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Background: Chronic obstructive pulmonary disease (COPD) is associated with airflow limitation resulting from a combination of small airway disease (SAD) and parenchymal destruction. Although various diagnostic methods for SAD exist, access to these tools can be limited. Objectives: This study aimed to explore the correlation between handgrip strength (HGS) and SAD in COPD patients. Design: Cross-sectional prospective study. Methods: HGS was measured using a hand dynamometer. SAD was evaluated using impulse oscillometry, with results reported as the difference between respiratory resistance at 5 and 20 Hz (R5–R20). SAD was defined as R5–R20 ⩾0.07 kPa/L/s. The receiver operator characteristic (ROC) curves, sensitivity, and specificity values were calculated to determine the optimal cutoff value of HGS for predicting SAD. Results: Sixty-four patients (90.6% male) were included. The average age was 72.1 ± 8.3 years, and body mass index was 23.4 ± 4.2 kg/m2. FEV1 was 71.6 ± 21.3%, and HGS was 30.2 ± 8.1 kg. R5–R20 was 0.11 ± 0.08 kPa/L/s. SAD was found in 64.1% of patients. A negative correlation between HGS and R5–R20 was observed (r = −0.332, p = 0.007). The best cutoff value for HGS in detecting SAD was determined to be 28.25 kg, with a sensitivity of 73.9%, specificity of 65.9%, and an area under ROC curve of 0.685 (95% CI 0.550–0.819, p = 0.015). Conclusion: SAD is common in COPD patients, and HGS is significantly negatively correlated with SAD. This tool might serve as an alternative or adjunctive assessment for small airway dysfunction in COPD patients. Registration: This study was registered with ClinicalTrials.gov with number NCT06223139. Plain language summary: Association of handgrip strength with small airway disease in COPD In chronic obstructive pulmonary disease (COPD), the condition of small airways (those less than 2 mm wide) is closely linked to disease severity. Small airway disease (SAD) leads to reduced lung function, increased retention of excess gas in the lung, and poorer health in COPD patients. While various diagnostic methods exist for SAD, they may not always be accessible. This study investigated handgrip strength as a potential alternative way to assess SAD. Our findings show a significant negative correlation between handgrip strength and SAD in COPD patients. This suggests that handgrip strength could be used alongside existing methods to evaluate small airway dysfunction in these patients. [ABSTRACT FROM AUTHOR]

Introduction: Impulse oscillometry (IOS) is an effortless test compared to spirometry. Numerous studies explored the role of IOS in spirometry-based chronic obstructive pulmonary disease (COPD), but most of them had limited sample sizes with poor statistical power. This systematic review and meta-analysis aimed to pool the individual data and quantitatively analyze the clinical value of IOS in COPD. Methods: PubMed, Web of Science, Ovid, Cochrane Library, China National Knowledge Internet, and Wanfang were searched for studies with comparisons of IOS indicators between COPD patients and healthy controls, including respiratory resistance at 5 Hz (R5) and 20 Hz (R20), difference between R5 and R20 (R5−R20), respiratory reactance at 5 Hz (X5), resonant frequency (Fres), and area of reactance (Ax). Meta-analyses were conducted to calculate the weighted mean differences (WMDs) and 95% confidence intervals (CIs). Results: 39 eligible studies were enrolled, involving 6,144 COPD patients and 4,611 healthy controls. Relative to healthy controls, COPD patients had significantly higher R5 (WMD: 0.17, 95% CI: 0.14, 0.20), R5−R20 (WMD: 0.13, 95% CI: 0.11, 0.15), Fres (WMD: 9.04, 95% CI: 7.66, 10.42), Ax (WMD: 1.24, 95% CI: 0.86, 1.61), and lower X5 (WMD: −0.15, 95% CI: −0.18, −0.11), and such differences became even greater as the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage escalated. Pooled correlation coefficients presented that R5, R5−R20, Fres, and X5 were significantly related to post-bronchodilator forced expiratory volume in the first second (FEV1)/forced vital capacity ratio (meta r = −0.37, −0.45, −0.53, and 0.42, respectively) and FEV1 as a percentage of predicted value (meta r = −0.43, −0.54, −0.59, and 0.56, respectively). Conclusion: IOS may be a supplement to spirometry in diagnosing and assessing COPD, especially when spirometry is inappropriate. More well-designed, large sample-sized, prospective studies are warranted to establish an IOS-based criterion for COPD management. [ABSTRACT FROM AUTHOR]

Jiying Xiao,1 Lingyue Liu,1 Kamran Ali,2 Suling Wu,1 Junsong Chen1 1Department of Pulmonology, Hangzhou Children’s Hospital, Hangzhou, Zhejiang, 310015, People’s Republic of China; 2Department of Surgery, The Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, Zhejiang, 322000, People’s Republic of ChinaCorrespondence: Junsong Chen, Department of Pulmonology, Hangzhou Children’s Hospital, NO. 195 Wenhui Road, Gongshu Distract, Hangzhou, Zhejiang, 310015, People’s Republic of China, Tel +86-15990067220, Email doctorsong999@126.comObjective: We aimed to observe and analyze the differences in impulse oscillometry (IOS) and fractional expiratory nitric oxide (FeNO) in relation to asthma control among preschool children, and to explore the predictive value of IOS combined with FeNO for uncontrolled asthma.Methods: This study enrolled 171 preschool children with asthma and 30 healthy preschool children between June 2022 and June 2023. We categorized the asthmatic children as having controlled asthma (n=85) and uncontrolled asthma (n=86) after a 3-month follow-up. IOS and FeNO were collected on the first visit at baseline. Differences in metrics were compared between controlled asthma, uncontrolled asthma and healthy control groups. The area under the receiver operating characteristic curve (AUROC) was utilized to explore the discriminative ability of IOS and FeNO, alone or in combination, against uncontrolled asthma.Results: Compared to the controlled asthma group, the IOS values of R5, X5, R5-R20, and Fres were significantly higher in the uncontrolled asthma group, except for R20. R5 and R5-R20 had the highest area under the curve (AUC), which could reach 0.74 (95% CI 0.66– 0.82) and 0.72 (95% CI 0.64– 0.80). R20 had the lowest AUC of 0.59. The AUC for FeNO alone was 0.88 (95% CI 0.84– 0.93) with a cutoff value of 17.50 ppb, sensitivity and specificity of 0.73 and 0.89. The AUCs of all IOS metrics combined with FeNO were significantly higher, with the highest AUC of 0.92 (95% CI 0.87– 0.96) for R5-R20+FeNO, and with a sensitivity and specificity of 0.88 and 0.84.Conclusion: There were significant differences in IOS and FeNO in relation to asthma control among preschooler children. FeNO might be the best predictor of asthma control, and adding any of IOS metrics increased moderately the predictive value.Keywords: asthma control, impulse oscillometry, fractional expiratory nitric oxide, preschool children

Abstract Background The use of machine learning(ML) methods would improve the diagnosis of small airway dysfunction(SAD) in subjects with chronic respiratory symptoms and preserved pulmonary function(PPF). This paper evaluated the performance of several ML algorithms associated with the impulse oscillometry(IOS) analysis to aid in the diagnostic of respiratory changes in SAD. We also find out the best configuration for this task. Methods IOS and spirometry were measured in 280 subjects, including a healthy control group (n = 78), a group with normal spirometry (n = 158) and a group with abnormal spirometry (n = 44). Various supervised machine learning (ML) algorithms and feature selection strategies were examined, such as Support Vector Machines (SVM), Random Forests (RF), Adaptive Boosting (ADABOOST), Navie Bayesian (BAYES), and K-Nearest Neighbors (KNN). Results The first experiment of this study demonstrated that the best oscillometric parameter (BOP) was R5, with an AUC value of 0.642, when comparing a healthy control group(CG) with patients in the group without lung volume-defined SAD(PPFN). The AUC value of BOP in the control group was 0.769 compared with patients with spirometry defined SAD(PPFA) in the PPF population. In the second experiment, the ML technique was used. In CGvsPPFN, RF and ADABOOST had the best diagnostic results (AUC = 0.914, 0.915), with significantly higher accuracy compared to BOP (p

Background: β-thalassemia syndromes are a group of hereditary blood diseases characterized by reduced or absent β-globin chain synthesis, resulting in reduced hemoglobin in red blood cells. Pulmonary dysfunction ranging from restrictive to obstructive was reported among those with β- thalassemia. Aim of the work: to evaluate the pulmonary functions in patients with β-thalassemia. Patients and Methods: We conducted a cross-sectional study that included 60 ß-thalassemia patients following up at the Hematology Outpatient Clinic of Cairo University Children’s Hospital. They all underwent assessment of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximal expiratory flow (MEF) and peak expiratory flow (PEF) using spirometry and assessment of resistance (R) and reactance (Z) to different frequencies by impulse oscillometry (IOS). Results: The mean ± SD age of the studied group was 10.63 ± 3.53 years. Of them, 32 (53.3%) were females and 28 (46.7%) were males. 39 (65%) were transfusion dependent, 23 (38.3%) were compliant to chelation therapy and only 8 (13.3%) did not need chelation therapy. 30 (50%) patients showed restrictive pattern in spirometry (FVC80%”) and 15 (50%) of them also showed abnormal high impulse IOS to 5 and 20HZ (readings above 150%). The non-compliant patients had airway obstructive pattern by spirometry MEF50 (p=0.075), and higher IOS resistance pattern to R5Hz (p= 0.007), R20Hz (p=0.007) and X5Hz (p= 0.003). Higher airway resistance on IOS (0.0001) was associated with transfusion dependency, and need for chelation therapy (p=0.039). Poor compliance to chelation therapy correlated with spirometry restrictive pattern (p=0.0006). Conclusion: Restrictive lung disease is a common pulmonary dysfunction among children with ß-thalassemia. Compliance to adequate chelation therapy decreases the incidence of pulmonary dysfunction.

