Prevalence Of Small Airway Dysfunction Research Articles

Oscillometry-Defined Small Airway Dysfunction in Patients with Chronic Obstructive Pulmonary Disease.

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. 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. 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). 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.

Prevalence of small airway dysfunction in the Swiss PneumoLaus Cohort.

Recent evidence identified exposure to particulate matter of size ≤2.5 µm (PM2.5) as a risk factor for high prevalence of small airway dysfunction (SAD). We assessed the prevalence of SAD in a European region with low air pollution levels. SAD was defined as a maximum mid-expiratory flow (MMEF) <65% of predicted value (PV) or MMEF <lower limit of normal (LLN) measured by spirometry in the Swiss PneumoLaus cohort. We performed bivariate and multivariable analysis with MMEF criteria, age, sex, body mass index, respiratory symptoms and smoking status. Mean PM2.5 values were obtained from a Swiss national database. Among 3351 participants (97.6% Caucasian, 55.7% female sex, mean age 62.7 years), we observed MMEF <65% PV in 425 (12.7%) and MMEF <LLN in 167 (5.0%) individuals. None of the participants had both MMEF <LLN and ≥65% PV. MMEF <65% PV and MMEF <LLN were significantly associated with age, smoking status, cough, sputum and dyspnoea, whereas a positive association with MMEF <65% PV was observed for individuals aged >65 years only. In an area where ambient PM2.5 concentration was <15 µg·m-3 during the observation period (2010 and 2020), ≥72% of participants with SAD were ever-smokers. The observed low prevalence of SAD of 5.0-12.7% depending on criteria employed may be related to lower PM2.5 exposure. Smoking was the main factor associated with SAD in an area with low PM2.5 exposure. Employing a MMEF threshold <65% PV carries a risk of SAD overdiagnosis in elderly individuals.

The role of small airway function parameters in preschool asthmatic children

BackgroundSmall airways are the major sites of inflammation and airway remodeling in all severities of asthma patients. However, whether small airway function parameters could reflect the airway dysfunction feature in preschool asthmatic children remain unclear. We aim to investigate the role of small airway function parameters in evaluating airway dysfunction, airflow limitation and airway hyperresponsiveness (AHR).MethodsEight hundred and fifty-one preschool children diagnosed with asthma were enrolled retrospectively to investigate the characteristics of small airway function parameters. Curve estimation analysis was applied to clarify the correlation between small and large airway dysfunction. Spearman’s correlation and receiver-operating characteristic (ROC) curves were employed to evaluate the relationship between small airway dysfunction (SAD) and AHR.ResultsThe prevalence of SAD was 19.5% (166 of 851) in this cross-sectional cohort study. Small airway function parameters (FEF25-75%, FEF50%, FEF75%) showed strong correlations with FEV1% (r = 0.670, 0.658, 0.609, p<0.001, respectively), FEV1/FVC% (r = 0.812, 0.751, 0.871, p<0.001, respectively) and PEF% (r = 0.626, 0.635, 0.530, p<0.01, respectively). Moreover, small airway function parameters and large airway function parameters (FEV1%, FEV1/FVC%, PEF%) were curve-associated rather than linear-related (p<0.001). FEF25-75%, FEF50%, FEF75% and FEV1% demonstrated a positive correlation with PC20 (r = 0.282, 0.291, 0.251, 0.224, p<0.001, respectively). Interestingly, FEF25-75% and FEF50% exhibited a higher correlation coefficient with PC20 than FEV1% (0.282 vs. 0.224, p = 0.031 and 0.291 vs. 0.224, p = 0.014, respectively). ROC curve analysis for predicting moderate to severe AHR showed that the area under the curve (AUC) was 0.796, 0.783, 0.738, and 0.802 for FEF25-75%, FEF50%, FEF75%, and the combination of FEF25-75% and FEF75%, respectively. When Compared to children with normal lung function, patients with SAD were slightly older, more likely to have a family history of asthma and airflow obstruction with lower FEV1% and FEV1/FVC%, lower PEF% and more severe AHR with lower PC20 ( all p<0.05).ConclusionSmall airway dysfunction is highly correlated with large airway function impairment, severe airflow obstruction and AHR in preschool asthmatic children. Small airway function parameters should be utilized in the management of preschool asthma.

