Tracheal Morphology Research Articles

Slide Tracheoplasty in Long Segment Tracheobronchial Stenosis.

Long segmental congenital tracheal and tracheobronchial stenosis are a rare congenital airway anomaly with variable arborizations. This study aims to analyze presentations and outcomes of slide- tracheoplasty in long segmental congenital tracheal and tracheobronchial stenosis with variable arborizations METHODS: Retrospective analysis of all patients underwent slide tracheoplasty between March 1995 to Feb 2023 for long segmental congenital tracheal and tracheobronchial stenosis. Preoperative airway morphology was divided into anatomic types based on the Great Ormond Street Children Hospital Morphological Classification. Preoperative, intraoperative, postoperative and follow-up parameters were analyzed and compared among different arborizations with long segmental congenital tracheal and tracheobronchial stenosis. 210 patients underwent slide-tracheoplasty for long segmental congenital tracheal and tracheobronchial stenosis. Median age at surgery was 6 months (3, 15) and weight was 6.4 Kgs (4.2, 8.7). 40% (n = 85) had abnormal arborization and tracheal bronchus morphology was the most common among them. 24% (n = 50) patients had stenosis extending to one or more bronchus. Patients with carinal trifurcation presented early with critical airway stenosis, requiring ventilation support (60%) and ECMO support (35 %) as bridge to slide-tracheoplasty. The duration of post-operative ventilation was higher among the patients with congenital tracheobronchial stenosis (P = 0.006). Morphology with trifurcation arborization had higher mortality (23%) and stent requirement (35%). Slide-tracheoplasty remains the standard surgery for long segmental congenital tracheal and tracheobronchial stenosis even with different arborizations. Preoperative identification of tracheal arborizations and extend of stenosis help in surgical strategies for better outcomes.

Tracheal Ultrasound for Diagnosis of Tracheal Cartilaginous Sleeve in Patients with Syndromic Craniosynostosis.

The aim of this study was to assess the utility of ultrasound (US) imaging for diagnosis of abnormal tracheal morphology, such as tracheal cartilaginous sleeves (TCS), in patients with syndromic craniosynostosis (SC). Age-matched cohort study. Tertiary pediatric hospital. Two age-matched cohorts were identified: patients with SC and known TCS based upon airway endoscopy and normal controls without tracheal pathology. Enrolled patients underwent awake US of the neck which were randomized and reviewed by blinded pediatric radiologists and rated on presence or absence of normal tracheal cartilage morphology and visualization or nonvisualization of a tracheostomy tube. Fisher's exact test was used to assess pooled data. Fleiss' Kappa (κ) was calculated to assess inter-rater reliability. Ten patients were included in each cohort. Control patients were gender and age-matched to TCS patients with a mean difference of 3.7 months (±3.9 months). Across all raters, cartilage type was correctly identified in 93% (95% confidence interval [CI]: 84%-98%) and tracheostomy visualization in 97% (95% CI: 89%-99%). The sensitivity and specificity for detection of abnormal cartilage pathology was 87% and 100%, respectively. Inter-rater reliability for cartilage assessment was κ = 0.88 (95% CI: 0.67-1.00, P < .05) and 0.83 (95% CI: 0.58-1.00, P < .05) for tracheostomy presence. This study demonstrated that tracheal US is a feasible, accurate screening tool for TCS, and can be successfully performed non-sedated in patients up to 18 years of age, both with and without tracheostomy tubes in place.

