Airway Airflow Research Articles

Investigation of inter-subject variation in ultrafine particle deposition across human nasal airways: A study involving children, adults, and the elderly

The airflow and particle dynamics in adult nasal airways have been extensively investigated, but the impact of age-related anatomical changes in children and the elderly remains underexplored. This study systematically investigates age-related anatomical variations and associated influence on nasal airflow dynamics and ultrafine particle deposition characteristics by using Computational Fluid-Particle Dynamics (CFPD) approach. Numerical simulations were conducted for 9 healthy nasal subjects spanning a wide age range. 6 Nasal subjects from the Development Group were used as the primary models for data analysis and deposition correlation development, while 3 subjects from the Validation Group were used to validate the reliability of the derived total and subregional deposition correlations. Our results reveal distinctive variations across age groups. Specifically, the elderly and children exhibit unique patterns that differ from those of young adults. While total deposition efficiency differs significantly between children and adults, filtration efficiency in the subregion with most deposition, main respiratory, remains consistent. Lastly, overall and subregional empirical equations for deposition efficiency were developed by incorporating the combined diffusion parameter, Sca∆b, corroborating the use of geometrical characteristic parameters for each specific subject in predicting nasal deposition efficiency across different age groups. Our findings are expected to improve the predictive nanoparticle exposure analysis in nasal airways across different age groups, thereby improving the respiratory health for individuals throughout the life span.

Impact of Intra-Phenotypic Nasal Vestibular Variation on Local Airflow Dynamics.

Many individuals with healthy normal nasal anatomy and function exhibit a prominent notch indentation at the junction of the ala and sidewall, specifically around the anterior-superior region of the unilateral nasal vestibule up to the internal nasal valve. This study evaluates the influence of various sizes of notched indentations at the anterior nasal airway on local airflow pattern. A retrospective study involving 25 healthy individuals, each exhibiting at least one unilateral notched indentation (40 total airways). Each individual's notched indentation was quantified after subject-specific three-dimensional nasal airway reconstruction from radiographic images. Computational fluid dynamics modeling was used to simulate nasal inspiratory airflow in each nasal airway at 15 L/min. Localized airflow distributions passing through the inferior, middle, and superior regions were calculated at 15 cross sections. Notched indentation size ranged 1.75-86.84 mm2 (average = 22.37 mm2). At the anterior airway, notched size significantly correlated with inferior airflow volume (R = 0.32, p = 0.04) but not in the middle (R = 0.21, p = 0.20) or superior (R = 0.06, p = 0.70) regions, whereas middle and superior regional resistance values were significantly correlated with notched size (middle: R = 0.54, p < 0.001; superior: R = 0.41, p = 0.009). Medially, resistance at the middle region significantly correlated with notched size (R = 0.56, p < 0.001). At the posterior airway, airflow distributions through the inferior, middle, and superior regions demonstrated weak correlation with notched size (inferior: R = 0.24, p = 0.14, middle: R = 0.24, p = 0.13; superior:R = 0.03, p = 0.83), whereas resistance was significantly correlated in the middle and inferior regions (middle: R = 0.56, p < 0.001;inferior: R = 0.43, p = 0.006). Anterior nasal airway notched indentation size had significantly stronger influence on localized airflow volume through the anterior-inferior airway than other regions of the nasal passage. N/A Laryngoscope, 2024.

Influence of Personal Factors on Quality of Life in Patients with Chronic Obstructive Pulmonary Disease (COPD)

Chronic Obstructive Pulmonary Disease (COPD) is a disease characterized by restriction of airflow in airways. Smoking is a major risk factor for disease. Other factors are air pollution from fuels, industrial dust, chemical agents and genetic causes. Main symptoms are shortness of breath, chronic cough with or without sputum and rapid fatigue. Chronic obstructive pulmonary disease /COPD/ is a source of stress and anxiety, due to severity of disease, need for long-term treatment and detachment from social life. Study cohort consisted of 124 patients with a diagnosis of COPD and a control group of 162 without lung disease. Persons studied are over 18 years of age, of different sexes, of Bulgarian ethnic origin and different family and social status. Chronic obstructive pulmonary disease is a disease of increasing social importance and, according to forecast of WHO, by 2030 it is expected to become third leading cause of death in world. Aim of pilot study was to determine influence of some personal risk factors (anxiety and type D personality in dimensions: "negative affectivity" and "social inhibition") on quality of life and social adaptation of patients with COPD.

