Percentage Change In FEV1 Research Articles

A comparative study of bronchodilator response: utilizing pre-bronchodilator versus predicted normal values

BackgroundA positive bronchodilator response has been defined as a 12% increase in the forced expiratory volume in one second (FEV1) or forced vital capacity (FVC) from their respective pre-bronchodilator values, combined with at least a 0.2 L absolute change. Recent recommendations suggested the use of the percent change in FEV1 and FVC relative to their predicted normal values without having applied them in patients with airflow obstruction. The aim of the current study was to compare the two approaches over a wide range of pre-bronchodilator FEV1 and FVC values.MethodsA retrospective review of consecutive patients undergoing spirometry and bronchodilator testing was completed. The change in FEV1 and FVC with a bronchodilator was expressed relative to the pre-bronchodilator and predicted normal FEV1 and FVC.ResultsIn 1,040 patients with a non-paradoxical change in FEV1, 19.0% had a ≥ 12% change in FEV1 using their pre-bronchodilator value compared to 5.7% using their predicted normal value. For FVC, the respective values were 12.7% vs. 5.8%. The difference was retained in patients with a ≥ 0.2 L change in FEV1 or FVC. In unobstructed patients, the upper threshold (two standard deviations above the mean) of the bronchodilator response was 14% for FEV1 and 10% for FVC using predicted normal values.ConclusionsExpressing the percent change in FEV1 and FVC relative to predicted normal values reduces the over-estimation of the bronchodilator response, especially in patients with a very low pre-bronchodilator FEV1, including in those with a ≥ 0.2 L change in FEV1. Irrespective of pre-bronchodilator values, a ≥ 14% change in FEV1 and ≥ 10% change in FVC relative to the predicted normal values could be considered a positive bronchodilator response.

Risk Factors of Rapid FEV1 Decline in a Real-World Chronic Obstructive Pulmonary Disease Cohort

Background: Rapid forced expiratory volume in 1 s (FEV₁) decliners have been considered a unique subgroup of patients with chronic obstructive pulmonary disease (COPD). Rapid FEV₁ decline manifests early and is associated with poor prognosis. This necessitates the pre-emptive identification of risk factors for rapid FEV₁ decline. Objectives: We aimed to determine the risk factors and clinical outcomes in patients with COPD. Methods: This longitudinal, observational study was based on the Korea COPD Subgroup Study cohort (NCT02800499) from January 2012 to December 2019 across 54 medical centers in South Korea. Eligible patients were followed up for 3 years with serial spirometric tests. We calculated the annualized percentage change in FEV₁ from baseline. Rapid decliners were defined as the quartile of patients with the highest annualized percentage FEV₁ decline. Results: Of the 518 patients, 130 were rapid decliners who lost 6.2%/year and 100 mL/year of FEV₁. The multivariable logistic regression identified male sex, current smoking, blood eosinophil count <150/µL, and high forced vital capacity as the independent risk factors for rapid FEV₁ decline. Among rapid decliners, the lung function deteriorated more rapidly in current smokers and patients with severe dyspnea, while triple combination therapy attenuated lung function decline in comparison with mono-bronchodilator therapy. Rapid decliners had a higher rate of severe exacerbation than nonrapid decliners (0.2/year vs. 0.1/year, p value = 0.032). Conclusions: We identified the independent risk factors for rapid FEV₁ decline. This information may assist physicians in the early detection and pertinent management of rapid decline among patients with COPD.

Exercise induced bronchodilation: a phenomenon more common, greater magnitude and more prolonged in older adults than in adolescents