A preliminary study of tracheal morphology in mixed-breed dog cadavers: Anatomical variation of tracheal cartilaginous rings

A preliminary study of tracheal morphology in mixed-breed dog cadavers: Anatomical variation of tracheal cartilaginous rings

Tracheoplasty should be proactively considered within the surgical strategy for treating the ring-sling complex

To examine the safety and effectiveness of proactive tracheoplasty for pediatric ring-sling complex. We retrospectively collected data from 304 children who were diagnosed with a ring-sling complex and underwent surgery at 3 cardiac centers in China between January 2010 and June 2023. The children were categorized into 3 surgical groups: concurrent sling and tracheal surgery (group A; n=258), staged sling and tracheal surgery (group B; n=25), and sling-only surgery (group C; n=21). We compared perioperative clinical characteristics, tracheal morphology changes, and outcomes across the 3 groups. The median age of the children was 1.2years (interquartile range, [IQR], 0.7-1.9years). The anomalous tracheobronchial arborization rates were higher in group A (52.5%) and group B (60.0%) compared to group C (15.0%). The preoperative narrow-wide ratio (NWR) was lower in groups A and B than in group C, with values of 0.44 (IQR, 0.35-0.52), 0.44 (IQR, 0.33-0.59), and 0.68 (IQR, 0.54-0.72), respectively (P<.001). Preoperative subcarina angles were similar among the groups (P=.54). After specific surgeries, the NWR and subcarina angle were improved significantly in groups A and B but not in group C. There were 7 in-hospital deaths and 2 postdischarge deaths. Respiratory symptoms improved in groups A and B, but 7 children in group C remained in respiratory dysfunction. Six children presented with residual stenosis of the left pulmonary artery. Concurrent sling and tracheal surgeries for children with the ring-sling complex are safe and effective and are especially preferable for those with NWR ≤0.6, long-segment or diffuse tracheal stenosis, anomalous tracheobronchial arborization, and pronounced respiratory symptoms.

Micro-CT Imaging of Tracheal Development in Down Syndrome and Non-Down Syndrome Fetuses.

Down syndrome (DS) is associated with airway abnormalities including a narrowed trachea. It is uncertain whether this narrowed trachea in DS is a consequence of deviant fetal development or an acquired disorder following endotracheal intubation after birth. This study aimed to compare the tracheal morphology in DS and non-DS fetuses using microfocus computed tomography (micro-CT). Twenty fetal samples were obtained from the Dutch Fetal Biobank and divided into groups based on gestational age. Micro-CT images were processed to analyze tracheal length, volume, and cross-sectional area (CSA). Mean tracheal length and tracheal volume were similar in DS and non-DS fetuses for all gestational age groups. Mean, minimum, and maximal tracheal CSA were statistically significantly increased in the single DS fetus in the group of 21-24 weeks of gestation, but not in other gestational age groups. In 90% of all studied fetuses, the minimum tracheal CSA was located in the middle third of the trachea. Tracheal development in DS fetuses was similar to non-DS fetuses between 13 and 21 weeks of gestation. This suggests that the narrowed tracheal diameter in DS children may occur later in fetal development or results from postnatal intubation trauma. The narrowest part of the trachea is in majority of DS and non-DS fetuses the middle third. 3 Laryngoscope, 134:4389-4395, 2024.

Inflammatory responses and barrier disruption in the trachea of chicks following Mycoplasma gallisepticum infection: a focus on the TNF-α-NF-κB/MLCK pathway

Mycoplasma gallisepticum (MG) can induce persistent inflammatory damage to the tracheal mucosa of poultry and cause chronic respiratory diseases in chickens. To further investigate the mechanism of MG-induced injury to the tracheal mucosa, we used chick embryo tracheal organ culture (TOC) as a model to study the invasion and reproduction of MG, the effect of MG on tracheal morphology, and the potential factors that promote MG tissue invasion. The results showed that MG infection significantly damaged the tracheal epithelial structure and weakened tracheal epithelial barrier function; MG also increased the occurrence of bacterial displacement, with a significant (p < 0.05) increase in the bacterial load of the infected TOCs at 5 and 7 days post-infection. In addition, MG significantly (p < 0.05) increased the expression levels of inflammatory cytokines, such as TNF-α, interleukin-1β (IL-1β), and IL-6, and activated the NF-κB signalling pathway, leading to increased nuclear translocation of NF-κB p65. Simultaneously, the map kinase pathway (MAPK) was activated. This activation might be associated with increased myosin light chain (MLC) phosphorylation, which could lead to actin-myosin contraction and disruption of tight junction (TJ) protein function, potentially compromising epithelial barrier integrity and further catalysing MG migration into tissues. Overall, our results contribute to a better understanding of the interaction between MG and the host, provide insight into the mechanisms of damage to the tracheal mucosa induced by MG infection, and provide new insights into the possible pathways involved in Mycoplasma gallisepticum infection in vivo.