Comparative assessment of small airway dysfunction by impulse oscillometry and spirometry in chronic obstructive pulmonary disease and asthma with and without fixed airflow obstruction.

Small airways play a major role in the pathogenesis and prognosis of chronic obstructive pulmonary disease (COPD) and asthma. More data on small airway dysfunction (SAD) using spirometry and impulse oscillometry (IOS) in these populations are required. The objective of this study was to compare the two methods, spirometry and IOS, for SAD detection and its prevalence defined by spirometry and IOS in subjects with COPD and asthma with and without fixed airflow obstruction (FAO). This is a cross-sectional study. Spirometric and IOS parameters were compared across four groups (COPD, asthma with FAO, asthma without FAO, and healthy subjects). SAD defined by spirometry and IOS criteria were compared. A total of 262 subjects (67 COPD, 55 asthma with FAO, 101 asthma without FAO, and 39 healthy controls) were included. The prevalence of SAD defined by using IOS and spirometry criteria was significantly higher in patients with COPD (62.7 and 95.5%), asthma with FAO (63.6 and 98.2%), and asthma without FAO (38.6 and 19.8%) in comparison with healthy control (7.7 and 2.6%). IOS is more sensitive than spirometry in the detection of SAD in asthma without FAO (38.6% vs. 19.8%, p = 0.003) However, in subjects with FAO (COPD and asthma with FAO), spirometry is more sensitive than IOS to detect SAD (95.5% vs. 62.7%, p < 0.001 and 98.2% vs. 63.6%, p < 0.001, respectively). Small airway dysfunction was significantly detected in COPD and asthma with and without FAO. Although IOS shows more sensitivity than spirometry in the detection of SAD in asthma without FAO, spirometry is more sensitive than IOS in patients with FAO including COPD and asthma with FAO.

Small airway dysfunction in pneumoconiosis: a cross-sectional study

BackgroundAlthough several histological studies have documented airway inflammation and remodelling in the small airways of dust-exposed workers, little is known regarding the prevalence and risk factors of small airway dysfunction (SAD) in pneumoconiosis. The present study investigated the prevalence and characteristics of spirometry-defined SAD in pneumoconiosis and assessed the risk factors for associated with SAD.MethodsA total of 1255 patients with pneumoconiosis were invited to participate, of whom 1115 patients were eligible for final analysis. Spirometry was performed to assess SAD using the following three indicators: maximal mid-expiratory flow and forced expiratory flow 50% and 75%. SAD was defined as at least two of these three indicators being less than 65% of predicted value. Logistic regression analyses were used to analyse the relationships between clinical variables and SAD.ResultsOverall, 66.3% of patients with pneumoconiosis had SAD, among never-smokers the prevalence of SAD was 66.7%. The proportion of SAD did not differ among the subtypes of pneumoconiosis. In addition, SAD was present across the patients with all stages of pneumoconiosis. Even among those with forced expiratory volume in 1 s (FEV1) ≥ 80% and FEV1/forced vital capacity ratio ≥ 70%, 40.8% of patients had SAD. Patients with SAD were older than patients without SAD, more likely to be women and heavy smokers. Importantly, patients with SAD had more severe airflow obstruction, air trapping, and diffusion dysfunction. All patients with both pneumoconiosis and chronic obstructive pulmonary disease had SAD. Based on multivariate analysis, overall, aged 40 years and older, female sex, heavy smoking, body mass index ≥ 25.0 kg/m2 and pneumoconiosis stage III were significantly associated with increased risk of SAD. Among the never smokers, risk factors for SAD included female sex, BMI ≥ 25.0 kg/m2, pneumoconiosis stage II and stage IIIConclusionSpirometry-defined SAD is one of the common functional abnormalities caused by occupational dust exposure and should be taken into account when monitoring respiratory health of workers to guide the early precautions and management in pneumoconiosis.

