Changes In Airway Resistance Research Articles

Retrospective Analysis of the Ventilatory Workload Kinetic Index during Stability and Crisis in Patients with Asthma and COPD in a Monitored Program.

To assess ventilatory evolution through the Ventilatory Workload Kinetic Index (VWKI) in patients with asthma and chronic obstructive pulmonary disease (COPD) during stability and exacerbation. Retrospective analysis. Conducted at the Padre Alberto Hurtado Hospital, Santiago, Chile. Ten patients with asthma and fifty-five with COPD participated. Sixty-five clinical records were reviewed. The VWKI in stability and exacerbation of these patients was extracted. When analyzing the baseline with the peak in both asthma and COPD, there was a significant increase in the VWKI. Similarly, the loads, translations, and supports significantly increased from the baseline to the peak. However, in the loads, there were no changes in airway resistance for asthma or in cough for COPD. Likewise, the supports for asthma and COPD showed no changes in the O2. The VWKI determined ventilatory issues in outpatients and made locating the greatest compromise in loads, translations, or supports possible.

The Use and Efficacy of Oral Phenylephrine Versus Placebo Treating Nasal Congestion Over the Years on Adults: A Systematic Review.

Nasal congestion is a common issue stemming from various factors such as allergies and anatomical variations. Allergic rhinitis frequently leads to nasal congestion. The pathophysiology involves inflammation, swelling, and mucus production in the nasal mucosa. Multiple treatments are available, including oral phenylephrine, an over-the-counter or prescription option. However, the effectiveness and safety of phenylephrine have been subjects of debate. This systematic review aims to provide an updated perspective on the efficacy of oral phenylephrine versus placebo in addressing nasal congestion in adults. We conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, a systematic review involving searches on PubMed, Cochrane, and Scopus databases. Inclusion/exclusion criteria were defined to identify high-quality studies. The focus was on randomized controlled trials (RCTs) and case-control studies published in English between 1998 and 2023, involving adult populations. The interventions compared oral phenylephrine with placebo or standard care, with outcomes centering on changes in nasal congestion symptoms and nasal airway resistance. We identified four articles that met the criteria. These studies exhibited varied designs and populations. The findings consistently indicated that phenylephrine was not more effective than a placebo in relieving nasal congestion.This systematic review demonstrates that oral phenylephrine did not offer substantial relief from nasal congestion compared to a placebo in adults. The studies featured diverse designs, yet the prevailing conclusion was that phenylephrine's efficacy was limited. Safety assessments showed no life-threatening adverse events, with common side effects including headaches and mild discomfort. In summary, this systematic review indicates that oral phenylephrine is not significantly more effective than a placebo in alleviating nasal congestion in adults. Clinicians should explore alternative treatment options, considering the review's limitations. Additional research may be needed to clarify the role of oral phenylephrine in managing nasal congestion.

Exercise‐induced bronchoconstriction assessed by a ratio of surface diaphragm EMG to tidal volume

AbstractExercise‐induced bronchoconstriction (EIB) is usually assessed by changes in forced expiratory volume in 1 s (FEV1) which is effort dependent. The purpose of this study was to determine whether the diaphragm electromyogram (EMGdi) recorded from chest wall surface electrodes could be used to reflect changes in airway resistance during an exercise challenge test and to distinguish patients with EIB from those without EIB. Ninety participants with or without asthma history were included in the study. FEV1 was recorded before and 5, 10, 15, and 20 min after exercise. EIB was defined as an FEV1 decline greater than 10% after exercise. A ratio of root mean square of EMGdi to tidal volume (EMGdi/VT) was used to assess changes in airway resistance. Based on changes in FEV1, 25 of 90 participants exhibited EIB; the remainder were defined as non‐EIB participants. EMGdi/VT in EIB increased by 124% (19%–478%) which was significantly higher than that of 21% (−39% to 134%) in non‐EIB participants (p < 0.001). At the optimal cutoff point (54% in EMGdi/VT), the area under the ROC curve (AUC) for detection of a positive test was 0.92 (p < 0.001) with sensitivity 92% and specificity 88%. EMGdi/VT can be used to assess changes in airway resistance after exercise and could be used to distinguish participants with EIB from those without EIB.