Objective There are few studies in clinically healthy subjects describing and quantifying exercise-induced bronchodilation (EIBd). This study aimed to describe and compare the magnitude and time course changes in post-exercise forced expired volume at the first second (FEV1) in healthy adolescents, younger adults, and older adults. Methods Adolescent (n = 73, aged 10–17 years), younger adult (n = 35, aged 18–25 years), and older adult (n = 25, aged 35–66 years) subjects with normal spirometry z-scores completed a maximal cardiopulmonary exercise test using the standardized exponential exercise test protocol on a cycle ergometer performed at stable temperature and humidity. Spirometry was performed pre-exercise and at 1-, 3-, 5-, and 10-minutes post-exercise to determine the percentage change in FEV1 compared to baseline. EIBd was defined as a ≥ 5% increase in post-exercise FEV1. Results Increases in FEV1 at one-minute post-exercise were observed in the adolescents (1.3%) and young adults (6.0%) with FEV1 returning to baseline after ten minutes. Compared to the adolescents, the older adults showed significantly greater and sustained increases in FEV1 at 1-, 3-, 5-, and 10-minutes post-exercise (6.4, 4.6, 4.7, and 3.8%, p < 0.05). At 1-minute post exercise a significantly greater proportion of younger adults (54%, p < 0.01) and older adults (64%, p < 0.01) demonstrated EIBd compared to the adolescent group (15%). Conclusion Healthy older adults had a higher prevalence, greater magnitude and more prolonged EIBd compared to healthy adolescent and young adult subjects.

Efficacy of a house dust mite sublingual immunotherapy tablet as add-on dupilumab in asthma with rhinitis

BackgroundHDM SLIT is one of the disease-modifying treatment for allergic asthma, and has demonstrated efficacy in clinical trials. Dupilumab, blocks IL-4 and IL-13 signaling, key drivers of type 2 inflammation, and is approved for patients with uncontrolled, moderate-to-severe asthma. The aim of this study was to evaluate outcomes after HDM SLIT initiation in asthma with rhinitis not optimally controlled with dupilumab in a real-world setting. MethodsAt baseline and 48 weeks after treatment, asthma control questionnaire (ACQ)-5, asthma quality of life questionnaire (AQLQ) and rhinoconjunctivitis quality of life questionnaire (RQLQ) were assessed. Spirometry, type 2 inflammatory biomarkers and quantitative computed tomographic parameters of airway remodeling were also collected. ResultsOf 47 patients received HDM SLIT and 41 completed the study. Combined HDM SLIT and dupilumab improved ACQ-5 (p < 0.05), AQLQ (p < 0.05), RQLQ (p < 0.05), and increased lung function and reduced FeNO (p < 0.05) and airway percentage wall area, and wall thickness (each, p < 0.05). The change in ACQ-5 and AQLQ score correlated with both changes in FeNO and FEV1 percent predicted. Multiple regression analysis showed that the change in FEV1 percent predicted was independent factor for improvement of AQLQ (r2 = 0.510, p = 0.012). Based on ROC analysis for predicting SLIT responders, the baseline area under the curves in serum HDM specific-IgE, total IgE and FEV1 percent predicted were high (>0.8). ConclusionsThese results support the benefits of adding HDM SLIT to pharmacotherapy plus dupilumab in uncontrolled asthma with rhinitis.

Longitudinal Changes in Spirometry in Deployed Air Force Firefighters.

Inhalational exposures are common among service members who deploy to southwest Asia. The objective of this study is to determine if deployed Air Force firefighters have any decline in spirometry related to deployment. This study is a retrospective chart review. The database search identified 302 firefighters with documentation of two separate spirometry examinations. For deployed firefighters, mean change in forced expiratory volume at 1 second (FEV1) percent predicted was -1.01 ± 7.86, forced vital capacity (FVC) was -0.46 ± 10.26 predicted, and mid-expiratory flow (FEF25-75) was -0.13 ± 12.97. For firefighters who had never deployed, mean change in FEV1 percent predicted was +0.08 ± 7.09, FVC was +0.72 ± 7.75, and FEF25-75 was -0.66 ± 16.17. There does not appear to be evidence that deployment causes a significant change in lung function as measured by spirometry.