Simulation of Multiple Source Vocalization in the Larynx: How True Folds, False Folds, and Aryepiglottic Folds May Interact.

This study was a modest beginning to determine dominance and entrainment between three soft tissues in the larynx that can be set into flow-induced oscillation and act as sound sources. The hypothesis was that they interact as coupled oscillators with observable bifurcations as energy is exchanged between them. The true vocal folds, the ventricular (false) folds, and the aryepiglottic folds were part of a soft-walled airway that produced airflow for sound production. The methodology was computational, based on a simplified Navier-Stokes solution of convective and compressible airflow in a variable-geometry airway. Three serially connected sources could all produce flow-induced self-oscillation with soft wall tissue and small cross-sectional area. When the glottal cross-sectional areas were similar, bifurcations such as subharmonics, delayed voice onset, and aphonia occurred in the coupled oscillations. Closely spaced sound sources in the larynx are highly interactive. They appear to entrain to the source that has the combined advantage of small cross-sectional glottal area and proximity to a downstream vocal tract that supports oscillation with acoustic inertance.

Computational Fluid Dynamics Analysis of Varied Cross-Sectional Areas in Sleep Apnea Individuals across Diverse Situations

Obstructive sleep apnea (OSA) is a common medical condition that impacts a significant portion of the population. To better understand this condition, research has been conducted on inhaling and exhaling breathing airflow parameters in patients with obstructive sleep apnea. A steady-state Reynolds-averaged Navier–Stokes (RANS) approach and an SST turbulence model have been utilized to simulate the upper airway airflow. A 3D airway model has been created using advanced software such as the Materialize Interactive Medical Image Control System (MIMICS) and ANSYS. The aim of the research was to fill this gap by conducting a detailed computational fluid dynamics (CFD) analysis to investigate the influence of cross-sectional areas on airflow characteristics during inhale and exhale breathing in OSA patients. The lack of detailed understanding of how the cross-sectional area of the airways affects OSA patients and the airflow dynamics in the upper airway is the primary problem addressed by this research. The simulations revealed that the cross-sectional area of the airway has a notable impact on velocity, Reynolds number, and turbulent kinetic energy (TKE). TKE, which measures turbulence flow in different breathing scenarios among patients, could potentially be utilized to assess the severity of obstructive sleep apnea (OSA). This research found a vital correlation between maximum pharyngeal turbulent kinetic energy (TKE) and cross-sectional areas in OSA patients, with a variance of 29.47%. Reduced cross-sectional area may result in a significant TKE rise of roughly 10.28% during inspiration and 10.18% during expiration.

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.

Significance of Plasma Irisin, Adiponectin, and Retinol Binding Protein-4 Levels as Biomarkers for Obstructive Sleep Apnea Syndrome Severity.

Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder that is caused by the reduction or cessation of airflow in the upper airway. Irisin, retinol-binding protein-4 (RBP-4), and adiponectin are the three significant factors in the metabolic process of the human body. The objective of this study was to investigate whether plasma irisin, RBP-4, and adiponectin levels are associated with the severity of OSAS. According to inclusion and exclusion criteria, 125 patients with OSAS and 46 healthy, gender-matched controls were included in this study. The patients were classified according to the apnea hypopnea index (AHI) as 14 mild cases (5 < AHI < 15), 23 moderate OSAS cases (15 < AHI < 30), and 88 severe OSAS cases (AHI > 30). The plasma irisin, RBP-4, and adiponectin levels were measured and compared between groups. RBP-4 levels were higher in severe OSAS compared to other groups, and irisin levels were significantly lower in severe OSAS compared to other groups. There was a negative correlation between irisin and RBP-4 (r = -0.421; p < 0.001), and irisin and AHI (r = -0.834; p < 0.001), and a positive correlation between irisin and adiponectin (r = 0.240; p = 0.002). There was a negative correlation between RBP-4 and adiponectin (r = -0.507; p < 0.001) and a positive correlation between RBP-4 and AHI (r = 0.473; p < 0.001). As a predictor of OSAS, adiponectin showed the highest specificity (84.8%) and RBP-4 the highest sensitivity (92.0%). Circulating adiponectin, irisin, and RBP-4 may be new biomarkers in OSAS patients in addition to risk factors such as diabetes, obesity, and hypertension. When polysomnography is not available, these parameters and clinical data can be used to diagnose the disease. As a result, patients with an AHI score greater than thirty should be closely monitored for metabolic abnormalities.