Radiological and Anatomical Evaluation of the Tracheal Morphology and Morphometry in Turkish Adults

Radiological and Anatomical Evaluation of the Tracheal Morphology and Morphometry in Turkish Adults

3D-bioprinted cell-laden hydrogel with anti-inflammatory and anti-bacterial activities for tracheal cartilage regeneration and restoration

Despite the notable advances in tissue-engineered tracheal cartilage (TETC), there remain several challenges that need to be addressed, such as uneven cell distribution for cartilage formation, customized C-shaped tracheal morphology, local inflammatory reactions, and infections. To overcome these challenges, this study proposed the addition of icariin (ICA) and chitosan (CS) into a gelatin methacryloyl (GelMA) hydrogel to develop a new ICA/CS/GelMA hydrogel with anti-inflammatory and anti-bacterial properties, and three-dimensional (3D)-bioprinting feasibility. The aim of this study was to construct a TETC, a customized C-shaped cartilage structure, with uniform chondrocyte distribution as well as anti-inflammatory and anti-bacterial functions. Our results confirmed that ICA/CS/GelMA hydrogel provides desirable rheological properties, suitable printability, favorable biocompatibility, and simulated microenvironments for chondrogenesis. Moreover, the addition of ICA stimulated chondrocyte proliferation, extracellular matrix synthesis, and anti-inflammatory ability, while the encapsulation of CS enhanced the hydrogels&amp;rsquo; anti-bacterial ability. All these led to the formation of an enhanced TETC after submuscular implantation and an elevated survival rate of experimental rabbits after orthotopic tracheal transplantation. This study provides a reliable cell-laden hydrogel with anti-inflammatory and anti-bacterial activities, suitable printability, and significant advancements in in vivo cartilage regeneration and in situ tracheal cartilage restoration.

NDR kinase tricornered genetically interacts with Ccm3 and metabolic enzymes in Drosophila melanogaster tracheal development.

The Germinal Center Kinase III (GckIII) pathway is a Hippo-like kinase module defined by sequential activation of Ste20 kinases Thousand and One (Tao) and GckIII, followed by nuclear dbf2-related (NDR) kinase Tricornered (Trc). We previously uncovered a role for the GckIII pathway in Drosophila melanogaster tracheal (respiratory) tube morphology. The trachea form a network of branched epithelial tubes essential for oxygen transport, and are structurally analogous to branched tubular organs in vertebrates, such as the vascular system. In the absence of GckIII pathway function, aberrant dilations form in tracheal tubes characterized by mislocalized junctional and apical proteins, suggesting that the pathway is important in maintaining tube integrity in development. Here, we observed a genetic interaction between trc and Cerebral cavernous malformations 3 (Ccm3), the Drosophila ortholog of a human vascular disease gene, supporting our hypothesis that the GckIII pathway functions downstream of Ccm3 in trachea, and potentially in the vertebrate cerebral vasculature. However, how GckIII pathway signaling is regulated and the mechanisms that underpin its function in tracheal development are unknown. We undertook biochemical and genetic approaches to identify proteins that interact with Trc, the most downstream GckIII pathway kinase. We found that known GckIII and NDR scaffold proteins are likely to control GckIII pathway signaling in tracheal development, consistent with their conserved roles in Hippo-like modules. Furthermore, we show genetic interactions between trc and multiple enzymes in glycolysis and oxidative phosphorylation, suggesting a potential function of the GckIII pathway in integrating cellular energy requirements with maintenance of tube integrity.

Knockdown of Na,K-ATPase β-subunits in Oncopeltus fasciatus induces molting problems and alterations in tracheal morphology.