Background Bronchiectasis is a chronic respiratory disease that leads to airway inflammation, destruction, and airflow limitation, which reflects its severity. Impulse oscillometry (IOS) is a non-invasive method that uses sound waves to estimate lung function and airway resistance. The aim of this study was to assess the usefulness of IOS in predicting the severity of bronchiectasis. Methods We retrospectively reviewed the IOS parameters and clinical characteristics in 145 patients diagnosed with bronchiectasis between March 2020 and May 2021. Disease severity was evaluated using the FACED score, and patients were divided into mild and moderate/severe groups. Results Forty-four patients (30.3%) were in the moderate/severe group, and 101 (69.7%) were in the mild group. Patients with moderate/severe bronchiectasis had a higher airway resistance at 5 Hz (R5), a higher difference between the resistance at 5 and 20 Hz (R5−R20), a higher resonant frequency (Fres), and a higher area of reactance (AX) than patients with mild bronchiectasis. R5 ≥0.43, resistance at 20 Hz (R20) ≥0.234, R5−R20 ≥28.3, AX ≥1.02, reactance at 5 Hz (X5) ≤−0.238, and Fres ≥20.88 revealed significant univariable relationships with bronchiectasis severity (p

Background: The use of machine learning(ML) methods would improve the diagnosis of small airway dysfunction(SAD) in subjects with chronic respiratory symptoms and preserved pulmonary function(PPF). This paper evaluated the performance of several ML algorithms associated with the impulse oscillometry(IOS) analysis to aid in the diagnostic of respiratory changes in SAD. We also find out the best configuration for this task. Methods: IOS and spirometry were measured in 280 subjects, including a healthy control group (n = 78), a group with normal spirometry (n = 158) and a group with abnormal spirometry (n = 44). Various supervised machine learning (ML) algorithms and feature selection strategies were examined, such as Support Vector Machines (SVM), Random Forests (RF), Adaptive Boosting (ADABOOST), Navie Bayesian (BAYES), and K-Nearest Neighbors (KNN). Results: The first experiment of this study demonstrated that the best oscillometric parameter (BOP) was R5, with an AUC value of 0.642, when comparing a healthy control group(CG) with patients in the group without lung volume-defined SAD(PPFN). The AUC value of BOP in the control group was 0.769 compared with patients with spirometry defined SAD(PPFA) in the PPF population. In the second experiment, the ML technique was used. In CGvsPPFN, RF and ADABOOST had the best diagnostic results (AUC = 0.914, 0.915), with significantly higher accuracy compared to BOP (p < 0.01). In CGvsPPFA, RF and ADABOOST had the best diagnostic results (AUC = 0.951, 0.971) and significantly higher diagnostic accuracy (p < 0.01). In the third, fourth and fifth experiments, different feature selection techniques allowed us to find the best IOS parameters (R5, (R5-R20)/R5 and Fres). The results demonstrate that the performance of ADABOOST remained essentially unaltered following the application of the feature selector, whereas the diagnostic accuracy of the remaining four classifiers (RF, SVM, BAYES, and KNN) is marginally enhanced. Conclusions: IOS combined with ML algorithms provide a new method for diagnosing SAD in subjects with chronic respiratory symptoms and PPF. The present study's findings provide evidence that this combination may help in the early diagnosis of respiratory changes in these patients. [ABSTRACT FROM AUTHOR]

Air pollution, particularly from particulate matter (PM2.5) and black carbon (eBC), has been implicated in airway pathologies. This study aims to assess the relationship between exposure to these pollutants and respiratory function in various populations, including healthy individuals, while seeking an accurate assessment method. A cross-sectional study was conducted in Bogotá, evaluating respiratory function in the users of bicycles, minivans, and buses through spirometry and impulse oscillometry. Measurements were taken along two main avenues, assessing the PM2.5 and eBC concentrations. The results reveal higher pollutant levels on AVE KR 9, correlating with changes in oscillometry values post-travel. Cyclists exhibited differing pre- and post-travel values compared to bus and minivan users, suggesting aerobic exercise mitigates pollutant impacts. However, no statistically significant spirometry or impulse oscillometry variations were observed among routes or modes. Public transport and minivan users showed greater PM2.5 and eBC exposure, yet no significant changes associated with environmental contaminants were found in respiratory function values. These findings underscore the importance of further research on pollutant effects and respiratory health in urban environments, particularly concerning different transport modes. [ABSTRACT FROM AUTHOR]

Introduction: Impaired lung function has been observed in patients following COVID‐19 infection, with studies reporting persistent lung volume and diffusing capacity impairments. Some studies have demonstrated significantly higher small airway resistance in COVID‐19 positive cases. This retrospective study aims to examine impulse oscillometry (IOS) data of patients with persistent symptoms after COVID‐19 infection, focusing on the relationship between time and symptoms. Material and Method: The study analyzed data from adult patients with persistent symptoms who underwent IOS testing within and after 84 days from the diagnosis date. Result: The results showed that patients within 84 days and those between 31 and 84 days had higher small airway resistance values, indicating peripheral airway disease. Patients with dyspnea exhibited higher IOS values compared to those with cough symptoms, suggesting more significant impairment in the peripheral airways. Conclusion: The study highlights the importance of using comprehensive diagnostic tools like IOS to assess respiratory impairments in post‐COVID‐19 patients, particularly in the small airways. Understanding the relationship between time and symptoms can provide valuable insights for the treatment of peripheral airway dysfunction in post‐COVID‐19 patients. [ABSTRACT FROM AUTHOR]

Junsong Chen,1 Jiying Xiao,1 Lingyue Liu,1 Kamran Ali,2 Suling Wu1 1Department of Pulmonology, Hangzhou Children’s Hospital, Hangzhou, Zhejiang, 310015, People’s Republic of China; 2Department of Oncology, the Fourth Affiliated Hospital, International Institutes of Medicine, Zhejiang University School of Medicine, Yiwu, Zhejiang, 322000, People’s Republic of ChinaCorrespondence: Suling Wu, Department of Pulmonology, Hangzhou Children’s Hospital, No. 195 Wenhui Road, Gongshu Distract, Hangzhou, 310015, Zhejiang, People’s Republic of China, Tel +86-18758853716, Email 565969515@qq.comObjective: Prediction of asthma in preschool children is challenging and lacks objective indicators. The aim is to observe and analyze the variances between impulse oscillometry (IOS) and fractional expiratory nitric oxide (FeNO) in preschool children with wheezing, establish a joint prediction model, and explore the diagnostic value of combining IOS with FeNO in diagnosing asthma among preschool children.Patients and methods: This study enrolled children aged 3– 6 years with wheezing between June 2021 and June 2022. They were categorized as asthmatic (n=104) or non-asthmatic (n=109) after a 1-year follow-up. Clinical data, along with IOS and FeNO measurements from both groups, underwent univariate regression and multiple regression analyses to identify predictive factors and develop the most accurate model. The prediction model was built using the stepwise (stepAIC) method. The receiver operating characteristic curve (ROC), calibration curve, Hosmer-Lemeshow test, and decision curve analysis (DCA) were employed to validate and assess the model.Results: During univariate analysis, a history of allergic rhinitis, a history of eczema or atopic dermatitis, and measures including FeNO, R5, X5, R20, Fres, and R5-R20 were found to be associated with asthma diagnosis. Subsequent multivariate analysis revealed elevated FeNO, R5, and X5 as independent risk factors. The stepAIC method selected five factors (history of allergic rhinitis, history of eczema or atopic dermatitis, FeNO, R5, X5) and established a prediction model. The combined model achieved an AUROC of 0.94, with a sensitivity of 0.89 and specificity of 0.88, surpassing that of individual factors. Calibration plots and the HL test confirmed satisfactory accuracy.Conclusion: This study has developed a prediction model based on five factors, potentially aiding clinicians in early identification of asthma risk among preschool children.Keywords: asthma, impulse oscillometry, fractional expiratory nitric oxide, prediction model, preschool children

Abstract Background Cough variant asthma (CVA) is one of the most common causes of chronic cough in children worldwide. The diagnosis of CVA in children remains challenging. This study aimed to assess the diagnostic utility of impulse oscillometry (IOS) pulmonary function in children with CVA. Methods This study included children aged 4 to 12 years diagnosed with CVA who underwent IOS pulmonary function and bronchodilation (BD) tests. A control group of healthy children was matched. Pre- and post-BD IOS parameters were recorded and presented as mean ± standard deviation or median. Receiver operating characteristic (ROC) curves were plotted, and the area under the curve (AUC) was calculated to evaluate the discriminatory potential of the IOS parameters for diagnosing CVA. Results A total of 180 patients with CVA and 65 control subjects were included. The baseline IOS parameters in the CVA group, except X5%pred, were significantly greater compared to the control group. After inhalation of salbutamol sulfate, all IOS parameters improved significantly in the CVA group. However, Z5%pred, R5%pred, and R20%pred remained greater in the CVA group compared to the control group. The improvement rates of IOS parameters in the CVA group significantly surpassed those in the control group. The ROC curve results for pre-BD IOS parameters and the improvement rate during the BD test showed that the combinations of pre-Z5%pred+△Z5% and pre-R5%pred+△R5% achieved the highest AUC value of 0.920 and 0.898, respectively. The AUC values of these combined parameters surpassed those of individual ones. Conclusions This study highlights that children with CVA exhibit greater IOS parameters compared to healthy children. The changes in IOS parameters during the BD test provided valuable diagnostic information for CVA, and the combination of various parameters can help pediatricians accurately identify CVA in children.

