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Journal of Clinical Medicine Jan 2024induced sputum is used to assess different inflammatory phenotypes in asthma, but is not used routinely. We aimed to determine the proportion of inflammatory asthma...
BACKGROUND AND OBJECTIVES
induced sputum is used to assess different inflammatory phenotypes in asthma, but is not used routinely. We aimed to determine the proportion of inflammatory asthma phenotypes based on induced sputum, to find biomarkers that can discriminate between phenotypes, and to evaluate biomarkers in patients with and without biological therapy in different inflammatory asthma phenotypes.
MATERIALS AND METHODS
this cross-sectional study investigated clinical characteristics, asthma control tests, skin prick test, impulse oscillometry (IOS), spirometry, induced sputum, biomarkers (IgE, eosinophils, fractional exhaled nitric oxide (FeNO), serum periostin, IL-5, IL-6, IL-8, IL-17A, IL-33) in 80 asthmatics. A total of 17/80 patients were treated with biologics (10 with omalizumab, 7 with benralizumab).
RESULTS
a total of 31% of patients had eosinophilic asthma (EA), 30% had mixed granulocytic asthma (MGA), 24% had paucigranulocytic asthma (PGA), and 15% had neutrophilic asthma (NA). The difference was found in blood eosinophils ( = 0.002), the highest observed in EA. The cut-off ≥ 240/μL eosinophils, with 64% sensitivity and 72.7% specificity, identified EA (AUC = 0.743, = 0.001). A higher IL-8 level was associated with NA ( = 0.025). In 63 non-biologic asthma group, eosinophils were higher in EA than in NA, MGA, and PGA ( = 0.012, = 0.028, and = 0.049, respectively). A higher IL-17A was associated with EA without biologics ( = 0.004). A significantly higher IL-5 was found in EA treated with biologics, in comparison with EA without biologics ( = 0.043). The number of leucocytes and neutrophils was higher in MGA without biologics ( = 0.049, = 0.019), while IL-5, IL-6, and IL-8 levels were higher in MGA treated with biologics ( = 0.012, = 0.032, = 0.038, respectively).
CONCLUSIONS
EA and MGA were the most prevalent asthma phenotypes. Blood eosinophils can identify EA, both in patients with and without biologics. Apart from the clinical profile, a broad spectrum of biomarkers for assessing inflammatory phenotypes is necessary for an adequate therapy approach to patients with asthma.
PubMed: 38256660
DOI: 10.3390/jcm13020526 -
Physiological Reports Jan 2024Lingering breathing difficulties are common after COVID-19. However, the underlying causes remains unclear, with spirometry often being normal. We hypothesized that...
Lingering breathing difficulties are common after COVID-19. However, the underlying causes remains unclear, with spirometry often being normal. We hypothesized that small airway dysfunction (SAD) can partly explain these symptoms. We examined 48 individuals (32 women, 4 hospitalized in the acute phase) who experienced dyspnea and/or cough in the acute phase and/or aftermath of COVID-19, and 22 non-COVID-19 controls. Time since acute infection was, median (range), 65 (10-131) weeks. We assessed SAD using multiple breath washout (MBW) and impulse oscillometry (IOS) and included spirometry and diffusing-capacity test (DLCO). One-minute-sit-to-stand test estimated physical function, and breathing difficulties were defined as answering "yes" to the question "do you experience lingering breathing difficulties?" Spirometry, DLCO, and IOS were normal in almost all cases (spirometry: 90%, DLCO: 98%, IOS: 88%), while MBW identified ventilation inhomogeneity in 50%. Breathing difficulties (n = 21) was associated with increased MBW-derived S . However, physical function did not correlate with SAD. Among individuals with breathing difficulties, 25% had reduced physical function, 25% had SAD, 35% had both, and 15% had normal lung function and physical function. Despite spirometry and DLCO being normal in almost all post-COVID-19 individuals, SAD was present in a high proportion and was associated with lingering breathing difficulties.
