Lung Function Measurements Research Articles

Impaired Cardiovascular Response to Exercise in Patients with Severe Asthma: A Case-Control Study.

Although asthmatics may present reduced exercise capacity, data on their cardiovascular responses during exercise testing have been scarcely investigated. The aim of this pilot case-control study is to test: a) whether double product (DP), an index of cardiovascular reserve, differs among patients with severe and mild-moderate asthma, and b) whether DP is associated with asthma control level, physical activity (PA) and exercise capacity, in asthmatics population. A group of patients with severe asthma (group S) and a matched group of patients with mild-moderate asthma (group M) was studied. All participants completed asthma control and physical activity (IPAC) questionnaires, lung function measurements and six-minute walk test. The exercise capacity (as 6-minute walk distance (6MWD) and corresponding work), the Borg Dyspnea, the rating of perceived excursion and the average PA METS were recorded. A total of 18 patients were studied. DP at exercise end was significantly lower in group S, compared to group M (16412.2±4732.1 vs. 18594.8±3984.4 mmHgXbpm; p=0.041) and was moderately associated with % predicted 6MWD (r=0.592; p=0.001). Group S patients were also presented with lower moderate intensity PA, compared to group M, while exercise capacity was similar between the groups. Asthma control level had no impact on exercise capacity nor PA parameters. Patients with severe asthma may have impaired cardiovascular reserve as established by DP, even when exercise capacity is indifferent from patients with milder disease. As an easy-to-assess parameter, DP may offer further information in the functional evaluation of these patients.

A smartphone-based algorithm comprising cough analysis and patient-reported symptoms identifies acute exacerbations of asthma: a prospective, double blind, diagnostic accuracy study

Objective: Early and accurate recognition of asthma exacerbations reduces the duration and risk of hospitalization. Current diagnostic methods depend upon patient recognition of symptoms, expert clinical examination, or measures of lung function. Here, we aimed to develop and test the accuracy of a smartphone-based diagnostic algorithm that analyses five cough events and five patient-reported features (age, fever, acute or productive cough and wheeze) to detect asthma exacerbations.Methods: We conducted a double-blind, prospective, diagnostic accuracy study comparing the algorithm with expert clinical opinion and formal lung function testing. Results: One hundred nineteen participants >12 years with a physician-diagnosed history of asthma were recruited from a hospital in Perth, Western Australia: 46 with clinically confirmed asthma exacerbations, 73 with controlled asthma. The groups were similar in median age (54yr versus 60yr, p=0.72) and sex (female 76% versus 70%, p=0.5). The algorithm’s positive percent agreement (PPA) with the expert clinical diagnosis of asthma exacerbations was 89% [95% CI: 76%, 96%]. The negative percent agreement (NPA) was 84% [95% CI: 73%, 91%]. The algorithm’s performance for asthma exacerbations diagnosis exceeded its performance as a detector of patient-reported wheeze (sensitivity, 63.7%). Patient-reported wheeze in isolation was an insensitive marker of asthma exacerbations (PPA=53.8%, NPA=49%). Conclusions: Our diagnostic algorithm accurately detected the presence of an asthma exacerbation as a point-of-care test without requiring clinical examination or lung function testing. This method could improve the accuracy of telehealth consultations and might be helpful in Asthma Action Plans and patient-initiated therapy.

Associations of multiple metals with lung function in welders by four statistical models

BackgroundExposure to heavy metals has been related to decreased lung function in workers. However, due to limitations in statistical methods for mixtures, previous studies mainly focused on single or several toxic metals, with few studies involving metal exposome and lung function. ObjectivesThe study aimed to evaluate the effects of co-exposure to the metal mixtures on multiple parameters of pulmonary function tests and to identify the elements that play an essential role in elastic-net regression (ENET), multivariate linear regression, bayesian kernel machine regression (BKMR), and quantile g-computation (QG-C) models. MethodsWe have recruited 186 welders from Anhui (China) in 2019. And their end-of-shift urine and lung function measure data were collected with informed consent. The urinary concentrations of 23 metals were measured by inductively coupled urinary mass spectrometry. The lung function measures including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and peak expiratory flow (PEF) were also detected as outcome indicators. Four statistical methods, ENET, multivariate linear regression, BKMR, and QG-C models were used to evaluate the associations of element mixtures on lung function comprehensively. ResultsLead and cadmium were negatively associated with FVC and FEV1, nickel and chromium were inversely associated with PEF, and strontium showed significant positive effects in linear regression models, which were consistent with the results in BKMR and QG-C models. Both BKMR and QG-C models showed a significantly negative overall effect of metal mixtures on lung function parameters (FVC, FEV1, and PEF). Meanwhile, BKMR showed the non-linear relationships of cadmium with FVC. ConclusionMulti-pollutant mixtures of metals were negatively associated with lung function. Lead, cadmium, nickel, and strontium might be crucial elements. Our findings highlight a need to prioritize workers' environmental health, and guide future research into the toxic mechanisms of metal-mediated lung function injury.

