Reproducibility of inspiratory muscle endurance testing using PowerBreathe for COPD patients.

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.

Effects of Inspiratory Muscle Training and Calisthenics-and-Breathing Exercises in COPD With and Without Respiratory Muscle Weakness.

BACKGROUND: Patients with COPD may experience respiratory muscle weakness. Two therapeutic approaches to the respiratory muscles are inspiratory muscle training and calisthenics-and-breathing exercises. The aims of the study are to compare the effects of inspiratory muscle training and calisthenics-and-breathing exercises associated with physical training in subjects with COPD as an additional benefit of strength and endurance of the inspiratory muscles, thoracoabdominal mobility, physical exercise capacity, and reduction in dyspnea on exertion. In addition, these gains were compared between subjects with and without respiratory muscle weakness. METHODS: 25 subjects completed the study: 13 composed the inspiratory muscle training group, and 12 composed the calisthenics-and-breathing exercises group. Subjects were assessed before and after training by spirometry, measurements of respiratory muscle strength and test of inspiratory muscle endurance, thoracoabdominal excursion measurements, and the 6-min walk test. Moreover, scores for the Modified Medical Research Council dyspnea scale were reported. RESULTS: After intervention, there was a significant improvement in both groups of respiratory muscle strength and endurance, thoracoabdominal mobility, and walking distance in the 6-min walk test. Additionally, there was a decrease of dyspnea in the 6-min walk test peak. A difference was found between groups, with higher values of respiratory muscle strength and thoracoabdominal mobility and lower values of dyspnea in the 6-min walk test peak and the Modified Medical Research Council dyspnea scale in the inspiratory muscle training group. In the inspiratory muscle training group, subjects with respiratory muscle weakness had greater gains in inspiratory muscle strength and endurance. CONCLUSIONS: Both interventions increased exercise capacity and decreased dyspnea during physical effort. However, inspiratory muscle training was more effective in increasing inspiratory muscle strength and endurance, which could result in a decreased sensation of dyspnea. In addition, subjects with respiratory muscle weakness that performed inspiratory muscle training had higher gains in inspiratory muscle strength and endurance but not of dyspnea and submaximal exercise capacity. (ClinicalTrials.gov registration NCT01510041.).

Limitation of Activities of Daily Living and Quality of Life Based on COPD Combined Classification.

BACKGROUND: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2011 update recommends that the management and treatment of COPD be made to combine the impact of disease and future risk of exacerbation. These patients have worsening quality of life and limitation of activities of daily living (ADLs), which can be manifested as a decrease in S(pO2) and progressive dyspnea. The aim of this study was to determine whether the COPD combined classification proposed by GOLD 2011 is able to differentiate patients with ADL limitation, such as oxygen desaturation or dyspnea, and impaired quality of life. METHODS: This was an observational, cross-sectional study. Forty-four subjects were categorized in 4 GOLD groups (A-D). The mean age was 69 ± 8.8 y, with FEV1 of 1.33 ± 0.53 L (49 ± 15.7% of predicted). The Modified Medical Research Council dyspnea and London Chest Activity of Daily Living (LCADL) scales and the St George Respiratory Questionnaire (SGRQ) were applied. The 6-min walk test and ADL simulation in an appropriate laboratory were also conducted. RESULTS: There was no association between the COPD combined evaluation groups and the presence of oxygen desaturation and dyspnea (chi-square test), although a higher prevalence of oxygen desaturation was noticed in group D subjects. With regard to dyspnea, there were subjects with dyspnea in all groups when ADLs were performed. No correlation between dyspnea and oxygen desaturation variation was found. Group B and D subjects showed higher ADL dyspnea (total LCADL scores of 28% and 30%) compared with group A subjects. Group D subjects showed poorer quality of life (total SGRQ score of 49.3%) compared with less symptomatic groups. CONCLUSIONS: The COPD combined classification was not efficient in determining oxygen desaturation and dyspnea while subjects were performing ADLs. The subjects in the symptomatic groups with increased risk of exacerbation showed poorer quality of life and higher dyspnea levels. (ClinicalTrials.gov registration NCT01977469).