Abstract Background The clinical significance of the impulse oscillometry-defined small airway bronchodilator response (IOS-BDR) is not well-known. Accordingly, this study investigated the clinical characteristics of IOS-BDR and explored the association between lung function decline, acute respiratory exacerbations, and IOS-BDR. Methods Participants were recruited from an Early Chronic Obstructive Pulmonary Disease (ECOPD) cohort subset and were followed up for two years with visits at baseline, 12 months, and 24 months. Chronic obstructive pulmonary disease (COPD) was defined as a post-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio

Background Obstructive airway diseases, including chronic obstructive pulmonary disease (COPD) and asthma, pose significant global health challenges. Early and accurate diagnosis is crucial for effective management. Although Spirometry has traditionally been the cornerstone of diagnostics, Impulse Oscillometry (IOS) has emerged as a promising alternative. This study aims to compare the diagnostic performance of Spirometry and IOS in patients attending the Respiratory Medicine Department at the Acharya Vinoba Bhave Rural Hospital, Sawangi, India. Methods A Comparative Observational Study was conducted between August 2022 and August 2024, enrolling patients who met specific inclusion criteria. Data were collected through a comprehensive medical history, clinical examination, routine blood tests, chest radiography, High-resolution computed tomography (HRCT), spirometry, and IOS. Key parameters, including Forced expiratory volume in the first second FEV1, FEV1/FVC (Forced Expiratory Volume), (Forced Expiratory Volume) FVC, (Forced Expiratory Flow) FEF 25-75 for Spirometry, and R5, R20, fres, X5, and AX for IOS, were analyzed using the Chi-Square Test and Student’s t-test with SPSS 27.0 and GraphPad Prism 7.0. Expected outcome The study included 130 participants with the primary objective of evaluating IOS’s diagnostic advantages of IOS over spirometry. Our findings demonstrate that IOS offers enhanced sensitivity for diagnosing early small airway diseases, which is a crucial factor for early diagnosis in both pediatric and adult populations.

We aimed to develop and validate a machine learning model using impulse oscillometry system (IOS) profiles for accurately classifying patients into three assessment-based categories: no airflow obstruction, asthma, and chronic obstructive pulmonary disease (COPD). Our research questions were as follows: (1) Can machine learning methods accurately classify obstructive disease states based solely on multidimensional IOS data? (2) Which IOS parameters and modeling algorithms provide the best discrimination? We used data for 480 patients (240 with COPD and 240 with asthma) and 84 healthy individuals for training. Physiological and IOS parameters were combined into six feature combinations. The classification algorithms tested were logistic regression, random forest, neural network, k-nearest neighbor, and support vector machine. The optimal feature combination for identifying individuals without pulmonary obstruction, with asthma, or with COPD included 15 IOS and physiological features. The neural network classifier achieved the highest accuracy (0.786). For discriminating between healthy and unhealthy individuals, two combinations of twenty-three features performed best in the neural network algorithm (accuracy of 0.929). When distinguishing COPD from asthma, the best combination included 15 features and the neural network algorithm achieved an accuracy of 0.854. This study provides compelling technical evidence and clinical justifications for advancing IOS data-driven models to aid in COPD and asthma management. [ABSTRACT FROM AUTHOR]

BACKGROUND: Impulse oscillometry (IOS) is a noninvasive technique that measures lung physiology independently of patient effort. In the present study, we aimed to investigate the utility of IOS parameters in comparison with pulmonary function testing (PFT) among hospitalized subjects, with emphasis on obstructive and small airway diseases. METHODS: Sixty-one subjects hospitalized either with unexplained dyspnea or for pre-surgery evaluation were included in the study. All subjects underwent PFTs and IOS test. The correlation between IOS results and PFTs was examined in different subgroups. The ability of IOS parameters to predict abnormal PFTs was evaluated using the area under the receiver operating characteristic (ROC) curve, and optimal cutoff values were calculated. RESULTS: IOS results were found to correlate with PFT values. Subgroup analysis revealed that these correlations were higher in younger (age < 70) and non-obese (body mass index < 25kg/m²) subjects. The resonant frequency was an independent predictor and had the best predictive ability for abnormal FEV1/FVC (area under the ROC curve 0.732 [95% CI 0.57-0.90], optimal cutoff 17 Hz, 87% sensitivity, 62% specificity) and abnormal forced expiratory flow during the middle half of the FVC maneuver (area under the ROC curve 0.667 [95% CI 0.53-0.81], optimal cutoff 15 Hz, 77% sensitivity, 54% specificity). Area of reactance and the difference in respiratory resistance at 5 Hz and 20 Hz also showed a good predictive ability for abnormal FEV1/FVC (area under the ROC curve 0.716 and 0.730, respectively). CONCLUSIONS: We found that the IOS performed well in diagnosing small airway and obstructive diseases among hospitalized subjects. IOS might serve as an alternative to standard PFTs in non-cooperative or dyspneic hospitalized patients. [ABSTRACT FROM AUTHOR]

Background: The clinical significance of the impulse oscillometry-defined small airway bronchodilator response (IOS-BDR) is not well-known. Accordingly, this study investigated the clinical characteristics of IOS-BDR and explored the association between lung function decline, acute respiratory exacerbations, and IOS-BDR. Methods: Participants were recruited from an Early Chronic Obstructive Pulmonary Disease (ECOPD) cohort subset and were followed up for two years with visits at baseline, 12 months, and 24 months. Chronic obstructive pulmonary disease (COPD) was defined as a post-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio < 0.70. IOS-BDR was defined as meeting any one of the following criteria: an absolute change in respiratory system resistance at 5 Hz ≤ − 0.137 kPa/L/s, an absolute change in respiratory system reactance at 5 Hz ≥ 0.055 kPa/L/s, or an absolute change in reactance area ≤ − 0.390 kPa/L. The association between IOS-BDR and a decline in lung function was explored with linear mixed-effects model. The association between IOS-BDR and the risk of acute respiratory exacerbations at the two-year follow-up was analyzed with the logistic regression model. Results: This study involved 466 participants (92 participants with IOS-BDR and 374 participants without IOS-BDR). Participants with IOS-BDR had higher COPD assessment test and modified Medical Research Council dyspnea scale scores, more severe emphysema, air trapping, and rapid decline in FVC than those without IOS-BDR over 2-year follow-up. IOS-BDR was not associated with the risk of acute respiratory exacerbations at the 2-year follow-up. Conclusions: The participants with IOS-BDR had more respiratory symptoms, radiographic structural changes, and had an increase in decline in lung function than those without IOS-BDR. Trial registration: Chinese Clinical Trial Registry, ChiCTR1900024643. Registered on 19 July, 2019. [ABSTRACT FROM AUTHOR]

Background/aim: There is limited information on the pathologic changes in the small airways among obese and nonobese patients with obstructive sleep apnea syndrome (OSAS). Impulse oscillometry (IOS) measures airway resistance and reactance independently of patient effort. This study aimed to compare airway resistance in small airways using IOS between obese and nonobese patients with OSAS. Materials and methods: In this real-life cross-sectional study, demographic information was collected from obese and nonobese subjects diagnosed with moderate and severe OSAS without any other underlying diseases. Spirometry and IOS measurements were conducted, and the values of both groups were statistically analyzed. Results: The nonobese group had a mean age of 45.6 ± 11.7 years (median 45), while the obese group had a mean age of 48.4 ± 9.5 years (median 47.5). The mean body mass index (BMI) for the nonobese group was 26.2 ± 2.1 kg/m2 (median 27 kg/m2), and for the obese group, it was 35.6 ± 6.4 kg/m2 (median 33 kg/m2). Statistically significant differences were observed between the two groups in R5 - R20 percentage, reactance area (AX), and resonant frequency (Fres) values (p < 0.05). Conclusion: Among obese OSAS patients, there is an increase in resistance in small airways as indicated by IOS values. IOS shows promise as a potential screening tool for diagnosing OSAS. [ABSTRACT FROM AUTHOR]

