Measurement of the lengths of different sections of the upper airway and their predictive factors.

BACKGROUND: No studies have been conducted to define the lengths of the upper airway's different segments in normal healthy adults. AIMS/OBJECTIVES: This study aimed to determine the length of the subglottis and extrathoracic trachea and the factors affecting it. MATERIAL AND METHODS: This was an observational retrospective review study. Included 102 adult patients who underwent CT scan during the quiet inspiration phase of the upper airway. RESULTS: The results revealed significant positive linear relationships between height and both anterior and posterior subglottic measurements (p < 0.001). Additionally, a statistically significant, moderately strong negative correlation between age and extrathoracic tracheal measurements (p > 0.001) was observed. Men exhibited longer anterior (p < 0.001) and posterior (p > 0.001) subglottic measurements. In both sexes, the average length of the anterior subglottis was 14.16 (standard deviation [SD]: 2.72) mm, posterior subglottis was 14.51 (SD: 2.85) mm and extrathoracic trachea was 66.37 (SD: 13.71) mm. CONCLUSION AND SIGNIFICANCE: We concluded that a normal healthy adult's anterior subglottis length is 6.3-19.3 mm (mean: 14.16 [SD: 2.72] mm), posterior subglottis length is 6.1-20.0 mm (mean: 14.51 [SD: 2.85] mm) and extrathoracic trachea length is 25.2-98.5 mm (mean: 66.37 [SD: 13.71] mm). Age, height and sex affected the upper airway length.

The sex of organ geometry.

Organs have a distinctive yet often overlooked spatial arrangement in the body1-5. We propose that there is a logic to the shape of an organ and its proximity to its neighbours. Here, by using volumetric scans of many Drosophila melanogaster flies, we develop methods to quantify three-dimensional features of organ shape, position and interindividual variability. We find that both the shapes of organs and their relative arrangement are consistent yet differ between the sexes, and identify unexpected interorgan adjacencies and left-right organ asymmetries. Focusing on the intestine, which traverses the entire body, we investigate how sex differences in three-dimensional organ geometry arise. The configuration of the adult intestine is only partially determined by physical constraints imposed by adjacent organs; its sex-specific shape is actively maintained by mechanochemical crosstalk between gut muscles and vascular-like trachea. Indeed, sex-biased expression of a muscle-derived fibroblast growth factor-like ligand renders trachea sexually dimorphic. In turn, tracheal branches hold gut loops together into a male or female shape, with physiological consequences. Interorgan geometry represents a previously unrecognized level of biological complexity which might enable or confine communication across organs and could help explain sex or species differences in organ function.

Regional variations and sex-related differences of stiffness in human tracheal ligaments.

PURPOSE: There have been numerous studies focused on the stiffness of tracheal cartilage. However, no research has been conducted specifically on the annular ligament, nor have any regional differences in the annular ligament been identified. The purpose of this study was to investigate the stiffness of the ligaments present between the thyroid, cricoid and tracheal cartilages. METHODS: The ligaments were identified in the cervical region of living subjects with ultrasonography. The stiffness of the ligaments was measured from the body surface using a digital palpation device (MyotonPRO). Since it is impossible to measure the entire trachea in a living subject, an additional measurement was performed on human cadavers. RESULTS: Both in vivo and cadaveric investigations found that the stiffness of annular ligaments decreased gradually from the superior to inferior parts. There was no difference in the stiffness between males and females in the superior part of the trachea. However, the stiffness of the middle and inferior parts was predominantly higher in females than in males. Furthermore, males showed significant differences in stiffness between the superior and middle parts, while females showed no significant differences. CONCLUSION: These results reveal that there are regional and sex-related differences in the stiffness of human tracheal ligaments.

Comprehensive experimental and numerical validation of Lattice Boltzmann fluid flow and particle simulations in a child respiratory tract.

