Airway Resistance Research Articles

Airway mechanics alters generation of cough motor pattern.

Effects of sequential increase in airway resistance: no, low (5 kPa.s/l), high (24 kPa.s/l), and complete block in the inspiratory or expiratory phase of mechanically induced cough on the cough motor pattern were studied in 16 anesthetized (pentobarbital) spontaneously breathing cats (3.70±0.15 kg, 11♂, 5♀). Esophageal pressure and electromyographic activities of the diaphragm during inspiration and abdominal muscles during expiration were analyzed. No significant changes in the number of coughs occurred. Inspiratory occlusion caused a prolongation of cough inspiratory phase, cough inspiratory diaphragm activity, and all cough-related activity. Inspiratory occlusion along with high resistance increased inspiratory esophageal pressure amplitude, total cough cycle duration and the time between maximum activity of the diaphragm and abdominal muscles. High expiratory resistance and occlusion resulted in increased cough expiratory esophageal pressure amplitude, a longer active portion of cough expiration, and cough abdominal activity. Expiratory occlusion also prolonged cough expiratory phase, all cough activity, and total cough cycle. Significantly increased airway resistance and occlusion induce secondary, in addition to mechanical, changes in cough by significantly modulating the generated cough motor pattern. A certain level of resistance appears to be successfully compensated, resulting in minimal changes in coughing characteristics, including expiratory airflow and the rising time of the airflow. Afferent feedback from the respiratory tract, particularly volume feedback, represents a significant factor in modulating cough, mainly under various pathological conditions in the respiratory system.

The storage mite Tyrophagus putrescentiae induces greater lung inflammation than house dust mites in mice.

Exposure to storage mite (SM) and house dust mite (HDM) allergens is a risk factor for sensitization and asthma development; however, the related immune responses and their pathology have not been fully investigated. The HDMs Dermatophagoides farinae and Dermatophagoides pteronyssinus and SM Tyrophagus putrescentiae are potent allergens that induce asthma. Most SM-related studies have focused on the allergic reactions of individuals by measuring their immunoglobulin (Ig)E expression. Considering the limited research on this topic, the present study aims to investigate the differences in the immune responses induced by HDMs and SMs and histologically analyze lung tissues in a mouse asthma model to understand the differential effects of HDM and SM. The results revealed that all mite species induced airway inflammation. Mice challenged with T. putrescentiae had the highest airway resistance and total cell, eosinophil, and neutrophil counts in the bronchoalveolar lavage fluid (BALF). The SM-sensitized groups showed more severe lesions and mucus hypersecretions than the HDM-sensitized groups. Although the degree of HDM and SM exposure was the same, the damage to the respiratory lung tissue was more severe in SM-exposed mice, which resulted in excessive mucin secretion and increased fibrosis. Furthermore, these findings suggest that SM sensitization induces a more significant hypersensitivity response in mucosal immunity than HDM sensitization in asthma models.

Negative impact of face masks in patients with interstitial lung disease: A prospective study.

Face masks increase airway resistance, data on the actual extent of this effect are scarce. The aim of this study was to assess the effect of different mask types on clinical parameters during moderate exercise in healthy non-smokers, active smokers and patients with interstitial lung disease (ILD) without the need of oxygen therapy. In a prospective observational pilot study participants performed a six-minute walk test without mask, with a surgical mask, a well-fitted FFP2 mask and with a valved FFP3 mask. Respiratory rate, blood pressure, heart rate, blood gas analysis parameters, dyspnoea and six-minute walk distance were measured. Data were analysed in an ANOVA model. 21 healthy participants, 17 active smokers without known pulmonary disease and 15 patients with interstitial lung disease were included. Participants with ILD had a significant lower walking distance, a higher respiratory rate and a lower pO2 when using FFP2 masks, but not with valved FFP3 masks or surgical masks compared to not wearing a mask. For patients with ILD without the need of oxygen therapy wearing an FFP2 mask had a negative impact on pO2, respiratory rate and walking distance in the six-minute walk test. This effect was not seen with valved FFP3 masks or surgical masks.