Correlation between lung function tests and peak oxygen consumption in post-TB lung disease.

BACKGROUND: After TB treatment, many patients have post-TB lung disease (PTLD), associated with increased mortality and morbidity. Nevertheless, relationships between lung function testing and exercise capacity in people with PTLD are poorly understood.METHODS: This single-centre study investigated the association between lung function testing and peak oxygen consumption (VO₂peak) and percentage-predicted VO₂peak (VO₂peak (%pred)) in adults with PTLD investigated for surgery.RESULTS: Eighty-two patients (52 males, 30 females) with a mean age of 43.2 years (SD 11.3) were included. Spirometric values of forced vital capacity (FVC) percentage predicted (%pred) and forced expiratory volume in 1 sec (FEV1) %pred suggested significant correlations with VO₂peak (%pred) (P < 0.001 and P < 0.001), whereas FEV1/FVC did not. Diffusing capacity for carbon monoxide (DLCO) %pred also correlated significantly with VO₂peak (%pred) (P = 0.002). However, the magnitude of all significant correlation coefficients were weak. No significant correlations for any plethysmographic values with VO₂peak (%pred) could be robustly concluded. Correlations with VO₂peak (ml/kg/min) for most physiological variables were less robust than for VO₂peak (%pred).CONCLUSIONS: Although statistically significant, the correlations between any measure of lung function and VO₂peak or VO₂peak (%pred) were weak, with only FVC correlation coefficient surpassing 0.50.

Functional and structural impairments of the pulmonary system in middle-aged people with cervical and upper thoracic spinal cord injuries

Objectives To describe functional and structural impairments of the pulmonary system in middle-aged people with cervical and upper thoracic spinal cord injuries (SCI), and compare findings to the general population. To determine if the neurological level of injury (NLI) is related to functional and structural impairments, and if age is related to structural impairments. Design Cross-sectional study with matched controls. Data from the Swedish SPinal Cord Injury Study on Cardiopulmonary and Autonomic Impairment (SPICA). Matched control data were obtained from the Swedish CArdioPulmonary bioImage Study (SCAPIS). Setting Outpatient SCI unit in southern Sweden. Participants 25 people (20% women, mean age 58 years, mean time since injury 28 years, NLIs C2-T6, American Spinal Injury Association Impairment Scale A-C). Interventions Not applicable. Outcome measures Lung function was assessed with spirometry, diffusing capacity and impulse oscillometry. Structural assessments were performed with computed tomography. Results Pulmonary function was generally worse compared to the controls. Structural impairments were common (75% of the participants and 65% of the controls; P = 0.36, NS). NLI was significantly related to some of the functional and structural impairments. Conclusions Middle-aged people with long-term cervical and upper thoracic SCI can have substantial pulmonary functional impairments, whereas structural impairments do not differ considerably from the general population. Further larger and longitudinal studies should focus on the clinical impact of these impairments over time.

Dupilumab Reduces Oral Corticosteroid Use in Patients With Corticosteroid-Dependent Severe Asthma: An Analysis of the Phase 3, Open-Label Extension TRAVERSE Trial