Glucagon-like Peptide-1 Receptor Pathway Attenuates Platelet Activation in Aspirin-Exacerbated Respiratory Disease.

Platelets are key contributors to allergic asthma and aspirin-exacerbated respiratory disease (AERD), an asthma phenotype involving platelet activation and IL-33-dependent mast cell activation. Human platelets express the glucagon-like peptide-1 receptor (GLP-1R). GLP-1R agonists decrease lung IL-33 release and airway hyperresponsiveness in mouse asthma models. We hypothesized that GLP-1R agonists reduce platelet activation and downstream platelet-mediated airway inflammation in AERD. GLP-1R expression on murine platelets was assessed using flow cytometry. We tested the effect of the GLP-1R agonist liraglutide on lysine-aspirin (Lys-ASA)-induced changes in airway resistance, and platelet-derived mediator release in a murine AERD model. We conducted a prospective cohort study comparing the effect of pretreatment with liraglutide or vehicle on thromboxane receptor agonist-induced invitro activation of platelets from patients with AERD and nonasthmatic controls. GLP-1R expression was higher on murine platelets than on leukocytes. A single dose of liraglutide inhibited Lys-ASA-induced increases in airway resistance and decreased markers of platelet activation and recruitment to the lung in AERD-like mice. Liraglutide attenuated thromboxane receptor agonist-induced activation as measured by CXCL7 release in plasma from patients with AERD and CD62P expression in platelets from both patients with AERD (n = 31) and nonasthmatic, healthy controls (n = 11). Liraglutide, a Food and Drug Administration-approved GLP-1R agonist for treatment of type 2 diabetes and obesity, attenuates invivo platelet activation in an AERD murine model and invitro activation in human platelets in patients with and without AERD. These data advance the GLP-1R axis as a new target for platelet-mediated inflammation warranting further study in asthma.

The effect of inhaled extrafine beclometasone dipropionate/formoterol fumarate/glycopyrronium bromide on distal and central airway indices, assessed using Functional Respiratory Imaging in COPD (DARWiIN)

BackgroundThis study, in patients with symptomatic chronic obstructive pulmonary disease (COPD), explored switching therapy from non-extrafine high-dose inhaled corticosteroid/long-acting β2-agonist (ICS/LABA; fluticasone propionate/salmeterol [FP/SLM]) to extrafine medium-dose beclometasone dipropionate/formoterol fumarate dihydrate/glycopyrronium (BDP/FF/G), both via dry-powder inhaler. Functional Respiratory Imaging, a quantitative computed tomography method with 3D reconstructions of pulmonary anatomy, was used to assess airway geometry and lung function.MethodsPatients receiving a stable ICS/LABA regimen for ≥ 8 weeks were switched to FP/SLM 500/50 µg, one inhalation twice-daily (high-dose ICS) for 6 weeks. After baseline assessments (Visit 2 [V2]), therapy was switched to BDP/FF/G 100/6/10 µg, two inhalations twice-daily (medium-dose ICS) for 6 weeks, followed by V3. The primary endpoints were percentage changes in specific image-based airway volume (siVaw) and resistance (siRaw) from baseline to predose at V3 (i.e., chronic effects), assessed at total lung capacity (TLC) in central and distal lung regions. Secondary endpoints included siVaw and siRaw changes from pre-dose to post-dose at V2, and from pre-dose to post-dose at V3 at TLC (i.e., acute effects), and chronic and acute changes in siVaw and siRaw at functional residual capacity (FRC). Pre-dose forced expiratory volume in 1 s (FEV1) and COPD Assessment Test (CAT) were also assessed.ResultsThere were no significant changes in pre-dose siVaw or siRaw at TLC from baseline to V3, although at FRC there was a significant decrease in mean siRaw in the distal airways (− 63.6%; p = 0.0261). In addition, in the distal airways there were significant acute effects at TLC on mean siVaw and siRaw (siVaw: 39.8% and 62.6%; siRaw: − 51.1% and − 57.2%, V2 and V3, respectively; all p < 0.001) and at FRC at V2 (siVaw: 77.9%; siRaw: − 67.0%; both p < 0.001). At V3, the mean change in pre-dose FEV1 was 62.2 mL (p = 0.0690), and in CAT total score was − 3.30 (p < 0.0001).ConclusionsIn patients with symptomatic COPD receiving high-dose ICS/LABA, adding a long-acting muscarinic antagonist while decreasing the ICS dose by switching to medium-dose extrafine BDP/FF/G was associated with improved airway indices, especially in the distal airways, together with improvements in respiratory health status.Trial registration ClinicalTrials.gov (NCT04876677), first posted 6th May 2021