Assessment of nasal respiration and three-dimensional airway volume changes in orthognathic surgery patients

ObjectivesThe aim of this study was to evaluate the effect of maxillary movements in orthognathic surgery on nasal airway volume change and its correlation with airflow and resistance. Materials and methodsThis study included 25 patients (8 male, 17 female) with Class II (6 patients) or Class III (19 patients) malocclusion. All patients underwent Le Fort I and bilateral sagittal split ramus osteotomy. Nasal airflow and resistance were measured by using rhinomanometry and acoustic rhinometry pre and six months post-operatively. Nasal volume was measured using computed tomography before surgery and six months after surgery. ResultsNasal volume increased in 10 out of 11 patients with CCW (counterclockwise) rotation and decreased in 1 patient while, nasal volume increased in 5 patients with CW (clockwise) rotation and decreased in 9 patients. Superior nasal airway volume increased significantly, while the effects on nasal flow and resistance were not significant. Additionally, no significant correlation was found between airway volume changes and variations in airflow and resistance. ConclusionCCW rotation in orthognathic surgery patients significantly increased superior nasal airway volume but did not improve nasal airway flow and resistance

Oral infection with periodontal pathogens induced chronic obstructive pulmonary disease-like lung changes in mice

BackgroundEpidemiological studies have demonstrated that periodontitis is an independent risk factor for chronic obstructive pulmonary disease (COPD). However, the mechanism underlying the association between these two diseases remains unclear. The lung microbiota shares similarities with the oral microbiota, and there is growing evidence to suggest that the lung microbiome could play a role in the pathogenesis of COPD. This study aimed to investigate whether periodontal pathogens could contribute to the pathogenesis of COPD in a mouse model.MethodsWe established mouse models with oral infection by typical periodontal pathogens, porphyromonas gingivalis (Pg group) or fusobacterium nucleatum (Fn group), over a three-month period. Mice that did not receive oral infection were set as the control group (C group). We assessed the level of alveolar bone resorption, lung function, and histological changes in the lungs of the mice. Additionally, we measured the levels of inflammatory factors and tissue damage associated factors in the lung tissues.ResultsLung function indices, including airway resistance, peak inspiratory/expiratory flow and expiratory flow-50%, were significantly reduced in the Fn group compared to the C group. Additionally, histological examination revealed an increased number of inflammatory cells and bullae formation in the lung tissue sections of the Fn group. Meanwhile, levels of inflammatory factors such as IL-1β, IL-6, IFN-γ, and TNF-α, as well as tissue damage associated factors like matrix metalloproteinase-8 and neutrophil elastase, were significantly elevated in the lung tissue of the Fn group in comparison to the C group. The Pg group also showed similar but milder lung changes compared to the Fn group. Pg or Fn could be detected in the lungs of both oral infected groups.ConclusionThe results indicated that oral periodontal pathogens infection could induce COPD-like lung changes in mice, and they may play a biological role in the association between periodontitis and COPD.

Nasal airway resistance in patients with different degrees of operated unilateral cleft lip: Evaluation of ventilation in 112 patients

ObjectiveThe aim of this study was to compare the nasal airway resistance between the cleft and non-cleft sides in operated unilateral cleft lip (UCL) patients with varying severities at birth, as well as to assess the differences in nasal airway resistance between UCL patients and healthy individuals. MethodsThis retrospective study was conducted on 112 UCL patients who have undergone primary lip reconstructions but not advanced surgeries as the study group and 20 healthy participants as the control group between February 2023 to March 2024. The study group patients were grouped based on the severity of their cleft lip at birth, divided into occult cleft lip group, incomplete cleft lip group, and complete cleft lip group. The anterior rhinomanometry was used to evaluate nasal resistance, including unilateral effective resistances during inspiration (Reffin), expiration (Reffex), and the entire breath (ReffT), as well as unilateral vertex resistance during inspiration (VRin) and expiration (VRex). The Kolmogorov-Smirnov test was used to assess normality. Paired t-tests were utilized to analyze the differences in nasal resistance between the healthy and affected sides within the same group of patients. Student's t-test was used to analyze the differences in nasal resistance among patients with different degrees of cleft lip. A p-value of <0.05 was considered statistically significant. ResultsThe nasal resistances of the occult cleft and incomplete cleft lip groups showed no significant differences between the cleft and non-cleft sides, and were similar to the control group. However, in the complete cleft lip group, the cleft side nasal resistance was significantly higher than the non-cleft side and control group. Among the groups, the complete cleft lip group had significantly higher nasal resistances on the cleft side for Reffin, VRin, and ReffT compared to the occult cleft group. ConclusionUnderstanding the nasal resistance of different degrees of operated UCL patients can benefit clinical diagnosis and treatment. Patients with complete cleft lip have more severe nasal obstruction on the cleft side, with greater impact on inhalation than exhalation. For these patients, treatment by an otolaryngologist is recommended to improve nasal airflow.