Computational modelling of airflow in distal airways using hybrid lung model

ABSTRACT A major challenge in computational fluid dynamics (CFD) modelling of the human respiratory system is allowing for the variation of geometric scale. A methodology is proposed that enables CFD analysis from the middle through the distal airways to the alveolar level. The methodology relies on a hybrid lung geometry integrating a primary tracheobronchial tree (TBT) up to the fifth generation (section 1) and distal airway (section 2). Section 1 comprises of the middle airways reconstructed from patient CT scans. Section 2 comprises of the distal airway branching tree generated based on deterministic algorithm. The hybrid model allows the application of physiologically relevant boundary conditions in lieu of simplistic approximations used in previous studies. Two different breathing conditions are considered adapted from previous studies, representing resting and exercise activity. The predicted flow variables are assessed for numerical accuracy and validated by comparison with published experimental and numerical data.

Development of an Active Mechanical Lung for Simulating Human Pulmonary Ventilation

At present, the passive simulated lung including the splint lung is an important device for hospitals and manufacturers in testing the functions of a respirator. However, the human respiration simulated by this passive simulated lung is quite different from the actual respiration. And it is not able to simulate the spontaneous breathing. Therefore, including" the device simulating respiratory muscle work "," the simulated thorax" and" the simulated airway", an active mechanical lung to simulate human pulmonary ventilation was designed:3D printed human respiratory tract was developed and connected the left and right air bags at the end of the respiratory tract to simulate the left and right lungs of the human body. By controlling a motor running to drive the crank and rod to move a piston back and forth, and to deliver an alternating pressure in the simulated pleural, and so as to generate an active respiratory airflow in airway. The experimental respiratory airflow and pressure from the active mechanical lung developed in this study are consistent with the target airflow and pressure which collected from the normal adult. The developed active mechanical lung function will be conducive to improve the quality of the respirator.

Associations between short-term exposure to ambient air pollution and lung function in adults.

Evidence of the acute effects of high-level air pollution on small airway function and systemic inflammation in adults is scarce. To examined the associations of short-term (i.e., daily) exposure to multiple air pollutants with lung function and inflammatory markers. We assessed short-term (daily) effects of air pollutants, including particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) and 10 μm (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO), on lung function and peripheral immune cell counts over various lag times using generalized linear regression models. A total of 4764 adults were included from the general community-dwelling population in Shanghai, China. Exposure to air pollutants and lung function were negatively correlated. Decline in FEF between 25% and 75% of vital capacity (FEF25-75%) were found associated with PM2.5, SO2, and CO, and decline in forced expiratory volume in 3 s (FEV3) to forced vital capacity (FVC) ratio were associated with all examined pollutants, indicating obstruction in small airways. Obstructed airflow in large and middle airways as indicated by decline in FEV1/FVC were also associated with all pollutants. In subgroup analysis, significant negative associations between the five pollutants and SAD parameters were found only in males but not in females. The difference in the associations of SO2 with FEF75% between males and females achieved statistical significance. Additionally, all examined pollutants were significantly associated with lower peripheral neutrophil count. Acute exposure to air pollutants were associated with airflow-limitation. Both small airways and proximal airways were affected. Acute exposure to air pollutants were accompanied with a lower neutrophil count.

Establishment and digital simulation of upper airway in patients with adenoid hypertrophy