The ubiquitously expressed transmembrane enzyme Na,K-ATPase (NKA) is vital in maintaining functionality of cells. The association of α- and β-subunits is believed to be essential for forming a functional enzyme. In the large milkweed bug Oncopeltus fasciatus four α1-paralogs and four β-subunits exist that can associate into NKA complexes. This diversity raises the question of possible tissue-specific distribution and function. While the α1-subunits are known to modulate cardenolide-resistance and ion-transport efficiency, the functional importance of the β-subunits needed further investigation. We here characterize all four different β-subunits at the cellular, tissue, and whole organismal scales. A knockdown of different β-subunits heavily interferes with molting success resulting in strongly hampered phenotypes. The failure of ecdysis might be related to disrupted septate junction (SJ) formation, also reflected in β2-suppression-induced alteration in tracheal morphology. Our data further suggest the existence of isolated β-subunits forming homomeric or β-heteromeric complexes. This possible standalone and structure-specific distribution of the β-subunits predicts further, yet unknown pump-independent functions. The different effects caused by β knockdowns highlight the importance of the various β-subunits to fulfill tissue-specific requirements.

Comparison of Slide Tracheoplasty Technique on Postoperative Anatomic Outcomes in Three‐Dimensional Printed Models

We hypothesized that the use of three-dimensional (3D) printed tracheal models to reproducibly simulate surgical technique variations in slide tracheoplasty would demonstrate the quantitative impact of surgical variables on postoperative tracheal dimensions. Prospective analysis of three-dimensional printed surgical simulation models. Slide tracheoplasty was performed on 3D printed long segment tracheal stenosis models with combinations of tracheal transection incision angle (90°, 45° beveled superior to inferior, 45° beveled inferior to superior) and tracheal transection location relative to the stenosis (at midpoint, 2 mm each superior and inferior to midpoint). Postoperative computed tomography (CT) scans measured changes in tracheal length, volume, and cross-sectional area compared to controls. Statistical analysis was performed using one-way analysis of variance and unpaired two-tailed t-tests. Slide tracheoplasty yielded 27 reconstructed tracheas. On average, slide tracheoplasty reduced total tracheal length by 36%. Beveled tracheal incisions yielded 9.5% longer final tracheas than straight transection incisions (P < .0001). Cross-sectional area at the stenosis midpoint increased from 9.0 mm2 to 45 mm2 but did not vary with technique (P > .05). Total tracheal luminal volume increased from 900 mm3 to 1378 mm3 overall and was largest with beveled incisions (P=.03). More material was discarded with straight incisions compared to beveled (89 mg vs. 19 mg, P < .0001). Beveled tracheal transection incisions resulted in increased tracheal length, longer anastomotic segments, increased volume, and reduced tissue waste as compared to straight incisions. Offsetting the incision from the midpoint of stenosis did not significantly affect reconstructed tracheal morphology. Using 3D printed models for surgical simulation can be helpful for the quantitative study of the effect isolated surgical variables on technical outcomes. 3 Laryngoscope, 132:1306-1312, 2022.