Intranasal administration of a synthetic TLR4 agonist INI-2004 significantly reduces allergy symptoms following therapeutic administration in a murine model of allergic sensitization.

Atopic diseases have been steadily increasing over the past decades and effective disease-modifying treatment options are urgently needed. These studies introduce a novel synthetic Toll-like receptor 4 (TLR4) agonist, INI-2004, with remarkable efficacy as a therapeutic intranasal treatment for seasonal allergic rhinitis. Using a murine airway allergic sensitization model, the impact of INI-2004 on allergic responses was assessed. One or two intranasal doses of INI-2004 significantly reduced airway resistance, eosinophil influx, and Th2 cytokine production - providing strong evidence of allergic desensitization. Further investigations revealed that a liposomal formulation of INI-2004 exhibited better safety and efficacy profiles compared to aqueous formulations. Importantly, the liposomal formulation demonstrated a 1000-fold increase in the maximum tolerated intravenous dose in pigs. Pre-clinical GLP toxicology studies in rats and pigs confirmed the safety of liposomal INI-2004, supporting its selection for human clinical trials. These findings lay the groundwork for the ongoing clinical evaluation of INI-2004 in allergic rhinitis as a stand-alone therapy for individuals poly-sensitized to multiple seasonal allergens. The study underscores the significance of innovative immunotherapy approaches in reshaping the landscape of allergic rhinitis management.

Effects of nursing team communication and collaboration on treatment outcomes in intensive care unit patients with severe pneumonia.

Severe pneumonia is a common severe respiratory infection worldwide, and its treatment is challenging, especially for patients in the intensive care unit (ICU). To explore the effect of communication and collaboration between nursing teams on the treatment outcomes of patients with severe pneumonia in ICU. We retrospectively analyzed 60 patients with severe pneumonia who were treated at the ICU of the hospital between January 1, 2021 and December 31, 2023. We compared and analyzed the respiratory mechanical indexes [airway resistance (Raw), mean airway pressure (mPaw), peak pressure (PIP)], blood gas analysis indexes (arterial oxygen saturation, arterial oxygen partial pressure, and oxygenation index), and serum inflammatory factor levels [C-reactive protein (CRP), procalcitonin (PCT), cortisol (COR), and high mobility group protein B1 (HMGB1)] of all patients before and after treatment. Before treatment, there was no significant difference in respiratory mechanics index and blood gas analysis index between 2 groups (P > 0.05). However, after treatment, the respiratory mechanical indexes of patients in both groups were significantly improved, and the improvement of Raw, mPaw, plateau pressure, PIP and other indexes in the combined group after communication and collaboration with the nursing team was significantly better than that in the single care group (P < 0.05). The serum CRP and PCT levels of patients were significantly decreased, and the difference was statistically significant compared with that of nursing group alone (P < 0.05). The levels of serum COR and HMGB1 before and after treatment were also significantly decreased between the two groups. The communication and collaboration of the nursing team have a significant positive impact on respiratory mechanics indicators, blood gas analysis indicators and serum inflammatory factor levels in the treatment of severe pneumonia patients in ICU.