Computational fluid dynamics comparison of the upper airway velocity, pressure, and resistance in cats using an endotracheal tube or a supraglottic airway device.

In veterinary medicine, airway management of cats under general anesthesia is performed with an endotracheal tube (ETT) or supraglottic airway device (SGAD). This study aims to describe the use of computational fluid dynamics (CFD) to assess the velocities, pressures, and resistances of cats with ETT or SGAD. A geometrical reconstruction model of the device, trachea, and lobar bronchi was carried out from computed tomography (CT) scans that include the head, neck, and thorax. Twenty CT scans of cats under general anesthesia using ETT (n = 10) and SGAD (n = 10) were modeled and analyzed. An inspiratory flow of 2.4 L/min was imposed in each model and velocity (m/s), general and regional pressures (cmH2O) were computed. General resistance (cmH2O/L/min) was calculated using differential pressure differences between the device inlet and lobar bronchi. Additionally, regional resistances were calculated at the device's connection with the breathing circuit (region A), at the glottis area for the SGAD, and the area of the ETT exit (bevel) (region B) and the device itself (region C). Recirculatory flow and high velocities were found at the ETT's bevel and at the glottis level in the SGAD group. The pressure gradient (Δp) was more enhanced in the ETT cases compared with the SGAD cases, where the pressure change was drastic. In region A, the Δp was higher in the ETT group, while in regions B and C, it was higher in the SGAD group. The general resistance was not statistically significant between groups (p = 0.48). Higher resistances were found at the region A (p = <0.001) in the ETT group. In contrast, the resistance was higher in the SGAD cases at the region B (p = 0.001). Overall, the provided CT-based CFD analysis demonstrated regional changes in airway pressure and resistance between ETT and SGAD during anesthetic flow conditions. Correct selection of the airway device size is recommended to avoid upper airway obstruction or changes in flow parameters.

Association between Childhood Asthma Control Test scores and lung pathophysiologic indicators in longitudinal measurements.

Childhood Asthma Control Test (C-ACT) is a well-validated questionnaire for asthma controls among 4-11 years old children. This study aims to examine if longitudinal C-ACT score changes could also reflect lung pathophysiologic changes. Thirty-seven children (43% female) aged 5 to 10 years old with mild or moderate asthma were followed up for 6 weeks with bi-weekly assessments of C-ACT, airway mechanics, lung function and respiratory inflammation. Associations of longitudinal changes in C-ACT score with lung pathophysiologic indicators were evaluated using linear mixed-effects models. A two-point worsening of total C-ACT score (sum of child and caregiver-reported) was associated with significant decreases in forced expiratory volume during the 1st second (FEV1) by 1.7% (P=0.04) and forced vital capacity (FVC) by 1.6% (P=0.01) and increased total airway resistance [airway resistance at 5 Hz (R5)] by 3.8% (P=0.05). A two-point worsening in child-reported score was significantly associated with 3.1% and 2.5% reductions in FEV1 and FVC, respectively, and with increases in R5 by 6.5% and large airway resistance [airway resistance at 20 Hz (R20)] by 5.5%. In contrast, a two-point worsening of caregiver-reported score was associated with none of the concurrent lung pathophysiologic measurements. Worsening of total C-ACT score was significantly associated with increased respiratory inflammation [fractional exhaled nitric oxide (FeNO)] in a subset (n=23) of children without eosinophilic airway inflammation. C-ACT scores were associated with none of the small airway measures. In children with mild or moderate asthma, longitudinal C-ACT score changes could reflect acute changes in large airway resistance and lung function. Measures of small airway physiology would provide valuable complementary information for asthma control. Asthma phenotype may affect whether C-ACT score could reflect respiratory inflammation.