Volumetric Morphology of Segmental Trachea Sections

Introduction & Objective The trachea is the airway between the larynx and primary bronchi, extending from the inferior aspect of the cricoid cartilage to its bifurcation at the carina. Its anterior and lateral walls are comprised of 16-22 C-shaped cartilaginous rings held together by annular ligaments, while its posterior wall consists primarily of trachealis muscle. Studies of trachea length, coronal and sagittal diameters, and dynamics are well represented in the literature with significant differences reported between genders. However, studies regarding volumetric morphology of the trachea are limited. Several structures (e.g., thyroid gland, brachiocephalic trunk, left brachiocephalic vein, etc.) are in contact with different regions of the trachea and could potentially affect lumen volumes. The objective of this study was to investigate tracheal volumetric morphology through segmental area analysis of cadaveric male and female tracheas and compare those results to a known case of distal trachea constriction. Materials & Methods Tracheas of seven male and seven female human cadavers were dissected, eviscerated, and photographed (iPad Pro, Apple Inc.). Trachea lengths were recorded to the nearest millimeter via gross measurement. Tracheas were covered at the proximal end and filled with water. Water volumes were subsequently measured in triplicate. Tracheas were then sectioned into ten equal segments and photographed (iPad Pro, Apple Inc.). Lumen areas of each segment were measured in triplicate (ImageJ, 1.52q), and mean segmental areas were multiplied by trachea length to determine segmentally derived trachea volumes. T-tests were used to compare segmentally derived volumes to actual volumes measured by water displacement. Male and female data were compared separately, and comparable data from a separate clinical case of distal tracheal constriction in a female cadaver was compared to the female data collected in this study. Results Male tracheas were longer (11.9 ± 0.7 cm vs. 10.3 ± 0.7 cm, p < 0.05) and of greater volume (28.7 ± 5.0 mL vs. 16.5 ± 0.8 mL, p < 0.05) compared to female tracheas. While sequential comparison of segmentally derived volumes in both genders suggest similar regions of natural trachea constriction (middle third) and dilation (distal third), both regions were statistically indifferent from actual trachea volume. The segmentally derived volumes from the distal half of the clinically constricted trachea were considerably less than the female volumetric data (distal half) quantified in this study (8.82 ± 1.36 mL vs. 14.86 ± 0.90 mL, p < 0.05). Conclusions & Significance While variations in lumen area of sequential trachea segments are apparent, they have little to no significant effect on total trachea volume unless substantially impacted by a clinical condition. Certain segments of the trachea may be more accurate for estimating its total volume. The noted mid-section constriction is believed to be caused by the brachiocephalic artery and left brachiocephalic vein crossing obliquely over the anterior aspect of trachea but merits more study. This study and future data expansion via additional tracheal measurements will help define “normal” tracheal volumetric morphology. This information may be valuable to physicians performing surgical procedures and diagnosing abnormalities of the trachea.

Diaphragmatic excursion: Quantitative measure to assess adequacy of expiratory phase CT chest images

ObjectiveTo evaluate diaphragmatic excursion as a quantitative metric for change in lung volume between inspiratory and expiratory chest computed tomography (CT) images. MethodsA 12-month retrospective review identified 226 chest CT exams with inspiratory and expiratory phase imaging, 63 in individuals referred with diagnosis of asthma by ICD9/10 code. Exams acquired in the supine position at 1.25 mm slice thickness in each phase were included (n = 30, mean age = 62, M = 15, F = 15). Diaphragmatic excursion was calculated as the difference between axial slices through the lungs on inspiration and expiration, using the lung apex as the cranial bound, and the hemidiaphragm caudally. Inspiratory and expiratory lung and tracheal volumes were calculated through volumetric segmentation. Tracheal morphology was assessed at 1 cm above the level of the aortic arch, and 1 cm above the carina. ResultsInspiratory and expiratory lung volumes were higher in men (mean I = 5 + 1.6 L, E = 3.1 + 1.2 L) than women (mean I = 3.6 + 0.8 L, E = 2.4 + 0.7 L), p = .005 and p = .047, respectively. Average inspiratory and expiratory tracheal volumes were higher in men (I = 61 + 17 mL, E = 43 + 14) than women (I = 44 + 14, E = 30 + 8), p = .006 and p = .005. Average change in lung and tracheal volume between inspiratory and expiratory scans did not significantly differ between men and women. Average diaphragmatic excursion was 2.5 cm between inspiratory and expiratory scans (2.7 cm in men, 2.3 cm in women; p = .5). There was a strong positive correlation between diaphragmatic excursion and change in lung (r = .84) and tracheal volume (r = .79). A moderate correlation was also found between change in tracheal volume and change in lung volume (r = 0.67). Change in tracheal morphology between inspiratory and expiratory imaging was associated with change in tracheal volume at both 1 cm above the aortic arch (p = .04) and 1 cm above the carina (p = .008); there was no association with diaphragmatic excursion or lung volume. ConclusionsDiaphragmatic excursion is a quantitative measure of expiratory effort as validated by both lung and tracheal volumes in asthma patients, and may be more accurate than qualitative assessment based on tracheal morphology.