Topics: Female; Humans; COVID-19; Dyspnea; Respiration; Spirometry; Lung
PubMed: 38253977
DOI: 10.14814/phy2.15918 -
Tuberculosis and Respiratory Diseases Apr 2024The prevalence of small airway dysfunction (SAD) in patients with chronic obstructive pulmonary disease (COPD) across different ethnicities is poorly understood. This...
BACKGROUND
The prevalence of small airway dysfunction (SAD) in patients with chronic obstructive pulmonary disease (COPD) across different ethnicities is poorly understood. This study aimed to estimate the prevalence of SAD in stable COPD patients.
METHODS
We conducted a cross-sectional study of 196 consecutive stable COPD patients. We measured pre- and post-bronchodilator (BD) lung function and respiratory impedance. The severity of COPD and lung function abnormalities was graded in accordance with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. SAD was defined as either difference in whole-breath resistance at 5 and 19 Hz > upper limit of normal or respiratory system reactance at 5 Hz < lower limit of normal.
RESULTS
The cohort consisted of 95.9% men, with an average age of 66.3 years. The mean forced expiratory volume 1 second (FEV1) % predicted was 56.4%. The median COPD assessment test (CAT) scores were 14. The prevalence of post-BD SAD across the GOLD grades 1 to 4 was 14.3%, 51.1%, 91%, and 100%, respectively. The post-BD SAD and expiratory flow limitation at tidal breath (EFLT) were present in 62.8% (95% confidence interval [CI], 56.1 to 69.9) and 28.1% (95% CI, 21.9 to 34.2), respectively. COPD patients with SAD had higher CAT scores (15.5 vs. 12.8, p<0.01); poor lung function (FEV1% predicted 46.6% vs. 72.8%, p<0.01); lower diffusion capacity for CO (4.8 mmol/min/kPa vs. 5.6 mmol/min/kPa, p<0.01); hyperinflation (ratio of residual volume to total lung capacity % predicted: 159.7% vs. 129%, p<0.01), and shorter 6-minute walk distance (367.5 m vs. 390 m, p=0.02).
CONCLUSION
SAD is present across all severities of COPD. The prevalence of SAD increases with disease severity. SAD is associated with poor lung function and higher symptom burden. Severe SAD is indicated by the presence of EFLT.
PubMed: 38225686
DOI: 10.4046/trd.2023.0139 -
Respirology (Carlton, Vic.) Apr 2024Chronic, low-intensity air pollution exposure has been consistently associated with reduced lung function throughout childhood. However, there is limited research...
BACKGROUND AND OBJECTIVE
Chronic, low-intensity air pollution exposure has been consistently associated with reduced lung function throughout childhood. However, there is limited research regarding the implications of acute, high-intensity air pollution exposure. We aimed to determine whether there were any associations between early life exposure to such an episode and lung growth trajectories.
METHODS
We conducted a prospective cohort study of children who lived in the vicinity of the Hazelwood coalmine fire. Lung function was measured using respiratory oscillometry. Z-scores were calculated for resistance (R ) and reactance at 5 Hz (X ) and area under the reactance curve (AX). Two sets of analyses were conducted: (i) linear regression to assess the cross-sectional relationship between post-natal exposure to mine fire-related particulate matter with an aerodynamic diameter of less than 2.5 micrometres (PM ) and lung function at the 7-year follow-up and (ii) linear mixed-effects models to determine whether there was any association between exposure and changes in lung function between the 3- and 7-year follow-ups.
RESULTS
There were no associations between mine fire-related PM and any of the lung function measures, 7-years later. There were moderate improvements in X (β: -0.37 [-0.64, -0.10] p = 0.009) and AX (β: -0.40 [-0.72, -0.08] p = 0.014), between the 3- and 7-year follow-ups that were associated with mean PM , in the unadjusted and covariance-adjusted models. Similar trends were observed with maximum PM .
CONCLUSION
There was a moderate improvement in lung stiffness of children exposed to PM from a local coalmine fire in infancy, consistent with an early deficit in lung function at 3-years after the fire that had resolved by 7-years.