Little research has been conducted to evaluate the correlation between impulse oscillometry (IOS), Childhood Asthma Control Test (C-ACT), and Test for Respiratory and Asthma Control in Kids (TRACK). This study was conducted at China Medical University Hospital between September 1, 2019, and March 31, 2021. Children aged 2–6 years who had been diagnosed with asthma with acute exacerbation were enrolled and followed-up until the end of the study. Correlations between the parameters of IOS, C-ACT and TRACK were assessed. The validity and reliability of TRACK were verified. A total of 114 children with asthma and acute exacerbations were recruited. Their mean age was 4.1 ± 1.1 years, and 60.5% were males. After a year of treatment, the change of R5-R20 from baseline 0.64 ± 0.38 kPa/L/s to 12th month 0.48 ± 0.2 kPa/L/s (p = 0.022). TRACK and C-ACT scores were significantly correlated during the observation period. R5-R20 in IOS at baseline and at the 12th month of follow-up as well as the change in IOS parameters were significantly associated with C-ACT (p = 0.003, 0.015, and 0.001, respectively). R5% and R5-R20 changes in IOS were associated with TRACK (p = 0.04 and 0.025, respectively). Sensitivity and specificity of TRACK were 80.8% (67.5–90.4) and 100% (94.1–100), respectively, with cut-off points >95 and AUC 93.8%. TRACK score appears to have a stronger association with the IOS parameter than C-ACT score. Our findings indicate that TRACK is a valid tool for assessing asthma control in preschool children. [ABSTRACT FROM AUTHOR]

Background and Objectives: Data on characteristics of asthma in children with sickle cell disease (SCD) is conflicting. Recently, the L-arginine pathway has gained attention in the pathogenesis of asthma and SCD. This study aimed to determine the distinctive clinical and laboratory features and the role of arginine metabolism in asthmatic children with SCD. Materials and Methods: A total of 52 children and adolescents with SCD, including 24 with asthma (SCD-A) and 28 without asthma (SCD-NA), and 40 healthy controls were included. A questionnaire, atopy tests, fractional exhaled nitric oxide (FeNO), and lung function tests were employed. Serum metabolites of the arginine pathway were measured. The results of the three groups were compared. Results: The demographic characteristics and atopy markers of the three groups were similar. FEV1%, FEV1/FVC, MMEF%, and total lung capacity (TLC%) values of SCD-A patients were not significantly different from the SCD-NA group, but they were significantly lower than the values measured in the controls. FeNO values greater than 35 ppb were present only in the SCD-A group. In impulse oscillometry, median resistance values at 5 Hz (R5)% were higher in both SCD subgroups than in healthy controls (p = 0.001). The (R5-20/R5)% values were higher in the SCD-A group (p = 0.028). Serum arginine levels and arginine bioavailability indices were significantly lower in the SCD-A group than in the SCD-NA group and healthy controls (p = 0.003 and p < 0.001). Conclusions: Asthma in children with SCD was not associated with atopy or low FEV1/FVC levels. However, lower arginine bioavailability and higher FeNO levels differentiated asthma in patients with SCD. High R5% and (R5-20/R5)% values indicated increased airway resistance in SCD, with a predominance of small airway disease in asthmatics. [ABSTRACT FROM AUTHOR]

IntroductionSmall airways dysfunction contributes to asthma pathophysiology and clinical outcomes including exacerbations and asthma control. Respiratory oscillometry is a simple, non-invasive and effort independent lung function test that provides vital information about small airway function. However, interpretation and clinical utility of respiratory oscillometry has been in part limited by lack of agreed parameters and the respective cutoffs. The aim of this study was to determine the prevalence of small airways dysfunction based on published impulse oscillometry (IOS) definition in patients with asthma referred to a tertiary asthma clinic and the extent to which it correlates with asthma clinical outcomes.MethodsWe retrospectively reviewed the medical records of all patients with asthma managed in the severe asthma clinic between January 2019 and December 2022 who underwent routine lung function tests with oscillometry and spirometry. Small airways dysfunction was determined from various published IOS parameter cutoffs, and the data were analysed to determine correlations between IOS parameters and asthma outcomes.ResultsAmongst the 148 patients, the prevalence of small airways dysfunction ranged from 53% to 78% depending on the defining oscillometry parameter. All oscillometry parameters correlated with the severity of airflow obstruction (FEV1% predicted, p 1.5 (OR 2.97, p = 0.022) or ACT

Background: The current morphological condition of an individual is described by a somatotype, which is a three-number scale. The endomorph, mesomorph and ectomorph components are presented in the same sequence, and each number corresponds to one of the three basic components of body composition. Methods: We recruited 50 healthy male subjects with a mean age of 24.10 ± 4.55 yrs. Somatotype was determined by the Heath and Carter method. Impulse oscillometry was performed followed by spirometry according to the European Respiratory Society (ERS) or American Thoracic Society (ATS) guidelines. Resistance at 5 Hz (R5) %pred, R20%pred, R5–R20, X5%pred, X20, area of reactance (Ax) and resonant frequency (Fres) were obtained by doing impulse oscillometry. Slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC ratio and maximum mid-expiratory flow (MMEF) were assessed by doing spirometry. Results: Endomorphs (0.05 (0.00–0.09) vs 0.01 (0.00–0.04); P < 0.0001) and mesomorphs (0.04 (0.000.09) vs 0.01 (0.00–0.04); P = 0.002) had significantly higher R5–R20 than ectomorphs. Similarly, endomorphs (0.32 (0.07–0.82) vs 0.15 (0.08–0.35); P = 0.001) and mesomorphs (0.28 (0.17–0.64) vs 0.15 (0.08–0.35); P = 0.015) also showed significantly higher Ax than ectomorphs, Fres of endomorphs (15.37 (8.43–21.85) vs 10.08 (8.94–14.30); P < 0.0001) and mesomorphs (14.32 (10.24–20.86) vs 10.08 (8.94-14.30); P < 0.0001) were significantly high than ectomorphs. Moreover, spirometric measures reveal significant variation in which mesomorphs had significantly higher values of % predicted of FVC than ectomorphs (92.49 ± 7.211 vs 83.86 ± 7.861; P = 0.042) and the ratio of FEV1 to FVC was significantly higher in ectomorphs than in endomorphs (89.00 ± 5.80 vs 85.04 ± 5.73; P = 0.03). Conclusion: Peripheral airway dysfunction was observed in endomorphs and mesomorphs as compared to ectomorphs. Mesomorphs had a relatively higher FVC that may be due to their greater muscular strength.

Background. Impulse oscillometry (IOS) is an effort independent method of studying lung mechanics. Aim. To study the diagnostic significance of IOS in assessing lung mechanics after COVID-19. Materials and methods. Spirometry, body plethysmography, diffusion test (DLco), IOS parameters were analyzed in 315 patients (the median age 48 years), the median period from the beginning of COVID-19 to the study was 50 days. Statistical analysis included descriptive statistics, correlation analysis and one-dimensional logistic regression analysis with an assessment of odds ratios. Results. In general group, spirometry and body plethysmography parameters were in normal values, while DLCO was reduced in 61% of patients. Parameters of IOS were analyzed in the general group and between the groups, depending on the value of DLco and total lung capacity (TLC): normal or reduced. In general group, reactance area (AX), hererogeneity of resistance Rrs5–Rrs20, resistance at 5 Hz (Rrs5), reactance at 5 Hz (ΔXrs5) were increased in 29.8%, 17.8%, 6%, 4.8% of patients, respectively, and were statistically significantly higher in the group with reduced TLC, whereas in the group with reduced DLco AX, Rrs5–Rrs20 were statistically significantly higher. Logistic regression analysis showed that patients with Rrs5-Rrs200.07 kPa×sec/l or AX0.32 kPa/l had a 1.99-fold and 2.24-fold increased risk for decrease DLco, respectively, while the risk of decrease in TLC was 2.25-fold (p=0.012) and 3.16-fold (p0.001) higher, respectively. Conclusion. IOS allow to detect both dysfunction of small airways (if AX or Rrs5–Rrs20 are increased) and the risk of restrictive pattern and lung diffusion impairment after COVID-19.