Airway closing index in school-age children during exercise bronchoprovocation

Objective Airway Closing Index (ACI), the ratio of % change in FVC to % change in FEV1 with bronchoprovocation, may represent changes in airflow due to airway closure, as opposed to airway narrowing. The objective of this study was to evaluate ACI during exercise bronchoprovocation (EB) in children. Methods Children, 6 to 18 years of age, who underwent EB using a stationary bicycle ergometer over a 6-year period were reviewed. Pulmonary function, including ACI, in patients with a positive exercise challenge, defined as ≥10% decrease in FEV1 following exercise, were compared to patients with a negative challenge. Results A total of 1030 children with a median age of 13 (IQR 11–15) underwent EB, of which 376 (37%) had a positive exercise challenge. There was wide variability in ACI, with a median of 0.75 (0.28–1.21). Median ACI in those with a positive test was 0.68 (IQR 0.41–0.93) compared to 0.84 (IQR 0.09–1.06) for those with a negative test, p = 0.017. Median ACI was higher in older children (p < 0.001) and females (p < 0.0001). Median percent change in FEV1 following bronchodilator for children in the highest quintile for ACI was 4.5 (IQR 1.3–8.1) compared to 5.5 (IQR 2–9.2) for children in the lowest quintile, p = 0.04. Conclusions There is wide variability in the ACI in children undergoing EB. ACI was lower in children with a positive challenge, the significance is unknown. Children with higher ACI may have increased airway closure with bronchoprovocation, and less response to bronchodilators.

Aerosolized lancovutide in adolescents (≥12 years) and adults with cystic fibrosis – a randomized trial

BackgroundLancovutide activates a chloride channel (TMEM-16A) other than the cystic fibrosis (CF) transmembrane conductance regulator protein and could benefit CF patients. MethodsIn this randomized, multi-center, double-blind, placebo-controlled, parallel-group trial 161 patients ≥12 years with a confirmed diagnosis of CF were randomized to either placebo (saline) or active drug in 3 different dosing schemes of 2.5mg inhaled lancovutide (once daily, every other day or twice a week) for eight weeks. The primary endpoint was the change in the forced expiratory volume in 1 second (FEV1) percent predicted. Secondary endpoints included further lung function parameters (FEV1 (absolute), functional vital capacity percent predicted, forced expiratory flow percent predicted, pulse oximetry), quality of life assessment, pulmonary exacerbations, hospitalization due to pulmonary exacerbations, time to first pulmonary exacerbation, duration of anti-inflammatory, mucolytic or antibiotic treatment, and safety. ResultsThere was no significant difference in the change in FEV1 percent predicted, quality of life, other lung function parameters, pulmonary exacerbations or requirement of additional treatment between groups. Overall, the inhalation of lancovutide was safe although a higher rate of adverse events, especially related to the respiratory system, occurred as compared to placebo. ConclusionsLancovutide did not improve FEV1 percent predicted when compared to placebo (NCT00671736).

A European Multi‐Center, Randomized, Double‐Blind Trial of Pirfenidone in Bronchiolitis‐Obliterans‐Syndrome Grade 1‐3 in Lung Transplant Recipients (European Trial of Pirfenidone in BOS (EPOS))

Bronchiolitis obliterans syndrome (BOS), the most common form of chronic lung allograft dysfunction (CLAD), and the major limitation to long-term survival after lung transplantation. BOS affects up to 50% of lung transplant recipients within 5 years after transplant, causing significant morbidity and mortality. BOS manifesting early after transplantation shows a poorer prognosis than late-onset BOS. There are only few studies assessing treatment efficacy, but only a minority of patients respond to current treatment options. From trans-bronchial surveillance biopsies and autopsies from diseased transplant recipients, the BOS lesions reveal interstitial fibrosis, which suggest the possible use of anti-fibrotic agent like Pirfenidone. We hypothesized that there is a statistically significant difference between randomized study groups in the change in FEV1 from baseline to 6 months. This trial is investigator-initiated and including nine European expert lung transplant centers. Patients with new onset progressive BOS were randomized in a 1:1 ratio to receive either Pirfenidone or the matching placebo treatment for 6 months. Progressive BOS was defined by the following: at least 3 FEV1-measurements in the last 6 months, each at least 3 weeks apart, a total decline of at least 200ml in FEV1, and a mean decline of at least 50 ml in the last two measurements, as well as the exclusion of other reasons for FEV1 decline by an expert panel. All patients had to be on at least 250mg Azithromycin 3 times a week for at least 4 weeks prior to inclusion. A total of 80 patients were planned included in the study 40 in each group. The primary endpoint is to evaluate the effect of Pirfenidone on the change in FEV1 (ml) over 6 months in lung transplant recipients with BOS, who are treated with Azithromycin. Secondary endpoints are as follows; Categorical percentage change in FEV1, Change in FVC, Change in TLC, Change in FEV1/FVC ratio, Number of patients with treatment failure, Change in BOS grade, Change in percent predicted diffusion capacity (DLco), Change in functional level as assessed by 6MWT, Hospital admission for any reason, Death or re-transplantation rates, Change in quality of life assessed by EQ5D.

