Incremental shuttle walking test: a reproducible and valid test to evaluate exercise tolerance in adults with noncystic fibrosis bronchiectasis.

OBJECTIVE: To analyze the reliability, validity, and determinants of the incremental shuttle walk test (ISWT) in adults with noncystic fibrosis bronchiectasis. DESIGN: Cross-sectional study. SETTING: Outpatient clinic. PARTICIPANTS: Subjects (N=75; 26 men) underwent, on different days, cardiopulmonary exercise testing (CPET) and 2 ISWTs, 30 minutes apart. The number of steps in daily life was recorded. Concurrent validity was tested by the relation between distance walked with peak load and oxygen consumption (V˙o2). INTERVENTIONS: None. MAIN OUTCOME MEASURES: Distance walked (m) was compared between the first and second ISWTs; greatest distance walked was correlated with peak load and Vo2peak obtained from CPET, steps per day, and dyspnea evaluated by the Medical Research Council (MRC) scale; and desaturation was compared between CPET and the ISWT. RESULTS: Distance walked was equivalent between the first ISWT (441±152m) and the second ISWT (445±153m) with an excellent intraclass correlation coefficient (.995; 95% confidence interval, .99-.997). There were significant correlations between distance walked and peak load (r=.82), V˙o2 (r=.72), steps per day (r=.61), and the MRC scale (r=-.69). Age, body mass index, sex, forced vital capacity (% predicted), dyspnea, and steps per day explained 70% of the variation in distance walked (m) and 60% of the variance when expressed as percent predicted. Higher desaturation was observed during the ISWT (-4%±4%) than cycling (-2±3%) (P<.001). CONCLUSIONS: The ISWT is reliable, represents functional capacity, and induces greater desaturation than cycling. Age, body composition, pulmonary function, dyspnea, and physical activity in daily life are determinants of the distance walked on the ISWT.

Comparison of cardiopulmonary responses during 2 incremental step tests in subjects with COPD.

BACKGROUND: It is well established that the work rate increment size affects the duration of test and physiological responses to exercise during cycling in patients with COPD. However, this has never been tested for incremental step tests. OBJECTIVE: To compare the exercise tolerance time, cardiopulmonary stress, and perception of effort between the Chester step test (CST) and a modified incremental step test (MIST). METHODS: Thirty-two subjects with COPD (FEV(1) 50 ± 15% of predicted) were randomized to perform the CST and MIST on the same day, an hour apart, on a single step (20 cm high). During tests, pulmonary gas exchange was measured continuously by a portable metabolic system. RESULTS: CST had shorter duration and also lower number of steps, in comparison with MIST. However, similar cardiopulmonary responses were observed at exercise peak: oxygen uptake (V(.)(O(2))) 1.22 ± 0.59 L/min vs 1.24 ± 0.55 L/min, minute ventilation (V(.)(E)) 30.8 ± 12.7 L/min vs 30.0 ± 11.7 L/min, heart rate 86 ± 13 beats/min vs 85 ± 13 beats/min, and S(pO(2)) 87 ± 7% vs 87 ± 6%. Dyspnea and leg fatigue scores when correcting for exercise duration were higher for CST. CONCLUSIONS: The slower the work rate increment during step test, the higher the exercise tolerance. Regardless of the work rate increment, cardiopulmonary stress and exertion effort at peak exercise were equivalent between tests.

Chester step test in patients with COPD: reliability and correlation with pulmonary function test results.

BACKGROUND: The 5-stage Chester step test assesses aerobic capacity in healthy subjects. It has not been tested in patients with COPD. OBJECTIVE: To determine the reliability of the Chester step test in patients with COPD and correlation with pulmonary function test and exercise test results. METHODS: Thirty-two patients (mean ± SD FEV(1) 46 ± 15% of predicted) undertook 2 Chester step tests and two 6-min walk tests, on different days, in random order. A subgroup of 11 patients performed incremental cycle ergometry. RESULTS: Thirty-one patients performed stage 1 of the Chester step test. Nineteen patients performed stage 2 of the Chester step test. The number of steps was highly reproducible: 66 ± 41 steps vs 68 ± 41 steps. There was no difference in heart rate or S(pO(2)) between the 2 Chester step tests at the peak of exercise or at the end of each stage. There was a significant correlation between number of steps and FEV(1) (r = 0.43, P = .02), and 6-min walk distance (r = 0.60, P = .001). Heart rate increased according to advanced stages of the Chester step test, up to 81 ± 13% of predicted. There was a significant correlation between number of steps and peak heart rate (r = 0.55, P = .001). In the 11 patients who performed the incremental cycling test there was a significant correlation between number of steps and peak work load (r = 0.69, P = .02). In the 6 patients in whom oxygen uptake could be estimated from the Chester step test, oxygen uptake was higher than that measured at the peak of the cycling test (30.8 ± 5.1 mL/kg/min vs 17.4 ± 4.5 mL/kg/min, respectively, P = .001). CONCLUSIONS: Despite being highly reproducible, the Chester step test had a very short duration in patients with COPD. The number of steps incremented in each stage seems to be too large for these patients. An adaptation of the Chester step test should be considered for patients with COPD.