The numerical simulation of inhaled aerosols in medical research starts to play a crucial role in understanding local deposition within the respiratory tract, a feat often unattainable experimentally. Research on children is particularly challenging due to the limited availability of in vivo data and the inherent morphological intricacies. CFD solvers based on Finite Volume Methods (FVM) have been widely employed to solve the flow field in such studies. Recently, Lattice Boltzmann Methods (LBM), a mesoscopic approach, have gained prominence, especially for their scalability on High-Performance Computers. This study endeavours to compare the effectiveness of LBM and FVM in simulating particulate flows within a child's respiratory tract, supporting research related to particle deposition and medication delivery using LBM. Considering a 5-year-old child's airway model at a steady inspiratory flow, the results are compared with in vitro experiments. Notably, both LBM and FVM exhibit favourable agreement with experimental data for the mean velocity field and the turbulence intensity. For particle deposition, both numerical methods yield comparable results, aligning well with in vitro experiments across a particle size range of 0.1-20 µm. Discrepancies are identified in the upper airways and trachea, indicating a lower deposition fraction than in the experiment. Nonetheless, both LBM and FVM offer invaluable insights into particle behaviour for different sizes, which are not easily achievable experimentally. In terms of practical implications, the findings of this study hold significance for respiratory medicine and drug delivery systems - potential health impacts, targeted drug delivery strategies or optimisation of respiratory therapies.

Homology and the evolution of vocal folds in the novel avian voice box.

The origin of novel traits, those that are not direct modifications of a pre-existing ancestral structure, remains a fundamental problem in evolutionary biology. For example, little is known about the evolutionary and developmental origins of the novel avian vocal organ, the syrinx. Located at the tracheobronchial junction, the syrinx is responsible for avian vocalization, but it is unclear whether avian vocal folds are homologous to the laryngeal vocal folds in other tetrapods or convergently evolved. Here, we identify a core developmental program involved in avian vocal fold formation and infer the morphology of the syrinx of the ancestor of modern birds. We find that this ancestral syrinx had paired sound sources induced by a conserved developmental pathway and show that shifts in these signals correlate with syringeal diversification. We show that, despite being derived from different developmental tissues, vocal folds in the syrinx and larynx have similar tissue composition and are established through a strikingly similar developmental program, indicating that co-option of an ancestral developmental program facilitated the origin of vocal folds in the avian syrinx.

Ostrich (Struthio camelus) syrinx morphology and vocal repertoire across postnatal ontogeny and sex: Implications for understanding vocal evolution in birds.

Vocal production in birds has been the target of considerable research that mostly has focused on phylogenetically well-nested songbirds. Anatomical descriptions and recordings of many non-songbirds have often only focused on a single ontogenetic stage or sex. While basic morphology of the vocal organ (syrinx) of ostrich (Palaeognathae, Struthio camelus) has been known since the 1800s, descriptions of its vocal repertoire and syrinx anatomy since then have been incomplete or inconsistent. New toolkits now enable detailed qualitative description of internal anatomy and meristic data and allow it to be compared to vocal production. Here we describe the anatomy of the syrinx in Struthio camelus for three post-hatching ontogenetic stages and both an adult male and female utilizing dissection and contrast enhanced X-ray computed tomography (diceCT). We find changes in ring geometry and spacing through ontogeny as well as lateral labia thickness. We document a small unpaired, midline, cartilaginous structure, a "pessuliform process" at the tracheobronchial juncture present throughout ontogeny and in both males and females. Investigation of the vocal repertoire of ostriches across ontogeny using a new dataset of 77 recordings led to identification of four vocalizations not previously reported in the literature, including the simultaneous production of a hiss and tonal. We find syrinx morphology largely consistent across ontogeny and in male and female adults. Both are capable of producing long duration tonal calls, but these may be more frequent in male birds. Closed-mouth boom calls remain unique to males. A detailed understanding of diversity in parts of early diverging clades is pivotal in attempting to estimate features of the ancestral syrinx in birds and how avian vocalization evolved.

Bronchial tree of the human embryo: Examination based on a mammalian model.