Mechanism analysis of essential oil from Radix Bupleuri for the treatment of asthma through regulation of ectopic olfactory receptor

Ethnopharmacological relevanceRadix Bupleuri is the root of Bupleurum chinense DC. (BC) and a classic aromatic traditional Chinese medicine. The traditional pharmacological effects of Radix Bupleuri are alleviating bronchial spasms, dilating airways, and promoting the resolution of respiratory inflammation, thereby reducing asthma symptoms. Aim of the studyStudies have demonstrated the efficacy of water extracts from BC in asthma treatment. However, the potential role of volatile oil, another active constituent in BC, remains unexplored with asthma. Notably, volatile oil is renowned for its ease of absorption and direct targeting of affected areas, offering distinct advantages in alleviating airway inflammation. This study aims to explain the anti-asthmatic mechanism of BC-oil through in vivo and in vitro pharmacological experiments. Materials and methodsFirstly, the OVA-induced SD rat asthma model was utilized to evaluate the pharmacological effect of BC-oil by lung function monitoring, HE staining, flow cytometry, ELISA, and RT-qPCR. The anti-asthmatic mechanism was further analyzed by combining transcriptomic analysis of lung tissue from rat model and airway smooth muscle tissue from public database. Initially, GC-MS was used to analyze the components of BC-oil. The anti-asthmatic activity was evaluated in 16-HBE, RBL-2H3, and ASMC cells using CAMKII inhibitors to explore of the critical signal transduction regulated by BC-oil. Furthermore, molecular docking and calcium flow assay were utilized to screen and identify the active components from BC-oil. ResultsOral administration of BC-oil significantly enhanced pulmonary function in asthmatic SD rats by reducing airway resistance and elastic resistance. Additionally, BC-oil inhibited inflammatory cytokines, including serum IL-2, pulmonary Il1b, Tnf, and Cxcl13, demonstrating potent anti-inflammatory and immunomodulatory effects. In this study, we analyzed the significant role of OR2W3 in asthma using public transcriptomic data. Furthermore, we indicated that BC-oil regulated the expression of Olr1433 and GNAL in rat lung tissue. BC-oil reduced degranulation and inhibited gene expression of Il3 and Tnf in RBL-2H3 cells and suppressed gene expression of IL8 and TNF in 16-HBE cells. BC-oil also attenuated airway smooth muscle cell proliferation and expression of Acta2 and Ccnd1. Furthermore, BC-oil regulates asthma-related cellular processes by activating CAMKII. GC-MS analysis identified 11 components of BC-oil, and n-hexadecanoic acid, linoleic acid and oleic acid from BC-oil were identified to interact with OR2W3 by molecular docking. The calcium flow assay revealed linoleic acid as a significant activator of OR2W3 and indicated that BC-oil alleviated asthma through the ectopic olfactory signaling pathway. ConclusionsThe mechanism of BC-oil in treating asthma through signal transduction of OR2W3 is revealed at the molecular and cellular levels.

Breath-by-breath assessment of acute pulmonary edema using electrical impedance tomography, spirometry and volumetric capnography in a sheep (Ovis Aries) model.

The bedside diagnosis of acute pulmonary edema is challenging. This study evaluated the breath-by-breath information from electrical impedance tomography (EIT), respiratory mechanics and volumetric capnography (VCap) to assess acute pulmonary edema induced by xylazine administration in anesthetized sheep. To determine the ability and efficiency of each monitoring modality in detecting changes in lung function associated with onset of pulmonary edema. Twenty healthy ewes were anesthetized, positioned in sternal (prone) recumbency and instrumented. Synchronized recordings of EIT, spirometry and VCap were performed for 60 s prior to start of injection, during xylazine injection over 60 s (0-60 s) and continuously for 1 min (60-120 s) after the end of injection. After visual assessment of the recorded mean variables, statistical analysis was performed using a mixed effect model for repeated measures with Bonferroni's correction for multiple comparisons, to determine at which breath after start of injection the variable was significantly different from baseline. A significant change over time was defined as an adjusted p < 0.05. All statistics were performed using GraphPad Prism 0.1.0. Electrical impedance tomography showed significant changes from baseline in all but two variables. These changes were observed simultaneously during xylazine injection at 48 s and were consistent with development of edema in dependent lung (decreased end-expiratory lung impedance, ventilation in centro-ventral and ventral lung region) and shift of ventilation into non-dependent lung (decreased non-dependent silent spaces and increased center of ventilation ventral to dorsal and increased ventilation in centro-dorsal and dorsal lung region). All changes in lung mechanics also occurred during injection, including decreased dynamic respiratory system compliance and increased peak expiratory flow, peak inspiratory pressure and airway resistance at 48, 54 and 60 s, respectively. Changes in VCap variables were delayed with all occurring after completion of the injection. In this model of pulmonary edema, EIT detected significant and rapid change in all assessed variables of lung function with changes in regional ventilation indicative of pulmonary edema. Volumetric capnography complemented the EIT findings, while respiratory mechanics were not specific to lung edema. Thus, EIT offers the most comprehensive method for pulmonary edema evaluation, including the assessment of ventilation distribution, thereby enhancing diagnostic capabilities.