Many patients with severe asthma require chronic corticosteroid treatment to maintain asthma control. Are the reduction in oral corticosteroid (OCS) use and the clinical efficacy observed with dupilumab treatment maintained long-term in patients with severe OCS-dependent asthma? The LIBERTY ASTHMA TRAVERSE study (ClinicalTrials.gov identifier: NCT02134028) was a multinational, multicenter, single-arm, open-label extension study in patients≥ 12 years of age with asthma who participated in previous dupilumab studies. Treatment consisted of dupilumab 300mg every 2weeks for up to 96weeks. In this analysis, we present the data from patients who initially enrolled in the LIBERTY ASTHMA VENTURE study (ClinicalTrials.gov identifier: NCT02528214), a 24-week placebo-controlled study of dupilumab in patients with OCS-dependent severe asthma, and continued in the TRAVERSE study. The subgroups analyzed were: those who received dupilumab in both (dupilumab/dupilumab group) and those who received placebo in the VENTURE study and dupilumab in the TRAVERSE study (placebo/dupilumab group). Outcomes included OCS use, exacerbation rates, and measures of lung function and asthma control. Ninety patients treated with dupilumab/dupilumab and 97 patients treated with placebo/dupilumab in the VENTURE study were enrolled and treated in the TRAVERSE study, with a mean OCS dosage of 11.0mg/d (dupilumab) and 11.6mg/d (placebo) at VENTURE study baseline. At TRAVERSE week 0, the mean daily OCS dosage was 3.1mg/d and 6.4mg/d (percentage decrease from the VENTURE study baseline, 68.8%and 41.3%) for the dupilumab/dupilumab group and placebo/dupilumab group, respectively, and decreased to 2.2mg/d and 4.9mg/d (78.3%and 53.4%) at week 48 and to 1.2mg/d and 3.0mg/d (89.3%and 74.4%) at week 96, respectively. Exacerbation rates were low during the TRAVERSE study. Further improvements from the VENTURE to TRAVERSE studies also were seen in FEV1 and 5-item Asthma Control Questionnaire scores. Safety findings were consistent with the known dupilumab safety profile. In the open-label TRAVERSE study, dupilumab demonstrated the ability to sustain the OCS dosage reduction from the parent OCS-sparing study, while maintaining a low exacerbation rate and improved lung function. ClinicalTrials.gov; Nos.: NCT02134028 (TRAVERSE) and NCT02528214 (VENTURE); URL: www. gov.

Correlation of digital flow peak with spirometry in children with and without asthma

Introduction Spirometry and peak expiratory flow measurement (PEF) are combined during functional respiratory assessments. The new digital peak flow meter (DPM) evaluates the forced expiratory volume in the first second (FEV1) and PEF. Objective To compare lung function measurements using spirometry and DPM. Methods This cross-sectional analytical study assessed FEV1 and PEF in children with and without asthma. Statistical analysis was performed to assess the agreement between the measures using the intraclass correlation coefficient (ICC), Bland–Altman, and survival agreement plot. Results 125 (3–12 y) and 196 (6–18 y) children without and with asthma, respectively, were studied. In children without asthma, the ICC for FEV1 and PEF were 0.89 and 0.86, respectively, while the corresponding values were 0.87 and 0.79, respectively, in patients with asthma. The Bland–Altman method showed a difference of −0.4 to 0.5 for FEV1 in patients without asthma, with a tendency to increase as the FEV1 increased to a certain extent. In patients with asthma, the pattern was similar for FEV1, and the PEF had a greater dispersion than among those without asthma; however, a good agreement pattern was maintained. In the survival agreement plot, when accepting a tolerance of 0.150 mL for FEV1, there was an agreement of close to 55% in both groups. Likewise, when accepting a tolerance of 0.5 L/s for PEF, an agreement of close to 60% and 50% was observed in patients without and with asthma, respectively. Conclusion DPM was effective as a measure of lung function in pediatric patients with and without asthma.

Association between very to moderate preterm births, lung function deficits, and COPD at age 53 years: analysis of a prospective cohort study