Going underwater: multiple origins and functional morphology of piercing-sucking feeding and tracheal system adaptations in water scavenger beetle larvae (Coleoptera: Hydrophiloidea)

Abstract Larvae of water scavenger beetles (Coleoptera: Hydrophiloidea) are adapted to a wide variety of aquatic habitats, but little is known about functional and evolutionary aspects of these adaptations. We review the functional morphology and evolution of feeding strategies of larvae of the families Hydrophilidae and Epimetopidae based on a detailed scanning electron microscope (SEM) analysis, analysis of video records of feeding behaviour and observations of living larvae. There are two main types of feeding mechanisms: chewing and piercing-sucking. The character mapping using the latest phylogenetic hypothesis for Hydrophiloidea infers the chewing system as the ancestral condition. The piercing-sucking mechanism evolved at least four times independently: once in Epimetopidae (Epimetopus) and three times in Hydrophilidae (Berosini: Berosus + Hemiosus; Laccobiini: Laccobius group; Hydrobiusini: Hybogralius). The piercing-sucking apparatus allows underwater extra-oral digestion and decreases the dependence of larvae on an aerial environment. A detailed study of the tracheal morphology of the piercing-sucking lineages reveals four independent origins of the apneustic respiratory system, all of them nested within lineages with piercing-sucking mouthparts. We conclude that piercing-sucking mouthparts represent a key innovation, which allows for the subsequent adaptation of the tracheal system, influences the diversification dynamics of the lineages and allows the shift to new adaptive zones.

Current Practices in Endotracheal Tube Size Selection for Adults.

Intubation with inappropriately sized endotracheal tubes (ETT) can cause long-term tracheal and laryngeal injuries often requiring surgical intervention. Although tracheal size has been demonstrated to vary based on height and sex, it is unclear whether these guidelines are regularly implemented in patients undergoing endotracheal intubation. The objective of this study is to determine the rate of appropriate ETT size selection in patients undergoing intubation and assess provider decision making in ETT size selection. Retrospective cohort study. The study population was all patients who underwent endotracheal intubation over a two-week period at a tertiary academic medical center. Data were collected on patient age, gender, height, BMI, comorbidities, ETT size, duration of intubation, bronchoscopies, and type of practitioner who performed the intubation. A height-based nomogram for ETT size selection was used to determine the recommended ETT size for each patient. One hundred five patients met the inclusion criteria. 22% of patients were intubated with an inappropriately large tube, defined as 1.0 mm larger than the recommended size. Women were more likely to be intubated with an inappropriately large ETT (OR=13.58, P=.001), as were patients with height less than 160 cm (OR=141, P=.001). Other factors related to disease severity, anticipation for bronchoscopy, and BMI were not risk factors for the use of inappropriately large ETT. Although there is compelling evidence that height is a strong predictor of tracheal morphology and appropriate ETT size, height-based guidelines have yet to be universally adopted for ETT size selection. Laryngoscope, 131:1967-1971, 2021.

Genotype-Phenotype Correlation of Tracheal Cartilaginous Sleeves and Fgfr2 Mutations in Mice.