Efficacy of dupilumab for severe chronic rhinosinusitis with nasal polyps and asthma: A prospective study

BackgroundDupilumab exerts clinical effects, including improved sinus opacification, olfactory function, and quality of life, in patients with severe chronic rhinosinusitis with nasal polyps (CRSwNPs). Meanwhile, only a few studies have reported its effects on nasal airway resistance and olfactory function, particularly in the Japanese population. Predictors of response remain unclear. ObjectiveTo assess the comprehensive efficacy and therapeutic response to dupilumab in patients with severe CRSwNP with comorbid asthma. MethodsIn 16 adult patients with severe CRSwNP with comorbid asthma, the efficacy of 48-week dupilumab treatment, including olfactory function measured by a T&T olfactometer, nasal airway resistance measured by rhinomanometry, nasal polyp score, Lund-Mackay computed tomography score, and 22-item Sinonasal Outcome Test (SNOT-22), was assessed. Regarding asthma, the annualized rate of exacerbations, 7-item Asthma Control Questionnaire (ACQ-7), and spirometry were assessed. Treatment responsiveness was analyzed. ResultsWith 48-week dupilumab treatment, olfactory function, nasal airway resistance, nasal polyp score, Lund-Mackay computed tomography score, and SNOT-22 scores improved significantly. Regarding comorbid asthma, the annualized rate of exacerbations decreased, and ACQ-7 scores and lung function improved significantly. According to the European Position Paper on Rhinosinusitis and Nasal Polyps 2020/European Forum for Research and Education in Allergy and Airway Diseases criteria, 15 patients (94%) were moderate-to-excellent responders at 48 weeks of treatment. Patients with higher SNOT-22 scores, ACQ-7 scores, the rate of asthma exacerbations in the previous year, and blood eosinophil counts benefited more from the treatment. ConclusionDupilumab improved upper and lower airway outcomes especially in patients with severe CRSwNP with comorbid, poorly controlled asthma. Trial RegistrationUMIN Clinical Trials Registry: UMIN000038669.

Associations between TLRs 2 and 4, and β-lactam antibiotics in COPD patients complicated with pulmonary infections.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the world. We aimed to investigate the associations between toll-like receptors 2 and 4 (TLR-2 and TLR-4) and β-lactam antibiotics in COPD patients complicated with pulmonary infections. A total of 156 COPD patients complicated with pulmonary infections were included. Their blood gas, airway resistance, health status, expression levels of TLR-2 and TLR-4, and pulmonary function were analyzed after treatment with β-lactam antibiotics. Blood gas indices oxygen saturation, partial pressure of oxygen, and partial pressure of carbon dioxide at one day before treatment, on the fifteenth day of treatment, and on the first day after the end of treatment showed significant differences (p < 0.01). Significant differences were also detected in airway resistance indices (p < 0.01). The differences in the mRNA expression levels of TLR-2 and TLR-4 were significant (p < 0.05). Downward trends were observed in the clinical pulmonary infection score and acute physiology and chronic health evaluation II score, which indicated alleviation of the disease. Pulmonary function indices recorded vital capacity (VC)/predicted VC (%), recorded forced vital capacity at 1 s (FEV1)/predicted FEV1 (%), and residual volume/total lung capacity were significantly different (p < 0.05). β-Lactam antibiotics had obvious therapeutic effects on COPD patients complicated with pulmonary infections, probably by suppressing or attenuating TLR-2- and TLR-4-mediated inflammatory responses. It is necessary to comprehensively evaluate and choose appropriate antibiotics, aiming for maximum relief of the pain to help patients recover quickly.