A Longitudinal Study of Respiratory Mechanics in Pregnant Women with Obesity and Overweight.

Respiratory mechanics and the role of sex hormones in pregnancy are not well elucidated. We examined longitudinal and positional changes in lung mechanics in pregnancy and investigated the role of sex hormones. A longitudinal study enrolled 135 women with obesity in early pregnancy. Fifty-nine percent of women identified as White; median body mass index at enrollment was 34.4kg/m2. Women with respiratory disease were excluded. We obtained measurements of airway resistance and respiratory system reactance in various positions using impedance oscillometry and sex hormones in early and late pregnancy. With pregnancy progression, there was a significant increase in resonant frequency (Fres) (p = 0.012), integrated area of low frequency reactance (AX) (p = 0.0012) and R5-R20Hz (p = 0.038) in the seated position,and a significant increase in R5Hz (p = 0.000), Fres (p = 0.001), AX (p < 0.001 = 0.000), and R5-R20Hz (p = 0.014) in the supine position. Compared to the seated position, the supine position was associated with a significant increase in R5Hz, R20Hz, X5Hz, Fres, and AX in early (p-values < 0.026) and late pregnancy (p-values ≤ 0.001). Changes in progesterone levels between early and late pregnancy predicted the change in R5, Fres, and AX (p-values ≤ 0.043). Resistive and elastic loads increase with pregnancy progression and a change in body position from seated to supine increases resistive and elastic loads in both early and late pregnancies. The increase in airway resistance is primarily related to an increase in peripheral rather than central airways resistance. There was an association between the change in progesterone levels and airway resistance.

Computational fluid dynamics can detect changes in airway resistance for patients after COVID-19 infection

Infection with COVID-19 can cause severe complication in the respiratory system, which may be related to increased respiratory resistance. Computational fluid dynamics(CFD) was used in this study to calculate the airway resistance based on the airway anatomy and a common air flowrate. The correlation between airway resistance and COVID-19 prognosis was then investigated. A total of 23 COVID-19 patients with 54 CT scans were grouped into the good prognosis and bad prognosis group based on whether the CT scan shows significant decrease in the pneumonia volume after one week treatment and retrospectively analyzed. A baseline group of 8 healthy people with the same age and gender ratio is enrolled for comparison. Results show that the airway resistance at admission is significantly higher for COVID-19 patients with poor prognosis than those with good prognosis and the baseline(0.063 ± 0.055 vs 0.029 ± 0.011 vs 0.017 ± 0.006 Pa/(ml/s),p = 0.01). In the left superior lobe (r = 0.3974,p = 0.01),left inferior lobe (r = 0.4843,p < 0.01), the right inferior lobe (r = 0.5298,p < 0.0001), the airway resistance was significantly correlated with the degree of pneumonia infection. It is concluded that for COVID-19 patients’, airway resistance at admission is closely associated with their prognosis, and has the clinical potential to be used as an index for patients’ diagnosis.

Systems Engineering Approach to Modeling and Analysis of Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by airflow limitation. This study develops a systems engineering framework for representing important mechanistic details of COPD in a model of the cardiorespiratory system. In this model, we present the cardiorespiratory system as an integrated biological control system responsible for regulating breathing. Four engineering control system components are considered: sensor, controller, actuator, and the process itself. Knowledge of human anatomy and physiology is used to develop appropriate mechanistic mathematical models for each component. Following a systematic analysis of the computational model, we identify three physiological parameters associated with reproducing clinical manifestations of COPD: changes in the forced expiratory volume, lung volumes, and pulmonary hypertension. We quantify the changes in these parameters (airway resistance, lung elastance, and pulmonary resistance) as the ones that result in a systemic response that is diagnostic of COPD. A multivariate analysis of the simulation results reveals that the changes in airway resistance have a broad impact on the human cardiorespiratory system and that the pulmonary circuit is stressed beyond normal under hypoxic environments in most COPD patients.