To characterize tracheal cartilage morphology in mouse models of fibroblast growth factor receptor (Fgfr2)-related craniosynostosis syndromes. To establish relationships between specific Fgfr2 mutations and tracheal cartilaginous sleeve (TCS) phenotypes in these mouse models. Postnatal day 0 knock-in mouse lines with disease-specific genetic variations in the Fgfr2 gene (Fgfr2C342Y/C342Y , Fgfr2C342Y/+ , Fgfr2+/Y394C , Fgfr2+/S252W , and Fgfr2+/P253R ) as well as line-specific controls were utilized. Tracheal cartilage morphology as measured by gross analyses, microcomputed tomography (μCT), and histopathology were compared using Chi-squared and single-factor analysis of variance statistical tests. A greater proportion of rings per trachea were abnormal in Fgfr2C342Y/+ tracheas (63%) than Fgfr2+/S252W (17%), Fgfr2+/P253R (17%), Fgfr2+/Y394C (12%), and controls (10%) (P < .001 for each vs. Fgfr2C342Y/+ ). TCS segments were found only in Fgfr2C342Y/C342Y (100%) and Fgfr2C342Y/+ (72%) tracheas. Cricoid and first-tracheal ring fusion was noted in all Fgfr2C342Y/C342Y and 94% of Fgfr2C342Y/+ samples. The Fgfr2C342Y/C342Y and Fgfr2C342Y/+ groups were found to have greater areas and volumes of cartilage than other lines on gross analysis and μCT. Histologic analyses confirmed TCS among the Fgfr2C342Y/C342Y and Fgfr2C342Y/+ groups, without appreciable differences in cartilage morphology, cell size, or density; no histologic differences were observed among other Fgfr2 lines compared to controls. This study found TCS phenotypes only in the Fgfr2C342Y mouse lines. These lines also had increased tracheal cartilage compared to other mutant lines and controls. These data support further study of the Fgfr2 mouse lines and the investigation of other Fgfr2 variants to better understand their role in tracheal development and TCS formation. NA Laryngoscope, 131:E1349-E1356, 2021.

Lung Parenchymal and Tracheal CT Morphology: Evaluation before and after Bariatric Surgery.

Background There is significant pulmonary functional deficit related to obesity, but no prospective CT studies have evaluated the effects of obesity on the lungs and trachea. Purpose To evaluate lung parenchymal and tracheal CT morphology before and 6 months after bariatric surgery, with functional and symptomatic correlation. Materials and Methods A prospective longitudinal study of 51 consecutive individuals referred for bariatric surgery was performed (from November 2011 to November 2013). All individuals had undergone limited (three-location) inspiratory and end-expiratory thoracic CT before and after surgery, with concurrent pulmonary function testing, body mass index calculation, and modified Medical Research Council (mMRC) dyspnea scale and Epworth scoring. Two thoracic radiologists scored the CT extent of mosaic attenuation, end-expiratory air trapping, and tracheal shape. The inspiratory and end-expiratory cross-sectional areas of the trachea were measured. The paired t test or Wilcoxon signed-rank test was used for pre- and postsurgical comparisons. Spearman correlation and logistic regression were used to evaluate correlations between CT findings and functional and symptom indexes. Results A total of 51 participants (mean age, 52 years ± 8 [standard deviation]; 20 men) were evaluated. Before surgery, air trapping extent correlated most strongly with decreased total lung capacity (Spearman rank correlation coefficient [rs] = -0.40, P = .004). After surgery, there were decreases in percentage mosaic attenuation (0% [interquartile range {IQR}: 0%-2.5%] vs 0% [IQR: 0%-0%], P < .001), air trapping (9.6% [IQR: 5.8%-15.8%] vs 2.5% [IQR: 0%-6.7%], P < .001), and tracheal collapse (201 mm2 [IQR: 181-239 mm2] vs 229 mm2 [186-284 mm2], P < .001). After surgery, mMRC dyspnea score change correlated positively with air trapping extent change (rs = 0.46, P = .001) and end-expiratory tracheal shape change (rs = 0.40, P = .01). At multivariable analysis, air trapping was the main determinant for decreased dyspnea after surgery (odds ratio, 1.2; 95% confidence interval: 1.1, 1.2; P = .03). Conclusion Dyspnea improved in obese participants after weight reduction, which correlated with less tracheal collapse and air trapping at end-expiration chest CT. © RSNA, 2020 Online supplemental material is available for this article.

The effect of ambient oxygen on the thermal performance of a cockroach, Nauphoeta cinerea.