Systemic Inflammation and Oxidative Stress in Adults with Bronchiectasis: Association with Clinical and Functional Features.

OBJECTIVES: To compare the inflammatory and oxidative stress (OS) states of adults with bronchiectasis with those of healthy controls and correlate inflammatory and OS levels with lung function and physical capacity. METHODS: This study used a cross-sectional design. Seventy-four adults with bronchiectasis (age: 49±15 years, forced expiratory volume in 1 second [FEV1]: 52.5±25.6%) and 42 healthy controls (age: 44±17 years, FEV1: 95.9±14.0%) performed cardiopulmonary exercise tests and incremental shuttle walking tests. Their physical activity in daily life, inflammatory cytokine, and antioxidant levels in plasma were measured. RESULTS: Compared to that of the controls, the levels of interleukin (IL)-6 (p<0.001), IL-10 (p<0.001), carbonylated proteins (p=0.001), and superoxide anions (p=0.046) were significantly increased in adults with bronchiectasis. Catalase activity was also reduced in this group (p<0.001). The inflammatory markers IL-1ß, IL-6, and tumor necrosis factor-α correlated negatively with aerobic capacity (r=-0.408, r=-0.308, and r=-0.207, respectively). We observed similar correlations with OS markers (thiobarbituric acid and carbonyls; r=-0.290 and r=0.379, respectively), and these markers also significantly correlated with the aerobic capacity. CONCLUSIONS: Adults with bronchiectasis presented an increased systemic inflammatory response that correlated negatively with physical capacity.

Reduced Physical Activity With Bronchiectasis.

BACKGROUND: Bronchiectasis leads to reduced functional capacity, which might have implications for physical activity. The impact of dyspnea and long-term oxygen therapy on physical activity has never been investigated in subjects with bronchiectasis. Based on these findings, specific strategies could be applied to allow individuals to be more active in their daily life. In this study we aimed to evaluate physical activity, the impact of dyspnea and long-term oxygen therapy on physical activity, and the determinants of physical activity in subjects with bronchiectasis. METHODS: We performed a cross-sectional study in 139 subjects with bronchiectasis (age 45 ± 13 y, FVC 70 ± 22% of predicted, FEV1 54 ± 25% of predicted) and 49 healthy subjects as controls. Physical activity was assessed using steps per day (measured with a pedometer), spirometry, incremental shuttle walking test (ISWT), and dyspnea. RESULTS: Reduced physical activity was observed in subjects with bronchiectasis, who recorded a median (interquartile range) of 8,007 (5,131-10,432) steps/d compared with controls, who recorded 10,994 (8,551-14,078) steps/d (P < .001). Significant correlations were observed between physical activity and FVC (r = 0.43), FEV1 (r = 0.36), ISWT (r = 0.37), and dyspnea (r = -0.48). Determinants for reduced physical activity included pulmonary function (R2 = 0.150), dyspnea (R2 = 0.075), ISWT (R2 = 0.044), and long-term oxygen therapy (R2 = 0.038); these factors explained 32% of the physical activity. CONCLUSION: Subjects with bronchiectasis exhibited reduced physical activity compared with healthy peers. Dyspnea has a negative impact on physical activity. Independent factors associated with physical activity included pulmonary function, dyspnea, functional capacity, and long-term oxygen therapy. These findings will guide strategies to enhance daily physical activity and to encourage subjects with bronchiectasis to be more active.

Determinants of Peripheral Muscle Strength and Activity in Daily Life in People With Bronchiectasis.

