden of respiratory diseases.

Antenatal Endotoxin Induces Dysanapsis in Experimental Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, is characterized by impaired lung development with sustained functional abnormalities due to alterations of airways and the distal lung. Although clinical studies have shown striking associations between antenatal stress and BPD, little is known about the underlying pathogenetic mechanisms. Whether dysanapsis, the concept of discordant growth of the airways and parenchyma, contributes to late respiratory disease as a result of antenatal stress is unknown. We hypothesized that antenatal endotoxin (ETX) impairs juvenile lung function as a result of altered central airway and distal lung structure, suggesting the presence of dysanapsis in this preclinical BPD model. Fetal rats were exposed to intraamniotic ETX (10 μg) or saline solution (control) 2 days before term. We performed extensive structural and functional evaluation of the proximal airways and distal lung in 2-week-old rats. Distal lung structure was quantified by stereology. Conducting airway diameters were measured using micro-computed tomography. Lung function was assessed during invasive ventilation to quantify baseline mechanics, response to methacholine challenge, and spirometry. ETX-exposed pups exhibited distal lung simplification, decreased alveolar surface area, and decreased parenchyma-airway attachments. ETX-exposed pups exhibited decreased tracheal and second- and third-generation airway diameters. ETX increased respiratory system resistance and decreased lung compliance at baseline. Only Newtonian resistance, specific to large airways, exhibited increased methacholine reactivity in ETX-exposed pups compared with controls. ETX-exposed pups had a decreased ratio of FEV in 0.1 second to FVC and a normal FEV in 0.1 second, paralleling the clinical definition of dysanapsis. Antenatal ETX causes abnormalities of the central airways and distal lung growth, suggesting that dysanapsis contributes to abnormal lung function in juvenile rats.

Upper Airway Dimensions among Different Skeletal Malocclusions: A Retrospective Observational Study by Cephalometric Analysis.

In this retrospective cross-sectional study, lateral cephalometric radiographs of adult patients referred for orthodontic consultation were collected. Cephalometric tracing was performed with dedicated software. For each measure, descriptive statistics were calculated. Cephalometric measurements between the different skeletal classes were compared. Linear regressions were performed between upper airway diameters and cephalometric measurements, sex and age. Significance was predetermined for p < 0.05. Lateral cephalometric radiographs of 120 patients were reviewed. Nasopharynx length (NL) and depth (PD) measurements were significantly shorter in skeletal class III patients (p < 0.05). The superior pharyngeal airway space (SPAS) was found to be significantly shorter in class III patients as compared to class II patients (p < 0.05), and the mean airway space (MAS) of class I patients was found to be significantly shorter compared to class II patients (p < 0.05). Palate length (PL) values were found to be significantly longer in class I (p < 0.05). Linear regressions showed that the sella-nasion-A point angle (SNA) and Riedel's angle between point A, the nasion and point B (ANB) significantly influenced NL and PD (p < 0.05). Class III patients show significantly shorter nasopharynx measurements; clinicians should consider that this sagittal discrepancy could be related to an altered anatomy of the upper respiratory tract.

Significance of slow vital capacity, difference between slow and forced vital capacity, ratio of FEV1/SVC with increasing age and BMI in healthy males and females