Objective: To analyze the flow field characteristics of the upper airway in patients with different adenoid hypertrophy using computational fluid dynamics (CFD). Methods: From November 2020 to November 2021, the cone-beam CT (CBCT) data of 4 patients [2 males and 2 females,age range 5-7 years, mean (6.0±1.2) years] with adenoid hypertrophy who were hospitalized in the Department of Orthodontics and the Department of Otolaryngology at Hebei Eye Hospital were selected. The degree of adenoid hypertrophy in the 4 patients was divided into normal S1 (A/N<0.6), mild hypertrophy S2 (0.6≤A/N<0.7), moderate hypertrophy S3 (0.7≤A/N<0.9) and severe hypertrophy S4 (A/N≥0.9) according to the ratio of adenoid thickness to the width of nasopharyngeal cavity (A/N). The CFD model of the upper airway was established using ANSYS 2019 R1 software, and the internal flow field of the CFD model was numerically simulated. Eight sections were selected as observation and measurement planes for flow field information. Relevant flow field information includes airflow distribution, velocity variation, and pressure variation. Results: In the S1 model, the maximum pressure difference occurred in the 4th and 5th observation planes (ΔP=27.98). The lowest pressures and the maximum flow rates of S2 and S3 were located in the 6th observation plane. The airflow in S1 and S2 models completely passed through the nasal cavity. In the S3 model, the mouth-to-nasal airflow ratio was close to 2∶1. In S4 model, the airflow completely passed through the mouth; in the S1 and S2 models, hard palates were subjected to a downward positive pressure with a pressure difference of 38.34 and 23.31 Pa, respectively. The hard palates in S3 and S4 models were subjected to a downward negative pressure with a pressure difference of -2.95 and -21.81 Pa, respectively. Conclusions: The CFD model can objectively and quantitatively describe the upper airway airflow field information in patients with adenoid hypertrophy. With the increasing degree of adenoid hypertrophy, the nasal ventilation volume gradually decreased, whereas the oral space ventilation volume gradually increased, and the pressure difference between the upper and lower surfaces of the palate gradually decreased until the pressure became negative.

Motor neuron involvement threatens survival in spinocerebellar ataxia type 1.

Motor neuron involvement threatens survival in spinocerebellar ataxia type 1.

Evaluation of computational fluid dynamics models for predicting pediatric upper airway airflow characteristics.

Computational fluid dynamics (CFD) has the potential for use as a clinical tool to predict the aerodynamics and respiratory function in the upper airway (UA) of children; however, careful selection of validated computational models is necessary. This study constructed a 3D model of the pediatric UA based on cone beam computed tomography (CBCT) imaging. The pediatric UA was 3D printed for pressure and velocity experiments, which were used as reference standards to validate the CFD simulation models. Static wall pressure and velocity distribution inside of the UA under inhale airflow rates from 0 to 266.67mL/s were studied by CFD simulations based on the large eddy simulation (LES) model and four Reynolds-averaged Navier-Stokes (RANS) models. Our results showed that the LES performed best for pressure prediction; however, it was much more time-consuming than the four RANS models. Among the RANS models, the Low Reynolds number (LRN) SST k-ω model had the best overall performance at a series of airflow rates. Central flow velocity determined by particle image velocimetry was 3.617m/s, while velocities predicted by the LES, LRN SST k-ω, and k-ω models were 3.681, 3.532, and 3.439m/s, respectively. All models predicted jet flow in the oropharynx. These results suggest that the above CFD models have acceptable accuracy for predicting pediatric UA aerodynamics and that the LRN SST k-ω model has the most potential for clinical application in pediatric respiratory studies.

P068 Computational fluid dynamic study in Obstructive Sleep Apnea patients

Abstract Introduction Obstructive sleep apnea (OSA) is a common disorder which may need surgery to widen the airway. However, the success rate of surgery is variable. Thus, it is necessary to predict the outcome of the surgery preoperatively. The purpose of this study is to evaluate the mechanical parameter of upper airway airflow in OSA patients using computational fluid dynamics (CFD) method. Method We conducted a study on the patients with snoring, underwent the full night polysomnograpny (PSG) and paranasal sinus computed tomography(CT). The patients with past history of previous trauma or surgery were excluded. Three-demensional reconstructions of the upper airway were created in the medical imaging software Mimics 16.0 using paranasal CT. The reconstructions extended from nasopharynx to hypopharynx. Steady-state, turbulent, inspiratory airflow simulations were conducted in Fluent 17.0 with following boundary conditions The mechanical parameters (wall shear stress, pressure, plane velocity) were calculated in the three levels of nasopharynx, retropalatal, retrolingual area. Results The maximum wall shear stress values were shown at the retropalatal plane in all patients. There is a tendency for the wall shear stress value of the retropalatal area to increase as the AHI increases. The maximum velocity values were shown at the retropalatal plane in all patients. The maximum pressure values were shown at the nasopharynx plane in all patients. Conclusion the maximum wall shear stress values were shown at the retropalatal plane and the wall shear stress value of the retropalatal area increased as the AHI increased. Thus, the palatal surgery might help the OSA patients.