Small Airway Dysfunction in Cough Variant Asthma: Prevalence, Clinical, and Pathophysiological Features.

Introduction: Small airway dysfunction (SAD) commonly presents in patients with classic asthma, which is associated with airway inflammation, disease severity, and asthma control. However, the prevalence of SAD, its relationship with cough severity and airway inflammation, and its development after antiasthmatic treatment in patients with cough variant asthma (CVA) need to be clarified. This study aimed to investigate the prevalence of SAD and its relationship with clinical and pathophysiological characteristics in patients with CVA and the change in small airway function after antiasthmatic treatment.Methods: We retrospectively analyzed 120 corticosteroid-naïve patients with CVA who had finished a standard questionnaire and relevant tests in a specialist cough clinic, such as cough visual analog scale (VAS), differential cells in induced sputum, fractional exhaled nitric oxide (FeNO) measurement, spirometry, and airway hyper-responsiveness. Information of 1-year follow-up was recorded in a part of patients who received complete cough relief after 2 months of treatment. SAD was defined as any two parameters of maximal mid-expiratory flow (MMEF)% pred, forced expiratory flow at 50% of forced vital capacity (FEF50%) pred, and forced expiratory flow at 75% of forced vital capacity (FEF75%) pred measuring <65%.Results: SAD occurred in 73 (60.8%) patients with CVA before treatment. The patients with SAD showed a significantly longer cough duration (24.0 vs. 6.0, p = 0.031), a higher proportion of women (78.1 vs. 59.6%, p = 0.029), older mean age (41.9 vs. 35.4, p = 0.005), and significantly lower forced expiratory volume in 1 s (FEV1%) pred, FEV1/FVC, MMEF% pred, FEF50% pred, FEF75% pred, PEF% pred, and PD20 (all p < 0.01) as compared with patients without SAD. There were no significant differences in cough VAS, sputum eosinophils count, FeNO, and TIgE level between patients with SAD and those without SAD. Among 105 patients who completed 2 months of antiasthmatic treatment and repeatedly experienced spirometry measurement, 57 (54.3%) patients still had SAD, despite a significant improvement in cough VAS, sputum eosinophils, FeNO, FEF50% pred, and PEF% pred (all p < 0.01). As compared with patients without SAD, patients with SAD showed no significant differences in the relapse rate (50.0 vs. 41.9%, p = 0.483) and wheeze development rate (10.4 vs. 0%, p = 0.063) during the follow-up.Conclusions: Small airway dysfunction occurred in over half of patients with CVA and persisted after short-term antiasthmatic treatment, which showed distinctive clinical and pathophysiological features.

Joint Effects of Carbon Black Exposure and Dietary Antioxidant Vitamin Intake on Small Airway Dysfunction.

Objectives: Small airway dysfunction is considered as a precursor of chronic obstructive pulmonary disease and asthma. Our aim was to explore the joint effects of carbon black (CB) exposure and antioxidant vitamin intake on small airway dysfunction.Methods: A total of 70 CB packers (CBPs) and 107 non-CBPs were enrolled from an established cohort of CBP. Carbon content in airway macrophage (CCAM) quantified in induced sputum was used as a bio-effective dosimetry for exposure to CB. Logistic regression models were used to examine the odds ratios (ORs) of CB and dietary intake of antioxidant vitamins on small airway dysfunction, and the dose–response association.Results: The prevalence of small airway dysfunction was 32.9% (23 of 70) among CBPs, and 19.6% (21 of 107) among non-CBPs. For each 2.72-fold increase in CCAM, the OR of small airway dysfunction was 2.31 (95% CI = 1.20–4.44). For every 10 mg day−1 increase of the vitamin C intake, the risk of small airway dysfunction decreased by 6% (OR = 0.94, 95% CI = 0.88–0.99). Compared to non-CB exposure and higher vitamin C intake, CB exposure and lower vitamin C intake (OR = 7.56, 95% CI = 1.80 to 31.81) were associated with an increased risk of small airway dysfunction.Conclusions: Chronic exposure to a high level of CB aerosol increased the risk of small airway dysfunction in CB baggers. Dietary intake of vitamin C might be a modifiable factor for preventing small airway dysfunction.