The symmetry of the right and left bronchi, proposed in a previous comparative anatomical study as the basic model of the mammalian bronchial tree, was examined to determine if it applied to the embryonic human bronchial tree. Imaging data of 41 human embryo specimens at Carnegie stages (CS) 16-23 (equivalent to 6-8 weeks after fertilization) belonging to the Kyoto collection were obtained using phase-contrast X-ray computed tomography. Three-dimensional bronchial trees were then reconstructed from these images. Bronchi branching from both main bronchi were labeled as dorsal, ventral, medial, or lateral systems based on the branching position with numbering starting cranially. The length from the tracheal bifurcation to the branching point of the labeled bronchus was measured, and the right-to-left ratio of the same labeled bronchus in both lungs was calculated. In both lungs, the human embryonic bronchial tree showed symmetry with an alternating pattern of dorsal and lateral systems up to segmental bronchus B9 as the basic shape, with a more peripheral variation. This pattern is similar to that described in adult human lungs. Bronchial length increased with the CS in all labeled bronchi, whereas the right-to-left ratio was constant at approximately 1.0. The data demonstrated that the prototype of the human adult bronchial branching structure is formed and maintained in the embryonic stage. The morphology and branching position of all lobar bronchi and B6, B8, B9, and the subsegmental bronchus of B10 may be genetically determined. On the other hand, no common structures between individual embryos were found in the peripheral branches after the subsegmental bronchus of B10, suggesting that branch formation in this region is influenced more by environmental factors than by genetic factors.

Radiological and Anatomical Evaluation of the Tracheal Morphology and Morphometry in Turkish Adults / Evaluación Radiológica y Anatómica de la Morfología y Morfometría Traqueal en Adultos Turcos

SUMMARY: The trachea is a tubular organ lying between larynx and lungs containing smooth muscle, membranes, and cartilage. This paper evaluated the dimessions of the trachea and main bronchi morphometry in healthy adults using Computed Tomography. This retrospective observational study was performed with 170 healthy adult subjects (89 females, 52.35 %; 81 males,47.65 %). The length of the trachea, the anteroposterior and transverse diameter of the trachea and the right and left main bronchi were measured. From these measurements, the trachea shape were calculated and four types of trachea were identified as circular, oval, horseshoe-shaped, and rectangular. All measurements were significantly higher in males than females (excluding tracheal bifurcation angle). According to the value obtained by dividing the anteroposterior by the width of the trachea, tracheal shapes are considered; the circular shape was seen 104 subjects (61.2 %), followed by oval type (34 subjects), horseshoe type (24 subjects) and rectangular type. (8 subjects). Also, the most frequently seen was circular type in both females and males. Hovewer, there was no significant difference between sex in terms of trachea shape. Additionally, a striking finding was that trachea morphometry and morphology showed the significance according to age dependent changes. Trachea measurements were affected several reasons such as used methods, age, sex, or race. This study has many clinical importance as it may reduce the risk of accidental damage to these area by clinicians such as cardiothoracic surgeons, anesthetist, or radiologist.

La tráquea es un órgano tubular que se encuentra entre la laringe y los pulmones y que contiene músculo liso, membranas y cartílago. Este trabajo evaluó las dimensiones de la tráquea y la morfometría de los bronquios principales en adultos sanos mediante Tomografía Computarizada. Este estudio observacional retrospectivo se realizó con 170 sujetos adultos sanos (89 mujeres, 52,35 %; 81 hombres, 47,65 %). Se midió la longitud de la tráquea, el diámetro anteroposterior y transversal de la tráquea y los bronquios principales derecho e izquierdo. A partir de estas mediciones, se calculó la forma de la tráquea y se identificaron cuatro tipos de tráquea: circular, ovalada, en forma de herradura y rectangular. Todas las mediciones fueron significativamente mayores en hombres que en mujeres (excluyendo el ángulo de bifurcación traqueal). Según el valor que se obtiene al dividir el anteroposterior por el ancho de la tráquea, se consideran las formas traqueales; la forma circular fue observada en 104 sujetos (61,2 %), seguida del tipo ovalado (34 sujetos), tipo herradura (24 sujetos) y tipo rectangular (8 sujetos). Además, el tipo más frecuente fue el circular tanto en mujeres como en hombres. Sin embargo, no hubo diferencias significativas entre sexos en términos de forma de la tráquea. Además, un hallazgo sorprendente fue que la morfometría y la morfología de la tráquea mostraron importancia según los cambios dependientes de la edad. Las mediciones morfométricas de la tráquea se vieron afectadas por varios motivos, como los métodos utilizados, la edad, el sexo o la raza. Este estudio tiene importancia clínica ya que puede reducir el riesgo de daño accidental por parte de médicos como cirujanos cardiotorácicos, anestesistas o radiólogos.