A stepwise lung recruitment maneuver using I-gel can improve respiratory parameters: A prospective observational study.

I-gel has been used in various clinical situations. The study investigated alterations in respiratory parameters following a stepwise lung recruitment maneuver (LRM) using the i-gel. The research involved 60 patients classified as American Society of Anesthesiologists class I-II, aged 30 to 75 years, undergoing elective urologic surgery. Various respiratory parameters, including lung compliance, airway resistance, leak volume, airway pressure, and oxygen reserve index, were recorded at different time points: before LRM, immediately after LRM, and at 5, 15, and 30 minutes after LRM, as well as at the end of the surgery. The primary outcome was to assess an improvement in lung compliance. Dynamic lung compliance (mean ± SD) was significantly increased from 49.2 ± 1.8 to 70.15 ± 3.2 mL/cmH2O (P < .05) after LRM. Static lung compliance (mean ± SD) was increased considerably from 52.4 ± 1.7 to 65.0 ± 2.5 mL/cmH2O (P < .05) after the LRM. Both parameters maintained a statistically significant increased status for a certain period compared to baseline despite a decreased degree of increment. Airway resistance (mean ± SD) was significantly reduced after the LRM from 12.05 ± 0.56 to 10.41 ± 0.64 L/cmH2O/s (P < .05). Stepwise LRM using i-gel may improve lung compliance and airway resistance. Repeated procedures could lead to prolonged improvements in respiratory parameters.

Elevated neutrophil-to-lymphocyte ratio combined with decreased lymphocyte-to-monocyte ratio is associated with increased peripheral airway resistance in patients with hepatic steatosis.

Although the link between hepatic steatosis and lung function has been confirmed, the focus has largely been on central airways. The association between hepatic steatosis and increased peripheral airway resistance has not yet been explored. Hepatic steatosis and increased peripheral resistance are connected with immunity dysregulation. High neutrophil-to-lymphocyte ratio (NLR) and low lymphocyte-to-monocyte ratio (LMR) have been recognized as indicators of immunity dysregulation. In this study, the association between hepatic steatosis and increased peripheral airway resistance was evaluated, and the effect of immunity dysregulation (high NLR/low LMR) on the increased peripheral airway resistance among patients with hepatic steatosis was explored. In this retrospective study, chest or abdomen CT scans and spirometry/impulse oscillometry (IOS) from 2018 to 2019 were used to identify hepatic steatosis and increased central/peripheral airway resistance in patients. Among 1391 enrolled patients, 169 (12.1%) had hepatic steatosis. After 1:1 age and abnormal ALT matching was conducted, clinical data were compared between patients with and without hepatic steatosis. A higher proportion of patients with hepatic steatosis had increased peripheral airway resistance than those without hepatic steatosis (52.7% vs 40.2%, P = .025). Old age, high body mass index, history of diabetes, and high NLR/low LMR were significantly correlated with increased peripheral airway resistance. The presence of hepatic steatosis is associated with increased peripheral airway. High NLR/low LMR is an independent associated factor of increased peripheral airway resistance in patients with hepatic steatosis. It is advisable for patients with hepatic steatosis to regularly monitor their complete blood count/differential count and undergo pulmonary function tests including IOS.

Pulmonary function in patients with ANCA-associated vasculitis.