Prematurity has been linked to reduced lung function up to age 33 years, but its long-term effects on lung function and chronic obstructive pulmonary disease (COPD) are unknown. To address this question, we investigated associations between prematurity, lung function, and COPD in the sixth decade of life using data from the Tasmanian Longitudinal Health Study (TAHS). Data were analysed from 1445 participants in the TAHS. Lung function was measured at 53 years of age. Gestational ages were very preterm (28 weeks to <32 weeks), moderate preterm (32 weeks to <34 weeks), late preterm (34 weeks to <37 weeks) and term (≥37 weeks). Linear and logistic regression models were fitted to investigate associations of prematurity with lung function measures (FEV1, forced vital capacity [FVC], FEV1/FVC ratio, forced expiratory flow at 25-75% of FVC [FEF25-75%], diffusing capacity for carbon monoxide [DLCO]) and COPD (post-bronchodilator FEV1/FVC less than the lower limit of normal), adjusting for sex, age, height, parental smoking during pregnancy, number of older siblings, maternal age at birth, and childhood socioeconomic status. Interactions with smoking and asthma were also investigated. Of 3565 individuals with available data on gestational age from the TAHS cohort, 1445 (41%) participants were included in this study, 740 (51%) of whom were female. Compared with term birth, very to moderate preterm birth was significantly associated with an increased risk of COPD at age 53 years (odds ratio 2·9 [95% CI 1·1-7·7]). Very-to-moderate preterm birth was also associated with lower post-bronchodilator FEV1/FVC ratio (beta-coefficient -2·9% [95% CI -4·9 to -0·81]), FEV1 (-190 mL [-339 to -40]), DLCO (-0·55 mmol/min/kPa [-0·97 to -0·13]), and FEF25-75% (-339 mL/s [-664 to -14]). The association between very-to-moderate preterm birth and FEV1/FVC ratio was only significant among smokers (pinteraction=0·0082). Similar findings were observed for moderate preterm birth when analysed as a separate group. Compared with term birth, late preterm birth was not associated with lower FEV1/FVC ratio or COPD. This is the first study to investigate the effect of prematurity on lung function into middle-age. Data show that very-to-moderate prematurity is associated with obstructive lung function deficits including COPD well into the sixth decade of life and that this effect is compounded by personal smoking. National Health and Medical Research Council (NHMRC) of Australia, European Union's Horizon 2020, The University of Melbourne, Clifford Craig Medical Research Trust of Tasmania, The Victorian, Queensland & Tasmanian Asthma Foundations, The Royal Hobart Hospital, Helen MacPherson Smith Trust, and GlaxoSmithKline.

Factors Predisposing the Response to Lumacaftor/Ivacaftor in People with Cystic Fibrosis.

Lumacaftor/ivacaftor (LUMA-IVA) therapy is prescribed to people with cystic fibrosis (pwCF) homozygous for the Phe508del-CFTR variant to restore CFTR protein function. There is, however, large inter-individual variability in treatment response. Here, we seek to identify clinical and/or genetic factors that may modulate the response to this CFTR modulator therapy. A total of 765 pwCF older than 12 years under LUMA-IVA therapy and with lung function and nutritional measurements available before and after treatment initiation were included. Response to treatment was determined by the change in lung function and nutritional status, from baseline and over the first two years after initiation, and it was assessed by weighted generalized estimating equation models. Gains in lung function and nutritional status were observed after 6 months of treatment (on average 2.11 ± 7.81% for percent predicted FEV1 and 0.44 ± 0.77 kg/m2 for BMI) and sustained over the 2 years. We observed that the more severe patients gained the most in lung function and nutritional status. While females started with a nutritional status more impaired than males, they had a larger response and regained BMI Z-score values similar to men after 2 years of treatment. We observed no association between variants in solute carrier (SLC) genes and the respiratory function response to LUMA-IVA, but the SLC6A14 rs12839137 variant was associated with the nutritional response. Further investigations, including other genomic regions, will be needed to fully explore the inter-individual variability of the response to LUMA-IVA.

Effect of indacaterol/glycopyrronium on ventilation and perfusion in COPD: a randomized trial

RationaleThe long-acting β2-agonist/long-acting muscarinic antagonist combination indacaterol/glycopyrronium (IND/GLY) elicits bronchodilation, improves symptoms, and reduces exacerbations in COPD. Magnetic resonance imaging (MRI) of the lung with hyperpolarized gas and gadolinium contrast enhancement enables assessment of whole lung functional responses to IND/GLY.ObjectivesThe primary objective was assessment of effect of IND/GLY on global ventilated lung volume (%VV) versus placebo in COPD. Lung function, regional ventilation and perfusion in response to IND/GLY were also measured.MethodsThis double-blind, randomized, placebo-controlled, crossover study assessed %VV and pulmonary perfusion in patients with moderate-to-severe COPD after 8 days of once-daily IND/GLY treatment (110/50 µg) followed by 8 days of placebo, or vice versa, using inhaled hyperpolarized 3He gas and gadolinium contrast-enhanced MRI, respectively. Lung function measures including spirometry were performed for each treatment after 8 days.Measurements and main resultsOf 31 patients randomized, 29 completed both treatment periods. IND/GLY increased global %VV versus placebo (61.73% vs. 56.73%, respectively, least squares means treatment difference: 5.00% [90% CI 1.40 to 8.60]; P = 0.025). IND/GLY improved whole lung index of ventilation volume to perfusion volume (V/Q) ratio versus placebo; 94% (90% CI 83 to 105) versus 86% (90% CI 75 to 97; P = 0.047), respectively. IND/GLY showed a trend to improve diffusing capacity for carbon monoxide (DLCO) (+ 0.66 mL/min/mmHg; P = 0.082). By Day 8, forced expiratory volume in 1 s (FEV1) was increased by 0.32 L versus placebo (90% CI 0.26 to 0.38; P < 0.0001), substantiating earlier findings and providing evidence of assay sensitivity for this trial.ConclusionsIND/GLY improved lung ventilation assessed by 3He MRI after 1 week of treatment. This observation may provide mechanistic support for the symptomatic clinical benefit shown with IND/GLY in COPD.Clinical trial registered with www.clinicaltrials.gov (NCT02634983).