Quantitative CT Metrics for the Prediction of Therapeutic Effect in Asthma.

Background: Few studies have explored the correlation between asthma medication and features on HRCT images. We aim to analyse the differences and temporal changes of lung function and airway resistance in asthma with diverse HRCT phenotypes in a short period after inhalation of budesonide/formoterol. Method: This observational study recruited 55 adult patients with varying severities of asthma. We performed detailed airway metrics measurements of chest CT scans, such as airway wall thickness (WT), wall area percentage (WA%), wall thickness percentage (T/OR), and airways with an inner perimeter of 10 mm (Pi10). The effect of lung structural features on asthma medication response was explored according to the WA% and T/OR twelve hours post-drug administration. Using multivariable regression models, we then assessed the influence of WA% on lung function. Results: WA% (p < 0.001) and T/OR (p < 0.001) significantly increased in asthma than in healthy control subjects. Compared to mild asthma, airway walls were further thickened (WA%, p = 0.023; T/OR: p = 0.029) and associated with lumen narrowing (Pi10, p = 0.055) in moderate to severe asthma. WA% and T/OR correlated well with lung function (FEV1, FVC, MMEF, and PEF) and airway resistance (R5, R20, Rp, and Fres). Regression analysis showed that MEF25 decreased with increasing age and WA% (R2 = 0.58, p < 0.001). Patients with thickened airway walls experienced a maximal increase in FVC, FEV1, and PEF at 2 h (p < 0.001) and a maximal decrease of R5, Z5, and Rp at 2 h (p < 0.001) in those with a thickened airway pattern. Conclusions: Asthma patients with different bronchial wall thicknesses exhibited variable lung function changes. Specifically, patients with thick airway wall patterns were more sensitive to inhaled budesonide in the short term.

Guishaozichuan granules can attenuate asthma in rats via the MUC5AC/EGFR signaling pathway.

Background: Guishaozichuan (GSZC) granules are a traditional Chinese medicine formulation created by Professor Li (Chinese-Japanese Friendship Hospital, Beijing, China) we studied the effect of GSZC granules in rats suffering from asthma. Methods: Specific pathogen-free Sprague-Dawley rats were divided randomly into seven groups. Ovalbumin (OVA) and Al (OH)3 gel were used to create an asthma model. On day 1, rats were injected with OVA (10mg) and an Al(OH)3 gel suspension (100mg). One week later, rats were sensitized again. On day 15, rats were given aerosolized OVA (1%) for 30min/day for 10days. Gastric administration of OVA was 1h before nebulization. At 24h after the last stimulation, changes in airway resistance (RI) and dynamic compliance (Cdyn) in rat lungs were measured after challenge with methacholine at increasing concentrations. The contents of immunoglobulin (Ig)E, interleukin (IL)-4, IL-5, IL-13, and IL-17 in serum were measured by enzyme-linked immunosorbent assays. The percentage of eosinophils (EOS) and the white blood cell (WBC) count in bronchoalveolar lavage fluid (BALF) were counted under an optical microscope. Pathologic alterations in lung tissue were evaluated by optical microscopy, and lung injury score calculated. Expression of mucin 5AC, oligomeric mucus/gel-forming (MUC5AC) and epidermal growth factor receptor (EGFR) in lung tissue was measured by immunohistochemistry. mRNA expression of MUC5AC and EGFR in lung tissue was measured by real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Results: GSZC granules reduced RI markedly and improved Cdyn, decreased serum levels of IgE, IL-4, IL-5, IL-13, IL-17, %EOS and the WBC count in BALF. GSZC granules alleviated lung-tissue damage, diminished the Inflammation Score, and reduced mRNA and protein expression of MUC5AC and EGFR in lung tissue. Conclusion: GSZC granules could improve bronchial hyperresponsiveness, bronchial inflammation, and histopathologic damage in the lungs of rats suffering from asthma. This phenomenon may be related to its regulation of cytokine levels and the MUC5AC/EGFR signaling pathway.