Breath Carbon Monoxide Concentration”, An Indicator of Early Airway Inflammation in Asymptomatic Smokers

&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Measurement of carbon monoxide(CO) concentration in expired air canbe used for detecting and monitoring cytokine mediated inflammation and oxidative stress in the respiratory tract of smokers if smokers are made to abstain from smoking for 8 hrs. Total 48 apparently healthy male volunteers (24 were asymptomatic male tobacco smokers and rest 24 were healthy non-smoker males) with age between 18–25 years participated in the study. Exhaled CO level measured by the breath CO analyzer.&#x0D; Baseline Pulmonary function test(PFT) was done using RMS Helios Series Computer based Spirometer. Exercise challenge test was doneusing treadmill and PFT was recorded immediately, 5min., 10min. and 20min. of recovery period. Comparison of lung function before and after exercise in healthy volunteers and asymptomatic smokers respectively was done using paired t test. Correlation between post exercise percentage change in FEV1 and exhaled COwas seen using Pearson's coefficient of correlation. A negative correlation was found between CO concentration in exhaled breath and improvement in FEV1 after exercise challenge test. Hence, Breath CO analyser can be used to measure endogenous CO in so called “healthy smokers” as a tool to detect early inflammation and also to motivate them to quit smoking before the disease becomes irreversible.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

Asthma control test reflects not only lung function but also airway inflammation in children with stable asthma

Objective: Various numerical asthma control tools have been developed to distinguish different levels of symptom control. We aimed to examine whether the asthma control test (ACT) is reflective of objective findings such as lung function, fractional exhaled nitric oxide (FeNO) and laboratory data in patients with stable asthma.Methods: We included patients who were enrolled in the Korean Childhood Asthma Study. ACT, spirometry, blood tests and FeNO were performed in patients after stabilization of their asthma. We examined differences among spirometry parameters, blood tests and FeNO according to control status as determined by ACT and investigated for any significant correlations.Results: The study population consisted of 441 subjects. Spirometry showed that forced expiratory volume in one second (FEV1), forced expiratory flow between 25% and 75% of forced vital capacity and FEV1/forced vital capacity were all significantly higher in the controlled asthma group. Likewise, FeNO and percent-change in FEV1 were both significantly lower in the controlled asthma group. In blood tests, the eosinophil fraction was significantly lower in the controlled asthma group while white blood cell count was significantly higher in the controlled asthma group. Lastly, among the various factors analyzed, only provocative concentration of methacholine causing a 20% fall in FEV1 significantly correlated with ACT score.Conclusion: ACT is useful as part of the routine evaluation of asthmatic children and should be used as a complement to existing tools such as spirometry and FeNO measurement.

GLCCI1 Polymorphism rs37973 and Response to Treatment of Asthma With Inhaled Corticosteroids.

The response to asthma treatment is highly variable, and having pharmacogenetic markers that predict response to treatment would bring us one step closer to personalized treatment. Genome-wide association studies have shown that polymorphisms in GLCCI1 could be associated with the response to inhaled corticosteroids (ICSs) in asthma patients. We genotyped rs37973 in GLCCI1 in 208 adult asthma patients treated with ICSs. The percentage change in FEV1, % predicted was analyzed after short-term treatment (3 months) and long-term treatment (at least 3 years). Treatment was defined as successful when FEV1 decreased by <30 mL/year. After 3 months of treatment, FEV1, % predicted was higher in patients with the GG genotype than in patients with the AG+AA genotype, and this genotype-dependent difference was only evident in nonsmokers. Similar results were found in nonsmokers and patients with atopy after at least 3 years of treatment, when all patients were analyzed. Even though no differences were observed for success of treatment (good vs poor response) when the whole group of patients was analyzed, genotype-dependent treatment success was highly influenced by smoking and atopy. The GG genotype was overrepresented in nonsmokers and patients with atopy and a good response. rs37973 was associated with response to short- and long-term treatment; however, smoking and atopy had a considerable effect on pharmacogenetic association. Furthermore, in contrast with findings from genome-wide association studies, we found the GG genotype to be associated with better treatment response.