Small Airway Dysfunction Links Asthma Severity with Physical Activity and Symptom Control

Little is known about the role of small airway dysfunction (SAD) and its complex relation with asthma control and physical activity (PA). To investigate the interrelations among SAD, risk factors for asthma severity, symptom control, and PA. We assessed SAD by impulse oscillometry and other sophisticated lung function measures including inert gas washout in adults with asthma (mild to moderate, n= 140; severe, n= 128) and 69 healthy controls from the All Age Asthma Cohort. We evaluated SAD prevalence and its interrelation with risk factors for asthma severity (older age, obesity, and smoking), type 2 inflammation (sputum and blood eosinophils, fractional exhaled nitric oxide), systemic inflammation (high-sensitivity C-reactive protein), asthma control (AC), and PA (accelerometer for 1 week). We applied a clinical model based on structural equation modeling that integrated causal pathways among these clinical variables. The prevalence of SAD ranged from 75% to 90% in patients with severe asthma and from 53% to 64% in mild to moderate asthma. Severe SAD was associated with poor AC and low PA. Structural equation modeling indicated that age, obesity, obesity-related systemic inflammation, T2 inflammation, and smoking are independent predictors of SAD. Small airway dysfunction was the main determinant factor of AC, which in turn affected PA. Obesity affected AC directly and through its contribution to SAD and low PA. In addition, PA had bidirectional associations with obesity, SAD, and AC. Structural equation modeling also indicated interrelations among distal airflow limitation, air trapping, and ventilation heterogeneity. Small airway dysfunction is a highly prevalent key feature of asthma that interrelates a spectrum of distal lung function abnormalities with risk factors for asthma severity, asthma control, and physical activity.

Impulse oscillometry for detection of small airway dysfunction in subjects with chronic respiratory symptoms and preserved pulmonary function

BackgroundSubjects with chronic respiratory symptoms and preserved pulmonary function (PPF) may have small airway dysfunction (SAD). As the most common means to detect SAD, spirometry needs good cooperation and its reliability is controversial. Impulse oscillometry (IOS) may complete the deficiency of spirometry and have higher sensitivity. We aimed to explore the diagnostic value of IOS to detect SAD in symptomatic subjects with PPF.MethodsThe evaluation of symptoms, spirometry and IOS results in 209 subjects with chronic respiratory symptoms and PPF were assessed. ROC curves of IOS to detect SAD were analyzed.Results209 subjects with chronic respiratory symptoms and PPF were included. Subjects who reported sputum had higher R5–R20 and Fres than those who didn’t. Subjects with dyspnea had higher R5, R5–R20 and AX than those without. CAT and mMRC scores correlated better with IOS parameters than with spirometry. R5, R5–R20, AX and Fres in subjects with SAD (n = 42) significantly increased compared to those without. Cutoff values for IOS parameters to detect SAD were 0.30 kPa/L s for R5, 0.015 kPa/L s for R5–R20, 0.30 kPa/L for AX and 11.23 Hz for Fres. Fres has the largest AUC (0.665, P = 0.001) among these parameters. Compared with spirometry, prevalence of SAD was higher when measured with IOS. R5 could detect the most SAD subjects with a prevalence of 60.77% and a sensitivity of 81% (AUC = 0.659, P = 0.002).ConclusionIOS is more sensitive to detect SAD than spirometry in subjects with chronic respiratory symptoms and PPF, and it correlates better with symptoms. IOS could be an additional method for SAD detection in the early stage of diseases.