The minimal important difference of the pulmonary functional status and dyspnea questionnaire in patients with severe chronic obstructive pulmonary disease.

BACKGROUND: The modified version of the Pulmonary Functional Status and Dyspnea Questionnaire (PFSDQ-M) is used in patients with COPD to obtain information about their functional status. It consists of 3 components (change in activities, dyspnea and fatigue) ranging from 0 to 100 and has been shown to be responsive following pulmonary rehabilitation (PR). The interpretation of changes in PFSDQ-M score after an intervention is difficult in the absence of the minimal important difference (MID) of the PFSDQ-M. This study aims at investigating the MID of the PFSDQ-M. METHODS: We enrolled 301 patients with COPD (FEV1 42 ± 15%pred) that completed the PFSDQ-M before and after a 3-month PR program (∆Chronic Respiratory Disease Questionnaire (CRDQ) +16 ± 12 points, ∆Six-minute walking distance (6MWD) +47 ± 89 m, both p < 0.001). An anchor-based approach consisted of calculating the correlation between the ∆PFSDQ-M and anchors with an established MID (∆CRDQ and ∆6MWD). Linear regression analyses were performed to predict the MID from these anchors. Secondly several distribution-based approaches (Cohen's effect size, empirical rule effect size and standard error of measurement method) were used. RESULTS: Anchor-based estimates for the different PFSDQ-M-components were between -3 and -5 points based on CRDQ score and -6 (only calculated for change in activities) based on 6MWD. Using the distribution-based methods, the estimates of MID ranged from -3 to -5 points for the different components. CONCLUSIONS: We concluded that the estimate of MID of the PFSDQ-M after pulmonary rehabilitation corresponds to a change of 5 points (range - 3 to -6) in each component in patients with severe COPD.

Validity of physical activity monitors during daily life in patients with COPD.

Symptoms during physical activity and physical inactivity are hallmarks of chronic obstructive pulmonary disease (COPD). Our aim was to evaluate the validity and usability of six activity monitors in patients with COPD against the doubly labelled water (DLW) indirect calorimetry method. 80 COPD patients (mean ± sd age 68 ± 6 years and forced expiratory volume in 1 s 57 ± 19% predicted) recruited in four centres each wore simultaneously three or four out of six commercially available monitors validated in chronic conditions for 14 consecutive days. A priori validity criteria were defined. These included the ability to explain total energy expenditure (TEE) variance through multiple regression analysis, using TEE as the dependent variable with total body water (TBW) plus several physical activity monitor outputs as independent variables; and correlation with activity energy expenditure (AEE) measured by DLW. The Actigraph GT3X (Actigraph LLC, Pensacola, FL, USA), and DynaPort MoveMonitor (McRoberts BV, The Hague, the Netherlands) best explained the majority of the TEE variance not explained by TBW (53% and 70%, respectively) and showed the most significant correlations with AEE (r=0.71, p<0.001 and r=0.70, p<0.0001, respectively). The results of this study should guide users in choosing valid activity monitors for research or for clinical use in patients with chronic diseases such as COPD.

Assessment of exercise capacity among asthmatic and healthy adolescents.

OBJECTIVES: To compare the physical performance and responses obtained in the six-minute walking test (6MWT) and the six-minute step test (6MST) between asthmatic and healthy adolescents; and to investigate the relationship between the responses obtained in the tests and the body mass index (BMI), physical activity level and spirometric variables. METHODS: Nineteen asthmatic adolescents (AG) and 19 healthy adolescents (HG) of both sexes, aged between 11 and 15 years, were assessed by means of spirometry, the 6MWT and the 6MST, and their physical activity levels were quantified using the International Physical Activity Questionnaire (IPAQ). RESULTS: The AG had poorer physical performance, lower heart rate (HR) and greater lower-limb (LL) fatigue in the 6MST. In the 6MWT, the AG had positive correlations between walked distance (WD) and duration of intense activity, and between HR and BMI, whereas the HG had positive correlations between WD and HR and between WD and respiratory rate (RR). In the 6MST, the AG showed positive correlations between RR and maximum voluntary ventilation (MVV) and between duration of moderate activity and physical performance. The AG also showed negative correlations between physical performance in the 6MST and BMI, and between sensation of dyspnea and duration of walking. Also in the 6MST, the HG showed positive correlations between RR and MVV, and between BMI and LL fatigue (p < or = 0.05). CONCLUSION: The 6MST demonstrated differences in exercise capacity between the asthmatic and healthy individuals. Furthermore, the physical performance and responses obtained in the tests were correlated with the MVV, BMI and physical activity level.