Descelularización y regeneración de tráquea porcina: un acercamiento a la ingeniería tisular / Decellularization and Regeneration of Porcine Trachea: an Approach to Tissue Engineering

Resumen Antecedentes: la ingeniería tisular permite obtener órganos como injertos a partir de tejidos descelularizados, regenerados con células autólogas. Objetivo: descelularizar y regenerar tráqueas porcinas. Material y métodos: se descelularizaron tráqueas porcinas colocándolas cada una en el epiplón de cuatro cerdos Yorkshire para su regeneración in vivo. Una tráquea desce-lularizada con tritón (DT), descelularizada con desoxicolato (DD), descelularizada con desoxicolato y reforzada con un polímero y células epiteliales (DDR), y una nativa crio-preservada (NC). Después de 8 días se obtuvieron la DD, NC y DDR; y al día 15, la DT. Se las evaluó mecánica e histológicamente, se realizó el análisis casuístico. Resultados: las tráqueas descelularizadas conservaron la integridad del cartílago, sin diferencias mecánicas, excepto la DDR con mayor rigidez. Las tráqueas regeneradas presentaron menor rigidez, excepto la DDR que además perdió el epitelio y la vascula-ridad. Las DT, DD mostraron epitelio no respiratorio, fibrosis y vasculogénesis con in-flamación. Conclusiones: las matrices conservaron sus características mecánicas. La regenera-ción in vivo ofrece ventajas como la esterilidad, interacción celular, nutrientes; es senci-llo, factible y económico, pero no hay control del crecimiento celular y vascularización, y los tejidos presentaron alteraciones mecánicas e histológicas. El polímero impidió la re-epitelialización y revascularización. Este estudio abre la posibilidad de mejorar las me-todologías de ingeniería tisular aplicadas al tejido traqueal.

Abstract Introduction: tissue engineering makes it possible to obtain organs as grafts from de-cellularized tissues, regenerated with autologous cells.Objective: decellularize and regenerate porcine tracheas.ARTÍCULO ORIGINAL | Respirar, 2023; 15(3): 188-199 | ISSN 2953-3414 | https://doi.org/10.55720/respirar.15.3.5RECIBIDO: 9 agosto 2023ACEP TADO: 31 agosto 2023 Elisa Barrera-Ramírezhttps://orcid.org/0000-0002-2778-0882Rubén Efraín Garrido-Cardonahttps://orcid.org/0000-0001-6083-5403Alejandro Martínez-Martínezhttps://orcid.org/0000-0003-3448-910XLuis Fernando Plenge-Tellecheahttps://orcid.org/0000-0002-1619-5004Edna Rico-Escobarhttps://orcid.org/0000-0002-0933-0220Esta revista está bajo una licencia de Creative Commons Reconocimiento 4.0 Internacional. Respirar 2023; 15 (3): 189ARTÍCULO ORIGINAL / E. Barrera-Ramírez, R.E. Garrido-Cardona, A. Martínez-Martínez, L.F. Plenge-Tellechea, E. Rico-EscobarDescelularización y regeneración de tráqueaISSN 2953-3414Materials and Methods: Porcine tracheas were decellularized by placing each one in the omentum of four Yorkshire pigs for regeneration in vivo. A trachea decellularized with triton (DT), decellularized with deoxycholate (DD), decellularized with deoxycho-late and reinforced with a polymer, and epithelial cells (DDR), and a cryopreserved na-tive (NC). After 8 days, the DD, NC and DDR were obtained; and on day 15, the DT. The evaluation was mechanically and histologically, performing the case analysis.Results: the decellularized tracheas preserved the integrity of the cartilage, with no me-chanical differences, except for the DDR with greater rigidity. The regenerated trache-as presented less rigidity, except the DDR, which also lost the epithelium and vascular-ity. The DT, DD showed non-respiratory epithelium, fibrosis and vasculogenesis with inflammation.Conclusions: the matrices retained their mechanical characteristics, in vivo regenera-tion offers advantages such as sterility, cell interaction, nutrients; it is simple, feasible and economical, but there is no control of cell growth and vascularization, and the tis-sues presented mechanical and histological alterations. The polymer prevented re-epi-thelialization and revascularization. This study opens the possibility of improving tissue engineering methodologies applied to tracheal tissue.