The anti-asthmatic potential of Rho-kinase inhibitor hydroxyfasudil in the model of experimentally induced allergic airway inflammation

ObjectiveThis experimental study evaluated the anti-asthmatic potential of the Rho-kinase inhibitor hydroxyfasudil in the settings of allergen-induced allergen-induced experimental asthma. MethodsChronic allergic airway inflammation was caused by 28 days-sensitisation of guinea pigs with ovalbumin (OVA). Hydroxyfasudil was administered intraperitoneally in two doses for the last two weeks (1 mg/kg b.w.; 10 mg/kg b.w.). The degree of allergic inflammation was determined based on concentrations of inflammatory Th2 cytokines (IL-4, IL-13), Th1 cytokines (TNF-α and IFN-γ) in the lung homogenate and leukocyte count in the bronchoalveolar lavage fluid (BALF). The markers of remodelling and fibrosis, the growth factors (TGF-β1, EGF), EGF receptor, collagen type III and V were estimated in lung homogenate. The changes in specific airway resistance (sRaw) were used as an in vivo bronchial hyperreactivity parameter. ResultsHydroxyfasudil administration at both doses significantly reduced sRaw after a week of therapy. We observed a decline of IL-13, TNF-α and IFN-γ in lung homogenate and a lower presence of lymphocytes in BALF after 14 days of hydroxyfasudil administration at both tested doses. Hydroxyfasudil 14 days-treatment at both doses effectively reduced the concentrations of TGF-β1, EGF receptors, collagen type III and V in BALF and modulated EGF levels. ConclusionsThese findings indicate that RhoA/Rho-kinase is involved in the pathophysiology of allergic airway inflammation and suggest that Rho-kinase inhibitor hydroxyfasudil has therapeutic potential for asthma management.

Determinants of asthma control and exacerbations in moderate to severe asthma

Determinants of asthma control and exacerbations in moderate to severe asthma

Increased airway resistance can be related to the decrease in the functional capacity in obese women.

Background and objectiveObesity can increase the airways resistance, mainly in the periphery, leading to dyspnea perception that can impair the functional capacity. This study aimed to analyze if airways resistance could be related to the walking capacity of women with morbid obesity.MethodsThirty-seven women with grade III obesity in preoperative bariatric surgery were evaluated using the spirometry test, impulse oscillometry system (IOS), and six-minute walk test (6MWT). Additionally, data about their daily dyspnea perception and physical activity level were collected.ResultsVariables of the spirometry test did not detect ventilator disorders. Compared to the predicted values, the IOS identified significant increase in airways resistance (kPa/L/s) (R5: 0.36 (0.34; 0.36) and 0.53 (0.47; 0.61); R20: 0.30 (0.28; 0.30) and 0.41 (0.35; 0.45); R5-20: 0.06 (0.06; 0.06) and 0.14 (0.10; 0.15); X5: -0.03 (-0.04; -0.01) and -0.20 (-0.27; -0.18), respectively). The distance walked in the 6MWT, 491.4±60.4m was significantly correlated to R5 (rho = -0.41, p = 0.01), R5-20 (rho = -0.52, p = 0.001), and X5 (rho = 0.54, p = 0.0006).ConclusionThe IOS is able to identify changes in airway resistance even before the onset of symptoms. When evaluated by IOS women with severe obesity and normal spirometry exhibited central and peripheral airways obstruction. The correlations between the IOS and six-minute walk distance suggest that increased peripheral airways resistance could be related to worsening functional capacity.