Background: Bronchiectasis is characterized by a progressive structural lung damage, recurrent infections and chronic inflammation which compromise the exertion tolerance, and may have an impact on skeletal muscle function and physical function. Objective: The purpose of this study was to compare peripheral muscle strength, exercise capacity, and physical activity in daily life between participants with bronchiectasis and controls and to investigate the determinants of the peripheral muscle strength and physical activity in daily life in bronchiectasis. Design: This study used a cross-sectional design. Methods: The participants' quadriceps femoris and biceps brachii muscle strength was measured. They performed the incremental shuttle walk test (ISWT) and cardiopulmonary exercise testing, and the number of steps/day was measured by a pedometer. Results: Participants had reduced quadriceps femoris muscle strength (mean difference to control group = 7 kg, 95% CI = 3.8-10.1 kg), biceps brachii muscle strength (2.1 kg, 95% CI = 0.7-3.4 kg), ISWT (227 m, 95% CI = 174-281 m), peak VO2 (6.4 ml/Kg/min, 95% CI = 4.0-8.7 ml/Kg/min), and number of steps/day (3,332 steps/day, 95% CI = 1,758-4,890 steps/day). A lower quadriceps femoris strength is independently associated to an older age, female sex, lower body mass index (BMI), higher score on the modified Medical Research Council scale, and shorter distance on the ISWT (R2 = 0.449). Biceps brachii strength is independently associated with sex, BMI, and dyspnea (R2 = 0.447). The determinants of number of daily steps were dyspnea and distance walked in ISWT, explaining only 27.7% of its variance. Limitations: Number of steps per day was evaluated by a pedometer. Conclusions: People with bronchiectasis have reduced peripheral muscle strength, and reduced aerobic and functional capacities, and they also are less active in daily life. Modifiable variables such as BMI, dyspnea, and distance walked on the ISWT are associated with peripheral muscle strength and physical activity in daily life.

Systemic inflammation and oxidative stress in adults with bronchiectasis: association with clinical and functional features

OBJECTIVES: To compare the inflammatory and oxidative stress (OS) states of adults with bronchiectasis with those of healthy controls and correlate inflammatory and OS levels with lung function and physical capacity. METHODS: This study used a cross-sectional design. Seventy-four adults with bronchiectasis (age: 49±15 years, forced expiratory volume in 1 second [FEV1]: 52.5±25.6%) and 42 healthy controls (age: 44±17 years, FEV1: 95.9±14.0%) performed cardiopulmonary exercise tests and incremental shuttle walking tests. Their physical activity in daily life, inflammatory cytokine, and antioxidant levels in plasma were measured. RESULTS: Compared to that of the controls, the levels of interleukin (IL)-6 (p<0.001), IL-10 (p<0.001), carbonylated proteins (p=0.001), and superoxide anions (p=0.046) were significantly increased in adults with bronchiectasis. Catalase activity was also reduced in this group (p<0.001). The inflammatory markers IL-1β, IL-6, and tumor necrosis factor-α correlated negatively with aerobic capacity (r=-0.408, r=-0.308, and r=-0.207, respectively). We observed similar correlations with OS markers (thiobarbituric acid and carbonyls; r=-0.290 and r=0.379, respectively), and these markers also significantly correlated with the aerobic capacity. CONCLUSIONS: Adults with bronchiectasis presented an increased systemic inflammatory response that correlated negatively with physical capacity.

Expiratory Reserve Volume During Slow Expiration With Glottis Opened in Infralateral Decubitus Position (ELTGOL) in Chronic Pulmonary Disease: Technique Description and Reproducibility.

BACKGROUND: There has not been a detailed description of expiratory reserve volume (ERV) during slow expiration with glottis open in infralateral decubitus position (ELTGOL, for Expiration Lente Totale Glotte Ouverte en infraLatéral) and its reproducibility. The aim of this study was to determine ERV during ELTGOL and to evaluate ERV intra-observer and inter-observer reliability. METHODS: In this prospective study, subjects were 30-70 y of age with chronic lung disease. ELTGOL (an active-passive or active physiotherapy technique) was applied in random order by 3 observers: 2 trained physiotherapists (PT 1 and PT 2) and the subject him/herself. Two ELTGOL compressions (A and B) were applied by PT 1, PT 2, and the subject. RESULTS: Thirty-two subjects were evaluated with moderate lung obstruction, FEV1: 47.7 ± 15.4, and ERV: 61.7 ± 29.4. The mean value of ERV for PT 1 was 51.4 ± 24.8%; for PT 2, it was 54.3 ± 31.8%; and for the subject, it was 53.5 ± 26.2% (P = .49). Considering the mean value of ERV, the ELTGOL mobilized more than 80% of ERV. There was good reliability intra-PT: PT 1, intraclass correlation coefficient (ICC) 0.85 (0.70-0.93), P < .0001; PT 2, ICC 0.90 (0.80-0.95), P < .0001, and inter-PT (ICC 0.86 [95% CI 0.71-0.93], P < .001). The Bland-Altman plot with mean bias and limits of agreement for ERV of PT 1 and PT 2 was -3.3 (-42.7 to 35.9). CONCLUSIONS: ELTGOL mobilized more than 80% of ERV in subjects with moderate airway obstruction; there is no difference in ERV exhaled during the technique applied by a physiotherapist or by the subject. ELTGOL is a reproducible technique, determined by inter- and intra-observer testing.