Morphology of the syrinx of three species of birds from Brazilian cerrado (Psittacara leucophthalmus, Rhynchotus rufescens and Cariama cristata): Gross anatomy and light microscopy study.

The aim of this study was to describe the morphology of the trachea and syrinx at macroscopic and light microscopy levels of three species of birds from different orders that inhabit the Brazilian cerrado. For that, five adult specimens (three males and two females of each species) of white-eyed parakeet (Psittacara leucophthalmus), red-winged tinamou (Rhynchotus rufescens) and red-legged seriema (Cariama cristata) were used. The trachea and syrinx of the birds were collected and destined for anatomical and histological studies. The trachea of the studied birds presented an elongated path and originated in the larynx and extended caudally to the syrinx. No sexual dimorphism was observed in the syrinx of the studied species, probably because it is associated with their song, which is very similar between males and females of these species. The findings of this study allowed us to classify the syrinx as tracheal in the white-eyed parakeet and tracheobronchial in the red-winged tinamou and red-legged seriema. In general, the morphological features of the trachea and syrinx were similar to those described for other species of birds, such as the presence of intrinsic and extrinsic syringeal muscles, and the lateral and medial tympaniform membranes, which would represent important anatomical structures in sound production through vibration during expiration and eventual inspiration. The morphological structure of the syrinx in the three avian species of the Brazilian cerrado is consistent with the ability of these avian species to perform a potential vocalization, especially the red-legged seriema that emits characteristic sounds very loud and can carry several kilometres.

Evaluation of angles of the tracheobronchial tree with the 3-dimensional reconstruction method: a morphometric and radiologic study / Evaluación de los ángulos del árbol traqueobronquial con el método de reconstrucción tridimensional: un estudio morfométrico y radiológico

SUMMARY: The objective of the current research is to assess the branching angles of the tracheobronchial tree and the correlation between these angles and the lung volume using the 3-dimensional reconstruction method. Thorax CT (computed tomography) images of 150 individuals, who were over 18 years of age and did not have any pathology on CT, were obtained retrospectively. A 3-dimensional reconstruction of the trachea, bronchi, and lungs was carried out. External and internal angles between the trachea and main bronchi, between the main bronchi and lobar bronchi, and between the lobar bronchi were measured. The volume measurement of the right and left lungs was performed. The individuals included in the study were grouped by sex and age (20-40 years, 41-61 years, and 62-87 years). The left subcarinal angle (LSA), total subcarinal angle (TSA), and left interbronchial angle (LIA) were found to be greater in the 62-87 age group. Both the external angle (LULB-LMBE) and the internal angle (LULB- LMBI) between the left upper lobar bronchus and the left main bronchus were observed to be greater in males. In males, a statistically significant negative moderate correlation was identified between the right lung volume and the right subcarinal angle (RSA). In females, a statistically significant positive moderate correlation was revealed between the external (RULB-IBE) and internal angles (RULB-IBI) between the right upper lobar bronchus and the intermediate bronchus, and the right lung volume. In the literature review we performed, we did not find any studies investigating the correlation between the branching angles of the tracheobronchial tree and the lung volume using the 3-dimensional reconstruction method. Therefore, we are of the opinion that our study will contribute to the literature.