A LONGITUDINAL STUDY OF IMPULSE OSCILLOMETRY AND RESPIRATORY MECHANICS IN PREGNANCY: IMPLICATIONS FOR RESPIRATORY DISORDERS

TYPE: Late Breaking Abstract TOPIC: Pulmonary Physiology PURPOSE: Examine positional and longitudinal changes in airway resistance and reactance during early and late pregnancy. METHODS: A longitudinal observational study enrolled pregnant women in the first trimester. Impedance oscillometry was performed in the seated, supine, and most comfortable sleeping positions in early and late pregnancy. Airway resistance was measured at 5 and 20Hz, reactance at 5Hz. Lung volumes were simultaneously measured in the seated and supine positions. Progesterone and estradiol were measured at two time points. RESULTS: 242 women (59% White) were enrolled with mean BMI 34.4 Kg/m2, 135 with longitudinal measurements. Airway resistance and reactance significantly increased with the change from the seated to the supine, and to the most comfortable sleeping position, in early and late pregnancy (p<0.00001). Most comfortable sleeping position was associated with lower resistive load than supine position (p<0.0006). Airway resistance significantly increased with pregnancy progression (p<0.004) and related to increased small airway resistance (R5-R20Hz P=0.009). Increased airway resistance did not correlate with changes in serum progesterone. Airway reactance increased with pregnancy progression (P<0.00001). FRC dropped with position change at both time points (p<0.00001) but not with pregnancy progression. ERV dropped (13.3%) with pregnancy progression (p<0.00001). CONCLUSIONS: Resistive and elastic loads increase in the supine position in early and late pregnancy and with pregnancy progression. Resistive load increases with pregnancy progression relate mostly to increased small airway resistance, which may be due to reduced ERV. CLINICAL IMPLICATIONS: Increased resistive loads may contribute to asthma exacerbations, while increased elastic loads may contribute to respiratory complications in women with obesity or chest wall abnormalities. DISCLOSURE: No significant relationships. KEYWORD: airway resistance

Outdoor pollen concentration is not associated with exercise-induced bronchoconstriction in children.

Free running exercise test outdoors is an important method to diagnose asthma in children. However, the extent of how much exposure to pollens of outdoor air affects the results of the test is not known. We analyzed all reliable exercise challenge tests with impulse oscillometry in children (n = 799) between January 2012 and December 2014 in Tampere University Hospital. Pollen concentrations at the time of the test were collected from the register of Biodiversity Unit of the University of Turku. We compared the frequency of exercise-induced bronchoconstriction and pollen concentrations. The analyses were restricted to birch and alder pollen as high counts of grass and mugwort pollen were so infrequent. The relative change in resistance at 5 Hz after exercise or the frequency of exercise-induced bronchoconstriction were not related to alder or birch pollen concentrations over 10 grains/m3 (p = 0.125-0.398). In logistic regression analysis comparing the effects of alder or birch pollen concentrations, immunoglobulin E (IgE)-mediated alder or birch allergy and absolute humidity over 10 g/m3 only absolute humidity was independently associated with change in airway resistance (odds ratio [OR]: 0.32, confidence interval [CI]: 0.13-0.67, p: 0.006). In our large clinical sample, outdoor air pollen concentration was not associated with the probability of exercise-induced bronchoconstriction in free running test in children while low absolute humidity was the best predictor of airway obstruction.

Changes in head posture after rapid palatal expansion in mouth-breathing children.

Abstract Introduction. It is well known that previously has been demonstrated a correlation between respiratory function and the harmonious craniofacial development and head posture respectively. Aim of the study. The purpose of this study was to investigate the correlation between rapid maxillary expansion (RME) and the change in natural head position (NHP) resulting from the consequent change in airway resistance and to elucidate how RME influences NHP in terms of cephalometric angles in children with nasal obstruction. Material and methods. The study included 12 girls and 8 boys who had a history of mouth breathing, as confirmed by the parents and ORL specialist and due to this fact, they underwent RME as part of orthodontic treatment. Dental casts, clinical photographs and lateral skull radiographs exposed in natural head position were obtained at the first visit (T1) and 8-10 months (T2) later for all subjects. In order to evaluate the patient’s lateral skull radiographs, I used AudaxCeph software, within which I created a new type of analysis. Student T test and Pearson correlation test were used to statistically analyze the results. Results. Our findings demonstrate that no significant changes in any of the variables are observed in patients treated with rapid maxillary expansion, however a positive correlation was observed in the variables measured before and after the treatment, respectively between the anomaly and the measured values. Positivity can also be detected when examining the correlation between the patient’s gender and the measured values. Conclusions. Based on the obtained results, we cannot state that there is a correlation between rapid maxillary expansion and cervical posture.