Background: The slow vital capacity (SVC), forced vital capacity (FVC) difference, and forced expiratory volume in one second (FEV1)/SVC ratio are crucial for understanding respiratory health, especially in mild airway obstruction. These parameters are more reliable than traditional measures and are influenced by age and body mass index (BMI). Investigating their relationship can improve diagnostic accuracy and health-care interventions. Aims and Objectives: (i) To record peak expiratory flow rate (PEFR), FVC, FEV1 of expiration, FEV1/FVC ratio, forced expiratory flow rate (FEF25-75%), mean forced expiratory flow rate from 0.2 to 1.2 l of volume expired (FEF.2-1.2), SVC, and find the difference between SVC and FVC, ratio of FEV1/SVC. (ii) To correlate SVC, SVC-FVC, FEV1/SVC, and other pulmonary function tests (PFTs) with age, gender, and BMI emphasizing their importance in detecting airway obstruction. (iii) To assess these known indicators of airflow obstruction in healthy individuals to gain knowledge of changing lung health with respect to advancing age, gender, and BMI. Materials and Methods: The study included 200 individuals, comprising both men and women aged between 18 and 60 years, who were in good health. The sample was divided into five age groups, and participants were classified into categories of underweight, normal weight, overweight, and obese based on their BMI. Standard procedures were employed to record anthropometric measurements. PEFR was measured using Wright’s peak flow meter, whereas FVC, FEV1, FEV1/FVC ratio, forced expiratory flow between 25 and 75% of FVC (FEF25-75%), forced expiratory flow at 2-1.2 l (FEF.2-1.2), and SVC were assessed using an expirograph (Helios 401, RMS, India). Adequate statistical analysis was conducted on the gathered data. Results: There was a highly significant difference in the means of SVC, SVC-FVC, FEV1/SVC, and other PFTs (P &lt; 0.000) over the five age groups by ANOVA and a significant difference between younger and older age groups analyzed by post hoc test. It also showed a highly significant difference in the mean values of SVC, FEV1/SVC, and other PFTs over the categories of BMI and a significant difference between normal and obese groups by multiple comparisons. A small increase in mean values of SVC-FVC was seen in overweight, obese, and underweight compared to the normal BMI group. Females showed reduced mean values of SVC, FEV1/SVC, and other PFTs compared to males. (P &lt; 0.000). The mean value of SVC-FVC in females is greater than in males (P &lt; 0.01), which suggest that the tendency for airway obstruction may be greater in women compared to men due to smaller airway diameter and diffusion surface. PEFR, FVC, FEV1, FEV1/FVC, FEF25-75%, FEF.2-1.2, SVC, and FEV1/SVC were negatively correlated with age. SVC-FVC was positively correlated with age (r = 0.338, P &lt; 0.000). There was a negative correlation between PEFR, FVC, FEV1, FEF25-75%, FEF.2-1.2, SVC, and BMI. Conclusions: PFT serves as a crucial diagnostic tool in assessing respiratory health, with parameters such as FVC and FEV1 commonly utilized. However, SVC is gaining recognition for its nuanced insights into lung function. This article delves into the significance of SVC, highlights the differences between SVC and FVC, and explores the relationship between FEV1/SVC ratio, age, and BMI in healthy individuals. The current research was undertaken due to a scarcity of existing studies and demonstrated that SVC, the ratio of FEV1/SVC, and other PFTs diminish with age progression and increasing BMI. In addition, females exhibited decreased lung function, with a greater disparity between SVC and FVC than males.

Dynamic nasopharyngeal collapse in horses: What we know so far.

Dynamic nasopharyngeal collapse (NPC) is an obstructive upper airway disease that affects mainly the inspiratory phase of respiration in horses undergoing strenuous exercise. It occurs when the neuromuscular activity of the nasopharynx is overwhelmed by the intense negative pressures generated during exercise. This leads to collapse of at least one of the four components of the nasopharynx which is comprised of the two lateral walls, the dorsal roof and the ventral soft palate. As a result, the airway diameter and thus airflow become compromised. Even small changes in the airway diameter produces profound increases in negative inspiratory pressure, perpetuating the cycle of collapse. Compared to other dynamic upper respiratory tract disorders, the amount of literature on NPC as a disease entity is limited. The exact pathophysiology of NPC is unknown; however, it impacts up to one quarter of high-performance equine athletes presenting for poor performance. There is currently no definitive treatment for this severely performance-limiting condition. Thus, the prognosis for future athletic prognosis is guarded, with most horses being retired from racing or athletic use in general. Further research is warranted in this field to reduce the impact of disease and in turn, reduce the turnover rate and economic loss by enhancing the career longevity of elite equine athletes diagnosed with NPC.

Refinement of the acute inhalation limit test for inert, nano-sized dusts by an in silico dosimetry-based evaluation: case study for the dissolution of a regulatory dilemma.