Associations between lung function and physical and cognitive health in the Canadian Longitudinal Study on Aging (CLSA): A cross-sectional study from a multicenter national cohort.

Low lung function is associated with high mortality and adverse cardiopulmonary outcomes. Less is known of its association with broader health indices such as self-reported respiratory symptoms, perceived general health, and cognitive and physical performance. The present study seeks to address the association between forced expiratory volume in 1 second (FEV1), an indicator of lung function, with broad markers of general health, relevant to aging trajectory in the general population. From the Canadian general population, 22,822 adults (58% females, mean age 58.8 years [standard deviation (SD) 9.6]) were enrolled from the community between June 2012 and April 2015 from 11 Canadian cities and 7 provinces. Mixed effects regression was used to assess the cross-sectional relationship between FEV1 with self-reported respiratory symptoms, perceived poor general health, and cognitive and physical performance. All associations were adjusted for age, sex, body mass index (BMI), education, smoking status, and self-reported comorbidities and expressed as adjusted odds ratios (aORs). Based on the Global Lung Function Initiative (GLI) reference values, 38% (n = 8,626) had normal FEV1 (z-scores >0), 37% (n = 8,514) mild (z-score 0 to > -1 SD), 19% (n = 4,353) moderate (z-score -1 to > -2 SD), and 6% (n = 1,329) severely low FEV1 (z-score = < -2 SD). There was a graded association between lower FEV1 with higher aOR [95% CI] of self-reported moderate to severe respiratory symptoms (mild FEV1 1.09 [0.99 to 1.20] p = 0.08, moderate 1.45 [1.28 to 1.63] p < 0.001, and severe 2.67 [2.21 to 3.23] p < 0.001]), perceived poor health (mild 1.07 [0.9 to 1.27] p = 0.45, moderate 1.48 [1.24 to 1.78] p = <0.001, and severe 1.82 [1.42 to 2.33] p < 0.001]), and impaired cognitive performance (mild 1.03 [0.95 to 1.12] p = 0.41, moderate 1.16 [1.04 to 1.28] p < 0.001, and severe 1.40 [1.19 to 1.64] p < 0.001]). Similar graded association was observed between lower FEV1 with lower physical performance on gait speed, Timed Up and Go (TUG) test, standing balance, and handgrip strength. These associations were consistent across different strata by age, sex, tobacco smoking, obstructive, and nonobstructive impairment on spirometry. A limitation of the current study is the observational nature of these findings and that causality cannot be inferred. We observed graded associations between lower FEV1 with higher odds of disabling respiratory symptoms, perceived poor general health, and lower cognitive and physical performance. These findings support the broader implications of measured lung function on general health and aging trajectory.

Predicting Pulmonary Function From the Analysis of Voice: A Machine Learning Approach.

IntroductionTo self-monitor asthma symptoms, existing methods (e.g. peak flow metre, smart spirometer) require special equipment and are not always used by the patients. Voice recording has the potential to generate surrogate measures of lung function and this study aims to apply machine learning approaches to predict lung function and severity of abnormal lung function from recorded voice for asthma patients.MethodsA threshold-based mechanism was designed to separate speech and breathing from 323 recordings. Features extracted from these were combined with biological factors to predict lung function. Three predictive models were developed using Random Forest (RF), Support Vector Machine (SVM), and linear regression algorithms: (a) regression models to predict lung function, (b) multi-class classification models to predict severity of lung function abnormality, and (c) binary classification models to predict lung function abnormality. Training and test samples were separated (70%:30%, using balanced portioning), features were normalised, 10-fold cross-validation was used and model performances were evaluated on the test samples.ResultsThe RF-based regression model performed better with the lowest root mean square error of 10·86. To predict severity of lung function impairment, the SVM-based model performed best in multi-class classification (accuracy = 73.20%), whereas the RF-based model performed best in binary classification models for predicting abnormal lung function (accuracy = 85%).ConclusionOur machine learning approaches can predict lung function, from recorded voice files, better than published approaches. This technique could be used to develop future telehealth solutions including smartphone-based applications which have potential to aid decision making and self-monitoring in asthma.