Avaliação da capacidade de exercício em adolescentes asmáticos e saudáveis / Assessment of exercise capacity among asthmatic and healthy adolescents

OBJETIVOS: Comparar o desempenho físico e as respostas obtidas nos testes de caminhada de seis minutos (TC6) e do degrau de seis minutos (TD6) entre adolescentes asmáticos e saudáveis e correlacionar o índice de massa corpórea (IMC), o nível de atividade física e as variáveis espirométricas com as variáveis obtidas nos testes. MÉTODOS: Foram avaliados 19 adolescentes asmáticos (GA) e 19 saudáveis (GS), com idades entre 11 e 15 anos, de ambos os sexos, por meio da espirometria, do TC6 e do TD6 e foi quantificado o nível de atividade física pelo Questionário Internacional de Atividade Física (IPAQ). RESULTADOS: No TD6, observaram-se menores valores de desempenho físico (TD6-T) e frequência cardíaca (FC) e maiores valores de fadiga de membros inferiores (MMII) no GA. No TC6, houve correlação positiva no GA da distância percorrida (DP) com o tempo de atividade intensa e da FC com o IMC e, no GS, da DP com a FC e com a frequência respiratória (FR). No TD6, houve correlação positiva no GA da ventilação voluntária máxima (VVM) com a FR; do tempo de atividade moderada com o TD6-T; além de correlação negativa do TD6-T com o IMC e da dispneia com o tempo de caminhada; no GS, correlações positivas da VVM com a FR e da fadiga de MMII com IMC (p<0,05). CONCLUSÃO: O TD6 demonstrou diferença na capacidade para o exercício entre asmáticos e saudáveis. Além disso, o desempenho físico e as respostas obtidas nos testes correlacionaram-se com os valores de VVM, IMC e nível de atividade física.

OBJECTIVES: To compare the physical performance and responses obtained in the six-minute walking test (6MWT) and the six-minute step test (6MST) between asthmatic and healthy adolescents; and to investigate the relationship between the responses obtained in the tests and the body mass index (BMI), physical activity level and spirometric variables. METHODS: Nineteen asthmatic adolescents (AG) and 19 healthy adolescents (HG) of both sexes, aged between 11 and 15 years, were assessed by means of spirometry, the 6MWT and the 6MST, and their physical activity levels were quantified using the International Physical Activity Questionnaire (IPAQ). RESULTS: The AG had poorer physical performance, lower heart rate (HR) and greater lower-limb (LL) fatigue in the 6MST. In the 6MWT, the AG had positive correlations between walked distance (WD) and duration of intense activity, and between HR and BMI, whereas the HG had positive correlations between WD and HR and between WD and respiratory rate (RR). In the 6MST, the AG showed positive correlations between RR and maximum voluntary ventilation (MVV) and between duration of moderate activity and physical performance. The AG also showed negative correlations between physical performance in the 6MST and BMI, and between sensation of dyspnea and duration of walking. Also in the 6MST, the HG showed positive correlations between RR and MVV, and between BMI and LL fatigue (p<0.05). CONCLUSION: The 6MST demonstrated differences in exercise capacity between the asthmatic and healthy individuals. Furthermore, the physical performance and responses obtained in the tests were correlated with the MVV, BMI and physical activity level.