Diagnosis of small airway dysfunction in patients with chronic obstructive pulmonary disease

Background: Small airway dysfunction (SAD) is a functional hallmark of chronic obstructive pulmonary disease (COPD). However, SAD prevalence and its role in COPD pathophysiology are not yet sufficiently studied.Background: Small airway dysfunction (SAD) is a functional hallmark of chronic obstructive pulmonary disease (COPD). However, SAD prevalence and its role in COPD pathophysiology are not yet sufficiently studied.Aim: To assess the prevalence of SAD in COPD patients by various functional diagnostic methods, such as spirometry, body plethysmography, and impulse oscillometry (IOS).Materials and methods: This was an cross-sectional study. Spirometry, body plethysmography and IOS were used in 132 COPD patients in remission under standard anti-COPD treatments. The presence of SAD was confirmed by at least one of the following criteria or their combination: 1) by spirometry: the difference between vital capacity (VC) and forced vital capacity (FVC) &gt; 10%; 2) the presence of air trapping by body plethysmography; 3) identification of the frequency dependence of the resistive resistance at 5 to 20 Hz (R5 - R20 &gt; 0.07 kPa x s/l), as assessed by IOS.Results: Mean forced expiratory volume in 1 s (FEV1) was 42.9% of predicted. Depending on the severity of the obstruction, the patients were divided into 4 groups: 7 patients (group 1) had the obstruction corresponding to GOLD 1 stage, 37 (group 2) to GOLD 2, 49 (group 3) to GOLD 3, and 39 (group 4) to GOLD 4. SAD was found in 96% of COPD patients, whereas in those with severe obstruction (GOLD 3-4), it was present in 100% of the cases. By spirometry, SAD was identified only in 67% of COPD patients, by body plethysmography in 75% of COPD patients (in those with severe obstruction (GOLD 3 and 4) in 88 and 97%, respectively). With IOS, it was possible to identify SAD in 94% of patients and in 100% of those with severe obstruction (GOLD 3-4).Conclusion: With deterioration of obstructive pulmonary ventilation abnormalities in COPD patients, there is a progressive increase in small airway dysfunction. Impulse oscillometry seems to be the most effective method for diagnosis of small airway dysfunction, as it helped to identify SAD in 94% of COPD patients and in 100% of those with severe and very severe obstruction.

Prevalence and risk factors of small airway dysfunction, and association with smoking, in China: findings from a national cross-sectional study

Small airway dysfunction is a common but neglected respiratory abnormality. Little is known about its prevalence, risk factors, and prognostic factors in China or anywhere else in the world. We aimed to estimate the prevalence of small airway dysfunction using spirometry before and after bronchodilation, both overall and in specific population subgroups; assess its association with a range of lifestyle and environmental factors (particularly smoking); and estimate the burden of small airway dysfunction in China. From June, 2012, to May, 2015, the nationally representative China Pulmonary Health study invited 57 779 adults to participate using a multistage stratified sampling method from ten provinces (or equivalent), and 50 479 patients with valid lung function testing results were included in the analysis. We diagnosed small airway dysfunction on the basis of at least two of the following three indicators of lung function being less than 65% of predicted: maximal mid-expiratory flow, forced expiratory flow (FEF) 50%, and FEF 75%. Small airway dysfunction was further categorised into pre-small airway dysfunction (defined as having normal FEV1 and FEV1/forced vital capacity [FVC] ratio before bronchodilator inhalation), and post-small airway dysfunction (defined as having normal FEV1 and FEV1/FVC ratio both before and after bronchodilator inhalation). Logistic regression yielded adjusted odds ratios (ORs) for small airway dysfunction associated with smoking and other lifestyle and environmental factors. We further estimated the total number of cases of small airway dysfunction in China by applying present study findings to national census data. Overall the prevalence of small airway dysfunction was 43·5% (95% CI 40·7-46·3), pre-small airway dysfunction was 25·5% (23·6-27·5), and post-small airway dysfunction was 11·3% (10·3-12·5). After multifactor regression analysis, the risk of small airway dysfunction was significantly associated with age, gender, urbanisation, education level, cigarette smoking, passive smoking, biomass use, exposure to high particulate matter with a diameter less than 2·5 μm (PM2·5) concentrations, history of chronic cough during childhood, history of childhood pneumonia or bronchitis, parental history of respiratory diseases, and increase of body-mass index (BMI) by 5 kg/m2. The ORs for small airway dysfunction and pre-small airway dysfunction were similar, whereas larger effect sizes were generally seen for post-small airway dysfunction than for either small airway dysfunction or pre-small airway dysfunction. For post-small airway dysfunction, cigarette smoking, exposure to PM2·5, and increase of BMI by 5 kg/m2 were significantly associated with increased risk, among preventable risk factors. There was also a dose-response association between cigarette smoking and post-small airway dysfunction among men, but not among women. We estimate that, in 2015, 426 (95% CI 411-468) million adults had small airway dysfunction, 253 (238-278) million had pre-small airway dysfunction, and 111 (104-126) million had post-small airway dysfunction in China. In China, spirometry-defined small airway dysfunction is highly prevalent, with cigarette smoking being a major modifiable risk factor, along with PM2·5 exposure and increase of BMI by 5 kg/m2. Our findings emphasise the urgent need to develop and implement effective primary and secondary prevention strategies to reduce the burden of this condition in the general population. Ministry of Science and Technology of China; National Natural Science Foundation of China; National Health Commission of China.