Comparative modelling of inspiratory airflow and micron particle deposition patterns in monkey and human nasal airways

Laboratory animals have historically performed a vital function in evaluating health effects of human exposure to ambient particulate matter (PM). Due to the complexity of particle-laden flows and airway interactions that involve multiple species, in-depth knowledge of airflow and particle transport in both the non-human primate surrogates and human airways is still lacking. To advance the understanding in this field, this paper presents a numerical study that investigated the airflow and particle deposition characteristics of inhaled PMs in monkey and human nasal airways. Anatomically accurate macaca fuscata monkey and human nasal cavity models were reconstructed from CT images, micron particles with diameters less than 10 μm were included to conduct in silico exposure studies. Resultant particle deposition patterns were quantified by deposition enhancement factor (DEF) and deposition intensity (DI) along the airways to provide profound understanding of the similarities and differences in particle inhalation exposure characteristics across species. Anatomy comparison showed that the convoluted nasal passage of the monkey airway possessed higher level of complexity in terms of the surface-area-to-volume ratio compared to the two human nasal models, which could lead to higher evaluated nasal exposure to airborne particulate matter. Similar airflow patterns were observed from streamlines and wall shear stress distributions in all three nasal cavities of two species, with bulk air concentrated mainly in the middle and inferior meatuses in the nasal chambers. Despite the evidenced inter-subject deposition variations presented in all considered nasal cavity models, strong and similar micron particle deposition preferences with comparable DEF and DI levels were observed along the floor region of middle and inferior meatuses for both species. The methods and research findings presented in this work represent critical, initial steps towards establishing high-fidelity qualitative and quantitative linkages between the two species that enable more effective laboratory data extrapolations, improve study design, and facilitate validations of in vitro techniques currently being developed as part of international efforts to reduce or replace the use of animals in toxicity assessments for aerosol exposures.

Reduced forced expiratory flow between 25% and 75% of vital capacity in children with allergic rhinitis without asthmatic symptoms

ABSTRACT Introduction: Allergic rhinitis (AR) and asthma are closely associated in children. Reduced FEF25%-75% which reflects small airway airflow limitation is frequently observed in asthma. This study aimed to examine the proportion of small airway dysfunction in children with AR and to determine its associated factors. Methods: The medical records of 144 aged 6-18-year children with AR without overt asthmatic symptoms were retrospectively reviewed. Subjects were divided into 2 groups according to the FEF25%-75% values; normal FEF25%-75% group (n = 129) and reduced FEF25%-75% group (n = 15). Clinical data, allergen sensitization profile, exhaled nitric oxide, spirometry, and methacholine provocation test results were compared between the two groups. Results: The mean FEV1 and FEF25%-75% values in the reduced FEF25%-75% group (73.5 ± 9.4%pred and 56.0 ± 7.7%pred, respectively) were significantly lower than in the normal FEF25%-75% group (87.0 ± 12.5%pred and 99.1 ± 21.4%pred, respectively). The mean disease duration was significantly longer in the reduced FEF25%-75% group than in the normal FEF25%-75% group (5.39 ± 1.85 y vs 3.14 ± 1.80 y, p < 0.001). Subjects with positive bronchial hyperresponsiveness (MChPC20<16 mg/mL) were more frequently detected in the reduced FEF25%-75% group than in the normal FEF25%-75% group (26.7% vs 8.52%, p = 0.013). Long disease duration and severity of AR were significantly associated with impaired FEF25%-75% values. Conclusions: Subjects with AR alone may have impaired FEF25%-75% values which is considered as a marker of early bronchial involvement. Longer disease duration and severity of AR are important risk factors for progressive declines in small airway function. Physicians should be aware of need for the measurement of FEF25%-75% values for early detection of small airway dysfunction, particularly in children with severe long-lasting allergic rhinitis.