Although pulmonary manifestations occur frequently in ANCA-associated vasculitis (AAV), empirical evidence of their impact on pulmonary function is scarce. This study analyzed pulmonary function test (PFT) data from a large cohort of patients with AVV. Results were correlated with findings from diagnostic imaging and disease activity. Data from AAV patients with PFTs performed between 2008 and 2018 were extracted retrospectively from the database of a tertiary vasculitis center. Demographic and disease characteristics, imaging data and follow-up results were assessed and compared to PFT results. The final analysis encompassed 147 patients. The mean time between first PFT and follow-up was 7.0 ± 11.0 months. In Granulomatosis with Polyangiitis (GPA), forced expiratory vital capacity (FVCex, p<0.001), residual volume (RV, p<0.001) and the diffusion capacity of carbon oxide (TLCO, p=0.003) were significantly reduced compared to the reference value of 100% predicted. There was no significant difference between patients with or without pulmonary manifestations. In Microscopic Polyangiitis (MPA), reductions of FVCex (p<0.001), TLC (p=0.005), and TLCO (p=0.003) were observed. In Eosinophilic Granulomatosis with Polyangiitis (EGPA), total airway resistance (RAWtot, p=0.024) and RV (p=0.009) were significantly elevated and TLCO was reduced (p=0.014). Interstitial lung disease (ILD) is associated with a decline of FVCex (-15.7%, p=0.0028), TLC (-26.5%, p<0.001), RV (-38.9%, p=0.023) and TLCO (-29.1%, p=0.007). Significant differences were neither detected between first PFT and follow-up examination, nor between patients with active versus inactive disease. AAV patients presented with characteristic alterations in PFTs according to their respective pulmonary and/or airway manifestations. These results did not change over time and were independent from vasculitis activity.

Effect of Cholinergic Receptor Antagonists on the Potentiation of the Effect of Adenosine Receptor Blockers in People with Bronchial Asthma

Background: The interaction between adenosine receptor blockers and anticholinergic substances in the treatment of bronchial asthma is an area of interest. The efficacy of such combinations in managing bronchial asthma and bronchial hypersensitivity needs to be explored further. Understanding lung function parameters such as airway resistance and intrathoracic gas volume is crucial for evaluating the effects of these medications. Objective: This study aimed to investigate the effect of combining the adenosine receptor blocker, bamifylline, with the anticholinergic substance, ipratropium bromide spray, in patients with bronchial asthma. Specifically, the study sought to assess changes in lung function parameters, including airway resistance and intrathoracic gas volume, after administering ipratropium bromide alone and in combination with bamifylline. Methods: Sixteen patients with bronchial asthma were enrolled in the study. Lung function was evaluated using body plethysmography, with measurements of airway resistance (Raw), intrathoracic gas volume (ITGV), airway specific resistance (SRaw), and airway specific conductance (SGaw). Patients initially received ipratropium bromide inhalation (2 inhalations x 20µg), followed by Raw and ITGV measurements at intervals (5, 30, 60, and 120 minutes). Subsequently, patients received bamifylline (2 x 600 mg) daily for seven days at home. On the eighth day, they were administered ipratropium bromide spray (2 inhalations x 20µg), and lung function parameters were assessed similarly. Results: Administration of ipratropium bromide alone led to a significant reduction in airway resistance (p&lt;0.05). However, the combination of ipratropium bromide with bamifylline did not significantly enhance the effects of adenosine receptor blockade (p&lt;0.05). Specifically, there were no significant changes in Raw, ITGV, SRaw, or SGaw after combining ipratropium bromide with bamifylline. Conclusion: The study findings suggest that the addition of anticholinergic substances did not potentiate the action of adenosine receptor blockers in patients with bronchial asthma. Therefore, the anti-inflammatory effects of xanthines, such as bamifylline, were not augmented by anticholinergic substances in this study. These results highlight the need for further research to explore alternative therapeutic approaches in the management of bronchial asthma.

Research on portable airway impedance monitoring device based on expiratory oscillation

Monitoring airway impedance has significant clinical value in accurately assessing and diagnosing pulmonary function diseases at an early stage. To address the issue of large oscillator size and high power consumption in current pulmonary function devices, this study adopts a new strategy of expiration-driven oscillation. A lightweight and low-power airway impedance monitoring system with integrated sensing, control circuitry, and dynamic feedback system, providing visual feedback on the system's status, was developed. The respiratory impedance measurement experiments and statistical comparisons indicated that the system could achieve stable measurement of airway impedance at 5 Hz. The frequency spectrum curves of respiratory impedance ( R and X) showed consistent trends with those obtained from the clinical pulmonary function instrument, specifically the impulse oscillometry system (IOS). The differences between them were all less than 1.1 cm H 2O·s/L. Additionally, there was a significant statistical difference in the respiratory impedance R5 between the exercise and rest groups, which suggests that the system can measure the variability of airway resistance parameters during exercise. Therefore, the impedance monitoring system developed in this study supports subjects in performing handheld, continuous measurements of dynamic changes in airway impedance over an extended period of time. This research provides a foundation for further developing low-power, portable, and even wearable devices for dynamic monitoring of pulmonary function.