Pulmonary function testing for the diagnosis of asthma in preschool children.

To highlight the recent evidence of the lung function techniques used in preschool children to diagnose asthma. Several techniques are available to measure lung function and airway inflammation in preschool children, including spirometry (from age 5 years), impulse oscillometry (>3 years), whole-body plethysmography (>3 years), fractional exhaled nitric oxide (FeNO) (>5 years), multiple breath washout (>3 years), structured light plethysmography (>1-2 years) and impedance pneumography (>1 years). If applicable, measuring forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) ratio using spirometry is useful (cut-off < 80% predicted or below lower limit of normal [LLN] defined as z-score < -1.64) for diagnosing preschool asthma. For those unable to perform spirometry, whole-body plethysmography (sRaw > 1.6 kPa/s) and impulse oscillometry (Rrs and Xrs at 5 Hz z-score > 2) may be useful. Adding a bronchodilator reversibility test (FEV1 increase > 12%, sRaw decrease > 25-30%, Rrs at 5 Hz decrease > 40%) or a bronchial challenge test, for example, exercise test (FEV1 decrease > 10%), may improve the sensitivity of these tests. Elevated FeNO (>25-35 ppb) is a promising adjunctive test for diagnosing preschool asthma. With trained personnel, lung function testing can be done with high reliability even in children between 2 and 4 years of age. To avoid over and undertreatment of asthma, objective measurement of lung function is clinically important in preschool children.

Diet, Asthma, and Severe Asthma Exacerbations in a Prospective Study of Puerto Rican Youth

Poor diet quality may contribute to the disproportionate asthma burden in Puerto Rican youth. To examine whether an unhealthy diet at one or two study visits conducted over about 5 years was associated with asthma, severe asthma exacerbations, and worse lung function in Puerto Rican youth. This was a prospective study of 406 Puerto Rican youth aged 6 to 14 years at a baseline visit and 9 to 20 years at a follow-up visit. As in prior work, diet was assessed using a dietary score ranging from -2 to+2. The exposure of interest was an unhealthy diet, defined as a nonpositive dietary score (0 to -2) at one or both visits. Outcomes of interest were asthma (defined as physician-diagnosed asthma and one of more episode of wheeze in the year before the second visit), one or more severe asthma exacerbation in the year before the second visit, and change in percent predicted lung function measures (FEV1, FVC, and FEV1/FVC) between the first and second visits. In a multivariable analysis, an unhealthy diet at both visits was associated with increased odds of asthma (adjusted odds ratio= 3.38; 95% confidence interval, 1.74-6.57) and severe asthma exacerbations (adjusted odds ratio= 2.65; 95% confidence interval, 1.16-6.03), but not with change in lung function. An unhealthy diet at both visits was associated with increased odds of asthma and severe asthma exacerbations, compared with a healthy diet at both visits. Our findings support health policies promoting a healthy diet in Puerto Rican youth, a population at high risk for asthma.

Differences and agreement between two portable hand-held spirometers across diverse community-based populations in the Prospective Urban Rural Epidemiology (PURE) study.