217.9: Activation of Angiotensin-converting Enzyme 2 (ACE2) Modulates Lung Mechanics in a Brain Death Model and Attenuates Pulmonary Edema After Rat Lung Transplantation

Introduction: Lung transplantation is a therapeutic option established worldwide for end-stage lung diseases. However, as most donors evolve with brain death (BD), the donated lung may have been compromised. In view of the participation of the renin angiotensin system (RAS) and the use of angiotensin-converting enzyme 2 (ACE2) activators in several pathological processes, it was investigated how diminazene aceturate (DIZE), an ACE2 activator, modulates hemodynamic and blood gas changes, as well as lung function following transplantation in rats. Method: Male Lewis rats were randomly distributed in the following experimental groups: intact, brain death (BD) and BD + diminazene aceturate (BD+DIZE). The last two groups were submitted to brain death process, treated with saline (0.9%) or DIZE (15 mg/kg-1) and kept on mechanical ventilation for 6 hours (donor). After this period, cardiopulmonary block extraction and left unilateral transplantation (LTx) with independent graft ventilation was performed, followed by 2h reperfusion. Hemodynamics (mean arterial pressure - MAP), blood gas analysis, lung mechanics, and pulmonary edema were evaluated. Results are presented as S.E.M. (ANOVA; Tukey; p<0.05). (Approval # CEUA/FMUSP - 1630/2021). Results: The administration of DIZE, 3 hours after BD, prevented the increase in the MAP (210’ after BD-induction: BD – 110 ± 12 mmHg; n=5; BD+DIZE – 40 ± 12 mmHg; n=4/ p=0.0001) without associated blood gas and metabolic alterations. Changes in lung mechanics, such as decreased tissue damping (G) and histeresivity (n) followed by increased respiratory system compliance (Crs), were associated with BD+DIZE (G - 0,25 ± 0,03 cmH2O/mL; Crs - 0,71 ± 0,03 mL/cmH2O; n – 0,14 ± 0,008) compared to intact (G - 0,40 ± 0,02 cmH2O/mL, p = 0.01; Crs – 0,64 ± 0,01 mL/cmH2O, p = 0.02; n - 0,26 ± 0,01, p = 0.004) and BD groups (G – 0,41± 0,05 cmH2O/mL, p = 0.02; Crs – 0,61 ± 0,01 mL/cmH2O, p = 0.01; n - 0,25 ± 0,008, p = 0.01) (Figure 1). After LTx, MAP, gas exchange function, and lung mechanical parameters, were not different among the 3 groups (p>0.05). On the other hand, the DIZE treatment was capable to reduce wet-to-dry weight ratio (INTACT – 1,87 ± 0,13; BD – 2,59 ± 0,14; BD+DIZE – 1,93 ± 0,15/ p=0.01) (Figure 2). Conclusion: Our data suggests that activation of ACE2 is able to modulate donor hemodynamic and lung mechanical parameters, probably reducing tissue resistance and improving airflow in the peripheral airways, converging to a decrease in ventilation heterogeneity in the sudden onset model of brain death. Our data also indicates that DIZE attenuates pulmonary edema on grafts from BD donors after lung transplantation. Keywords: Diminazene aceturate. Renin-angiotensin system. Brain death. Lung mechanics. Lung transplantation.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico.

Characterization of nasal aerodynamics and air conditioning ability using CFD and its application to improve the empty nose syndrome (ENS) submucosal floor implant surgery – Part I methodology

BackgroundCFD simulation allows the visualization of airflow in nasal airways, but the predictions are rarely referenced in real surgeries. The limitations include having a reliable nasal geometry with reasonable boundary conditions and how the predictions corresponding to the symptoms. MethodsThe computational domain is developed from the computed tomography images and face profile of an empty nose syndrome patient with inferior turbinate reduction subtype before and after the submucosal floor implant surgery. The aerodynamics and the ability of conditioning the breathing air of the nasal cavities before and after the surgery are predicted using different breathing air conditions. Significant findingsThe surgery redistributes the airflow and improves the symptoms by having higher airflow fraction in sensor-rich inferior turbinate and shear stresses on superior turbinate olfactory region. The surgery enhances heat and water vapor fluxes from the mucus rich interior turbinate. After the surgery, the surface area on disease side with heat flux greater than the threshold 50 W/m2 increases at both anterior and turbinate, where receptors are rich to elevate the sense of the inhaled air. In summer and winter time, both the air temperature and relative humidity at choanae increases after the surgery by the enhanced nasal air conditioning ability.