Background: The current morphological condition of an individual is described by a somatotype, which is a three-number scale. The endomorph, mesomorph and ectomorph components are presented in the same sequence, and each number corresponds to one of the three basic components of body composition. Methods: We recruited 50 healthy male subjects with a mean age of 24.10 ± 4.55 yrs. Somatotype was determined by the Heath and Carter method. Impulse oscillometry was performed followed by spirometry according to the European Respiratory Society (ERS) or American Thoracic Society (ATS) guidelines. Resistance at 5 Hz (R5) %pred, R20%pred, R5–R20, X5%pred, X20, area of reactance (Ax) and resonant frequency (Fres) were obtained by doing impulse oscillometry. Slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC ratio and maximum mid-expiratory flow (MMEF) were assessed by doing spirometry. Results: Endomorphs (0.05 (0.00–0.09) vs 0.01 (0.00–0.04); P < 0.0001) and mesomorphs (0.04 (0.000.09) vs 0.01 (0.00–0.04); P = 0.002) had significantly higher R5–R20 than ectomorphs. Similarly, endomorphs (0.32 (0.07–0.82) vs 0.15 (0.08–0.35); P = 0.001) and mesomorphs (0.28 (0.17–0.64) vs 0.15 (0.08–0.35); P = 0.015) also showed significantly higher Ax than ectomorphs, Fres of endomorphs (15.37 (8.43–21.85) vs 10.08 (8.94–14.30); P < 0.0001) and mesomorphs (14.32 (10.24–20.86) vs 10.08 (8.94-14.30); P < 0.0001) were significantly high than ectomorphs. Moreover, spirometric measures reveal significant variation in which mesomorphs had significantly higher values of % predicted of FVC than ectomorphs (92.49 ± 7.211 vs 83.86 ± 7.861; P = 0.042) and the ratio of FEV1 to FVC was significantly higher in ectomorphs than in endomorphs (89.00 ± 5.80 vs 85.04 ± 5.73; P = 0.03). Conclusion: Peripheral airway dysfunction was observed in endomorphs and mesomorphs as compared to ectomorphs. Mesomorphs had a relatively higher FVC that may be due to their greater muscular strength. [ABSTRACT FROM AUTHOR]

Introduction: Recent studies have indicated the significance of the peripheral airways in asthma control. Methods estimating airway resistance, air trapping, and ventilation inhomogeneity are useful for assessing this area of the lung and have proven utility in the evaluation of asthma; however, it is unclear which method is most effective at characterising uncontrolled asthma. Aim: To evaluate the diagnostic accuracy of various peripheral airway function measurements in the assessment of asthma control in children. Material and methods: Children with controlled (n = 35) and uncontrolled (n = 29) asthma performed a sequence of pulmonary function tests (i.e. spirometry, body plethysmography, oscillometry, nitrogen washout test, and exhaled nitric oxide). The diagnostic accuracy of each peripheral airway measure was evaluated by an area under the receiver operating characteristic curve (AUC). Results: Most peripheral airway parameters were significantly increased in children with uncontrolled asthma compared with children with controlled asthma. The measures with the highest diagnostic accuracy for asthma control were lung clearance index (LCI) (AUC = 0.76), with high specificity (0.97) and modest sensitivity (0.46), acinar ventilation heterogeneity (Sacin) (AUC = 0.73), with high sensitivity (0.85) and modest specificity (0.54), and resonance frequency (Fres) (AUC= 0.74), with perfect specificity (1.0) but low sensitivity (0.38). Conclusions: LCI, Sacin and Fres had the highest discriminative capacity for distinguishing children with controlled and uncontrolled asthma among all evaluated peripheral airways measures. Discrepancies in the performance (i.e. sensitivity and specificity) of each parameter suggest that a combination may be most effective in determining asthma control status. [ABSTRACT FROM AUTHOR]

Objectives: Impulse oscillometry (IOS) is a type of oscillation technique that measures the input impedance (Z) of the respiratory system and can be used to detect pathological changes in the small airways at an early stage. Although coronavirus disease 2019 (COVID-19) affects the vascular and parenchymal structures in the lung, chronic postinfection coughs also may be attributed to small airway pathologies. Our research aimed to use IOS for the assessment of the presence of small airway resistance (R) in patients who have had COVID-19. Methods: Thirty-eight patients with past COVID-19 infections and without any presence or medical treatment of an airway disease who presented to the post-COVID outpatient clinicwith coughing symptoms were included in the study. The control group consisted of 17 patients with no past COVID-19 infection and without an airway disease. IOS and spirometry were performed twice in the case group, at 3 and 6 months after COVID-19. Results: The mean age of the case group was 44.7 ± 12.3 years, whereas the mean age of the control group was 49.4 ± 11.8 years. The case group consisted of 38 patients, whereas 17 patients constituted the control group. No statistically significant differencewas found between the two groups in the first and second test measurements, performed 3 months apart (P > 0.05). Conclusions: The fact that there was no difference between respiratory system impedance, airway resistance, and spirometry values between groupswith and without pastCOVID-19 infections supported the hypothesis that small airways were not affected 3 months after COVID-19. [ABSTRACT FROM AUTHOR]

BackgroundSulfur mustard (SM) exposure causes acute and chronic respiratory diseases. The extent of small airway dysfunction (SAD) in individuals exposed to SM is unclear. This study evaluated and compared SAD in SM-exposed and SM-unexposed participants using noninvasive lung function tests assessing small airway function.MethodsThis retrospective cohort study involved SM-exposed (n = 15, mean age: 53 ± 8 years) and SM-unexposed (n = 15, mean age: 53 ± 7 years) Kurdish-Swedish individuals in Sweden. Small airway resistance and reactance were assessed using impulse oscillometry (IOS). Nitrogen (N2) multiple breath washout (MBW) was employed to assess lung ventilation heterogeneity. The gas-exchanging capacity of the lungs was assessed using the diffusing capacity of the lungs for the carbon monoxide (DLCO) test. Lung function outcomes were reported as absolute values and z-scores. Group comparisons were performed using the Mann–Whitney U test.ResultsNo statistically significant differences in age, height, or body mass index were observed between the two groups. IOS showed significantly increased small airway resistance, while N2MBW exhibited significantly increased global and acinar ventilation heterogeneity in SM-exposed individuals compared to that in unexposed individuals. SAD was identified in 14 of 15 SM-exposed individuals, defined as at least one abnormal IOS difference between resistance at 5 and 20 Hz (R5-R20) and/or area of reactance (AX) or N2MBW lung’s acinar zone (Sacin), and DLCO adjusted to the alveolar volume (DLCO/VA) outcome. Of these 14 individuals, only 5 demonstrated concordant findings across the IOS and N2MBW tests.ConclusionExposure to SM was positively associated with long-term impairment of respiratory tract function in the small airways in the majority of the previously SM-exposed individuals in the present study. Furthermore, both IOS and N2MBW should be employed to detect SAD in SM-exposed survivors as they provide complementary information. Identifying and characterizing the remaining pathology of the small airways in survivors of SM exposure is a first step toward improved treatment and follow-up.

Abstract Background We conducted a retrospective observational study to explore the potential application of impulse oscillometry (IOS) as an alternative to high-resolution computed tomography (HRCT) for detecting pulmonary involvement in patients with rheumatoid arthritis (RA) because clinically evident interstitial lung disease (ILD) and airway involvement are common in this population. Methods We enrolled 72 patients with RA who underwent pulmonary function tests (PFTs) and IOS between September 2021 and September 2022. We aimed to identify the PFT and IOS variables associated with lung diseases shown on HRCT images. Results In our cohort of 72 patients, 48 underwent HRCT; of these, 35 had airway disease or ILD and 13 showed no obvious abnormalities on HRCT. Abnormal IOS and PFT parameters were observed in 34 and 23 patients, respectively, with abnormal HRCT images. The predicted percentages for forced vital capacity, the ratio of forced expiratory volume in the first one second to forced vital capacity, and forced mid-expiratory flow value were significantly lower in patients with abnormal HRCT. Lung resistance at 5 Hz, difference in resistance between 5 and 20 Hz, resonant frequency (Fres), and reactance area were higher in these patients and reactance at 5 Hz was lower. Compared to other parameters, Fres > 14.14 was significantly associated with alterations in HRCT and may be used as an indicator for monitoring disease. Conclusion Fres > 14.14 is significantly associated with lung involvement in RA patients. Performance of spirometry with IOS is more beneficial than spirometry alone for evaluating lung involvement in RA patients.

Air pollution, particularly from particulate matter (PM2.5) and black carbon (eBC), has been implicated in airway pathologies. This study aims to assess the relationship between exposure to these pollutants and respiratory function in various populations, including healthy individuals, while seeking an accurate assessment method. A cross-sectional study was conducted in Bogotá, evaluating respiratory function in the users of bicycles, minivans, and buses through spirometry and impulse oscillometry. Measurements were taken along two main avenues, assessing the PM2.5 and eBC concentrations. The results reveal higher pollutant levels on AVE KR 9, correlating with changes in oscillometry values post-travel. Cyclists exhibited differing pre- and post-travel values compared to bus and minivan users, suggesting aerobic exercise mitigates pollutant impacts. However, no statistically significant spirometry or impulse oscillometry variations were observed among routes or modes. Public transport and minivan users showed greater PM2.5 and eBC exposure, yet no significant changes associated with environmental contaminants were found in respiratory function values. These findings underscore the importance of further research on pollutant effects and respiratory health in urban environments, particularly concerning different transport modes.

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 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.