Portable spirometers are commonly used in longitudinal epidemiological studies to measure and track the forced expiratory volume in first second (FEV1) and forced vital capacity (FVC). During the course of the study, it may be necessary to replace spirometers with a different model. This raise questions regarding the comparability of measurements from different devices. We examined the correlation, mean differences and agreement between two different spirometers, across diverse populations and different participant characteristics. From June 2015 to Jan 2018, a total of 4,603 adults were enrolled from 628 communities in 18 countries and 7 regions of the world. Each participant performed concurrent measurements from the MicroGP and EasyOne spirometer. Measurements were compared by the intra-class correlation coefficient (ICC) and Bland-Altman method. Approximately 65% of the participants achieved clinically acceptable quality measurements. Overall correlations between paired FEV1 (ICC 0.88 [95% CI 0.87, 0.88]) and FVC (ICC 0.84 [0.83, 0.85]) were high. Mean differences between paired FEV1 (-0.038 L [-0.053, -0.023]) and FVC (0.033 L [0.012, 0.054]) were small. The 95% limits of agreement were wide but unbiased (FEV1 984, -1060; FVC 1460, -1394). Similar findings were observed across regions. The source of variation between spirometers was mainly at the participant level. Older age, higher body mass index, tobacco smoking and known COPD/asthma did not adversely impact on the inter-device variability. Furthermore, there were small and acceptable mean differences between paired FEV1 and FVC z-scores using the Global Lung Initiative normative values, suggesting minimal impact on lung function interpretation. In this multicenter, diverse community-based cohort study, measurements from two portable spirometers provided good correlation, small and unbiased differences between measurements. These data support their interchangeable use across diverse populations to provide accurate trends in serial lung function measurements in epidemiological studies.

Mucus Plugs Persist in Asthma, and Changes in Mucus Plugs Associate with Changes in Airflow over Time.

Rationale: Cross-sectional analysis of mucus plugs in computed tomography (CT) lung scans in the Severe Asthma Research Program (SARP)-3 showed a high mucus plug phenotype. Objectives: To determine if mucus plugs are a persistent asthma phenotype and if changes in mucus plugs over time associate with changes in lung function. Methods: In a longitudinal analysis of baseline and Year 3 CT lung scans in SARP-3 participants, radiologists generated mucus plug scores to assess mucus plug persistence over time. Changes in mucus plug score were analyzed in relation to changes in lung function and CT air trapping measures. Measurements and Main Results: In 164 participants, the mean (range) mucus plug score was similar at baseline and Year 3 (3.4 [0-20] vs. 3.8 [0-20]). Participants and bronchopulmonary segments with a baseline plug were more likely to have plugs at Year 3 than those without baseline plugs (risk ratio, 2.8; 95% confidence interval [CI], 2.0-4.1; P < 0.001; and risk ratio, 5.0; 95% CI, 4.5-5.6; P < 0.001, respectively). The change in mucus plug score from baseline to Year 3 was significantly negatively correlated with change in FEV1% predicted (rp = -0.35; P < 0.001) and with changes in CT air trapping measures (all P values < 0.05). Conclusions: Mucus plugs identify a persistent asthma phenotype, and susceptibility to mucus plugs occurs at the subject and the bronchopulmonary segment level. The association between change in mucus plug score and change in airflow over time supports a causal role for mucus plugs in mechanisms of airflow obstruction in asthma.

Clinical Validation of the Spirohome Clinic Ultrasonic Spirometer in Child and Adolescent Patients.

BackgroundSpirometers are critical devices that reveal the respiratory dynamics caused by respiratory problems and their severity and facilitate their diagnosis and follow-up. Hand-held spirometers have emerged relatively recently and offer several advantages over conventional desktop systems. There remains, however, a need for reassurance of high-quality spirometry testing with next-generation portable spirometers that connect over Bluetooth® to smart device applications. In this study, we examine the accuracy and repeatability of lung function measurements of a novel hand-held ultrasonic spirometer, the Spirohome Clinic and compare its clinical performance to a reference device, the EasyOne Air.MethodsBenchtop validation of the spirometers was conducted using a lung simulator device according to ATS/ERS guidelines and the ISO 26782 standard waveforms. Subsequently, 48 volunteers (pediatric patients between 6 and 11 years of age and adolescent patients between 12 and 18 years of age) performed spirometry with both the Spirohome Clinic and the EasyOne Air spirometer during their clinic visits. Spirometric data including repeated FEV1, FVC, FEV6, FEF25-75, and PEF measurements were collected.ResultsBoth the Spirohome Clinic and the EasyOne Air successfully passed requirements for accuracy stated in relevant guidelines and standards for spirometry. The only statistically significant (p<0.05) difference was for FVC measurement accuracy. Clinical comparisons revealed strong correlation between spirometers in the measurement of key pulmonary function parameters including FEV1 and FVC with a Pearson's correlation coefficient of 0.99. Bland–Altman plots showed good agreement between mean differences of FEV1 and FVC with the majority measurements remaining between the limits of 95% agreement for both the entire patient cohort and also in age and gender subsets.ConclusionThe present study demonstrated that the Spirohome Clinic spirometer conforms to ATS/ERS performance requirements and validates the clinical comparability of its measurement accuracy and repeatability to the EasyOne Air. These findings support the indicated use of the Spirohome Clinic for high-quality lung function testing in clinical settings.

