We studied the validity of a recently introduced, handheld, electronic loading device in providing automatically processed information on external inspiratory work, power and breathing pattern during loaded breathing tasks in patients with COPD. Thirty-five patients with moderate to severe COPD performed an endurance breathing task against a fixed resistive inspiratory load that corresponded to 55 ± 13% of their maximal inspiratory pressure. Flow and pressure signals during this task were sampled and processed at 500 Hz by the handheld loading device and at 100 Hz with an external, laboratory system that provided the "gold standard" reference data. Intra Class Correlations between methods were 0.97 for average mean inspiratory power, 0.98 for average mean pressure, 0.98 for average duty cycle, and 0.99 for total work (all p < 0.0001). We conclude that the handheld device provides automatically processed and valid estimates of physical units of energy during loaded breathing tasks. This enables health care providers to quantify the load on inspiratory muscles during these tests in daily clinical practice.
PMID: 23421970 DOI: 10.1016/j.rmed.2013.01.020

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is currently the fourth cause of mortality worldwide. Patients with COPD experience periods of dyspnea, fatigue, and disability, which impact on their life. The objective of this study was to investigate the effect of short-term inspiratory muscle training on exercise capacity, exertional dyspnea, and pulmonary lung function.
MATERIALS AND METHODS: A randomized, controlled trial was performed. Thirty patients (27 males, 3 females) with mild to very severe COPD were randomly assigned to a training group (group T) or to a control group (group C). Patients in group T received training for 8 weeks (15 min/day for 6 days/week) with flow-volumetric inspiratory exerciser named (Respivol). Each patient was assessed before and after 8 weeks of training for the following clinical parameters: exercise capacity by 6-min walking test (6MWT), exertional dyspnea by Borg scale, and pulmonary lung function by spirometry. Patients used training together with medical treatment. The data were analyzed using paired t-test and independent t-test.
RESULTS: Results showed statistically significant increase in 6MWT at the end of the training from 445.6 ± 22.99 to 491.06 ± 17.67 meters? (P < 0.001) and statistically significant decrease in dyspnea from 3.76 ± 0.64 to 1.13 ± 0.36 (P = 0.0001) in the training group but not in the control group. The values for exercise capacity and dyspnea improved after 8 weeks in group T in comparison with group C (P = 0.001 and P = 0.0001, respectively). No changes were observed in any measure of pulmonary function in both groups.
CONCLUSIONS: Short-term inspiratory muscle training has beneficial effects on exercise capacity and exertional dyspnea in COPD patients.
KEYWORDS: 6-min walking test; chronic obstructive pulmonary disease; exercise capacity; exertional dyspnea; inspiratory muscle training; pulmonary function
PMID: 26457101 PMCID: PMC4598910 DOI: 10.4103/1735-9066.164588

COPD is defined as airflow limitation that is not reversed by treatment. In asthma, airflow limitation is not only reversible, but also inducible. This is called 'airway hyperresponsiveness' (AHR) and is associated with thickening of the airway wall, predominantly the layer of airway smooth muscle, due to more cells, bigger cells and more extracellular matrix (ECM) in proportion to the increase in smooth muscle. AHR is also observed in COPD if the changes in airflow are expressed as a percent of the baseline lung function. However, the absolute change in baseline lung function that can be induced in COPD is actually less than that seen in normal subjects, suggesting that the airways in COPD are resistant not only to opening, but also to closing. This observation agrees with physiological measures showing increased airway wall stiffness in COPD. Like asthma, airway wall thickness is increased in COPD, including the layer of smooth muscle. Unlike asthma, however, fixed airflow obstruction appears to be characterized by a disproportionate increase in the ECM within the smooth muscle layer. In this review, we summarize the studies of airway matrix deposition in COPD and put forward the proposal that the airway remodelling in COPD is different from that in asthma and call for a systematic analysis of airway matrix deposition in COPD.
PMID: 27381663 DOI: 10.1111/resp.12841 KEYWORDS: airway remodelling; airway smooth muscle; asthma; chronic obstructive pulmonary disease; extracellular matrix

BACKGROUND: Resident loved ones of patients with COPD can play an important role in helping these patients engage in physical activity. We aimed to compare activity levels and exercise motivation between patients with COPD and their resident loved ones; to compare the same outcome measures in patients after stratification for the physical activity level of the loved ones; and to predict the likelihood of being physically active in patients with a physically active resident loved one.
METHODS: One hundred twenty-five patient/loved one dyads were cross-sectionally and simultaneously assessed. Sedentary behavior, light activities, and moderate to vigorous physical activity (MVPA) were measured with a triaxial accelerometer during free-living conditions for at least 5 days. Five exercise-motivation constructs were investigated: amotivation, external regulation, introjected regulation, identified regulation, and intrinsic regulation.
RESULTS: Patients spent more time in sedentary behavior and less time in physical activity than their loved ones (P < .0001). More intrinsic regulation was observed in loved ones compared with patients (P = .003), with no differences in other constructs. Despite similar exercise motivation, patients with an active loved one spent more time in MVPA (mean 31 min/d; 95% CI, 24-38 min/d vs mean, 18 min/d; 95% CI, 14-22 min/d; P = .002) and had a higher likelihood of being active (OR, 4.36; 95% CI, 1.41-13.30; P = .01) than did patients with an inactive loved one after controlling for age, BMI, and degree of airflow limitation.
CONCLUSIONS: Patients with COPD are more physically inactive and sedentary than their loved ones, despite relatively similar exercise motivation. Nevertheless, patients with an active loved one are more active themselves and have a higher likelihood of being active.
TRIAL REGISTRY: Dutch Trial Register (NTR3941).
KEYWORDS: COPD; family caregivers; outcome assessment; physical activity; sedentary lifestyle
PMID: 28087303 DOI: 10.1016/j.chest.2016.12.021

BACKGROUND: Assessing the strength and endurance of respiratory muscles is fundamental for characterizing respiratory muscle dysfunction. Although a variety of tests are used to evaluate respiratory muscle endurance, not all of them are applicable in clinical practice. Assessments can be made using a practical device called PowerBreathe®, but its reproducibility has not been tested in chronic obstructive pulmonary disease (COPD) patients.
AIM: To verify the reproducibility of the inspiratory muscle endurance test using a manometer and PowerBreathe® in COPD patients.
METHODS: A cross-sectional study was used. In total, 19 moderate-severe COPD patients, male and female, aged 50 to 80 years took part in the research. This evaluation consisted of 2 tests: an incremental test and a constant one held on the same day and repeated after 48 hr. The incremental test started with 10-cm H2 O, adding 10-cm H2 O every 2 min and taking 1 min of rest before increasing the load. The highest load that could be sustained for at least 1 min was considered the sustained maximum inspiratory pressure (SMIP) value. The constant test was performed at an intensity of 80% of the SMIP and the maximum time limit was 30 min.
RESULTS: In the incremental test, there was a significant increase in the SMIP compared to the test-retest (61 ± 24/64.7 ± 23.8; p = .015); the value of the relative reproducibility was 0.96, the standard error of the absolute measurement was 4.7 (95% confidence interval 9.2), and the minimum detectable difference was 10.9. In the Bland-Altman analysis, the mean error was 4.2 (confidence interval -7.6 to 16.1). The constant test was not reproducible.
CONCLUSION: It was observed that the incremental test was reproducible to evaluate inspiratory muscle endurance in COPD patients. Furthermore, 2 tests needed to be carried out due to the learning effect.
KEYWORDS: COPD; muscle endurance test; respiratory muscles; test-retest reproducibility
PMID: 28394092 DOI: 10.1002/pri.1687