Vancomycin Versus Vancomycin Plus Rifampin for the Treatment of Acute Pulmonary Exacerbations of Cystic Fibrosis.

This study aimed to compare the change in pulmonary function in children and adolescents with cystic fibrosis (CF) who were infected with methicillin-resistant Staphylococcus aureus (MRSA) treated with either vancomycin (VAN) alone or vancomycin plus rifampin (VAN-RIF). Included patients were ages 6 to 20 years; hospitalized for an acute pulmonary exacerbation (APE) of CF from May 1, 2012, to April 30, 2014; had a respiratory tract culture positive for MRSA within 1 month of index hospital admission; received at least 48 consecutive hours of VAN or VAN-RIF; and had admission and discharge pulmonary function tests. The primary end point was change in percent predicted forced expiratory volume in 1 second (FEV1). A total of 39 encounters met inclusion criteria: 24 in the VAN group (mean age 15.1 years) and 15 in the VAN-RIF group (mean age 13.7 years). There were no between-group differences in mean percent change in FEV1 (32.6% ± 28.8% vs. 21.1% ± 12.1%; p = 0.091), mean percent change in forced vital capacity (22.6% ± 25.8% vs. 14% ± 9.4%; p = 0.127), or return to baseline FEV1 (20 [83.3%] vs. 14 [93.3%] patients; p = 0.631). Median (IQR) length of stay (13 days [11-14 days] vs. 13 days [9-14 days]; p = 0.6) and median (IQR) time to readmission (82 days [43-129 days] vs. 147 days [78-219 days]; p = 0.2) were similar between the VAN and VAN-RIF groups, respectively. Vancomycin monotherapy appears to be adequate when treating APEs of CF in children and adolescents with moderate lung disease and high MRSA VAN minimum inhibitory concentrations. Therefore, the addition of RIF may be unnecessary; however, larger studies are needed to confirm these findings.

Pulmonary function disparities exist and persist in Hispanic patients with cystic fibrosis: A longitudinal analysis.

Hispanic patients with cystic fibrosis (CF) have decreased life expectancy compared to non-Hispanic white patients. Pulmonary function is a main predictor of life expectancy in CF. Ethnic differences in pulmonary function in CF have been understudied. The objective was to compare longitudinal pulmonary function between Hispanic and non-Hispanic white patients with CF. This cohort study of 15 018 6-25 years old patients in the CF Foundation Patient Registry from 2008 to 2013 compared FEV1 percent predicted and longitudinal change in FEV1 percent predicted in Hispanic to non-Hispanic white patients. We used linear mixed effects models with patient-specific slopes and intercepts, adjusting for 14 demographic and clinical variables. We did sub-analyses by CFTR class, F508del copies, and PERT use. Hispanic patients had lower FEV1 percent predicted (79.9%) compared with non-Hispanic white patients (85.6%); (-5.8%, 95%CI -6.7% to -4.8%, P < 0.001), however, there was no difference in FEV1 decline over time. Patients on PERT had a larger difference between Hispanic and non-Hispanic white patients in FEV1 percent predicted than patients not on PERT (-6.0% vs -4.1%, P = 0.02). The ethnic difference in FEV1 percent predicted was not statistically significant between CFTR classes (Class I-III: -6.1%, Class IV-V: -5.9%, Unclassified: -5.7%, P > 0.05) or between F508del copies (None: -7.6%, Heterozygotes: -5.6%, Homozygotes: -5.3%, P > 0.05). Disparities in pulmonary function exist in Hispanic patients with CF early in life and then persist without improving or worsening over time. It is valuable to investigate the factors contributing to pulmonary function in Hispanic patients with CF.