El objetivo de la investigación fue evaluar los ángulos de ramificación del árbol traqueobronquial y la correlación entre estos ángulos y el volumen pulmonar utilizando el método de reconstrucción tridimensional. Se obtuvieron retrospectivamente imágenes de tomografía computarizada de tórax de 150 individuos mayores de 18 años sin patología. Se realizó una reconstrucción tridimensional de la tráquea, los bronquios y los pulmones. Se midieron los ángulos externo e interno entre la tráquea y los bronquios principales, entre los bronquios principales y los bronquios lobares, y entre los bronquios lobares. Se realizó la medición del volumen de los pulmones derecho e izquierdo. Los individuos incluidos en el estudio fueron agrupados por sexo y edad (20-40 años, 41-61 años y 62-87 años). Se encontró que el ángulo subcarinal izquierdo, el ángulo subcarinal total y el ángulo interbronquial izquierdo eran mayores en el grupo de edad de 62 a 87 años. Tanto el ángulo externo (LULB-LMBE) como el ángulo interno (LULB-LMBI) entre el bronquio lobular superior izquierdo y el bronquio principal izquierdo era mayor en los hombres. En los hombres, se identificó una correlación moderada negativa estadísticamente significativa entre el volumen pulmonar derecho y el ángulo subcarinal derecho. En mujeres, se reveló una correlación positiva moderada estadísticamente significativa entre los ángulos externos (RULB-IBE) e internos (RULB-IBI) entre el bronquio lobar superior derecho y el bronquio intermedio, y el volumen pulmonar derecho. En la revisión bibliográfica que realizamos, no encontramos ningún estudio que analizara la correlación entre los ángulos de ramificación del árbol traqueobronquial y el volumen pulmonar utilizando el método de reconstrucción tridimensional. Por lo tanto, consideramos que nuestro estudio contribuirá a la literatura especializada del tema.

[Lesions of the visceral mediastinum]. / Läsionen des viszeralen Mediastinums.

BACKGROUND: The visceral or middle mediastinum contains nonvascular (trachea, carina, esophagus, and lymph nodes) and vascular structures (heart, ascending aorta, aortic arch, descending aorta, superior vena cava, intrapericardial pulmonary arteries, thoracic duct). OBJECTIVES: The various pathologies of the visceral mediastinum and imaging features are presented. MATERIALS AND METHODS: Plain film radiography shows the gross anatomy and allows visualization of larger pathologies. However, for detailed anatomic and structural classification more sophisticated imaging techniques are required. Especially computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are well suited for structural and functional assessment of mediastinal lesions. CONCLUSION: This article summarizes the major pathologies of the visceral mediastinum.

The Dynamic Tracheoesophageal Prosthesis Length.

OBJECTIVE: In a postlaryngectomy patient, tracheoesophageal (TE) speech is considered to be the most effective and preferred method of communication. Previous research has demonstrated that despite an appropriately sized TE prosthesis placement at the time of puncture, there are a portion of patients that require resizing postoperatively. The purpose of this study was to report on the variability of the tracheoesophageal prosthesis length. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary care academic medical center. METHODS: This was a retrospective chart review of 62 patients who underwent secondary tracheoesophageal puncture (TEP) at a tertiary care academic medical center from January 2008 to November 2019. Patient demographic information, average changes in prosthesis length, number of prosthesis adjustments, and timing of prosthesis exchanges were collected. RESULTS: 62 patients met criteria for study inclusion. Mean age was 61.96 years old with 49 being male (79%) and 13 (21%) females. Overall change in prosthesis length was - 3.85 mm ± 3.58 with time to first prosthesis change at 2.29 months ± 2.73. There was an average of 4.37 changes ± 3.43 before reaching a stable length. Twenty-six patients (41.9%) had increases in their prosthesis length resulting in closure of the tracheoesophageal fistula requiring seven patients (11.3%) to return to the operating room for repuncturing. History of smoking (P = 0.02), Blom-Singer prosthesis type (P = 0.03), and larger diameter (P = 0.01) appeared to be predisposing factors for a fluctuating prosthesis length. CONCLUSION: Tracheoesophageal prosthesis length decreases over time for secondary punctures, requiring adjustments with a speech language pathologist. There are a clinically significant portion that have fluctuations in prosthesis length resulting in an increased risk for requiring re-puncturing.