This case study aims to describe the dilemma faced when exposing rats to very high concentrations of fine, pulverulent materials for acute inhalation studies and to address the regulatory question of whether the effects seen here are relevant to humans and the subject of classification according to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS). Many powders match the definition of nanomaterials in the EU; therefore, information on acute inhalation testing of powders up to the GHS cutoff of 5mg/L is required. However, testing rats at such a high aerosol concentration can cause physical obstruction of the airways and even mortality by suffocation. Therefore, to evaluate whether the physical effects on airway obstruction in rats exposed to 5mg/L for 4hours and alternative exposures to 1 and 2mg/L are relevant for humans, an in silico evaluation of aerosol deposition was conducted using the multiple-path particle dosimetry (MPPD) model. For this evaluation, actual exposure conditions for an organic, nano-sized pigment which produced 100% lethality in rats at 5mg/L, but not at 1mg/L, were used to assess the potential for airway obstruction in rats and accordingly in humans. As an indicator of the potential for airway obstruction, the ratio of the diameter of the deposited, aggregated aerosol to airway diameter was calculated for each exposure condition. For rats exposed to 5mg/L for 4h, approximately 75% of tracheobronchial and 22% of pulmonary/alveolar airways were considered vulnerable to significant or complete obstruction (ratios >0.5). In humans, an equivalent exposure resulted in just over 96% of human tracheobronchial airways that received deposited mass to airway diameter ratios between 0.3 and 0.4 (nasal) or 0.4 and 0.5 (oral), with no airways with ratios >0.5. For the pulmonary/alveolar region, ∼88% of the airways following nasal or oral breathing were predicted to have deposited aerosol diameter to airway diameter ratios <0.1, with no airways with ratios >0.5. Thus, the in silico results obtained for rats are in line with the pathological findings of the animal test. The predicted results in humans, however, affirm the hypothesis of a rat-specific high dose effect which does not justify a classification according to GHS.

A MULTISCALE MULTIPHYSICS FINITE ELEMENT FOR LUNG

The previously formulated finite element for lung mechanics (MSCL) by the author is extended to include airflow and molecular transport by diffusion. The lung mechanics is analyzed in detail providing an insight into the deformation of the microstructural elements. Also, some refinements are introduced with respect to the previous model. Here, the finite element is extended to incorporate airflow and convective-diffusive particulate (molecular) transport. The smeared concept (the Kojic Transport Model – KTM) is implemented with lung small airway generations considered as subdomains within the KTM. The subdomains refer to a selected number of generations according to the airway diameters. Each domain has its own volumetric fraction and transport tensor specified in terms of the airway size. The computational procedure implemented in the PAK-BIO software consists of three passes within each time step: mechanics, airflow, and diffusion. The current geometry is used for the airflow where the alveolar sacs are considered as the source terms for the last domain, according to the rate of volumetric deformation and volumetric fraction of the sacs. The pressure distribution calculated in the pass 2 is used for the convective term in the diffusion. Here, the alveolar sacs are included as the last subdomain. The new element is now termed the General Lung Finite Element (GLFE). Coupling airflow in large airways, governed by the Navier-Stokes equations, to small airways (with the Hagen-Poiseuille equations) is presented; the same coupling is given for diffusion. Numerical examples illustrate the generality of the formulated finite element.

Effect of Intralesional Steroid Injections Among Patients with Acquired Laryngotracheal Stenosis Undergoing Endoscopic Balloon Dilation Using Pulmonary Function Tests.

Objectives: Laryngotracheal stenosis (LTS) is characterized by an abnormal decrease in the upper airway diameter. The pulmonary function test (PFT) is an effective adjunctive diagnostic tool for upper airway obstruction. LTS can be managed with either open surgery or less invasive endoscopic approaches, among which endoscopic balloon dilation is the main method; this may include concurrent intralesional steroid injection (ILSI), which has the potential of improving the outcomes. However, the effectiveness of ILSI is unclear. We aimed to compare the improvement in PFT parameters among patients with acquired LTS following endoscopic balloon dilation who received and did not receive ILSIs. We also compared the recurrence times and rates between the 2 patient cohorts. Methods: We retrospectively collected data regarding pre- and postoperative PFTs, as well as inter-dilation interval records, obtained between June 2015 and April 2020. Results: We included 34 patients with acquired etiologies. The most common cause of stenosis was intubation (52.9%), followed by trauma (29.4%). Further, 52.9% of the patients received ILSIs. Symptom recurrence was reported in 23 (67.6%) cases, with no significant between-group difference -0.1389 [95% confidence interval (CI): -0.4483, 0.1705]. The mean (standard deviation) duration of the first reintervention was 8.62 (8.00) and 7.38 (3.20) months among patients who did and did not receive ILSIs, respectively (mean difference -1.23, P = .614, 95% CI -6.30, 3.84). Conclusion: Our findings indicated that PFT parameters improved following endoscopic balloon dilation, with forced expiratory volume in 1 second being significantly higher with concurrent ILSI. However, there was no between-method difference in the treatment effectiveness. Additionally, the restenosis recurrence rate was consistent with that reported in the literature.