A symptom-limited incremental step test determines maximum physiological responses in patients with chronic obstructive pulmonary disease.

BACKGROUND: Step tests have been used to evaluate exercise tolerance and effort-related hypoxemia in different diseases. A symptom-limited incremental step test (IST) has never been tested in COPD patients. AIM: To compare maximal physiological responses between an IST and cardiopulmonary exercise testing (CPET), to test the reproducibility of the IST on different days, and to provide a predict equation to estimate VO2 from the IST in patients with COPD. MATERIAL AND METHODS: At the same day, thirty-four patients (VEF1 46 ± 14% of pred) underwent a CPET on cycle ergometer and the first IST (IST-1) (1 h apart). After 2-5 days, patients repeated the IST (IST-2). Pulmonary gas exchange was measured during all tests. RESULTS: Peak VO2 was significantly higher in IST-1 and IST-2 than in CEPT (Mean ± SD: 1.19 ± 0.39 L, 1.20 ± 0.40 L, 1.07 ± 0.35 L) with no difference for ventilation (VE), heart rate (HR), and perception of effort. ISTs were highly reproducible, with significant intraclass correlation coefficient (CCI [95% confidence interval]) for number of steps (0.98[0.95-0.99]), VO2 (0.99 [0.98-0.99]), VE (0.97[0.93-0.99]), HR (0.92[0.81-0.97]), and SpO2 (0.96[0.90-0.98]). Desaturation was significantly higher for IST-1 and IST-2 compared with cycling (Mean ± SD: -6 ± 5%, -6 ± 4%, -3 ± 3%). Number of steps and patient weight explained 81% of the variance in peak VO2 (p < 0.001). CONCLUSION: A symptom-limited incremental step test, externally paced, elicits maximal cardiopulmonary and metabolic responses, and is well tolerated and reproducible in patients with COPD.

Chest wall mobility is related to respiratory muscle strength and lung volumes in healthy subjects.

BACKGROUND: Chest wall mobility is often measured in clinical practice, but the correlations between chest wall mobility and respiratory muscle strength and lung volumes are unknown. We investigate the associations between chest wall mobility, axillary and thoracic cirtometry values, respiratory muscle strength (maximum inspiratory pressure and maximum expiratory pressure), and lung volumes (expiratory reserve volume, FEV(1), inspiratory capacity, FEV(1)/FVC), and the determinants of chest mobility in healthy subjects. METHODS: In 64 healthy subjects we measured inspiratory capacity, FVC, FEV(1), expiratory reserve volume, maximum inspiratory pressure, and maximum expiratory pressure, and chest wall mobility via axillary and thoracic cirtometry. We used linear regression to evaluate the influence of the measured variables on chest wall mobility. RESULTS: The subjects' mean ± SD values were: age 24 ± 3 years, axillary cirtometry 6.3 ± 2.0 cm, thoracic cirtometry 7.5 ± 2.3 cm; maximum inspiratory pressure 90.4 ± 10.6% of predicted, maximum expiratory pressure 92.8 ± 13.5% of predicted, inspiratory capacity 99.7 ± 8.6% of predicted, FVC 101.9 ± 10.6% of predicted, FEV(1) 98.2 ± 10.3% of predicted, expiratory reserve volume 90.9 ± 19.9% of predicted. There were significant correlations between axillary cirtometry and FVC (r = 0.32), FEV(1) (r = 0.30), maximum inspiratory pressure (r = 0.48), maximum expiratory pressure (r = 0.25), and inspiratory capacity (r = 0.24), and between thoracic cirtometry and FVC (r = 0.50), FEV(1) (r = 0.48), maximum inspiratory pressure (r = 0.46), maximum expiratory pressure (r = 0.37), inspiratory capacity (r = 0.39), and expiratory reserve volume (r = 0.47). In multiple regression analysis the variable that best explained the axillary cirtometry variation was maximum inspiratory pressure (R(2) 0.23), and for thoracic cirtometry it was FVC and maximum inspiratory pressure (R(2) 0.32). CONCLUSIONS: Chest mobility in healthy subjects is related to respiratory muscle strength and lung function; the higher the axillary cirtometry and thoracic cirtometry values, the greater the maximum inspiratory pressure, maximum expiratory pressure, and lung volumes in healthy subjects.