Anatomy of the Larynx and Cervical Trachea.

The larynx serves as the gateway between the upper and lower respiratory tracts and is involved in the tasks of phonation, deglutition, and airway protection. Familiarity with the complex anatomy of the larynx is critical for detecting and characterizing disease in the region, especially in cancer staging. In this article, we review the anatomy of the larynx and cervical trachea, including an overview of their cartilages, supporting tissues, muscles, mucosal spaces, neurovascular supply, and lymphatics, followed by correlation to the clinically relevant anatomic sites of the larynx. Imaging techniques for evaluating the larynx and trachea will also be discussed briefly.

Docosahexaenoic Acid Selectively Suppresses U46619- and PGF2α-Induced Contractions in Guinea Pig Tracheal Smooth Muscles.

We investigated the potential inhibitory effects of docosahexaenoic acid (DHA) on the contractions of guinea pig tracheal smooth muscles in response to U46619 (a thromboxane A2 (TXA2) mimetic) and prostaglandin F2α (PGF2α) to examine whether this n-3 polyunsaturated fatty acid suppresses prostanoid-induced tracheal contractions. DHA (3 × 10-5 M) significantly suppressed tracheal contractions elicited by lower concentrations of U46619 (10-8 M) and PGF2α (5 × 10-7 M) (vs. control), although it did not suppress the contractions induced by higher concentrations (U46619: 10-7 M; PGF2α: 10-5 M). Supporting these findings, DHA (4 × 10-5 M/6 × 10-5 M) shifted the concentration-response curves for U46619 (10-9-10-6 M) and PGF2α (10-8-10-5 M) to the right. However, the slope of the regression line in the Schild plot of DHA vs. U46619/PGF2α was larger than unity. The tracheal contractions induced by U46619 (10-8 M) and PGF2α (5 × 10-7 M) were significantly suppressed by the prostanoid TP receptor antagonist SQ 29,548 (10-6 M) (vs. ethanol-treated). In contrast, DHA (4 × 10-5 M) did not show significant inhibitory effects on the contractions induced by acetylcholine (10-8-10-4 M), histamine (10-8-10-4 M), and leukotriene D4 (10-11-10-7 M) (vs. ethanol-treated). These findings indicate that DHA selectively suppresses tracheal contractions induced by U46619 and PGF2α. Therefore, DHA may be a useful therapeutic agent against asthma associated with tracheal/bronchial hyper-constriction caused by prostanoids including TXA2 and PGF2α.

Anatomy of the respiratory system in the, "Portrait of a Musician" by Leonardo da Vinci.

The object of the research is the painting, Portrait of a Musician''. Upon closer examination of the painting, we discovered three details. Two have the shape of trachea and bronchi and the third a larynx. By moving the details through the program Paint X we got an image of the larynx, trachea and bronchi. The larynx is presented by thyroid and cricoid cartilage. The characteristic cartilaginous rings are distinguished on the trachea. The right and left main bronchi are also seen. In our opinion, Leonardo da Vinci reflected the elements of the respiratory system in the, Portrait of a Musician'', thus emphasizing the fact that the bronchi, trachea and larynx are involved in the production of sound.

An assessment of introducers used for airway management.