Dysanapsis is not associated with exertional dyspnoea in healthy male and female never-smokers aged 40 years and older.

In healthy adults, airway-to-lung (i.e., dysanapsis) ratio is lower and dyspnoea during exercise at a given minute ventilation (V̇E) is higher in females than in males. We investigated the relationship between dysanapsis and sex on exertional dyspnoea in healthy adults. We hypothesized that females would have a smaller airway-to-lung ratio than males and that exertional dyspnoea would be associated with airway-to-lung ratio in males and females. We analyzed data from n=100 healthy never-smokers aged≥40 years enrolled in the Canadian Cohort Obstructive Lung Disease (CanCOLD) study who underwent pulmonary function testing, a chest computed tomography scan, and cardiopulmonary exercise testing. The luminal area of the trachea, right main bronchus, left main bronchus, right upper lobe, bronchus intermedius, left upper lobe, and left lower lobe were 22%-37% smaller (all p<0.001) and the airway-to-lung ratio (i.e., average large conducting airway diameter relative to total lung capacity) was lower in females than in males (0.609±0.070vs. 0.674±0.082; p<0.001). During exercise, there was a significant effect of V̇E, sex, and their interaction on dyspnoea (all p<0.05), indicating that dyspnoea increased as a function of V̇E to a greater extent in females than in males. However, after adjusting for age and total lung capacity, there were no significant associations between airway-to-lung ratio and measures of exertional dyspnoea, regardless of sex (all r<0.34; all p>0.05). Our findings suggest that sex differences in airway size do not contribute to sex differences in exertional dyspnoea.

Comparison of ventilatory and oxygen consumption measurements of yearling Thoroughbred colts and fillies exercising unridden on an all-weather track

Sex effects on ventilatory and oxygen consumption (V̇O2) measurements during exercise have been identified in humans. This study’s aim was to evaluate the hypothesis that there are sex effects on ventilatory and V̇O2 measurements in exercising, untrained yearling Thoroughbreds (Tb). Forty-one Tbs (16 colts, 25 fillies; 19.8 ± 1.4 months old) were recruited. Physiological, ventilatory and exercise data were gathered from horses exercising unridden at high intensity on an all-weather track from a global positioning-heart rate unit and a portable ergospirometry system. Data were analysed with an unpaired Student’s t-test and the Benjamini-Hochberg correction for multiple testing (P ≤ 0.05 significant). Mean bodyweight (BW, P = 0.002) and wither height (P = 0.04) were greater for colts than fillies. There were no differences in physiological and exercise data and absolute peak V̇O2 between groups. However, fillies had a higher mass specific peak V̇O2 (P = 0.03) than colts (121.5 ± 21.6 mL/kg.min vs. 111.9 ± 27.4 mL/kg.min). The peak breathing frequency was greater for fillies (P < 0.001) while the peak inspiratory (P < 0.001) and expiratory air flow (P < 0.001), peak expiratory tidal volume (VTE; P < 0.001) and peak minute ventilation (V̇E; P = 0.01) were greater for colts; there were no differences for peak VTE and V̇E when adjusted for BW. Differences in BW explain the differences in mass specific peak V̇O2 between groups. Given their morphological differences, it is likely that lung volumes and airway diameters are smaller for fillies, resulting in greater resistance and lower air flows and volumes. Further research is required to investigate the ventilatory differences and how they may change with maturation and impact performance.