Th1 cytokines synergize to change gene expression and promote corticosteroid insensitivity in pediatric airway smooth muscle

BackgroundCorticosteroids remain a key therapy for treating children with asthma. Patients with severe asthma are insensitive, resistant, or refractory to corticosteroids and have poorly controlled symptoms that involve airway inflammation, airflow obstruction, and frequent exacerbations. While the pathways that mediate corticosteroid insensitivity in asthma remain poorly defined, recent studies suggest that enhanced Th1 pathways, mediated by TNFα and IFNγ, may play a role. We previously reported that the combined effects of TNFα and IFNγ promote corticosteroid insensitivity in developing human airway smooth muscle (ASM).MethodsTo further understand the effects of TNFα and IFNγ on corticosteroid sensitivity in the context of neonatal and pediatric asthma, we performed RNA sequencing (RNA-seq) on human pediatric ASM treated with fluticasone propionate (FP), TNFα, and/or IFNγ.ResultsWe found that TNFα had a greater effect on gene expression (~ 1000 differentially expressed genes) than IFNγ (~ 500 differentially expressed genes). Pathway and transcription factor analyses revealed enrichment of several pro-inflammatory responses and signaling pathways. Interestingly, treatment with TNFα and IFNγ augmented gene expression with more than 4000 differentially expressed genes. Effects of TNFα and IFNγ enhanced several pro-inflammatory genes and pathways related to ASM and its contributions to asthma pathogenesis, which persisted in the presence of corticosteroids. Co-expression analysis revealed several gene networks related to TNFα- and IFNγ-mediated signaling, pro-inflammatory mediator production, and smooth muscle contractility. Many of the co-expression network hubs were associated with genes that are insensitive to corticosteroids.ConclusionsTogether, these novel studies show the combined effects of TNFα and IFNγ on pediatric ASM and implicate Th1-associated cytokines in promoting ASM inflammation and hypercontractility in severe asthma.

Quality of Life and Excessive Daytime Sleepiness in Adults with Obstructive Sleep Apnea Who Are Treated with Multilevel Surgery or Adherent to Continuous Positive Airway Pressure.

Obstructive Sleep Apnea (OSA) syndrome is a respiratory sleep disorder characterized by a reduction (hypopnea) in or a complete cessation (apnea) of airflow in the upper airways at night, in the presence of breathing effort. The gold standard treatment for OSA is ventilation through continuous positive airway pressure (CPAP), although this often shows poor patient compliance. In recent years, transoral robotic surgery (TORS) has been proposed as a valid surgical treatment for patients suffering from OSA in a multilevel surgical setting. The aim of this study is to analyze the effects on QoL and daytime sleepiness of multilevel surgery for OSA (barbed pharyngoplasty + transoral robotic surgery). Furthermore, we compared the impact on QoL and daytime sleepiness of two different treatments for patients with moderate to severe OSA, such as CPAP and TORS. Sixty-seven OSA patients who underwent multilevel robotic surgery and sixty-seven OSA patients treated with CPAP were enrolled, defined as Group 1 and Group 2, respectively. The Glasgow Benefit Inventory (GBI) questionnaire was administrated to evaluate the changes in the QoL. Respiratory outcomes were evaluated and compared. Group 1 showed a GBI total average value of +30.4, whereas Group 2, a value of +33.2 (p = 0.4). General benefit score showed no difference between groups (p = 0.1). Better values of social status benefit (p = 0.0006) emerged in the CPAP Group, whereas greater physical status benefit (p = 0.04) was shown in the TORS Group. Delta-AHI (−23.7 ± 14.3 vs. −31.7 ± 15.6; p = 0.001) and Delta-ODI (−24.5 ± 9.5 vs. −29.4 ± 10.5; p = 0.001) showed better values in the CPAP group. Therapeutic success rate of the Multilevel TORS Group was 73.1% and 91% in the CPAP group (p = 0.01), respectively. Multilevel TORS and CPAP have a positive effect on the quality of life of OSA patients. Greater social support has been reported in the CPAP group and better physical health status in the TORS group. No statistical difference emerged in the reduction in daytime sleepiness between both groups.