Small airway dysfunction has been proved to be widespread in asthma, chronic obstructive pulmonary disease and other diseases, and its clinical manifestations are atypical and difficult to be detected early. Identifying SAD in time is conducive to early treatment, accurate judgment and improved prognosis of the disease. Impulse oscillometry is a new lung function test that is widely recognized as one of the most sensitive techniques for assessing small airway function. It can measure the resistance (R) and reactance (X) of the respiratory system of the inspected person during normal respiration, so as to understand the central and peripheral airway obstruction, and has the advantages of non-invasive, simple operation and good repeatability. [ABSTRACT FROM AUTHOR]

Background: We conducted a retrospective observational study to explore the potential application of impulse oscillometry (IOS) as an alternative to high-resolution computed tomography (HRCT) for detecting pulmonary involvement in patients with rheumatoid arthritis (RA) because clinically evident interstitial lung disease (ILD) and airway involvement are common in this population. Methods: We enrolled 72 patients with RA who underwent pulmonary function tests (PFTs) and IOS between September 2021 and September 2022. We aimed to identify the PFT and IOS variables associated with lung diseases shown on HRCT images. Results: In our cohort of 72 patients, 48 underwent HRCT; of these, 35 had airway disease or ILD and 13 showed no obvious abnormalities on HRCT. Abnormal IOS and PFT parameters were observed in 34 and 23 patients, respectively, with abnormal HRCT images. The predicted percentages for forced vital capacity, the ratio of forced expiratory volume in the first one second to forced vital capacity, and forced mid-expiratory flow value were significantly lower in patients with abnormal HRCT. Lung resistance at 5 Hz, difference in resistance between 5 and 20 Hz, resonant frequency (Fres), and reactance area were higher in these patients and reactance at 5 Hz was lower. Compared to other parameters, Fres > 14.14 was significantly associated with alterations in HRCT and may be used as an indicator for monitoring disease. Conclusion: Fres > 14.14 is significantly associated with lung involvement in RA patients. Performance of spirometry with IOS is more beneficial than spirometry alone for evaluating lung involvement in RA patients. [ABSTRACT FROM AUTHOR]

Aim:The aim of our study was to compare clinical severity scores and classic spirometry with impulse oscillometry (IOS) results and thoracic high resolution computed tomography (HRCT) scores in children with cystic fibrosis (CF) in order to determine the utility of the latter approach in patient follow-up.Materials and Methods:CF patients over 6 years of age were included. Shwachman-Kulczycki score, underclassical spirometry and IOS were performed when not in acute exacerbation. Thoracic HRCT images obtained within the previous 6 months were evaluated using the Bhalla scoring system.Results:The mean age of the children studied (n=30) was 12.1±4.2 years and 40% were female. Pseudomonas aeruginosa (P. aeroginosa) was isolated from sputum cultures of 40% of the patients. Patients with forced expiratory volume in one second (FEV1) below 80% exhibited significantly higher (resistance) R5, R10 values and significantly lower (reactance) X5 values on IOS (p=0.03, 0.027, 0.006, respectively). Patients with P. aeruginosa had significantly lower FEV1, forced vital capacity, and forced expiratory flow (25-75) values in classic spirometry when compared with patients without P. aeruginosa (p=0.002, p=0.002, and p=0.005, respectively). P. aeruginosa-positive patients showed significantly higher R5 and lower X5 values (p=0.047, 0.046, respectively). Bhalla scoring, bronchiectasis weight, peribronchial thickening, mucous plaques, saccularization, bronchial division, mosaic pattern parameters in groups with P. aeroginosa growth and/or FEV1

Background and Objectives: Data on characteristics of asthma in children with sickle cell disease (SCD) is conflicting. Recently, the L-arginine pathway has gained attention in the pathogenesis of asthma and SCD. This study aimed to determine the distinctive clinical and laboratory features and the role of arginine metabolism in asthmatic children with SCD. Materials and Methods: A total of 52 children and adolescents with SCD, including 24 with asthma (SCD-A) and 28 without asthma (SCD-NA), and 40 healthy controls were included. A questionnaire, atopy tests, fractional exhaled nitric oxide (FeNO), and lung function tests were employed. Serum metabolites of the arginine pathway were measured. The results of the three groups were compared. Results: The demographic characteristics and atopy markers of the three groups were similar. FEV1%, FEV1/FVC, MMEF%, and total lung capacity (TLC%) values of SCD-A patients were not significantly different from the SCD-NA group, but they were significantly lower than the values measured in the controls. FeNO values greater than 35 ppb were present only in the SCD-A group. In impulse oscillometry, median resistance values at 5 Hz (R5)% were higher in both SCD subgroups than in healthy controls (p = 0.001). The (R5-20/R5)% values were higher in the SCD-A group (p = 0.028). Serum arginine levels and arginine bioavailability indices were significantly lower in the SCD-A group than in the SCD-NA group and healthy controls (p = 0.003 and p < 0.001). Conclusions: Asthma in children with SCD was not associated with atopy or low FEV1/FVC levels. However, lower arginine bioavailability and higher FeNO levels differentiated asthma in patients with SCD. High R5% and (R5-20/R5)% values indicated increased airway resistance in SCD, with a predominance of small airway disease in asthmatics.

Lung function testing is an essential modality of investigation in children as it provides objective evidence of lung disease/health. With advances in technology, various tests are available that can aid in the diagnosis of lung disease, assess the progression and response to therapy and document the lung development and evolving lung diseases in infants. This narrative review discusses lung function tests in infants and children. Currently, lung function tests can be performed in every age group, from neonates to the elderly. Spirometry and peak expiratory flow rate (PEFR) are the most employed tests in children more than six years of age. Spirometry helps diagnose and monitoring of both obstructive and restrictive diseases. There is a need for expertise to perform and interpret spirometry correctly. The forced oscillation technique (FOT) or impulse oscillometry (IOS) is done with tidal volume breathing and is feasible even in preschool children. Their utility is mainly restricted to asthma in children at present. Lung function tests can be performed in neonates, infants and children using infant pulmonary function test (PFT) equipment, although their availability is limited. Diffusion capacity for carbon monoxide (DLCO) is a valuable tool in restrictive lung diseases. Lung volumes can be assessed by body plethysmography and multiple washout technique. The latter can also assess lung clearance index. It is essential to perform and interpret the lung function test results correctly and correlate them with the clinical condition for optimum treatment and outcome. [ABSTRACT FROM AUTHOR]

Background: Properly evaluating respiratory system dysfunction is essential in children with cystic fibrosis (CF). This prospective study aimed to assess the course of early lung disease based on multiple breath nitrogen washout (MBNW), impulse oscillometry (IOS), and conventional techniques, such as spirometry and body plethysmography. Methods: Over a 2 year recruitment period, subjects with CF aged 7–18 performed pulmonary function tests (PFTs). Moreover, the nutritional and microbiological status, frequency of pulmonary exacerbations (PExs), and patients' health-related quality of life (HRQoL) were assessed. Results: The mean age of the children (n = 69) was 14.09 ± 3.26 years; F/M 37/32. Spirometry-based diagnoses of normal lung function (forced expiratory volume in 1 s, FEV1 ≥ 90%pred), mild (FEV1 70–89%pred) and moderate (FEV1 40–69%pred) lung diseases were established in 34 (49.3%), 25 (36.2%), and 10 (14.5%) patients, respectively. An elevated lung clearance index (LCI > 6.98) was observed in 85% of the subjects with normal FEV1. The presence of Pseudomonas aeruginosa infection (n = 16) and the number of PExs treated with IV antibiotics were associated with significantly worse PFT results. Conclusions: MBNW and IOS are more helpful tools than conventional techniques in assessing early lung disease in CF. LCI is a more useful parameter for detecting functional abnormalities than FEV1 in school-age children. [ABSTRACT FROM AUTHOR]

Background: The derivatives-reactive oxygen metabolites (d-ROMs) and plasma antioxidant capacity (PAT) tests are oxidative indexes. Severe asthma has been related to oxidative stress. We aimed to investigate d-ROMs and PAT values in severely controlled asthmatics and the correlation of these values with lung function. Methods: Blood samples were collected from severely controlled asthmatics and centrifuged at 3000 rpm for 10 min. The supernatant was collected. The assays were performed within three hours of collection. The fraction of exhaled nitric oxide (FeNO), impulse oscillometry (IOS), and spirometry were determined. Symptom control was recorded using the asthma control test (ACT). Results: Approximately 40 patients with severe controlled asthma (75%: women), mean age of 62 ± 12 years, were recruited. Approximately 5% had obstructive spirometry. The IOS revealed airway abnormalities even though the spirometric results were within the normal range, with it being more sensitive than spirometry. The D-ROMs and PAT test values were higher than normal, indicating oxidative stress in severe asthmatics with controlled asthma. D-ROMs were positively correlated with R20 values, indicating central airway resistance. Conclusions: The IOS technique revealed an otherwise hidden airway obstruction with spirometry. The D-ROMs and PAT tests revealed a high level of oxidative stress in severe controlled asthmatics. D-ROMs correlate with R20, indicating central airway resistance. [ABSTRACT FROM AUTHOR]