Drop in lung function during asthma and COPD exacerbations - can it be assessed without spirometry?

BackgroundWhen assessing patients with exacerbation of asthma or COPD, it may be useful to know the drop in forced expiratory volume in 1 second (FEV1) compared with stable state, in particular when considering treatment with oral corticosteroids. The objective of the study was to identify indicators of drop in FEV1 during exacerbations.MethodsIn this prospective multicenter study from primary care, patients diagnosed with asthma or COPD were examined at stable state and during exacerbations the following year. Symptoms, chest findings, and pulse oximetry were recorded, and spirometry was performed. A fixed drop in FEV1 (10% and ≥200 mL) and percentage change in FEV1 were outcomes when possible indicators were evaluated.ResultsThree hundred and eighty patients attended baseline examination, and 88 with a subsequent exacerbation were included in the analysis. Thirty (34%) had a significant drop in FEV1 (10% and 200 mL). Increased wheezing was the only symptom associated with this drop with a likelihood ratio of 6.4 (95% confidence interval, 1.9–21.7). Crackles and any new auscultation finding were also associated with a significant drop in FEV1, as was a ≥2% drop in oxygen saturation (SpO2) to ≤92% in the subgroup diagnosed with COPD. Very bothersome wheezing and severe decrease in SpO2 were also very strong predictors of change in FEV1 in linear regression adjusted for age, gender, and baseline FEV1% predicted.ConclusionIncreased wheezing, as experienced by the patient, and a decreased SpO2 value strongly indicated a drop in lung function during asthma and COPD exacerbations and should probably be taken into account when treatment with oral corticosteroids is considered.

Endobronchial Valve Therapy in Patients with Homogeneous Emphysema. Results from the IMPACT Study.

Endobronchial valves (EBVs) have been successfully used in patients with severe heterogeneous emphysema to improve lung physiology. Limited available data suggest that EBVs are also effective in homogeneous emphysema. To evaluate the efficacy and safety of EBVs in patients with homogeneous emphysema with absence of collateral ventilation assessed with the Chartis system. Prospective, multicenter, 1:1 randomized controlled trial of EBV plus standard of care (SoC) or SoC alone. Primary outcome was the percentage change in FEV1 (liters) at 3 months relative to baseline in the EBV group versus the SoC group. Secondary outcomes included changes in FEV1, St. George's Respiratory Questionnaire (SGRQ), 6-minute-walk distance (6MWD), and target lobe volume reduction. Ninety-three subjects (age, 63.7 ± 6.1 yr [mean ± SD]; FEV1, % predicted, 29.3 ± 6.5; residual volume, % predicted, 275.4 ± 59.4) were allocated to either the EBV group (n = 43) or the SoC group (n = 50). In the intention-to-treat population, at 3 months postprocedure, improvement in FEV1 from baseline was 13.7 ± 28.2% in the EBV group and -3.2 ± 13.0% in the SoC group (mean between-group difference, 17.0%; P = 0.0002). Other variables demonstrated statistically and clinically significant changes from baseline to 3 months (EBV vs. SoC, respectively: SGRQ, -8.63 ± 11.25 vs. 1.01 ± 9.36; and 6MWD, 22.63 ± 66.63 m vs. -17.34 ± 52.8 m). Target lobe volume reduction at 3 months was -1,195 ± 683 ml (P < 0.0001). Of the EBV subjects, 97.2% achieved volume reduction in the target lobe (P < 0.0001). Procedure-related pneumothoraces occurred in 11 subjects (25.6%). Five subjects required removal/replacement of one or more valves. One subject experienced two valve migration events requiring removal/replacement of valves. EBV in patients with homogeneous emphysema without collateral ventilation results in clinically meaningful benefits of improved lung function, exercise tolerance, and quality of life.