Different introducers are available to assist with tracheal intubation. Subtle differences in the design of introducers can have a marked effect on safety and performance. The Difficult Airway Society's Airway Device Evaluation Project Team proposal states that devices should only be purchased for which there is at least a case-control study on patients assessing airway devices. However, resources are not currently available to carry out a case-control study on all introducers available on the market. This study comprised a laboratory and manikin-based investigation to identify introducers that could be suitable for clinical investigation. We included six different introducers in laboratory-based assessments (design characteristics) and manikin-based assessments involving the participation of 30 anaesthetists. Each anaesthetist attempted placement in the manikin's trachea with each of the six introducers in a random order. Outcomes included first-time insertion success rate; insertion success rate; number of attempts; time to placement; and distance placed. Each anaesthetist also completed a questionnaire. First-time insertion success rate depended significantly on the introducer used (p = 0.0016) and varied from 47% (Armstrong and P3) to 77% (Intersurgical and Frova). Median time to placement (including oesophageal placement) varied from 10 s (Eschmann and Frova) to 20 s (P3) (p = 0.0025). Median time to successful placement in the trachea varied from 9 s (Frova) to 22 s (Armstrong) (p = 0.037). We found that the Armstrong and P3 devices were not as acceptable as other introducers and, without significant improvements to their design and characteristics, the use of these devices in studies on patients is questionable. The study protocol is suitable for differentiating between different introducers and could be used as a basis for assessing other types of devices.

Length of the Cricoid and Trachea in Children: Predicting Intubation Depth to Prevent Subglottic Stenosis.

OBJECTIVE: Define the length of the subglottis and trachea in children to predict a safe intubation depth. METHODS: Patients <18 years undergoing rigid bronchoscopy from 2013 to 2020 were included. The carina and inferior borders of the cricoid and true vocal folds were marked on a bronchoscope and distances were measured. Patient age, weight, height, and chest height were recorded. Four styles of cuffed pediatric endotracheal tubes (ETT) were measured and potential positions of each cuff and tip were calculated within each trachea using five depth of intubation scenarios. Multivariate linear regression was performed to identify predictors of subglottic and tracheal length. RESULTS: Measurements were obtained from 210 children (141 male, 69 female), mean (SD) age 3.21 (3.66) years. Patient height was the best predictor of subglottic length (R2 : 0.418): Lengthsg (mm) = 0.058 * height (cm) + 2.8, and tracheal length (R2 : 0.733): Lengtht (mm) = 0.485 * height (cm) + 21.3. None of the depth of intubation scenarios maintained a cuff-free subglottis for all ETT styles investigated. A formula for depth of intubation: Lengthdi (mm) = 0.06 * height (cm) + 8.8 found that no ETT cuffs would be in the subglottis and all tips would be above the carina. CONCLUSION: Current strategies for determining appropriate depth of intubation pose a high risk of subglottic ETT cuff placement. Placing the inferior border of the vocal cords 0.06 * height (cm) + 8.8 from the superior border of the inflated ETT cuff may prevent subglottic cuff placement and endobronchial intubation. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:S1-S10, 2022.

Numerical study of the impact of glottis properties on the airflow field in the human trachea using V-LES.

The influences of the profiles and cross-sectional areas of glottal aperture on the upper respiratory airway are investigated using an idealized cast-based mouth-throat model and three dimensional computational fluid dynamics (CFD). The open source CFD code OpenFOAM is employed. The transient flows are modeled using the very-large eddy simulation with the Smagorinsky sub-grid scale (SGS) model. Five different shapes of glottis are considered, including circular glottis with 100 %, 75 % and 50 % cross-sectional area and elliptic glottis with 75 % and 50 % cross-sectional area. Both instantaneous and averaged flow fields are analyzed. It is found that the variations of glottis have great impacts on the properties of downstream flow fields such as the secondary flow, laryngeal jet, recirculation zone, turbulent kinetic energy, and vortex. Evident impacts are observed in the region within 6 tracheal diameters downstream of the glottis. The profile of the glottis has more impacts on the laryngeal shape, while the cross-sectional area has more impacts on velocity of the laryngeal jet and turbulent intensity. It is concluded that both the glottal areas and profiles are critical for an idealized geometrical mouth-throat model.