Abstract Background The role of airway impairment assessed by impulse oscillometry (IOS) in patients with chronic obstructive pulmonary disease (COPD) remains unclear. Therefore, this study aimed to analyze the proportion and clinical characteristics of airway impairment assessed by IOS across COPD severities, and explore whether airway impairment is a subtype of COPD. Methods This study was based on cross-sectional data from the ECOPD cohort in Guangdong, China. Subjects were consecutively recruited from July 2019 to August 2021. They filled out questionnaires and underwent lung function tests, IOS and computed tomography (CT). COPD was defined as post-bronchodilator forced expiratory volume in one second/forced vital capacity upper limit of normal or

Background Both diagnosis and assessment of chronic obstructive pulmonary disease (COPD) are based mainly on pulmonary-function tests that are of very important significance in COPD. Impulse oscillometry is a noneffort-dependent method to assess the mechanical structure of the respiratory system. Objectives The study aims to evaluate impulse oscillometry system (IOS) as a diagnosis tool of COPD, in a trial to clarify the sensitivity and correlations of IOS parameters with COPD severity. Patients and methods The study included 30 healthy volunteers, group I (control group): 15 smokers, 15 nonsmokers, and 60 patients with COPD, group II: 30 patients with mild-to-moderate COPD, and group III: 30 patients with severe COPD. All participants were sequentially assessed by IOS to detect impedance, after this, spirometry was done, and both were repeated 15–45 min after the first dose of inhalation therapy (salbutamol). IOS is more sensitive in detecting small-airway affection in mild-to-moderate COPD than spirometry. Results In COPD, a significant increase in IOS-resistant parameters (R5, R5–20), reactance parameter (AX), and a decrease in reactance (X5) parameter was observed in two groups of COPD (groups II and III) if compared with control group I. IOS parameters significantly correlated with spirometric parameters, particularly large-airway parameters (R5 correlated with forced expiratory volume in the first second postbronchodilator in group II and group III), small-airway parameters (R5–20, X5, and AX correlated with maximal mid-expiratory flow postbronchodilator in group III). Conclusions IOS is very useful in detecting small-airway affection in mild and moderate COPD and could be done as an alternative to spirometric tests in severe COPD patients with more accurate grading.

Background: Obesity is known to induce lung function impairment. Previous studies of decline in lung function associated with obesity are well established. Materials and Methods: In this cross-sectional study, to evaluate the effects of different obesity indices on lung mechanics, healthy subjects (males-23 and females-22) were recruited. Anthropometric parameters like body mass index (BMI), waist circumference (WC), hip circumference (HC) and neck circumference (NC) were measured and waist-hip ratio (WHR) was derived. Spirometry, impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO) measurements were performed to assess lung function. Subgroups were divided and analysed. Results: In males, increased WHR is associated with increased total airway resistance (R5). BMI correlates positively with R5, R5% predicted, resistance at 20 Hz (R20) and R20% predicted; likewise, WHR shows a positive correlation with R5. In females, increased WHR has significantly higher R5, R5% predicted, R20, R20% predicted, area of reactance (Ax), resonant frequency (Fres) and decreased reactance at 5 Hz (X5), reactance at 20 Hz (X20), X20% predicted. The female group with higher WC shows significantly increased R5, R5% predicted, R20, R20% predicted, Ax, Fres and lower fixed ratio of forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC), X5, X20, X20% predicted. The group with higher NC has a lower FEV1/FVC ratio. WHR positively correlated with R5% predicted and Fres while WC correlated positively with R5, R5% predicted, Ax and Fres; same way, NC with X5% predicted. Conclusion: Obesity/overweight causes significant changes in lung volumes, capacity and airway mechanics, Higher WC and WHR are associated with significant changes in lung mechanics, which are more prominent in females than in males. NC is not associated with changes in lung mechanics.

Background: Asthma is defined as a chronic inflammatory disorder of the airways, characterized by bronchial hyper-responsiveness and variable airflow obstruction, that is often reversible either spontaneously or with treatment. Impulse oscillometry is a newer diagnostic modality for asthma. It is based on the measurement of sound waves reflected by airway resistance. Objectives: The aim of this article is to study the role of impulse oscillometry in diagnosis and follow-up of bronchial asthma. Methods: Fifty-five clinically diagnosed bronchial asthma patients were evaluated with spirometry and impulse oscillometry before and after 3 months of inhaled treatment. The sensitivity to diagnose and follow-up was compared using proper statistical tests. Results: Impulse oscillometry was superior to spirometry in diagnosing bronchial asthma and also in accessing the treatment response after 3 months. Conclusion: Impulse oscillometry is superior in predicting bronchial asthma and its parameters are also more sensitive in accessing treatment response. It can replace spirometry as it is easy to perform and effort independent.

Alfredo Chetta,1 Nicola Facciolongo,2 Cosimo Franco,3 Laura Franzini,4 Alessio Piraino,4 Carmelina Rossi4 1Clinica Pneumologica, Università di Parma, Parma, Italy; 2UOC Pneumologia, Arcispedale Santa Maria Nuova, Reggio Emilia, Italy; 3UOC Pneumologia, Ospedale Guglielmo da Saliceto, Piacenza, Italy; 4Chiesi Italia SpA, Medical Affairs, Parma, ItalyCorrespondence: Alfredo Chetta, Tel +39 0521.703478, Email alfredoantonio.chetta@unipr.itAbstract: In recent years, the perspective of management of respiratory disease has been gradually changing in light of the increasing evidence of small airways as the major site of airflow obstruction contributing to the development of both COPD and asthma already in early stages of disease. First and foremost, the evidence is redefining disease severity, identifying small airways disease phenotypes and early signs of disease, and revising prevalence and overall epidemiological data as well. Much effort has been put toward the instrumental assessment of small airways’ involvement and early detection. Several clinical trials have evaluated the advantage of extra-fine formulations which can best target the small airways in uncontrolled asthma and severe COPD. Here, we briefly present a practical overview of the role of the small airways in disease, the most appropriate diagnostic methods for quantifying their impairment, and provide some insight into the costs of respiratory management in Italy, especially in sub-optimally controlled disease.Keywords: asthma, chronic obstructive pulmonary disease, small airways, impulse oscillometry, cost, extrafine particles

Abstract Background Aging has been evidenced to bring about some structural and functional lung changes, especially in COPD. However, whether aging affects SAD, a possible precursor of COPD, has not been well characterized. Objective We aimed to comprehensively assess the relationship between aging and SAD from computed tomography, impulse oscillometry, and spirometry perspectives in Chinese. Methods We included 1859 participants from ECOPD, and used a linear-by-linear association test for evaluating the prevalence of SAD across various age subgroups, and multivariate regression models for determining the impact of age on the risk and severity of SAD. We then repeated the analyses in these subjects stratified by airflow limitation. Results The prevalence of SAD increases over aging regardless of definitional methods. After adjustment for other confounding factors, per 10-yrs increase in age was significantly associated with the risk of CT-defined SAD (OR 2.57, 95% CI 2.13 to 3.10) and the increase in the severity of air trapping (β 2.09, 95% CI − 0.06 to 4.25 for LAA-856), airway reactance (β − 0.02, 95% CI − 0.04 to − 0.01 for X5; β 0.30, 95% CI 0.13 to 0.47 for AX; β 1.75, 95% CI 0.85 to 2.66 for Fres), as well as the decrease in expiratory flow rates (β − 3.95, 95% CI − 6.19 to − 1.71 for MMEF%predicted; β − 5.42, 95% CI − 7.88 to − 2.95 for FEF50%predicted) for SAD. All these associations were generally maintained in SAD defined by IOS or spirometry. After stratification of airflow limitation, we further found that the effect of age on LAA-856 was the most significant among almost all subgroups. Conclusions Aging is significantly associated with the prevalence, increased risk, as well as worse severity of SAD. CT may be a more optimal measure to assess aging-related SAD. The molecular mechanisms for the role of aging in SAD need to be explored in the future. Trial registration Chinese Clinical Trial Registry ChiCTR1900024643. Registered on 19 July 2019

Background: Surfactant protein D (SP D) is crucial in controlling the immunological response of the peripheral airways, Surfactant changes caused by airway inflammation may have a role in the pathophysiology of asthma. Aim of this study: was to assess the value of salivary SP D in Preschool asthmatic children. Methods: in our case control study including 30 non-asthmatic controls and 30 preschool asthmatic children aged 2-5 years old, we assessed salivary SP D and pulmonary functions using impulse oscillometry (IOS) then the correlations between salivary SP D levels and IOS indices were analyzed. Results: Salivary SP D levels were increased in asthmatic group with mean ± SD of 32.52±12.88 pg/ml compared to 5.98±2.87 pg/ml in healthy controls. Moreover, it was correlated with poor pulmonary functions using IOS indices with cutoff expression value of SP D >8.19 using ROC curve at the optimal sensitivity 83.3% and specificity 81.0% to differentiate asthmatic children from controls. Conclusion: Salivary SP D can be a useful marker for childhood asthma and can monitor deterioration in pulmonary functions in preschool asthmatic children. [ABSTRACT FROM AUTHOR]