Bronchodilating effect of deep inspirations in asthma and chronic cough

The pathophysiologic processes distinguishing classic asthma (CA), cough-variant asthma (CVA), and methacholine (MCh)-induced cough but normal airway sensitivity (COUGH) are inadequately understood and may be a result of differences in the ability to bronchodilate following a deep inspiration (DI). The purpose of this study was to compare the bronchodilating effect of DIs in individuals with CA, CVA, and COUGH using high-dose MCh. Individuals aged 18-65 yr with CA or suspected CVA completed high-dose MCh testing to a maximum change in forced expiratory volume in 1 s (FEV1) of 50% from baseline (MAX). Impulse oscillometry (IOS) measurements and partial and maximal-flow volume curves (used to calculate a DI index) were recorded at baseline and at each dose of MCh. Body plethysmography was performed at baseline and MAX. Twenty-eight subjects [25 women, 39.8 ± 11.9 yr (means ± SD)] were studied (n = 11 CA, n = 10 CVA, and n = 7 COUGH). At MAX, the percent change in FEV1 was greater in subjects with CA compared with those with CVA (P < 0.001) and COUGH (P < 0.001), and the percent change in forced vital capacity was greater in those with CA than with COUGH (P = 0.017). Subjects with CA and CVA developed dynamic hyperinflation and gas trapping. In subjects with CA and CVA, all IOS parameters were significantly increased from baseline to MAX, except for central respiratory resistance (R20). In individuals with COUGH, total respiratory resistance, R20, and resonant frequency were significantly increased from baseline. At MAX, the DI index was positive in all groups, suggesting preserved bronchodilation (CA, 0.67 ± 0.97; CVA, 0.51 ± 0.73; COUGH, 0.01 ± 0.36; P = 0.211). We conclude that the bronchodilating effect of DIs is preserved in individuals with CA, CVA, and borderline with COUGH; however, hyperinflation and gas trapping are avoided in subjects with COUGH alone.

Impact of varying physical activity levels on airway sensitivity and bronchodilation in healthy humans.

The purpose of this study was to determine if the amount of physical activity influences airway sensitivity and bronchodilation in healthy subjects across a range of physical activity levels. Thirty healthy subjects (age, 21.9 ± 2.6 years; 13 men/17 women) with normal pulmonary function reported to the laboratory on 2 separate occasions where they were randomized to breathe either hypertonic saline (HS) (nebulized hypertonic saline (25%) for 20 min) or HS followed by 5 deep inspirations (DIs), which has been reported to bronchodilate the airways. Pulmonary function tests (PFTs) were performed prior to both conditions and following the HS breathing or 5 DIs. Moderate to vigorous physical activity (MVPA) level was measured via accelerometer worn for 7 days. Following the HS breathing, forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) significantly decreased from baseline by -11.8% ± 8.4% and -9.3% ± 6.7%, respectively. A 2-segment linear model determined significant relationships between MVPA and percent change in FEV1 (r = 0.50) and FVC (r = 0.55). MVPA above ∼497 and ∼500 min/week for FEV1 and FVC, respectively, resulted in minor additional improvements (p > 0.05) in PFTs following the HS breathing. Following the DIs, FEV1 and FVC decreased (p < 0.05) by -7.3% ± 8.6% and -5.7% ± 5.7%, respectively, from baseline, but were not related (p > 0.05) to MVPA. In conclusion, these data demonstrate that higher MVPA levels attenuated airway sensitivity but not bronchodilation in healthy subjects.

Increased exhaled breath condensate 8-isoprostane after a swimming session in competitive swimmers

Objectives: This study aimed to evaluate the levels of 8-isoprostane (8-IsoP) in the airways of competitive swimmers at baseline and after a swimming session according to their airway responsiveness. Methods: Twenty-three swimmers and six lifeguards had a baseline spirometry and bronchoprovocative challenges. During a second visit, swimmers performed a usual swimming session while lifeguards stayed in the same pool environment for the same time period. Forced expiratory volume in one second (FEV1) was measured before and 5 min after the end of the session. Exhaled breath condensate (EBC) was sampled before and 10 min after the session and EBC 8-IsoP levels were analysed by enzyme immunoassay. Change in EBC 8-IsoP from baseline to post-swimming session was calculated. Results: We observed no relationships between airway hyper-responsiveness and 8-IsoP values before or after swimming in swimmers. The levels of 8-IsoP were significantly higher after the training session (mean value 2.9, s = 0.5 pg mL−1) than at baseline (mean value 1.9, s = 0.4 pg mL−1) in swimmers only (p = .012). EBC 8-IsoP levels after the swimming session significantly correlated with the percent change in FEV1 after swimming. Conclusions: EBC 8-IsoP levels were increased after training in swimmers but not in lifeguards, suggesting that exercise-induced hyperpnoea in a chlorinated pool environment increases airways oxidative stress.