Topics: Child; Humans; Smoke; Air Pollutants; Prospective Studies; Particulate Matter; Air Pollution; Lung; Environmental Exposure
PubMed: 38219238
DOI: 10.1111/resp.14657 -
American Journal of Respiratory and... Feb 2024
Topics: Humans; Oscillometry
PubMed: 38190700
DOI: 10.1164/rccm.202311-2127ED -
Heliyon Jan 2024Pulmonary function test, particularly in patients with COVID-19, is problematic because it involves forced expiration. Impulse oscillometry (IOS) reduces the potential...
BACKGROUND
Pulmonary function test, particularly in patients with COVID-19, is problematic because it involves forced expiration. Impulse oscillometry (IOS) reduces the potential exposure of health-care staff to infectious droplets. In this study, we investigated the correlation between IOS and spirometry and whether IOS can precisely predict spirometry-based diagnoses of chronic obstructive pulmonary disease (COPD).
METHODS
We retrospectively analyzed the data (January 1 to December 31, 2021) of patients who underwent both spirometry and IOS on the same date. One-way analysis of variance was performed to evaluate the IOS results of patients stratified into two (COPD and non-COPD) groups by spirometry results. IOS results were also analyzed using receiver operator characteristics curves to diagnose advanced COPD, which was indicated by a postbronchodilator (BD) forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio of <0.6. We further evaluated the accuracy of oscillometry as a predictor of spirometry-based COPD diagnosis.
RESULTS
A total of 115 patients were included in the analysis. The best parameters assessed for spirometry-based COPD diagnosis were area under reactance (AX) and airway resistance (predicted R5% × resonant frequency) in relation to body mass index (BMI). However, when the post-BD FEV1/FVC ratio was <0.6, BMI-adjusted airway resistance had an area under curve (0.782; 95 % confidence interval: 0.620-0.945) value larger than the corresponding AX. A BMI-adjusted airway resistance value of >160 moderately predicted spirometry-based COPD diagnosis.
CONCLUSIONS
BMI-adjusted airway resistance is a potential predictor of spirometry-based COPD diagnosis; the cutoff values of this parameter differ between individuals with and without obesity.
PubMed: 38187302
DOI: 10.1016/j.heliyon.2023.e23627 -
Respiratory Research Jan 2024Lung recruitment and continuous distending pressure (CDP) titration are critical for assuring the efficacy of high-frequency ventilation (HFOV) in preterm infants. The... (Observational Study)
Observational Study
RATIONALE
Lung recruitment and continuous distending pressure (CDP) titration are critical for assuring the efficacy of high-frequency ventilation (HFOV) in preterm infants. The limitation of oxygenation (peripheral oxygen saturation, SpO) in optimizing CDP calls for evaluating other non-invasive bedside measurements. Respiratory reactance (Xrs) at 10 Hz measured by oscillometry reflects lung volume recruitment and tissue strain. In particular, lung volume recruitment and decreased tissue strain result in increased Xrs values.
OBJECTIVES
In extremely preterm infants treated with HFOV as first intention, we aimed to measure the relationship between CDP and Xrs during SpO-driven CDP optimization.
METHODS
In this prospective observational study, extremely preterm infants born before 28 weeks of gestation undergoing SpO-guided lung recruitment maneuvers were included in the study. SpO and Xrs were recorded at each CDP step. The optimal CDP identified by oxygenation (CDP) was compared to the CDP providing maximal Xrs on the deflation limb of the recruitment maneuver (CDP).
RESULTS
We studied 40 infants (gestational age at birth = 22-27 wk; postnatal age = 1-23 days). Measurements were well tolerated and provided reliable results in 96% of cases. On average, Xrs decreased during the inflation limb and increased during the deflation limb. Xrs changes were heterogeneous among the infants for the amount of decrease with increasing CDP, the decrease at the lowest CDP of the deflation limb, and the hysteresis of the Xrs vs. CDP curve. In all but five infants, the hysteresis of the Xrs vs. CDP curve suggested effective lung recruitment. CDP and CDP were highly correlated (ρ = 0.71, p < 0.001) and not statistically different (median difference [range] = -1 [-3; 9] cmHO). However, CDP were equal to CDP in only 6 infants, greater than CDP in 10, and lower in 24 infants.