Background: A few studies have reported the medium-sized and small airway morphological abnormalities of bronchiolitis. Whether spirometry or impulse oscillometry (IOS) is correlated with airway remodeling of bronchiolitis remains unclear. Objectives: Aiming to demonstrate the airway morphological abnormalities of bronchiolitis obliterans (BO) and diffuse panbronchiolitis (DPB) assessed by endobronchial optical coherence tomography (EB-OCT), and elucidate whether spirometric and IOS parameters have correlation with the airway remodeling of bronchiolitis. Methods: We recruited 18 patients with bronchiolitis (BO, n = 9; DPB, n = 9) and 17 control subjects. Assessments of clinical features, St. George's respiratory questionnaire (SGRQ), chest computed tomography (CT), spirometry, IOS, and EB-OCT were performed in all enrolled subjects. The correlation between EB-OCT and lung function parameters was studied and analyzed. Results: The magnitude of abnormalities of spirometric and IOS parameters was significantly greater in patients with bronchiolitis than that in control subjects (p < 0.05). Patients with BO had notably lower forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, maximal mid-expiratory flow (MMEF)% pred and higher resonant frequency (Fres), and area of reactance (AX) than those with DPB (p < 0.05). The EB-OCT measurement among patients with bronchiolitis and between the bronchus in the left and the right lung demonstrated a heterogeneous distribution of airway calibers, presenting a high intra- and inter-individual variability. Patients with bronchiolitis had notably greater airway wall area (p < 0.05) compared with control, while BO presented greater magnitude of airway abnormalities than DPB. Fres and the difference in airway resistance at 5 and 20 Hz (R5–R20) correlated negatively with medium-sized and small airway inner area, and correlated positively with airway wall area (p < 0.05), whose correlation coefficients were higher than those of spirometric parameters. Conclusion: Bronchiolitis, BO and DPB, manifested a heterogeneous distribution of airway calibers with significant intra- and inter-individual variability. IOS parameters, rather than spirometry, correlated better with medium-sized and small airway remodeling in bronchiolitis assessed by EB-OCT measurement. [ABSTRACT FROM AUTHOR]

Objective: Some of the most common causes of chronic cough include cough variant asthma (CVA), bronchial asthma (BA), and asthma–COPD overlap (ACO). Although there is some overlap in the etiology of these diseases, it is clinically important to attempt an early differential diagnosis due to treatment strategies and prognoses. Methods: Spirometry and impulse oscillometry (IOS) before and after bronchodilator inhalation were analyzed for clinically diagnosed CVA (cCVA, n = 203), BA (cBA, n = 222), and ACO (cACO, n = 61). Results: A significant difference in ΔFEV1 was observed between cBA and cCVA (ΔFEV1 improvement of 122.5 mL/5.4% and 65.7 mL/2.2%, respectively), but no difference was observed in ΔPEF, ΔV50, or ΔV25. Except for R20 (resistance at 20 Hz), significant differences between the three groups were observed in IOS. In IOS, cCVA and cBA showed comparable peripheral airway response to bronchodilator which was thought to be commensurate with changes in V50 and V25. cACO improved ΔFEV1 improvement of 81.0 mL/6.2% and was distinguished by a downward respiratory system reactance (Xrs) waveform with a limited bronchodilator response. FEV1/FVC, %FEV1, and %V25 had relatively strong correlations with the three IOS parameters, X5 (reactance at 5 Hz), resonant frequency (Fres), and low-frequency reactance area (ALX), in the correlation between IOS and spirometers. Conclusion: Changes in IOS parameters were more sensitive in this study than changes in FEV1 or the flow-volume curve. Considering the benefits and relevance of the two different tests, simultaneous IOS and spirometry testing were useful in the diagnosis of asthmatic cough. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Small airway dysfunction is a pathological component of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), and impulse oscillometry is an easy-to-administer, effort-independent non-invasive test reflecting small airway dysfunction. We aimed to compare the impulse oscillometry (IOS) measurements between COPD and IPF patients and investigate their correlation with severity of both diseases and other conventional parameters. PATIENTS AND METHODS: This was a prospective, longitudinal study. We longitudinally evaluated the baseline demographic characteristics, COPD Assessment Test (CAT) and modified Medical Research Council (mMRC) dyspnea scale, Pulmonary Function Test (PFT), Carbon Monoxide Diffusing Capacity (DLCO), Hemogram and Impulse Oscillometry measurements of the patients diagnosed with COPD and IPF. RESULTS: The study included 60 IPF patients and 48 COPD patients. The CAT and mMRC scores were higher in COPD patients. The majority of COPD patients were classified into Category B (46%), while 68% of IPF patients had Stage 1 GAP. The mean FEF 25-75%, which is typically considered to reflect small airway disease, was 93% in IPF patients, while it was significantly lower in COPD patients (29%). Impulse oscillometry measurements were consistent with spirometry parameters. IOS resistance and reactance values were significantly higher in COPD patients than in IPF patients. CONCLUSIONS: IOS is advantageous in COPD and IPF patients who cannot exhale due to severe dyspnea, as it is easy to administer and reflects small airway resistance better. Diagnosis of small airway dysfunction may be beneficial in the management of patients with IPF and COPD. [ABSTRACT FROM AUTHOR]

Aim: The aim of our study was to compare clinical severity scores and classic spirometry with impulse oscillometry (IOS) results and thoracic high resolution computed tomography (HRCT) scores in children with cystic fibrosis (CF) in order to determine the utility of the latter approach in patient follow-up. Materials and Methods: CF patients over 6 years of age were included. Shwachman-Kulczycki score, underclassical spirometry and IOS were performed when not in acute exacerbation. Thoracic HRCT images obtained within the previous 6 months were evaluated using the Bhalla scoring system. Results: The mean age of the children studied (n=30) was 12.1±4.2 years and 40% were female. Pseudomonas aeruginosa (P. aeroginosa) was isolated from sputum cultures of 40% of the patients. Patients with forced expiratory volume in one second (FEV1) below 80% exhibited significantly higher (resistance) R5, R10 values and significantly lower (reactance) X5 values on IOS (p=0.03, 0.027, 0.006, respectively). Patients with P. aeruginosa had significantly lower FEV1, forced vital capacity, and forced expiratory flow (25-75) values in classic spirometry when compared with patients without P. aeruginosa (p=0.002, p=0.002, and p=0.005, respectively). P. aeruginosa-positive patients showed significantly higher R5 and lower X5 values (p=0.047, 0.046, respectively). Bhalla scoring, bronchiectasis weight, peribronchial thickening, mucous plaques, saccularization, bronchial division, mosaic pattern parameters in groups with P. aeroginosa growth and/or FEV1 <80%; was found to be significantly more serious than the non-reproductive group (p<0.005, respectively). Again, in the group with P. aeroginosa growth, Shwachman-Kulczycki score was found to be significantly lower (p=0.001). No significant correlation was found between thoracic score data such as bronchiectasis weight and mosaic pattern presence and IOS values. In addition, in the group with high clinical score of Shwachman Kulczycki, resistance values such as R5 R10 R15 which are IOS parameters, and FEV1 were found above 80% (p=0.016, p=0.037, p=0.042, 0.004, respectively). Conclusion: IOS and tomographic scoring can be used safely in early detection of impairment in lung function. Further studies are needed to evaluate the utility of IOS in the clinical monitoring of children with CF who are not compliant with spirometry maneuvers. [ABSTRACT FROM AUTHOR]

Introduction: Chronic Obstructive Pulmonary Disease (COPD) is a progressive, poorly reversible obstructive disease affecting mainly the small airways. Spirometry is the current standard diagnostic test for COPD. Impulse Oscillometry (IOS) is the commonest forced oscillation technique (FOT) in use and it shows promise as a diagnostic tool in the diagnosis of COPD. This systematic review aims to review the diagnostic yield of IOS compared to standard spirometry in COPD patients. Methods: PubMed, OVID, CINAHL, and Cochrane Library databases were searched with Mesh headings to locate studies linking IOS and Spirometry in the diagnosis of COPD. A systematic review is undertaken to assess the diagnostic yield of IOS in COPD. Results: Four studies were identified that fulfilled the inclusion criteria. A total of 358 patients were included in the data to inform the diagnostic yield of IOS compared with spirometry where R5-R20 and X5 and AX correlated consistently with FEV1 in the diagnosis of COPD. Conclusions: IOS is useful in the diagnosis of Chronic Obstructive Pulmonary Disease. [ABSTRACT FROM AUTHOR]

Premature birth is a risk factor for bronchopulmonary dysplasia (BPD); both of which are associated with obstructive airway disease throughout childhood. Impulse oscillometry (IOS) is an effort-independent, passive measure of tidal breathing, which could have benefits in assessing lung function amongst younger patients unable to perform valid spirometry. A literature search was conducted to investigate the use of IOS in prematurely born children and young people. IOS results correlate with those of spirometry. Reversibility of airway obstruction in children with BPD is variable. IOS could have benefits in assessing individual patient response and suitability for bronchodilator therapy. More work, however, is required to establish multi-ethnic reference ranges and standardise commercially available devices prior to its routine incorporation into clinical practice. [ABSTRACT FROM AUTHOR]