Sex differences in asthma control, lung function and exacerbations: the ATLANTIS study

BackgroundAsthma is a heterogeneous disease with a prevalence and severity that differs between male and female patients.QuestionWhat are differences between male and female patients with asthma with regard to asthma...

Early and late effects of volatile sedation with sevoflurane on respiratory mechanics of critically ill COPD patients

BackgroundThe objective was to compare sevoflurane, a volatile sedation agent with potential bronchodilatory properties, with propofol on respiratory mechanics in critically ill patients with COPD exacerbation.MethodsProspective study in an ICU enrolling critically ill intubated patients with severe COPD exacerbation and comparing propofol and sevoflurane after 1:1 randomisation. Respiratory system mechanics (airway resistance, PEEPi, trapped volume, ventilatory ratio and respiratory system compliance), gas exchange, vitals, safety and outcome were measured at inclusion and then until H48. Total airway resistance change from baseline to H48 in both sevoflurane and propofol groups was the main endpoint.ResultsSixteen patients were enrolled and were sedated for 126 h(61–228) in the propofol group and 207 h(171–216) in the sevoflurane group. At baseline, airway resistance was 21.6cmH2O/l/s(19.8–21.6) in the propofol group and 20.4cmH2O/l/s(18.6–26.4) in the sevoflurane group, (p = 0.73); trapped volume was 260 ml(176–290) in the propofol group and 73 ml(35–126) in the sevoflurane group, p = 0.02. Intrinsic PEEP was 1.5cmH2O(1–3) in both groups after external PEEP optimization. There was neither early (H4) or late (H48) significant difference in airway resistance and respiratory mechanics parameters between the two groups.ConclusionsIn critically ill patients intubated with COPD exacerbation, there was no significant difference in respiratory mechanics between sevoflurane and propofol from inclusion to H4 and H48.

The respiratory health effects of acute in vivo diesel and biodiesel exhaust in a mouse model

BackgroundBiodiesel, a renewable diesel fuel that can be created from almost any natural fat or oil, is promoted as a greener and healthier alternative to commercial mineral diesel without the supporting experimental data to back these claims. The aim of this research was to assess the health effects of acute exposure to two types of biodiesel exhaust, or mineral diesel exhaust or air as a control in mice. Male BALB/c mice were exposed for 2-hrs to diluted exhaust obtained from a diesel engine running on mineral diesel, Tallow biodiesel or Canola biodiesel. A room air exposure group was used as a control. Twenty-four hours after exposure, a variety of respiratory related end point measurements were assessed, including lung function, responsiveness to methacholine and airway and systemic immune responses. ResultsTallow biodiesel exhaust exposure resulted in the greatest number of significant effects compared to Air controls, including increased airway hyperresponsiveness (178.1 ± 31.3% increase from saline for Tallow biodiesel exhaust exposed mice compared to 155.8 ± 19.1 for Air control), increased airway inflammation (63463 ± 13497 cells/mL in the bronchoalveolar lavage of Tallow biodiesel exhaust exposed mice compared to 40561 ± 11800 for Air exposed controls) and indications of immune dysregulation. In contrast, exposure to Canola biodiesel exhaust resulted in fewer significant effects compared to Air controls with a slight increase in airway resistance at functional residual capacity and indications of immune dysregulation. Exposure to mineral diesel exhaust resulted in significant effects between that of the two biodiesels with increased airway hyperresponsiveness and indications of immune dysregulation. ConclusionThese data show that a single, brief exposure to biodiesel exhaust can result in negative health impacts in a mouse model, and that the biological effects of exposure change depending on the feedstock used to make the biodiesel.