Long-term Pulmonary Consequences of Coronavirus Disease 2019 (COVID-19): What We Know and What to Expect.

Long-term Pulmonary Consequences of Coronavirus Disease 2019 (COVID-19): What We Know and What to Expect.

Isolated Small Airway Dysfunction and Ventilatory Response to Cardiopulmonary Exercise Testing.

The effect of isolated small airway dysfunction (SAD) on exercise remains incompletely characterized. We sought to quantify the relationship between isolated SAD, identified with lung testing, and the respiratory response to exercise. We conducted a prospective evaluation of service members with new-onset dyspnea. All subjects underwent plethysmography, diffusing capacity of the lung for carbon monoxide (DLCO), impulse oscillometry, high-resolution computed tomography (HRCT), and cardiopulmonary exercise testing (CPET). In subjects with normal basic spirometry, DLCO, and HRCT, SAD measures were analyzed for associations with ventilatory parameters at submaximal exercise and at maximal exercise during CPET. We enrolled 121 subjects with normal basic spirometry (ie, FEV1, FVC, and FEV1/FVC), DLCO, and HRCT. Mean age and body mass index were 37.4 ± 8.8 y and 28.4 ± 3.8 kg/m2, respectively, and 110 (90.9%) subjects were male. The prevalence of SAD varied from 2.5% to 28.8% depending on whether FEV3/FVC, FEF25-75%, residual volume/total lung capacity, and R5-R20 were used to identify SAD. Agreement on abnormal SAD across tests was poor (kappa = -0.03 to 0.07). R5-R20 abnormalities were related to higher minute ventilation ([Formula: see text]) and higher [Formula: see text]/maximum voluntary ventilation (MVV) during submaximal exercise and to lower [Formula: see text] during maximal exercise. After adjustment for differences at baseline, there remained a trend toward a relationship between R5-R20 and an elevated [Formula: see text]/MVV during submaximal exercise (β = 0.04, 95% CI -0.01 to 0.09, P = .10), but there was no significant association with [Formula: see text] during submaximal exercise or with [Formula: see text] during maximal exercise. No other SAD measures showed a relationship with ventilatory parameters. In 121 subjects with normal basic spirometry, DLCO, and HRCT, we found poor agreement across tests used to detect SAD. Among young, healthy service members with postdeployment dyspnea, SAD as identified by lung function testing does not predict changes in the ventilatory response to exercise.