CONCLUSIONS
The Xrs changes described provide complementary information to oxygenation. Further investigation is warranted to refine recruitment maneuvers and CPD settings in preterm infants.
Topics: Humans; Infant, Newborn; Infant, Extremely Premature; Oscillometry; Lung; Lung Volume Measurements; High-Frequency Ventilation
PubMed: 38178216
DOI: 10.1186/s12931-023-02639-4 -
Frontiers in Medicine 2023Severe coronavirus disease 2019 (COVID-19) may require veno-venous extracorporeal membrane oxygenation (V-V ECMO). While V-V ECMO is offered in severe lung injury to...
BACKGROUND
Severe coronavirus disease 2019 (COVID-19) may require veno-venous extracorporeal membrane oxygenation (V-V ECMO). While V-V ECMO is offered in severe lung injury to COVID-19, long-term respiratory follow-up in these patients is missing. Therefore, we aimed at providing comprehensive data on the long-term respiratory effects of COVID-19 requiring V-V ECMO support during the acute phase of infection.
METHODS
In prospective observational cohort study design, patients with severe COVID-19 receiving invasive mechanical ventilation and V-V ECMO (COVID group, = 9) and healthy matched controls ( = 9) were evaluated 6 months after hospital discharge. Respiratory system resistance at 5 and 19 Hz (R, R), and the area under the reactance curve (AX) was evaluated using oscillometry characterizing total and central airway resistances, and tissue elasticity, respectively. R and R difference (R-R) reflecting small airway function was also calculated. Forced expired volume in seconds (FEV), forced expiratory vital capacity (FVC), functional residual capacity (FRC), carbon monoxide diffusion capacity (DLCO) and transfer coefficient (KCO) were measured.
RESULTS
The COVID group had a higher AX and R-R than the healthy matched control group. However, there was no significant difference in terms of R or R. The COVID group had a lower FEV and FVC on spirometry than the healthy matched control group. Further, the COVID group had a lower FRC on plethysmography than the healthy matched control group. Meanwhile, the COVID group had a lower DLCO than healthy matched control group. Nevertheless, its KCO was within the normal range.
CONCLUSION
Severe acute COVID-19 requiring V-V ECMO persistently impairs small airway function and reduces respiratory tissue elasticity, primarily attributed to lung restriction. These findings also suggest that even severe pulmonary pathologies of acute COVID-19 can manifest in a moderate but still persistent lung function impairment 6 months after hospital discharge.
TRIAL REGISTRATION
NCT05812196.
PubMed: 38173937
DOI: 10.3389/fmed.2023.1288679 -
BMC Pulmonary Medicine Jan 2024Idiopathic pulmonary fibrosis (IPF) is a progressive disease with a poor prognosis. Pulmonary function tests (PFTs) aid in evaluating the disease status of IPF. The...
BACKGROUND
Idiopathic pulmonary fibrosis (IPF) is a progressive disease with a poor prognosis. Pulmonary function tests (PFTs) aid in evaluating the disease status of IPF. The clinical significance of oscillometry measurements in interstitial lung diseases has recently been reported. Our previous study showed that respiratory reactance (Xrs) measured by oscillometry reflected disease severity and predicted subsequent lung capacity decline in patients with IPF. However, the direct impact of Xrs on survival needs to be determined, and there are currently no reference values in oscillometry to predict prognosis. Therefore, this study aimed to investigate the association between oscillometry measurements, particularly Xrs, and survival in patients with IPF and to determine the cutoff values of Xrs that predict 3-year survival.