Impact of Varying Physical Activity Levels on Airway Responsiveness and Bronchodilation in Healthy Humans

Airway hyperresponsiveness is a hallmark symptom of asthma. In healthy subjects, there is variability in airway responsiveness (AR) to a given stimulus with inactive subjects exhibiting more AR compared to endurance-trained runners. Additionally, AR has been shown to be attenuated with endurance training and negatively associated with frequency of exercise; however, the quantity of physical activity needed to attenuate AR is not known. Also, it is not known if the bronchodilatory response to a stimulus can also be modified with exercise training. PURPOSE: Therefore, the purpose of this study was to determine if the amount of physical activity influenced AR and if a threshold exists at which higher physical activity levels would not further improve AR. A secondary purpose was to determine if the degree of bronchodilation would be affected across a range of PA levels. METHODS: 30 healthy subjects (21.9±2.6yrs; 13M/17W) with normal pulmonary function reported to the lab on two different occasions (randomized). On one visit, subjects performed a nebulized hypertonic saline (25%) (HS) challenge and the second visit consisted of the HS challenge followed by five deep maximal inspirations (DIs). In both conditions, pulmonary function tests (PFTs) were initially completed followed by breathing hypertonic saline mist for 20 minutes in the absence of deep breaths. Then, subjects either completed the PFTs or performed 5 DIs prior to performing PFTs. Moderate-to-vigorous physical activity (MVPA) level was measured via accelerometer worn for 7 days. RESULTS: Following the HS challenge, FEV1 and FVC significantly decreased ∼12% and ∼9%, respectively. Men and women had similar (p>0.05) changes in PFTs following the HS challenge. A two-segment linear model determined significant relationships between MVPA and percent change in FEV1 (r=0.52) and FVC (r=0.57). MVPA above ∼530 and ∼500 min/week for FEV1 and FVC, respectively resulted in minor additional improvements (p>0.05) in PFTs following the HS challenge. Following the DIs, FEV1 and FVC decreased (p<0.05) ∼7% and ∼5%, respectively, but were not related (p>0.05) to MVPA. CONCLUSION: These data provide evidence that higher MVPA levels ameliorated airway responsiveness, but not bronchodilation in healthy subjects. Additionally, it appears that MVPA above ∼500 minutes per week resulted in minor improvements in airway responsiveness in healthy subjects.

Azithromycin improves lung function in patients with post-lung transplant bronchiolitis obliterans syndrome: a meta-analysis.

Azithromycin has been shown to reverse or halt the decline of forced expiratory volume in one s (FEV1) in patients with bronchiolitis obliterans (BOS) syndrome following lung transplant. The overall effect of azithromycin on the absolute values of FEV1 has not been compared between reported studies. We studied the effects of azithromycin on lung function in patients with post-lung transplant BOS syndrome. A meta-analysis was performed using studies identified following an extensive database search. To be included, studies were published in English or French and explicitly reported percentage change in FEV1 or hazard ratios. A total of 10 studies were included in this review. One hundred and forty patients were evaluated after treatment with azithromycin for an average follow-up period of seven months. The mean percentage increase in FEV1 was 8.8 (CI 5.1-12.47) p < 0.001. The pooled hazard ratio was 0.25 (CI 0.06-0.56) p = 0.041 for a mean follow-up period of 2.9 yr. This study demonstrated a significant improvement in lung function in patients with BOS syndrome following lung transplant after seven months of treatment. It remains uncertain whether this improvement stays after seven months. We also found that patients on azithromycin were less likely to die from BOS syndrome compared with patients who were not on azithromycin.