Role of ultrasonography in upper airway assessment: A comparison with computerized tomography measurements

IntroductionThis study aimed to compare ultrasonography (US) measurements of the upper airway to computerized tomography (CT) measurements. Our study's primary outcome is to research the accuracy of US measurements in the evaluation of upper airway diameters when CT is taken as the gold standard; the secondary outcome is to determine the time required to obtain US measurements. MethodsThis prospective study included patients ≥18 years old that had undergone thoracic or neck CT due to current clinical necessity. The US measurement for each patient was performed by two researchers with different levels of experience, both of whom were blinded to each other and the CT measurements. Measurements were obtained from the vocal cords and subglottic region. The duration of the US performance was also recorded. ResultsThe US and CT measurements were obtained from 94 patients. Concordance between US and CT measurements was found in the Bland-Altman analysis, with a mean −0.05 mm difference for vocal cord diameter and −1.2 mm for subglottic diameter. The intra-class correlation coefficients (ICC) between the CT and US measurements were 0.993, and 0.609 for vocal cord and subglottic diameter measurements, respectively. The ICC between US performers was 0.992 for vocal cord diameter and 0.959 for subglottic diameter. The US's mean time for vocal cord diameter measurement was 38 ± 23 s, and the mean time for subglottic diameter measurement was 49 ± 30 s. ConclusionThe concordance between US and CT measurements is high and the measurements of different practitioners with different experience levels are compatible with each other.

Dosimetry Sensitivity in a Lower Dimensional Model of Patient-Specific Asthma Subjects.

Experimental uncertainty will impact in silico model calculations of aerosol delivery and deposition. Patient-specific dosimetry models are often parameterized based on medical imaging data, which contain inherent experimental variability. Here, we created and parameterized 1D models of three subject-specific asthmatic subjects and randomly assigned perturbations of up to 15 % on airway diameter, segmental volume, and defected volume. Sensitivity of imaging data experimental variability on dosimetry metrics were quantified. Lobar particle delivery primarily depended on the distal segmental volumes; 15 % range of noise resulted in delivery to the upper right lobe to vary at most from 15.2 and 18.2 % for one of the severe subjects. Particle deposition was most sensitive to airway diameter; 95 % confidence intervals spanned from 8 to 10.6 % in the mild/moderate subject for 15 % variation on input metrics for 5 [Formula: see text] diameter particles. While these results provide possible ranges of dosimetry calculations for a specific subject, the perturbations were not sufficient to model the large observed inter-subject variability (8.9, 19, and 14.5 % deposition, subjects 1--3, respectively, 5 [Formula: see text] diameter particles). This study highlights that in silico model predictions are robust in the presence of experimental uncertainty and that it continues to be necessary to perform subject-specific simulations, especially within the presence of heterogeneous airway disease. Sensitivity analysis provides confidence in calculating deposition in the airways of asthmatic subjects within the presence of experimental uncertainty.

COVID-19 progression in hospitalized patients using follow-up in vivo CT and ex vivo microCT.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease-19 (COVID-19) which can lead to acute respiratory distress syndrome (ARDS) and evolve to pulmonary fibrosis. Computed tomography (CT) is used to study disease progression and describe radiological patterns in COVID-19 patients. This study aimed to assess disease progression regarding lung volume and density over time on follow-up in vivo chest CT and give a unique look at parenchymal and morphological airway changes in "end-stage" COVID-19 lungs using ex vivo microCT. Volumes and densities of the lung/lobes of three COVID-19 patients were assessed using follow-up in vivo CT and ex vivo whole lung microCT scans. Airways were quantified by airway segmentations on whole lung microCT and small-partition microCT. As controls, three discarded healthy donor lungs were used. Histology was performed in differently affected regions in the COVID-19 lungs. In vivo, COVID-19 lung volumes decreased while density increased over time, mainly in lower lobes as previously shown. Ex vivo COVID-19 lung volumes decreased by 60% and all lobes were smaller compared to controls. Airways were more visible on ex vivo microCT in COVID-19, probably due to fibrosis and increased airway diameter. In addition, small-partition microCT showed more deformation of (small) airway morphology and fibrotic organization in severely affected regions with heterogeneous distributions within the same lung which was confirmed by histology. COVID-19-ARDS and subsequent pulmonary fibrosis alters lung architecture and airway morphology which is described using in vivo CT, ex vivo microCT, and histology.