Possibilities of pulse oscillometry in the diagnosis of small airway dysfunction in patients with bronchial asthma

Small airway dysfunction (SAD) is associated with poorly controlled asthma and frequent exacerbations. Objective: To assess the prevalence of SAD in asthmatics using spirometry, body plethysmography, and impulse oscillometry (IOS). Materials and methods: The observational cross-sectional study of 61 patients with asthma was performed. Conclusion available SAD was made on the basis of identifying one of the criteria or their combination: 1) slow vital capacity (SVC) - forced vital capacity (FVC) &gt;10% according spirometry; 2) "air trapping" according body plethysmography; 3) presence of pathological frequency dependence of the resistance (R) at 5 and 20 Hz (R5-R20 &gt; 0,07 kPa•sec/l) according IOS. Results: The analysis was performed for the entire group as well as for patients with FEV1 &gt; 80 %pred. and FEV1/SVC &lt; 0,7 (group 1) and patients with FEV1 &gt; 80 %pred. and normal FEV1/SVC (group 2). SAD was most often diagnosed using IOS and the selected criterion R5-R20&gt;0,07 kPa •sec/l since 75% of patients had this deviation in the entire group, 65% of patients in group 1 and 55% of patients in group 2 whereas only in 48% and 24% of cases in the entire group according body plethysmography and spirometry, respectively. Conclusion: SAD is definitely observed in patients with asthma. IOS is a more effective method of diagnosing SAD compared to spirometry and body plethysmography and can serve as a supplement functional method, especially in cases of normal parameters of spirometry and body plethysmography in asthmatics.

Small airway dysfunction in smokers with stable ischemic heart disease.

BackgroundA higher prevalence of airflow limitation (AL) has been described in patients with ischemic heart disease (IHD). Although small airway dysfunction (SAD) is an early feature of AL, there is little information about its occurrence in IHD patients. Our objective was to describe the prevalence of SAD in IHD patients, while comparing patient-related outcomes and future health risk among IHD patients with AL, SAD and normal lung function.MethodsIn 118 consecutive smoking patients with stable IHD, comorbidities, utilization of healthcare resources, current treatment, blood biochemistry and health status were recorded. SAD was evaluated by impulse oscillometry, and pre- and post-bronchodilator spirometry was performed.ResultsThe prevalence of AL and SAD were 20.3 (95% CI, 13.1–27.6%) and 26.3% (95% CI, 18.3–34.2%), respectively. Compared to the normal lung function group, patients with SAD and without AL had lower spirometric values, poorer quality of life and higher levels of C-reactive protein (CRP), as well as increased cardiovascular risk and more vascular age. In patients with normal spirometry, the presence of SAD was independently associated with pack-years, HDL-cholesterol and CRP levels.ConclusionIn patients with IHD, the presence of SAD is common and that it is associated with reduced health status and increased future cardiac risk.

Prevalence of Small-Airway Dysfunction among COPD Patients with Different GOLD Stages and Its Role in the Impact of Disease

Background: In chronic obstructive pulmonary disease (COPD) patients, small-airway dysfunction (SAD) is considered a functional hallmark of disease. However, the exact role of SAD in the clinical presentation of COPD is not yet completely understood; moreover, it is not known whether SAD may have a relationship with the impact of disease. Objectives: To evaluate the prevalence of SAD among COPD patients categorized by the old and the new GOLD classification and to ascertain whether there is a relationship between SAD and impact of disease measured by the COPD Assessment Test (CAT) questionnaire. Methods: We prospectively enrolled COPD outpatients from the University Hospital of Parma. Using the impulse oscillometry system (IOS), we assessed the fall in resistance from 5 to 20 Hz (R5-R20), reactance at 5 Hz (X5), and resonant frequency (F_Res) as markers of peripheral airway dysfunction. According to R5-R20 ≥0.07 or <0.07, the cohort was also categorized in patients with and without SAD, respectively. Results: We studied 202 patients. In both GOLD classifications, a progressive increasing distribution of R5-R20 and F_Res was reported with a decreasing of X5. Moreover, there was a significant correlation between R5-R20 and CAT (r = 0.527, p < 0.001). Finally, the presence of SAD (OR 11.96; 95% CI 4.53-31.58; p < 0.001) and use of ICS + LABA + LAMA (OR 5.31; 95% CI 1.88-15.02; p = 0.002) were independent predictors of higher impact (CAT score ≥10). Conclusion: In COPD patients, the presence of SAD, as assessed by IOS, progressively increases with GOLD classifications and it is closely related to the high impact of disease on health status.