The oxygen and capacity-limited thermal tolerance (OCLTT) hypothesis proposes that the thermal tolerance of an animal is shaped by its capacity to deliver oxygen in relation to oxygen demand. Studies testing this hypothesis have largely focused on measuring short-term performance responses in animals under acute exposure to critical thermal maximums. The OCLTT hypothesis, however, emphasises the importance of sustained animal performance over acute tolerance. The present study tested the effect of chronic hypoxia and hyperoxia during development on moderate to long-term performance indicators at temperatures spanning the optimal temperature for growth in the speckled cockroach, Nauphoeta cinerea In contrast to the predictions of the OCLTT hypothesis, development under hypoxia did not significantly reduce growth rate or running performance, and development under hyperoxia did not significantly increase growth rate or running performance. The effects of developmental temperature and oxygen on tracheal morphology and metabolic rate were also not consistent with OCLTT predictions, suggesting that oxygen delivery capacity is not the primary driver shaping thermal tolerance in this species. Collectively, these findings suggest that the OCLTT hypothesis does not explain moderate to long-term thermal performance in N.cinerea, which raises further questions about the generality of the hypothesis.

Tracheal Size and Morphology on the Reconstructed CT Imaging.

To characterize the real size and morphology of tracheas in childhood for the optimal selection of endotracheal tube. A retrospective cohort study of pediatric patients who received CT scan of the cervical spine from July 2011 to March 2018. Cross-sectional CT images vertical to trachea were reconstructed and the accurate tracheal diameters were measured. The validity of the traditional age-based formula for predicting the endotracheal tube size was assessed for the best fit to trachea. Tertiary Emergency and Critical Care Center of Kyushu University Hospital. Children, who are 1 month to 15 years old, received CT scan of the cervical spine. None. We enrolled 86 children with median age of 53 months. The cross-sectional shape of pediatric trachea was circular at the cricoid level and elliptical at the infraglottic level. The narrowest part of pediatric trachea was the transverse diameter at the infraglottic level at any age. Significant positive correlation between age and the narrowest diameter was observed. When compared the transverse diameter at the infraglottic level with the outer diameter of endotracheal tubes, uncuffed endotracheal tubes selection based on the traditional age-based formula ran a significant risk of oversized endotracheal intubation until 10 years old compared with cuffed endotracheal tubes selection (60.0% vs 23.8%; p < 0.05). These findings indicate the safety and efficacy of cuffed endotracheal tubes in infants and children and the reconsideration for the airway management in pediatric anesthesia and intensive care.

Impact of salt-contaminated freshwater on osmoregulation and tracheal gill function in nymphs of the mayfly Hexagenia rigida

The impact of freshwater (FW) salinization on osmoregulation as well as tracheal gill morphology and function was examined in nymphs of the mayfly Hexagenia rigida following exposure to salt contaminated water (SCW, 7.25 g/l NaCl) for a 7-day period. Ionoregulatory homeostasis was perturbed in SCW exposed H. rigida nymphs as indicated by increased hemolymph Na+, K+ and Cl− levels as well as hemolymph pH and water content. Despite this, SCW did not alter gill Na+-K+-ATPase (NKA) or V-type H+-ATPase (VA) activity. In addition, NKA and VA immunolocalization in gill ionocytes did not show alterations in enzyme location or changes in ionocyte abundance. The latter observation was confirmed using scanning electron microscopy (SEM) to examine exposed tracheal gill ionocyte numbers. Ionocyte surface morphometrics also revealed that SCW did not change individual ionocyte surface area or ionocyte fractional surface area. Nevertheless, analysis of Na+ movement across the tracheal gill of mayfly nymphs using scanning ion-selective electrode technique indicated that FW nymphs acquired Na+ from surrounding water, while tracheal gills of SCW nymphs had the capacity to secrete Na+. Because Na+ secretion across the gill of SCW-exposed animals occurred in the absence of any change in (1) NKA and VA activity or (2) ionocyte numbers/surface exposure, it was reasoned that Na+ movement across the gill of SCW animals may be occurring, at least in part, through the paracellular pathway. The ultrastructure of tracheal gill septate junctions (SJs) supported this idea as they exhibited morphological alterations indicative of a leakier pathway. Data provide a first look at alterations in osmoregulatory mechanisms that allow H. rigida nymphs to tolerate sub-lethal salinization of their surroundings.