METHODS
We analyzed the relationship between the measured values of PFT and oscillometry derived from 178 patients with IPF. Univariate and multivariate Cox proportional hazards analyses were performed to investigate the relationships between clinical indices at the time of the first oscillometry and survival. We performed the time-dependent receiver operating characteristic (ROC) curve analysis to set the optimized cutoff values of Xrs for 3-year survival prediction. We examined the discriminating power of cutoff values of Xrs on survival using the Kaplan-Meier method and the log-rank test.
RESULTS
Xrs components, especially in the inspiratory phase (In), significantly correlated with the PFT values. In the multivariate analyses, Xrs (all of reactance at 5 Hz [X5], resonant frequency [Fres], and low-frequency reactance area [ALX] in the inspiratory phase) had a significant impact on survival (X5, p = 0.003; Fres, p = 0.016; ALX, p = 0.003) independent of age, sex, and other prognostic factors derived from the univariate analysis. The area under the ROC curve was 0.765, 0.759, and 0.766 for X5 In, Fres In, and ALX In, with cutoff values determined at - 0.98, 10.67, and 5.32, respectively. We found significant differences in survival after dividing patients using each of the cutoff values of Xrs.
CONCLUSIONS
In patients with IPF, Xrs measured by oscillometry significantly impacted survival. We also determined the cutoff values of Xrs to discriminate patients with poor prognoses.
Topics: Humans; Airway Resistance; Oscillometry; Lung; Respiratory Function Tests; Idiopathic Pulmonary Fibrosis
PubMed: 38167026
DOI: 10.1186/s12890-023-02776-y -
Radiology. Cardiothoracic Imaging Dec 2023Purpose To determine if proton (H) MRI-derived specific ventilation is responsive to bronchodilator (BD) therapy and associated with clinical biomarkers of type 2 airway...
Purpose To determine if proton (H) MRI-derived specific ventilation is responsive to bronchodilator (BD) therapy and associated with clinical biomarkers of type 2 airway inflammation and airways dysfunction in severe asthma. Materials and Methods In this prospective study, 27 participants with severe asthma (mean age, 52 years ± 9 [SD]; 17 female, 10 male) and seven healthy controls (mean age, 47 years ± 16; five female, two male), recruited between 2018 and 2021, underwent same-day spirometry, respiratory oscillometry, and tidal breathing H MRI. Participants with severe asthma underwent all assessments before and after BD therapy, and type 2 airway inflammatory biomarkers were determined (blood eosinophil count, sputum eosinophil percentage, sputum eosinophil-free granules, and fraction of exhaled nitric oxide) to generate a cumulative type 2 biomarker score. Specific ventilation was derived from tidal breathing H MRI and its response to BD therapy, and relationships with biomarkers of type 2 airway inflammation and airway dysfunction were evaluated. Results Mean MRI specific ventilation improved with BD inhalation (from 0.07 ± 0.04 to 0.11 ± 0.04, < .001). Post-BD MRI specific ventilation ( = .046) and post-BD change in MRI specific ventilation ( = .006) were greater in participants with asthma with type 2 low biomarkers compared with participants with type 2 high biomarkers of airway inflammation. Post-BD change in MRI specific ventilation was correlated with change in forced expiratory volume in 1 second ( = 0.40, = .04), resistance at 5 Hz ( = -0.50, = .01), resistance at 19 Hz ( = -0.42, = .01), reactance area ( = -0.54, < .01), and reactance at 5 Hz ( = 0.48, = .01). Conclusion Specific ventilation evaluated with tidal breathing H MRI was responsive to BD therapy and was associated with clinical biomarkers of airways disease in participants with severe asthma. MRI, Severe Asthma, Ventilation, Type 2 Inflammation © RSNA, 2023 See also the commentary by Moore and Chandarana in this issue.
Topics: Male; Humans; Female; Middle Aged; Protons; Prospective Studies; Asthma; Inflammation; Biomarkers; Magnetic Resonance Imaging
PubMed: 38166343
DOI: 10.1148/ryct.230054