Clinical characteristics of and risk factors for small airway dysfunction detected by impulse oscillometry

BackgroundSmall airway dysfunction (SAD) is an early lesion of chronic respiratory disease that is best detected using impulse oscillometry (IOS). Few studies have investigated risk factors for IOS-defined SAD (IOS-SAD) in a large population. We aimed to explore the clinical features of and risk factors for IOS-SAD in a community-based population. MethodsWe divided subjects into IOS-SAD and non-SAD groups based on a cutoff of >0.07 kPa/L/s in the difference between the resistance at 5 Hz versus the resistance at 20 Hz (R5–R20). All participants underwent spirometry, IOS, and completed a questionnaire; some participants underwent computed tomography (CT). We analyzed the risk factors for SAD based on binary logistic regression. ResultsThe total cohort comprised 1327 subjects. The prevalence of IOS-SAD was 32.9% (437/1327). Compared with the non-SAD group, the IOS-SAD group was older (64.0 ± 7.8 vs. 59.6 ± 7.8 years, p < 0.001), included less never-smokers (30.2% vs. 35.8%, p < 0.001), had greater airway resistance and worse lung function, indicated by a larger R5–R20 (0.15 ± 0.08 vs. 0.03 ± 0.02 kPa/L/s, p < 0.001) and smaller forced expiratory volume in 1 s to forced vital capacity after bronchodilation (60.2 ± 14.4% vs. 72.6 ± 10.0%, p < 0.001); on CT, the IOS-SAD group had higher prevalences of emphysema and gas trapping. Risk factors for SAD were older age, high BMI, smoking, childhood cough, and asthma. ConclusionSubjects with IOS-SAD had increased airway resistance and visible CT changes. Individuals with smoking exposure, advanced age, high BMI, childhood cough, and asthma were more prone to SAD. Clinical trial registrationChiCTR1900024643.

Identifying Responders and Exploring Mechanisms of Action of the Endobronchial Coil Treatment for Emphysema

Background: So far, 3 randomized controlled trials have shown that the endobronchial treatment using coils is safe and effective. However, the more exact underlying mechanism of the treatment and best predictors of response are unknown. Objectives: The aim of the study was to gain more knowledge about the underlying physiological mechanism of the lung volume reduction coil treatment and to identify potential predictors of response to this treatment. Methods: This was a prospective nonrandomized single-center study which included patients who were bilaterally treated with coils. Patients underwent an extensive number of physical tests at baseline and 3 months after treatment. Results: Twenty-four patients (29% male, mean age 62 years, forced expiratory volume in 1 s [FEV₁] 26% pred, residual volume (RV) 231% pred) were included. Three months after treatment, significant improvements were found in spirometry, static hyperinflation, air trapping, airway resistance, treated lobe RV and treated lobes air trapping measured on CT scan, exercise capacity, and quality of life. The change in RV and airway resistance was significantly associated with a change in FEV₁, forced vital capacity, air trapping, maximal expiratory pressure, dynamic compliance, and dynamic hyperinflation. Predictors of treatment response at baseline were a higher RV, larger air trapping, higher emphysema score in the treated lobes, and a lower physical activity level. Conclusions: Our results confirm that emphysema patients benefit from endobronchial coil treatment. The primary mechanism of action is decreasing static hyperinflation with improvement of airway resistance which consequently changes dynamic lung mechanics. However, the right patient population needs to be selected for the treatment to be beneficial which should include patients with severe lung hyperinflation, severe air trapping, and significant emphysema in target lobes.