Lung function at school age in infants with lower respiratory tract infections with and without wheezing: A birth cohort study.

To evaluate the relationship between lower respiratory tract infections (LRTI), in the first 2 years of life and lung function at school age in the Piccolipiù birth cohort (Italy). Data on LRTI (doctor diagnosis of bronchitis, bronchiolitis, pneumonia) and wheezing (≥3 episodes or a diagnosis of asthmatic bronchitis) in the first 2 years of life were obtained from parental questionnaires. Lung function was assessed at 7 years by spirometry and forced volume vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, forced expiratory flow between 25% and 75%, and at 75% of FVC (FEF25-75 and FEF75 ) were reported as Z-scores. The associations between LRTI and spirometric variables were estimated with linear regression models. Among 877 children studied, 22.1% had LRTI only, 5.4% wheezing only, 13.2% had both, and 59.3% had neither LRTI nor wheezing. Children with LRTI had lower FVC and FEV1 than children without (Z-score differences: -0.18 [95% confidence intervals: -0.31; -0.06] and -0.15 [-0.27; -0.03]). When children were stratified by history of both LRTI and wheezing, there was no association between LRTI only and spirometric values. Conversely, having had both LRTI and wheezing was inversely associated with all lung function measures: Z-score differences of -0.24 (-0.42; -0.07); -0.42 (-0.59; -0.24); -0.25 (-0.41; -0.08); -0.37 (-0.54; -0.21); -0.30 (-0.46; -0.14) for FVC, FEV1, FEV1 /FVC, FEF25-75 and FEF75, respectively. Infants with wheezing and LRTI, but not those with LRTI only, had reduced lung function at school-age.

Regional ventilation distribution in patients with scoliosis assessed by electrical impedance tomography: Is individual thorax shape required?

BackgroundElectrical impedance tomography (EIT) is a non-invasive non-radiological regional lung function measurement. The aim of the study was to examine the feasibility of assessing ventilation distribution with EIT in scoliosis patients using generic and individual thorax shape. MethodsEight subjects were measured with EIT before scoliosis surgery. Reconstructions with two different forward models were compared: the generic shape and the individual thorax shapes. Three EIT-based parameters measuring ventilation distribution were calculated: left lung to overall ratio, center of ventilation (CoV), global inhomogeneity index. ResultsEIT measurements were successfully conducted in all subjects. No statistical differences were found in the EIT-based parameters using the different reconstruction models. CoV based on the generic shape was significantly correlated to the main Cobb angle (r=-0.84, p < 0.01). ConclusionIt was feasible to monitor regional ventilation distribution in scoliosis patients with EIT. Individual thorax shapes might not be required for reliable patient assessment in a clinical setting.

Evaluation of Peak Expiratory Flow Rates (Pefr) among Healthy Children of Khairpur Mir’s City of Pakistan: A Cross-Sectional Study

Aim:To assess the peak expiratory flow rates (PEFR) among healthy children aged 6 to 12 years Study design: A cross-sectional study Place and Duration: This Study was conducted at Gambat Medical College Khairpur Mir’s, Pakistan from April 2019 to March 2020. Methodology: A study using a random sampling technique was conducted in primary schools. Healthy school children of either gender ages 6 to 12 years were enrolled in the study. An EU scale peak flow meter measured PEFR (60-800 l/min). While standing, their PEFR was determined. A total of three readings were taken, with the highest value being recorded. SPSS version 21 was used for statistical analysis. Results: Boys made up 56.15 percent (n=278) of the 495 participants. PEFR was measured at a minimum of 6 years old and a maximum of 12 years old in both genders. Boys aged 6 to 12 years had a PEFR of 179.71 ± 30.67 (L/Min), whereas girls had a PEFR of 159.15 ± 25.77 (L/Min). There was no discernible difference between genders and age categories (t=0.912, P=0.189). Conclusion: Mean PEFR values may vary between gender and age. PEFR results from this study can be utilized as a clinical reference for children aged 6 to 12 years of age. Clinicians can use these PEFR values to measure lung function and airway obstruction in this population subset. Keywords: Age, Gender, Lung Function Test, Peak Expiratory Flow Rates